WO2021111475A1 - Process for preparing tranexamic acid - Google Patents

Process for preparing tranexamic acid Download PDF

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WO2021111475A1
WO2021111475A1 PCT/IN2020/051005 IN2020051005W WO2021111475A1 WO 2021111475 A1 WO2021111475 A1 WO 2021111475A1 IN 2020051005 W IN2020051005 W IN 2020051005W WO 2021111475 A1 WO2021111475 A1 WO 2021111475A1
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formula
compound
temperature
range
solvent
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PCT/IN2020/051005
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French (fr)
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Balasubramanian Kalpattu Kuppuswamy
Vijayakumaran KUPPUSWAMY
Arul Selvan Mariadas
Veeramani GANAPATHI
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Kawman Pharma Private Limited
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C247/00—Compounds containing azido groups
    • C07C247/02—Compounds containing azido groups with azido groups bound to acyclic carbon atoms of a carbon skeleton
    • C07C247/04—Compounds containing azido groups with azido groups bound to acyclic carbon atoms of a carbon skeleton being saturated
    • C07C247/06—Compounds containing azido groups with azido groups bound to acyclic carbon atoms of a carbon skeleton being saturated and containing rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
    • C07C17/16—Preparation of halogenated hydrocarbons by replacement by halogens of hydroxyl groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
    • C07C227/04—Formation of amino groups in compounds containing carboxyl groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
    • C07C227/14—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from compounds containing already amino and carboxyl groups or derivatives thereof
    • C07C227/18—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton from compounds containing already amino and carboxyl groups or derivatives thereof by reactions involving amino or carboxyl groups, e.g. hydrolysis of esters or amides, by formation of halides, salts or esters
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/60—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by elimination of -OH groups, e.g. by dehydration
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
    • C07C51/27—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with oxides of nitrogen or nitrogen-containing mineral acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2601/00—Systems containing only non-condensed rings
    • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
    • C07C2601/14—The ring being saturated

Definitions

  • the present disclosure relates to the preparation process of Tranexamic acid or trans- 4-aminomethyl cyclohexane carboxylic acid of Formula I, in particular relates to an efficient greener preparation process of pure Tranexamic acid.
  • the disclosure relates to single pot preparation process of pure Tranexamic acid.
  • Tranexamic acid is an antifibrinolytic agent used in the prevention of hemorrhage due to dental procedures in hemophilics, cyclic heavy menstrual bleeding, hereditary angioedema and during surgery. Tranexamic acid is effective and the most preferred as it has lesser side effects, when compared with other fibrinolytic agents.
  • There are various preparation methods available for obtaining tranexamic acid WO2015104721A2 reveals the synthetic preparation of crude tranexamic acid starting from 4-cyanobenzylamine and use of bulk amine protecting agents for further purification.
  • US3923879 discloses a process for the preparation of tranexamic acid from p-cyanobenzoic acid by hydrogenation at high temperatures and pressures.
  • US4048222A reveals the preparation process from p-aminomethyl benzoic acid at higher temperatures and pressures. It can be understood from the prior art that preparation of tranexamic acid involved vigorous reaction temperatures and pressures. Also, the processes employed complex reagents which were recovered by a separate method. Thus, a large-scale synthesis of pure tranexamic acid has been a challenge and involved complicated process. Hence, there is a need in the state of art for a simple process which can produce high yield of pure tranexamic acid.
  • a process for preparing Tranexamic acid of Formula I comprising: a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III; wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of
  • a single pot process for preparing Tranexamic acid of Formula I comprising: a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI having A, A’ independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl ; d) reacting a compound of Formula IV with at least one
  • azidating agent refers to a chemical compound which is capable of acting as a source for azide (N3 ) ion .
  • the azidating agent includes but not limited to sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide .
  • the quaternary salts of azide includes but not limited to tetrabutyl ammonium azide or tetramethyl ammonium azide and can be generated insitu in the reaction process.
  • Ci-10 alkyl refers to a mono-radical, branched or unbranched, saturated hydrocarbon chain having from 1 to 10 carbon atoms. This term is exemplified by groups such as methyl, ethyl, propyl, n-butyl, iso-butyl, t-butyl, n-hexyl, and the like. The groups may be optionally substituted.
  • amine refers to primary or secondary or tertiary amine which is obtained from primary or secondary or tertiary amine salts of a carboxylic acids.
  • carboxylic acid refers to class of organic compounds in which a carbon (C) atom is bonded to an oxygen (O) atom by a double bond and to a hydroxyl group ( — OH) by a single bond.
  • alkali and alkaline earth metals refers to “alkali metals” and “alkaline earth metals”.
  • Alkali metals refer to group 1 elements of the periodic table which comprises lithium, sodium, potassium, rubidium, cesium, and francium.
  • Alkaline earth metals refer to group 2 elements of the periodic table which comprises beryllium, magnesium, calcium, strontium, barium, and radium.
  • halogenating agent refers to chemical compound which can act as a source for halogen in the reaction process.
  • the halogenating agent in the present disclosure includes but not limited to sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water.
  • the halogen is chlorine, bromine or iodine.
  • Hydrohalic acid refers to hydrochloric acid, hydrobromic acid or hydroiodic acid.
  • esterifying agent refers to a chemical compound which reacts with a carboxylic acid or salt of carboxylic acid to form an ester product.
  • the esterifying agent includes but not limited to Ci-io aliphatic alcohol.
  • Ci-io aliphatic alcohol refers to an organic compound in which the aliphatic alkane chain is substituted by a hydroxy group at unspecified position. The aliphatic alkane chain may be straight or branched and may be optionally substituted.
  • the Ci-io aliphatic alcohol may be methanol, ethanol, propanol and the like.
  • hydrogen source refers to a chemical species which is capable of donating hydrogen to another chemical compound.
  • the hydrogen source may be solid, liquid or in gaseous form.
  • hydrogen source includes but not limited to hydrogen gas, ammonium formate, cyclohexene or hydrazine hydrate.
  • hydrogen source is used in reducing the compound of Formula III.
  • oxidizing agent refers to a chemical compound which donates oxygen atom or accepts electrons or removes hydrogen atom.
  • the oxidizing agent includes but not limited to nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, TEMPO((2,2,6,6-Tetramethylpiperidin-l-yl)oxyl, (2, 2,6,6- tetramethylpiperidin-l-yl)oxidanyl), N- Hydroxy 3,4,5,6-Tetrachlorophthalimide and combinations thereof.
  • oxidizing agent used is nitric acid with catalytic amount of sodium nitrite.
  • the term “acidic source” refers to a chemical compound that can donate proton to another chemical compound.
  • acidic source includes but not limited to sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, or clay.
  • halogenated benzene refers to benzene substituted with halogen such as chlorine, iodine, bromine or fluorine.
  • halogenated aromatic compound refers to aromatic organic compound substituted with halogen such as chlorine, iodine, bromine or iodine.
  • hydrogen pressure refers to the pressure maintained/existing at the reaction vessel.
  • hydrogen pressure in the present disclosure refers to the pressure in the reaction vessel filled with hydrogen while reducing is carried out. In the present disclosure, reducing is carried out at a hydrogen pressure in the range of 1 to 10 kg/cm 2 .
  • the hydrogen pressure also refers to the atmospheric hydrogen pressure of the reaction vessel.
  • tranexamic acid The commercial demand for tranexamic acid is high due to its advantages over other compounds of same function.
  • the current processes that are available for obtaining tranexamic acid involved expensive reagents, catalysts under elevated temperatures and pressures.
  • the separation and purification of the isomers has been time consuming, difficult and complicated process.
  • the present disclosure provides one such process for the preparation of tranexamic acid.
  • the process involves cheaper raw materials with simple procedure and yet provide a higher yield of pure tranexamic acid.
  • the process exemplified in the present disclosure comprises the use of simple cheaper reagents and catalysts.
  • reaction procedures are sequenced in such a way that all the reaction steps occur in moderate temperatures and pressures.
  • the present disclosure also provides a single pot process which can reduce the reaction time as well as increase the capacity of large scale production of pure tranexamic acid. [0025] In an embodiment of the present disclosure, there is provided a process for preparing
  • Formula 1 said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III;
  • R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci- io alkyl
  • A is selected from the group consisting of chlorine, bromine and iodine
  • R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci- io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III where
  • Formula Ila Formula lib wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
  • Formula 1 said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III;
  • Formuia IV Formuia 111 wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci- io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of
  • Formula Ila Formula lib wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
  • a process for preparing Tranexamic acid of Formula I wherein the hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I is followed by acidification with acids selected from acetic acid, hydrochloric acid, hydrobromic acid or sulphuric acid.
  • a process for preparing Tranexamic acid of Formula I described herein wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C to obtain compound(s) of Formula VI;
  • Formula Vi! Formula Vi wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof;
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and
  • the at least one azidating agent is selected from the group consisting of sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof and the first solvent is selected from the group consisting of sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof.
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent selected from sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof, in the presence of a first solvent selected from sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof, at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or
  • a process as described herein wherein the reacting a compound of Formula IV is carried out in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal.
  • at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal.
  • the at least one second base is pre-cooled to a temperature in the range of 20 to 40°C.
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C, in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci- io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent selected from sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof, in the presence of a first solvent selected from sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof, at a temperature in the range of 70-120°C, in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b)
  • the at least one first base is selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal.
  • Tranexamic acid of Formula I said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base selected from hydroxide or carbonate or bicarbonate of alkali or
  • the at least one metal catalyst is selected from the group consisting of raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof.
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof; and at least one hydrogen source at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III where
  • the at least one hydrogen source is selected from the group consisting of hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof and the second solvent is selected from water, methanol, ethanol, ethyl acetate or combinations thereof.
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, and a second solvent selected from water, methanol, ethanol, ethyl a
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at
  • a process for preparing Tranexamic acid of Formula I comprising: (a) reacting a compound of Formula IV with at least one azidating agent selected from sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof, in the presence of a first solvent selected from sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof, at a temperature in the range of 70-120°C, in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b)
  • a process for preparing Tranexamic acid of Formula I wherein the compound of Formula IV is prepared by a process described herein, wherein the at least one halogenating agent is selected from the group consisting of sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof and the third solvent is selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound.
  • the at least one halogenating agent is selected from the group consisting of sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof and the third solvent is selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound.
  • a process for preparing Tranexamic acid of Formula I described herein wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent selected from sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof, in the presence of a third solvent selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound, at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain
  • Tranexamic acid of Formula I wherein the compound of Formula IV is prepared by a process described herein, wherein reacting a compound of Formula VII is carried out in the presence of metallic zinc or zinc halide or sulphuric acid.
  • a process for preparing Tranexamic acid of Formula I described herein wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C, carried out in the presence of metallic zinc or zinc halide or sulphuric acid, to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°
  • Tranexamic acid of Formula I wherein the compound of Formula IV is prepared by a process described herein, wherein the at least one oxidizing agent is selected from the group consisting of nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, and combinations thereof.
  • the at least one oxidizing agent is selected from the group consisting of nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, and combinations thereof.
  • the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent selected from nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, and combinations thereof, at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain
  • a process for preparing Tranexamic acid of Formula I wherein the compound of Formula IV is prepared by a process described herein, wherein the esterifying agent is selected from Ci-io aliphatic alcohol; and at least one acidic source is selected from the group consisting of sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, clay and combinations thereof.
  • the esterifying agent is selected from Ci-io aliphatic alcohol
  • at least one acidic source is selected from the group consisting of sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, clay and combinations thereof.
  • a process for preparing Tranexamic acid of Formula I described herein wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent selected from Ci-io aliphatic alcohol, with at least one acidic source selected from sulphuric acid, phosphoric acid, dry hydrochloric acid,
  • a process for preparing Tranexamic acid of Formula I described herein wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent selected from sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof, in the presence of a third solvent selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound, at a temperature in the range of 100-120°C, carried out in the presence of metallic zinc or zinc halide or sulphuric acid, to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at
  • a single pot process for preparing tranexamic acid of Formula I comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI having A, A’ independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl; (d) reacting a compound of Formula IV with at least one
  • a single pot process for preparing tranexamic acid of Formula I comprising: (a) reacting a compound of Formula VII with at least one halogenating agent selected from sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof in the presence of a third solvent selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound at a temperature in the range of 100-120°C, carried out in the presence of metallic zinc or zinc halide or sulphuric acid, to obtain compound(s) of Formula VI having A, A’ independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent selected from nitric acid, sodium n
  • the compound of Formula I is pure tranexamic acid is the trans isomer of purity in the range of 99.0-99.8%
  • the compound of Formula VII is a 90-100% trans isomer.
  • the compound of Formula VI has a mono halo compound with weight percentage in the range of 80-90% and di-halo compound with weight percentage in the range of 5-10%.
  • the yield of the mono-halo compound of Formula VI is dependent on quantity of solvent.
  • the present disclosure reveals a convenient and a simple process for obtaining the anti-fibrinolytic agent tranexamic acid. It can be understood from the prior art that the existing process for the preparation of tranexamic acid involved complex reagents and a complicated process. Also, the yield of pure trans isomer obtained from the existing processes were lower and required additional separation process using chromatographic techniques, Ion exchange methods and so on. The tranexamic acid was obtained in its salt form instead of pure form. Hence with a view to overcome the shortcomings as discussed in the background, the present disclosure provides a process for preparing pure tranexamic acid.
  • Example 1.1 Example 1.1
  • the optimized reaction conditions for attaining high yield of the mono bromo product and for minimizing the dibromo impurity were obtained by varying the equivalence of hydrobromic acid, solvent used and the quantity of solvent.
  • the reaction was carried out by varying the solvents. The reaction was carried out using dichlorobenzene, chlorobenzene, toluene, xylene and methylisobutyl ketone. The solvents chlorobenzene and dichlorobenzene were effective in attaining the least dibromo impurity.
  • Example 1.1 In another example, the process as explained in Example 1.1 was attempted by varying the quantity of solvent used. In this example, the amount of chlorobenzene equivalent to the reaction mixture was varied and its effect on the dibromo impurity was determined. When the quantity of solvent was higher, the product had the least dibromo impurity. [0069] In addition to said above, the process as explained in Example 1.1 was attempted by varying the amount of hydrobromic acid. The hydrobromic acid equivalence in the range of 1.05-1.15 was found to be effective in obtaining less dibromo impurity.
  • the process can also be performed by changing the mode of addition of reagents to obtain similar results but preferably as explained in example 1.1.
  • Example 1.1 The process as explained in Example 1.1 is an optimized process for attaining the compound of Formula VI with the least dibromo impurity.
  • the chloroform layers were combined and was extracted with dilute sodium hydroxide (30 g of sodium hydroxide in 150ml of water), the aqueous layer had the product 4- bromomethylcyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1 ,4-dibromomethylcyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0 g).
  • the dilute sodium hydroxide layer was acidified with hydrochloric acid (90 g) at 20 - 35 °C and to this slurry, 150ml of n-heptane was added at the same temperature and then cooled to about 10°C. The product was isolated by filtration.
  • the wet product was then washed with chilled water containing heptanes or n-heptane and dried at 40°C for 4 hours. 50 g of the pure trans isomer of Formula V with a molar yield of 71.4% (based on trans isomer and cis content 0.2%) was obtained. Also, recycling of the spent nitric acid was done. Spent nitric acid from the process had an assay of 45% which was then recycled by bringing its assay to 70% using highly concentrated nitric acid (assay more than 90%).
  • the compound of Formula VI from Example 1.1 is oxidized into the compound of Formula V as per the process described herein.
  • Nitric acid 200g, 2.0moles
  • chloroform 50ml
  • 5.0g of sodium nitrite was added in portions (for smaller scale single portion can be done) at 10°C followed by the addition of 4- bromo methylcyclohexane- 1 - methanol (Formula VI,100g, 0.48 moles) at 5- 20°C for about 2-4.0hours.
  • the mixture was stirred at 10-25°C for 8.0 hours until the reaction completion.
  • the completed reaction mass was extracted using 100ml of chloroform in two parts.
  • the chloroform layers were combined and was extracted with dilute sodium hydroxide (30g of NaOH in 150ml of water), the aqueous layer had the product 4- bromo methyl cyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1 ,4-dibromo methyl cyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0g).
  • the dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 - 35°C and to this, add 60ml of Toluene and then heated to 80-85°C separate the organic layer taken for next stage.
  • the compound of Formula VI from Example 1.1 is oxidized into the compound of Formula V as per the process described herein. Nitric acid (200g, 2.0moles) was cooled to 10°C and then to this 50ml of chloroform was added.
  • n-hydroxyphthalimide 5%) was added in portions (for smaller scale single portion can be done) at about 10°C followed by the addition of 4- bromo methylcyclohexane-1- methanol (Formula VI,100g, 0.48 moles) at 5- 20°C for about 2- 4.0hours.
  • the mixture was stirred at 10-25°C for 8.0hours until the reaction completion.
  • the completed reaction mass was extracted using 100ml of chloroform in two parts.
  • the chloroform layers were combined and was extracted with dilute sodium hydroxide (30gof NaOH in 150ml of water), the aqueous layer had the product 4-bromo methyl cyclohexane - 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1 ,4-dibromo methyl cyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0g).
  • the dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 -
  • the compound of Formula VI from Example 1.1 is oxidized into the compound of Formula V as per the process described herein. Nitric acid (200g, 2.0moles) was cooled to 10°C and then to this 50ml of chloroform was added.
  • the chloroform layers were combined and was extracted with dilute sodium hydroxide (30gof NaOH in 150ml of water), the aqueous layer had the product 4-chloro methyl cyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dichloro product- 1 ,4-dichloro methyl cyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0g).
  • the dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 - 35°C and add 0.6 times of toluene heated to 80-85°C maintain and then separated organic and taken for next stage Also, recycling of the spent nitric acid was done.Spent nitric acid from the process had an assay of 45% which was then recycled by bringing its assay to 70% using highly concentrated nitric acid (assay more than 90%).
  • the compound of Formula VI from Example 1.1 was oxidized into the compound of Formula V as per the process described herein.
  • Nitric acid 200g, 2.0moles
  • MDC methylene dichloride
  • 5.0g of sodium nitrite was added in portions (for smaller scale single portion can be done) at about 10°C followed by the addition of 4- bromo methylcyclohexane-1- methanol (Formula VI,100g, 0.48 moles) at 5- 20°C for about 2- 4.0hours.
  • the mixture was stirred at 10-25°C for 8.0hours until the reaction completion.
  • the completed reaction mass was extracted using 100ml of methylene dichloride in two parts.
  • the chloroform layers were combined and was extracted with dilute sodium hydroxide (30gof NaOH in 150ml of water), the aqueous layer had the product 4-bromo methyl cyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1,4- dibromo methyl cyclohexane) was in and was methylene dichloride layer recovered by simple evaporation (7.0g).
  • the dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 - 35°C and to this, add 60ml of Toluene and then heated to 80-85°C separate the organic layer taken for next stage .
  • Example 1.2 The process as explained in Example 1.2 was carried out by varying the quantity of oxidizing reagents sodium nitrite and nitric acid. The yield varied with varying quantity of reagents and hence an optimized quantity as explained in the Example 1.2 was derived. [0079] In addition, the process as described in Example 1.2 was carried out by varying the solvent for purification of the product of Formula V. The solvents such as water, hexanes, heptanes and cyclohexane were used to obtain the pure product of Formula V. The purification process was done twice with the same solvent and it was found that the purity of the product obtained varied based on the solvent used.
  • the solvents such as water, hexanes, heptanes and cyclohexane were used to obtain the pure product of Formula V.
  • the purification process was done twice with the same solvent and it was found that the purity of the product obtained varied based on the solvent used.
  • Toluene layer was evaporated completed to get oily product (1 lOg) and the crude product a compound of Formula IV was distilled to get pale yellow color product of 4-bromo methyl cyclohexane- 1-carboxylate (Formula IV,100g, molar yield 94%). Distilled product 4-bromo methyl cyclohexane- 1-carboxylate was taken for further conversion.
  • the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.lOOg of 4-chloro methyl cyclohexane- 1 -carboxylic acid in toluene (Formula V)was dissolved in mixture of 50ml of methanol.
  • the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.lOOg of 4- bromo methyl cyclohexane- 1 -carboxylic acid in toluene (Formula V) was dissolved in mixture of 50ml of Ethanol . To this mixture, sulphuric acid (30g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 8.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution.
  • the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.40g of 4- bromo methyl cyclohexane- 1 -carboxylic acid (Formula V)was dissolved in mixture of 50ml of methanol and 150 ml of toluene. To this mixture, sulphuric acid (35g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 8.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution.
  • top toluene layer had the product compound of Formula IV and middle layer had tetra butyl ammonium bromide and then the aqueous layer.
  • the top organic layer was washed with water and the toluene layer was evaporated completely to obtain the compound of Formula III of methyl 4-azidomethylcyclohexane- 1-carboxylate (molar yield 103%).
  • the product of Formula III along with residual toluene was taken for further stages.
  • the compound of Formula IV from Example 1.3 was subjected to azidation as described below to obtain the compound of Formula III.
  • 16g of sodium azide (l.Omole) in water was mixed with 16.2g of tetra butyl ammonium bromide, to this mixture 58g of 4-chloro methyl cyclohexane- 1 -carboxylate (Formula IV) was added at less than 40°C and then heated to 80-90°C. The reaction was maintained at the same temperature for about 24hours. After the completion of reaction, the reaction mass was diluted with 44ml of toluene.
  • top toluene layer has the product compound of Formula IV and middle layer had tetra butyl ammonium bromide and then aqueous layer.
  • the top organic layer was washed with water and the toluene layer was evaporated completely to obtain the compound of Formula III of 4-azido methyl cyclohexane- 1- carboxylate (molar yield as crude 87%).
  • the product of Formula III along with residual toluene was taken for further stages.
  • the compound of Formula IV from Example 1.3 was subjected to azidation as described below to obtain the compound of Formula III.
  • the compound of Formula IV from Example 1.3 was subjected to azidation as described below to obtain the compound of Formula III, sodium azide (22.4 g, 0.49 mol) was dissolved in 80 ml of water and heated to about 80°C. To this solution, 100 g
  • the aqueous layer was extracted with 50 ml of toluene and the combined toluene layer was re-extracted with 300ml water containing potassium hydroxide (32.79g of KOH of assay 85%).
  • Potassium salt of 4- azido methyl cyclohexane carboxylic acid (Formula Ila) in water was taken for further stages.
  • the azidation process as explained in Example 1.4.2 was carried out by varying the base as sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, triethyl amine and Ammonia. Sodium carbonate and sodium bicarbonate was preferably used.
  • the hydrolysis process was carried out in the presence of other bases such as sodium hydroxide, barium hydroxide, ammonia and triethyl amine.
  • bases such as sodium hydroxide, barium hydroxide, ammonia and triethyl amine.
  • the process was preferably carried out using potassium hydroxide.
  • the product was then filtered and the wet product of compound of Formula I (60 g) was dissolved in 240 ml of water and 60 ml of ammonia.
  • the solution was filtered using the micron filter and the clear filtrate was concentrated to a volume of 150 ml and then diluted with 125ml of IP A (isopropyl alcohol) and heated to reflux (about 80°C for 1.0 hour) and then cooled to 25- 30°C.
  • the obtained solution was then filtered and washed with IPA (30ml).
  • the product was dried under vacuum at 80- 90°C.
  • the final product obtained was 52 g of pure tranexamic acid with total impurity less than 0.2%.
  • the potassium acetate from this process was reused in the conversion of 1 ,4-dibromomethyl cyclohexane conversion to 1 ,4-cyclohexane dimethanol. [0099] The potassium acetate from this process can be reused in the conversion of 1,4- dibromo methyl cyclohexane conversion to 1,4-cyclohexane dimethanol.
  • the compound of Formula I was obtained by reducing the compound of Formula Ila from Example 1.5. .4- azido methyl cyclohexane- 1 -carboxylic acid was diluted with 34g (0.37 mole) of Aqueous ammonia solution and then add water (600ml) and to that lOg of dry Raney nickel was added at 30-40°C and then hydrogen gas was bubbled through the reaction mass for 12.0hours by maintaining the reaction . After the completion of reaction, the Raney nickel was removed by filtration. The reaction mass was distilled out water for ammonia traces remove add water and n-Butanol heated to 80-85°C maintain 30 mints and then cooled to 0-5 maintain and filtered it dry solid 22.4g (molar yield-52%).
  • the clear filtered was evaporated to almost dryness and then was diluted with 2part of Isopropanol.
  • the product is isolated from water and IPA mixture . .
  • the final product obtained was 8g (molar yield 40%) of pure tranexamic acid.
  • the compound of Formula VI obtained was as such added to pre-cooled nitric acid (276 g, 2.92moles) containing 5g of sodium nitrite and 75 ml of chloroform over 4-8hours. The reaction was stirred for 4-8hours at 10-20°C. The completed reaction mass was extracted twice with 100 ml of chloroform.
  • the chloroform layers were combined and was extracted with dilute sodium hydroxide (30 g of NaOH in 150 ml of water), the aqueous layer had the compound of Formula V and the dilute sodium hydroxide layer was acidified with hydrochloric acid(90 g) at 20-35 °C and extracted with toluene (200 ml).Toluene layer was distilled to remove residual water, then 50 ml of methanol was added followed by the addition of sulphuric acid (25 g) and heated to about 70°C for 10 hours. The top toluene layer containing methyl 4-bromomethylcyclohexane-l-carboxylate (Formula IV) was washed with dilute sodium carbonate solution (2x50ml).
  • Toluene layer was removed completely and the crude product (100 g) was purified by flash high vacuum distillation.
  • the distilled product (Formula IV) was added to 70ml of water containing 25g of sodium azide and tetra butyl ammonium bromide at 30-40°C and was stirred for over lhour and then the reaction mass was heated to 85-90°C. The reaction was maintained at the same temperature for about 24 hours. After the completion of reaction, the reaction mass was diluted with 200ml of toluene, then the toluene layer was separated, washed with water. Toluene layer was evaporated completely.
  • reaction mass temperature was raised to 45-55°C under hydrogen bubbling condition and maintained at the same temperature for 12 hours and then raised to 70-75°C, maintained for 2 hours and then the reaction mass was cooled to about 40°C.
  • Raney nickel was removed by filtration.
  • the reaction mass was neutralized with acetic acid to pH of 6-7.
  • the reaction was concentrated using charcoal treatment.
  • the residue was treated with methanol (300 ml) at about 65 °C and then cooled to 30°C.
  • the crude product of Formula I was filtered and then crystallized from IPA and water as explained in Example 1.6 resulting in 44.2g (40% yield starting from cyclohexane dimethanol) of pure tranexamic acid.
  • the compound of Formula VI obtained was as such added to pre-cooled nitric acid (276g, 2.92moles) containing 5 g of sodium nitrite and 75 ml of chloroform over 4-8 hours. The reaction was stirred for 4-8 hours at 10-20°C. The completed reaction mass was extracted twice with 100ml of chloroform. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30 g of NaOH in 150ml of water), the aqueous layer had the compound of Formula V and the dilute sodium hydroxide layer was acidified with hydrochloric acid (90g) at 20-35 °C and extracted with toluene (200ml).
  • Toluene layer was extracted with diluted potassium hydroxide solution (40g of potassium hydroxide in 500ml of water ). This solution was added to a solution containing 70ml of water with 25g of sodium azide at 80- 90°C for 5.0 hours and maintained at the same temperature for 10.0 hours. After the completion of reaction, the mass was acidified using sulphuric acid.
  • the extracted product using toluene (IX 200ml and lXlOOml) and the combine toluene layer was extracted with dilute potassium hydroxide solution (500ml of water containing 32g of potassium hydroxide) and trace of toluene was removed by distilling water under vacuum.
  • Raney Nickel (10 g) on dry basis was added to the reaction mass containing the compound of Formula II and then hydrogen gas was bubbled into the reaction mass.
  • the reaction mass temperature was raised to 45-55°C under hydrogen bubbling condition and maintained at the same temperature for 12hours and then raised to 70-75°C, maintained for 2hours and then the reaction mass was cooled to about 40°C.
  • Raney nickel was removed by filtration.
  • the reaction mass was neutralized with acetic acid to pH of 6-7.
  • the reaction was concentrated using charcoal treatment.
  • the residue was treated with methanol (300ml) at about 65 °C and then cooled to 30°C.
  • the crude product of Formula I was filtered. Wet product (65g) was then crystallized from IPA and water as explained in Example 1.6 resulting in 48.2g (43.6% yield starting from cyclohexane dimethanol) of pure tranexamic acid.
  • the process provided in the present disclosure is a simple efficient preparation process for pure Tranexamic acid from commercially available raw materials.
  • the process yields higher purity of the product Tranexamic acid.
  • the process involves effective recycling of all the minor products and the reagents used which makes the process more environment friendly.
  • the reagents used, and the reaction conditions are milder, hence the process is an enhanced process which is industrially applicable and cost effective.
  • the single pot preparation process reduces cycle time and is economically competent.

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Abstract

The present disclosure relates to a process for preparing tranexamic acid, the process comprising: a reacting a compound of Formula IV with at least one azidating agent to obtain a compound of Formula III, reducing the compound of Formula III to the compound of Formula I or hydrolyzing the compound of Formula III to the compound of Formula IIa, followed by reducing the compound of Formula IIa to the compound of Formula I or reducing the compound of Formula III to obtain a compound of Formula IIb, followed by hydrolyzing the compound of Formula IIb to obtain the compound of Formula I. The present disclosure also provides a single pot process for preparing Tranexamic acid of Formula I.

Description

PROCESS FOR PREPARING TRANEXAMIC ACID
FIELD OF INVENTION
[0001] The present disclosure relates to the preparation process of Tranexamic acid or trans- 4-aminomethyl cyclohexane carboxylic acid of Formula I, in particular relates to an efficient greener preparation process of pure Tranexamic acid. In addition, the disclosure relates to single pot preparation process of pure Tranexamic acid.
BACKGROUND OF THE INVENTION
[0002] Tranexamic acid is an antifibrinolytic agent used in the prevention of hemorrhage due to dental procedures in hemophilics, cyclic heavy menstrual bleeding, hereditary angioedema and during surgery. Tranexamic acid is effective and the most preferred as it has lesser side effects, when compared with other fibrinolytic agents. There are various preparation methods available for obtaining tranexamic acid. WO2015104721A2 reveals the synthetic preparation of crude tranexamic acid starting from 4-cyanobenzylamine and use of bulk amine protecting agents for further purification. US3923879 discloses a process for the preparation of tranexamic acid from p-cyanobenzoic acid by hydrogenation at high temperatures and pressures. US4048222A reveals the preparation process from p-aminomethyl benzoic acid at higher temperatures and pressures. It can be understood from the prior art that preparation of tranexamic acid involved vigorous reaction temperatures and pressures. Also, the processes employed complex reagents which were recovered by a separate method. Thus, a large-scale synthesis of pure tranexamic acid has been a challenge and involved complicated process. Hence, there is a need in the state of art for a simple process which can produce high yield of pure tranexamic acid.
SUMMARY OF THE INVENTION
[0003] In an aspect of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, the process comprising: a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III; wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15 - 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci- io alkyl in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
[0004] In another aspect of the present disclosure, there is provided a single pot process for preparing Tranexamic acid of Formula I the process comprising: a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI having A, A’ independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl ; d) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; and A is selected from the group consisting of chlorine, bromine and iodine; e) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I.
DESCRIPTION OF THE INVENTION
[0005] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.
Definitions
[0006] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below. [0007] The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.
[0008] The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. [0009] Throughout this specification, unless the context requires otherwise the word
“comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.
[0010] The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are used interchangeably.
[0011] The term “azidating agent” refers to a chemical compound which is capable of acting as a source for azide (N3 ) ion . In the present disclosure, the azidating agent includes but not limited to sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide . The quaternary salts of azide includes but not limited to tetrabutyl ammonium azide or tetramethyl ammonium azide and can be generated insitu in the reaction process.
[0001] The term “ Ci-10 alkyl” refers to a mono-radical, branched or unbranched, saturated hydrocarbon chain having from 1 to 10 carbon atoms. This term is exemplified by groups such as methyl, ethyl, propyl, n-butyl, iso-butyl, t-butyl, n-hexyl, and the like. The groups may be optionally substituted. [0012] The term “amine” refers to primary or secondary or tertiary amine which is obtained from primary or secondary or tertiary amine salts of a carboxylic acids. The term “carboxylic acid” refers to class of organic compounds in which a carbon (C) atom is bonded to an oxygen (O) atom by a double bond and to a hydroxyl group ( — OH) by a single bond.
[0013] The term “alkali and alkaline earth metals” refers to “alkali metals” and “alkaline earth metals”. Alkali metals refer to group 1 elements of the periodic table which comprises lithium, sodium, potassium, rubidium, cesium, and francium. Alkaline earth metals refer to group 2 elements of the periodic table which comprises beryllium, magnesium, calcium, strontium, barium, and radium.
[0014] The term “halogenating agent” refers to chemical compound which can act as a source for halogen in the reaction process. The halogenating agent in the present disclosure includes but not limited to sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water. The halogen is chlorine, bromine or iodine. Hydrohalic acid refers to hydrochloric acid, hydrobromic acid or hydroiodic acid.
[0015] The term “esterifying agent” refers to a chemical compound which reacts with a carboxylic acid or salt of carboxylic acid to form an ester product. In the present disclosure, the esterifying agent includes but not limited to Ci-io aliphatic alcohol. The term “Ci-io aliphatic alcohol” refers to an organic compound in which the aliphatic alkane chain is substituted by a hydroxy group at unspecified position. The aliphatic alkane chain may be straight or branched and may be optionally substituted. The Ci-io aliphatic alcohol may be methanol, ethanol, propanol and the like. [0016] The term “hydrogen source” refers to a chemical species which is capable of donating hydrogen to another chemical compound. The hydrogen source may be solid, liquid or in gaseous form. In the present disclosure, hydrogen source includes but not limited to hydrogen gas, ammonium formate, cyclohexene or hydrazine hydrate. In the present disclosure, hydrogen source is used in reducing the compound of Formula III. [0017] The term “oxidizing agent” refers to a chemical compound which donates oxygen atom or accepts electrons or removes hydrogen atom. In the present disclosure, the oxidizing agent includes but not limited to nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, TEMPO((2,2,6,6-Tetramethylpiperidin-l-yl)oxyl, (2, 2,6,6- tetramethylpiperidin-l-yl)oxidanyl), N- Hydroxy 3,4,5,6-Tetrachlorophthalimide and combinations thereof. In the present disclosure, oxidizing agent used is nitric acid with catalytic amount of sodium nitrite. [0018] The term “acidic source” refers to a chemical compound that can donate proton to another chemical compound. In the present disclosure, acidic source includes but not limited to sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, or clay.
[0019] The term “halogenated benzene” refers to benzene substituted with halogen such as chlorine, iodine, bromine or fluorine. The term “halogenated aromatic compound” refers to aromatic organic compound substituted with halogen such as chlorine, iodine, bromine or iodine.
[0020] The term “hydrogen pressure” refers to the pressure maintained/existing at the reaction vessel. The term “hydrogen pressure” in the present disclosure refers to the pressure in the reaction vessel filled with hydrogen while reducing is carried out. In the present disclosure, reducing is carried out at a hydrogen pressure in the range of 1 to 10 kg/cm2 . The hydrogen pressure also refers to the atmospheric hydrogen pressure of the reaction vessel. [0021] Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.
[0022] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference. [0023] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally- equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein. [0024] Tranexamic acid as an antifibrinolytic agent has a greater pharmaceutical importance and medicinal value. The commercial demand for tranexamic acid is high due to its advantages over other compounds of same function. As discussed in the background, the current processes that are available for obtaining tranexamic acid involved expensive reagents, catalysts under elevated temperatures and pressures. The separation and purification of the isomers has been time consuming, difficult and complicated process. Hence there requires an alternate efficient simple process for the preparation of tranexamic acid which should be economically cheaper. The present disclosure provides one such process for the preparation of tranexamic acid. The process involves cheaper raw materials with simple procedure and yet provide a higher yield of pure tranexamic acid. The process exemplified in the present disclosure comprises the use of simple cheaper reagents and catalysts. The reaction procedures are sequenced in such a way that all the reaction steps occur in moderate temperatures and pressures. The present disclosure also provides a single pot process which can reduce the reaction time as well as increase the capacity of large scale production of pure tranexamic acid. [0025] In an embodiment of the present disclosure, there is provided a process for preparing
Tranexamic acid of Formula I,
QOOH
Figure imgf000008_0001
Formula 1 said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III;
Figure imgf000009_0001
Formula IV Formu!a ill wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci- io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci- io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I
Figure imgf000010_0001
Formula Ila Formula lib wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl. [0026] In an embodiment of the present disclosure, there is provided a process for preparing
Tranexamic acid of Formula I,
COOH
Figure imgf000010_0002
Formula 1 said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III;
Figure imgf000010_0003
Formuia IV Formuia 111 wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci- io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I
Figure imgf000011_0001
Formula Ila Formula lib wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl. In another embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, wherein the hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I is followed by acidification with acids selected from acetic acid, hydrochloric acid, hydrobromic acid or sulphuric acid.
[0027] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I described herein, wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C to obtain compound(s) of Formula VI;
Figure imgf000012_0001
Formula Vi! Formula Vi wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof;
(b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and
Figure imgf000012_0002
Formula V
(c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl. In another embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I as described herein, wherein reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C to obtain compound(s) of Formula VI is carried out in batch mode or continuous mode. In yet another embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I as described herein, wherein the Formula VII has 65 to 100% trans isomer.
[0028] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and
(b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl, and wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula
V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl.
[0029] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: reacting the compound(s) of Formula
VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV wherein R is selected from Ci-io alkyl. In another embodiment of the present disclosure, there is provided a process described herein, wherein the compound of Formula V is extracted in the presence of hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal or ammonium or amine salt to obtain the compound of Formula IV having R selected from alkali or alkaline earth metal or ammonium or amine.
[0030] In an embodiment of the present disclosure, there is provided a process as described herein, wherein the at least one azidating agent is selected from the group consisting of sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof and the first solvent is selected from the group consisting of sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof. [0031] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent selected from sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof, in the presence of a first solvent selected from sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof, at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula IP wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base, at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
[0032] In an embodiment of the present disclosure, there is provided a process as described herein, wherein the reacting a compound of Formula IV is carried out in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal. In another embodiment of the present disclosure, there is provided a process as described herein, wherein the at least one second base is pre-cooled to a temperature in the range of 20 to 40°C.
[0033] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C, in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci- io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci- io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
[0034] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent selected from sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof, in the presence of a first solvent selected from sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof, at a temperature in the range of 70-120°C, in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
[0035] In an embodiment of the present disclosure, there is provided a process as described herein, wherein the at least one first base is selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal. [0036] In an embodiment of the present disclosure, there is provided a process for preparing
Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl. [0037] In an embodiment of the present disclosure, there is provided a process as described herein, wherein the at least one metal catalyst is selected from the group consisting of raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof. [0038] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof; and at least one hydrogen source at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15 - 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof, and at least one hydrogen source at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof;; and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
[0039] In an embodiment of the present disclosure, there is provided a process as described herein, wherein the at least one hydrogen source is selected from the group consisting of hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof and the second solvent is selected from water, methanol, ethanol, ethyl acetate or combinations thereof.
[0040] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, and a second solvent selected from water, methanol, ethanol, ethyl acetate or combinations thereof at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, and a second solvent selected from water, methanol, ethanol, ethyl acetate or combinations thereof at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst, at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof and a second solvent selected from water, methanol, ethanol, ethyl acetate or combinations thereof; at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
[0041] In an embodiment of the present disclosure, there is provided a process as described herein, wherein reducing is carried out at hydrogen pressure in the range of 1 to 10 kg/cm2. In another embodiment of the present disclosure, there is provided a process as described herein, wherein reducing is carried out at atmospheric hydrogen pressure. [0042] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl, and wherein reducing is carried out at hydrogen pressure in the range of 1 to 10 kg/cm2.
[0043] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, said process comprising: (a) reacting a compound of Formula IV with at least one azidating agent selected from sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof, in the presence of a first solvent selected from sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof, at a temperature in the range of 70-120°C, in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and (b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof, at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, and a second solvent selected from water, methanol, ethanol, ethyl acetate or combinations thereof at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof, and at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof, and at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl, and wherein reducing is carried out at hydrogen pressure in the range of 1 to 10 kg/cm2.
[0044] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, wherein the compound of Formula IV is prepared by a process described herein, wherein the at least one halogenating agent is selected from the group consisting of sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof and the third solvent is selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound.
[0045] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I described herein, wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent selected from sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof, in the presence of a third solvent selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound, at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30- 90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl. [0046] In an embodiment of the present disclosure, there is provided a process for preparing
Tranexamic acid of Formula I, wherein the compound of Formula IV is prepared by a process described herein, wherein reacting a compound of Formula VII is carried out in the presence of metallic zinc or zinc halide or sulphuric acid.
[0047] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I described herein, wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C, carried out in the presence of metallic zinc or zinc halide or sulphuric acid, to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl. [0048] In an embodiment of the present disclosure, there is provided a process for preparing
Tranexamic acid of Formula I, wherein the compound of Formula IV is prepared by a process described herein, wherein the at least one oxidizing agent is selected from the group consisting of nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, and combinations thereof. [0049] In an embodiment of the present disclosure, there is provided a process for preparing
Tranexamic acid of Formula I described herein, wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent selected from nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, and combinations thereof, at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl.
[0050] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I, wherein the compound of Formula IV is prepared by a process described herein, wherein the esterifying agent is selected from Ci-io aliphatic alcohol; and at least one acidic source is selected from the group consisting of sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, clay and combinations thereof.
[0051] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I described herein, wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100- 120°C to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent selected from Ci-io aliphatic alcohol, with at least one acidic source selected from sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, clay and combinations thereof, at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl.
[0052] In an embodiment of the present disclosure, there is provided a process for preparing Tranexamic acid of Formula I described herein, wherein the compound of Formula IV is prepared by a process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent selected from sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof, in the presence of a third solvent selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound, at a temperature in the range of 100-120°C, carried out in the presence of metallic zinc or zinc halide or sulphuric acid, to obtain compound(s) of Formula VI; wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent selected from nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, and combinations thereof, at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent selected from Ci-io aliphatic alcohol, with at least one acidic source selected from sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, clay and combinations thereof, at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci- io alkyl.
[0053] In an embodiment of the present disclosure, there is provided a single pot process for preparing tranexamic acid of Formula I, the process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI having A, A’ independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl; (d) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; and A is selected from the group consisting of chlorine, bromine and iodine; (e) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst and at least one hydrogen source at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I.
[0054] In an embodiment of the present disclosure, there is provided a single pot process for preparing tranexamic acid of Formula I, the process comprising: (a) reacting a compound of Formula VII with at least one halogenating agent selected from sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof in the presence of a third solvent selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound at a temperature in the range of 100-120°C, carried out in the presence of metallic zinc or zinc halide or sulphuric acid, to obtain compound(s) of Formula VI having A, A’ independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; (b) reacting the compound(s) of Formula VI with at least one oxidizing agent selected from nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, and combinations thereof, at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; (c) optionally esterifying the compound of Formula V in the presence of an esterifying agent selected from Ci- io aliphatic alcohol, with at least one acidic source selected from sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, clay and combinations thereof, at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci-io alkyl; (d) reacting a compound of Formula IV with at least one azidating agent selected from sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof, in the presence of a first solvent selected from sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof, at a temperature in the range of 70- 120°C, in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; and A is selected from the group consisting of chlorine, bromine and iodine; (e) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof, and at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula PI wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof, at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, and a second solvent selected from water, methanol, ethanol, ethyl acetate or combinations thereof at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst selected from raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof, at least one hydrogen source selected from hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof, and a second solvent selected from water, methanol, ethanol, ethyl acetate or combinations thereof at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal, at a temperature in the range of 15- 60°C to obtain the compound of Formula I, and wherein reduction is carried out at hydrogen pressure in the range of 1 to 10 kg/cm2.
[0055] In another embodiment of the present disclosure, wherein the compound of Formula I is pure tranexamic acid is the trans isomer of purity in the range of 99.0-99.8% [0056] In an embodiment of the present disclosure, there is provided a single pot process, wherein the compound of Formula VII is a 90-100% trans isomer.
[0057] In an embodiment of the present disclosure, the compound of Formula VI has a mono halo compound with weight percentage in the range of 80-90% and di-halo compound with weight percentage in the range of 5-10%. In another embodiment of the present disclosure, the yield of the mono-halo compound of Formula VI is dependent on quantity of solvent.
[0058] In an embodiment of the present disclosure, there is provided the process described herein, wherein the compound of Formula V is trans isomer with weight percentage in the range of 99.0-99.8%.
[0059] In an embodiment of the present disclosure, there is provided the process for preparing tranexamic acid of Formula I, wherein the compounds of Formula V, IV, III, Ila, lib and I are separated by extraction from organic and inorganic solvent layers. [0060] In an embodiment of the present disclosure, there is provided the process described herein, wherein the process involves recycling of the minor products and reagents.
[0061] In an embodiment of the present disclosure there is provided a compound of Formula I obtained by the processes described herein. [0062] Although the subject matter has been described in considerable detail with reference to certain examples and implementations thereof, other implementations are possible.
EXAMPLES
[0063] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may apply.
[0064] The present disclosure reveals a convenient and a simple process for obtaining the anti-fibrinolytic agent tranexamic acid. It can be understood from the prior art that the existing process for the preparation of tranexamic acid involved complex reagents and a complicated process. Also, the yield of pure trans isomer obtained from the existing processes were lower and required additional separation process using chromatographic techniques, Ion exchange methods and so on. The tranexamic acid was obtained in its salt form instead of pure form. Hence with a view to overcome the shortcomings as discussed in the background, the present disclosure provides a process for preparing pure tranexamic acid. Example 1.1
Halogenation of trans-1, 4-cyclohexane dimethanol to 4-bromomethylcyclohexane-l- methanol.
Figure imgf000031_0001
[0065] 0.69 moles of 1,4-cyclohexane dimethanol (Formula VII) (trans isomer 65%) was dissolved in hydrobromic acid (about 50% w/w, 0.76moles, 1.1 equivalent) at 20- 40°C. This mixture was added to pre -heated chlorobenzene (at 105-110°C) for 10 hours. Water was removed from the reaction mixture while pre-heating. The reaction mass was maintained at about 110°C for 5.0 hours. The product obtained was a compound of Formula VI which is a mixture of 85% mono bromo product and 6.0% of dibromo product. After the completion of reaction, the reaction mass was concentrated completely to get oily product with a molar yield of 98.6%. 4-bromomethyl cyclohexane- 1 -methanol (Formula VI) obtained was a mixture trans and cis isomer. The liquid product was taken to next stage with or without further purification.
[0066] The optimized reaction conditions for attaining high yield of the mono bromo product and for minimizing the dibromo impurity were obtained by varying the equivalence of hydrobromic acid, solvent used and the quantity of solvent. [0067] In the process explained in Example 1.1, the reaction was carried out by varying the solvents. The reaction was carried out using dichlorobenzene, chlorobenzene, toluene, xylene and methylisobutyl ketone. The solvents chlorobenzene and dichlorobenzene were effective in attaining the least dibromo impurity.
[0068] In another example, the process as explained in Example 1.1 was attempted by varying the quantity of solvent used. In this example, the amount of chlorobenzene equivalent to the reaction mixture was varied and its effect on the dibromo impurity was determined. When the quantity of solvent was higher, the product had the least dibromo impurity. [0069] In addition to said above, the process as explained in Example 1.1 was attempted by varying the amount of hydrobromic acid. The hydrobromic acid equivalence in the range of 1.05-1.15 was found to be effective in obtaining less dibromo impurity.
[0070] Furthermore, the process can also be performed by changing the mode of addition of reagents to obtain similar results but preferably as explained in example 1.1.
[0071] The process as explained in Example 1.1 is an optimized process for attaining the compound of Formula VI with the least dibromo impurity.
Example 1.2
Oxidation of 4-bromomethylcyclohexane-l-methanol to 4-bromomethyl cyclohexane -1-carboxylic acid
Figure imgf000032_0001
[0072] The compound of Formula VI from Example 1.1 was oxidized into the compound of Formula V as per the process described herein. Nitric acid (200 g, 2.0mol) was cooled to 10°C and then to this 50ml of chloroform was added. To this mixture, 5.0 g of sodium nitrite was added in portions at about 10°C followed by the addition of 4-bromomethylcyclohexane-
1 -methanol (Formula VI, lOOg, 0.48 moles, contains about 70 g of trans isomer) at 5- 20°C for about 2-4 hours. The mixture was stirred at 10-25°C for 8 hours until the reaction completion. The completed reaction mass was extracted using 100ml of chloroform in two parts. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30 g of sodium hydroxide in 150ml of water), the aqueous layer had the product 4- bromomethylcyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1 ,4-dibromomethylcyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0 g). The dilute sodium hydroxide layer was acidified with hydrochloric acid (90 g) at 20 - 35 °C and to this slurry, 150ml of n-heptane was added at the same temperature and then cooled to about 10°C. The product was isolated by filtration. The wet product was then washed with chilled water containing heptanes or n-heptane and dried at 40°C for 4 hours. 50 g of the pure trans isomer of Formula V with a molar yield of 71.4% (based on trans isomer and cis content 0.2%) was obtained. Also, recycling of the spent nitric acid was done. Spent nitric acid from the process had an assay of 45% which was then recycled by bringing its assay to 70% using highly concentrated nitric acid (assay more than 90%).
[0073] In another example, the compound of Formula VI from Example 1.1 is oxidized into the compound of Formula V as per the process described herein. Nitric acid (200g, 2.0moles) was cooled to 10°C and then to this 50ml of chloroform was added. To this mixture, 5.0g of sodium nitrite was added in portions (for smaller scale single portion can be done) at 10°C followed by the addition of 4- bromo methylcyclohexane- 1 - methanol (Formula VI,100g, 0.48 moles) at 5- 20°C for about 2-4.0hours. The mixture was stirred at 10-25°C for 8.0 hours until the reaction completion. The completed reaction mass was extracted using 100ml of chloroform in two parts. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30g of NaOH in 150ml of water), the aqueous layer had the product 4- bromo methyl cyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1 ,4-dibromo methyl cyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0g).The dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 - 35°C and to this, add 60ml of Toluene and then heated to 80-85°C separate the organic layer taken for next stage. Also, recycling of the spent nitric acid was done. Spent nitric acid from the process had an assay of 45% which was then recycled by bringing its assay to 70% using highly concentrated nitric acid (assay more than 90%). [0074] In yet another example, the compound of Formula VI from Example 1.1 is oxidized into the compound of Formula V as per the process described herein. Nitric acid (200g, 2.0moles) was cooled to 10°C and then to this 50ml of chloroform was added. To this mixture, 5.0g of n-hydroxyphthalimide (5%) (NHPI) was added in portions (for smaller scale single portion can be done) at about 10°C followed by the addition of 4- bromo methylcyclohexane-1- methanol (Formula VI,100g, 0.48 moles) at 5- 20°C for about 2- 4.0hours. The mixture was stirred at 10-25°C for 8.0hours until the reaction completion. The completed reaction mass was extracted using 100ml of chloroform in two parts. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30gof NaOH in 150ml of water), the aqueous layer had the product 4-bromo methyl cyclohexane - 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1 ,4-dibromo methyl cyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0g).The dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 -
35°C and to this, add 60m 1 of Toluene and then heated to 80-85°C separate the organic layer taken for next stage. Also, recycling of the spent nitric acid was done. Spent nitric acid from the process had an assay of 45% which was then recycled by bringing its assay to 70% using highly concentrated nitric acid (assay more than 90%). [0075] In one another example, the compound of Formula VI from Example 1.1 is oxidized into the compound of Formula V as per the process described herein. Nitric acid (200g, 2.0moles) was cooled to 10°C and then to this 50ml of chloroform was added. To this mixture, 5.0g of sodium nitrite was added in portions (for smaller scale single portion can be done) at about 10°C followed by the addition of 4- chloro methyl cyclohexane- 1- methanol (Formula VI,100g, 0.48 moles) at 5- 20°C for 2 to 4.0hours. The mixture was stirred at 10- 25°C for 8.0hours until the reaction completion. The completed reaction mass was extracted using 100ml of chloroform in two parts. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30gof NaOH in 150ml of water), the aqueous layer had the product 4-chloro methyl cyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dichloro product- 1 ,4-dichloro methyl cyclohexane) was in chloroform layer and was recovered by simple evaporation (7.0g).The dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 - 35°C and add 0.6 times of toluene heated to 80-85°C maintain and then separated organic and taken for next stage Also, recycling of the spent nitric acid was done.Spent nitric acid from the process had an assay of 45% which was then recycled by bringing its assay to 70% using highly concentrated nitric acid (assay more than 90%). [0076] In yet another example, the compound of Formula VI from Example 1.1 was oxidized into the compound of Formula V as per the process described herein. Nitric acid (200g, 2.0moles) was cooled to 10°C and then to this 50ml of methylene dichloride(MDC) was added. To this mixture, 5.0g of sodium nitrite was added in portions (for smaller scale single portion can be done) at about 10°C followed by the addition of 4- bromo methylcyclohexane-1- methanol (Formula VI,100g, 0.48 moles) at 5- 20°C for about 2- 4.0hours. The mixture was stirred at 10-25°C for 8.0hours until the reaction completion. The completed reaction mass was extracted using 100ml of methylene dichloride in two parts. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30gof NaOH in 150ml of water), the aqueous layer had the product 4-bromo methyl cyclohexane- 1 -carboxylic acid (Formula V) and the side product (the dibromo product- 1,4- dibromo methyl cyclohexane) was in and was methylene dichloride layer recovered by simple evaporation (7.0g).The dilute sodium hydroxide layer was acidified with spent nitric acid (80ml) at 20 - 35°C and to this, add 60ml of Toluene and then heated to 80-85°C separate the organic layer taken for next stage . .Also, recycling of the spent nitric acid was done. Spent nitric acid from the process had an assay of 45% which was then recycled by bringing its assay to 70% using highly concentrated nitric acid (assay more than 90%). [0077] The compound of Formula VI from Example 1 was oxidized into the compound of Formula V, Nitric acid (20g 0.22mole) was added to 4- bromo methylcyclohexane-1- methanol (Formula VI,10g, 0.048 moles) and during addition, the reaction is highly exothermic and hence 50% of product was formed and was further taken for esterification reaction . [0078] The process as explained in Example 1.2 was carried out by varying the quantity of oxidizing reagents sodium nitrite and nitric acid. The yield varied with varying quantity of reagents and hence an optimized quantity as explained in the Example 1.2 was derived. [0079] In addition, the process as described in Example 1.2 was carried out by varying the solvent for purification of the product of Formula V. The solvents such as water, hexanes, heptanes and cyclohexane were used to obtain the pure product of Formula V. The purification process was done twice with the same solvent and it was found that the purity of the product obtained varied based on the solvent used.
Example 1.3 Esterification of 4- bromomethylcyclohexane-l-carboxylic acid to methyl 4- bromomethylcy clohexane- 1 -carboxy late
Figure imgf000036_0001
[0080] The compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV. 100 g of 4- bromomethylcyclohexane- 1 -carboxylic acid (Formula V) was dissolved in mixture of 50ml of methanol and 150 ml of toluene. To this mixture, sulphuric acid (30g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 8.0 hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0% of aqueous sodium bicarbonate solution. Toluene layer was evaporated completely to get oily product (112 g) and was distilled to get pale yellow color product of methyl 4-bromomethyl cyclohexane- 1-carboxylate (Formula IV, 102 g, molar yield 96%). Distilled product methyl 4-bromomethylcyclohexane- 1 -carboxylate was taken for further conversion.
[0081] The compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.lOOg of 4- bromo methyl cyclohexane- 1 -carboxylic acid in toluene (Formula V)was dissolved in mixture of 50ml of methanol. To this mixture, ortho phosphoric acid (40g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 20.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution. Toluene layer was evaporated completed to get oily product (1 lOg) and the crude product a compound of Formula IV was distilled to get pale yellow color product of 4-bromo methyl cyclohexane- 1-carboxylate (Formula IV,100g, molar yield 94%). Distilled product 4-bromo methyl cyclohexane- 1-carboxylate was taken for further conversion. [0082] In another example, the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.lOOg of 4-chloro methyl cyclohexane- 1 -carboxylic acid in toluene (Formula V)was dissolved in mixture of 50ml of methanol. To this mixture, sulphuric acid (35g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 8.0 hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution. Toluene layer was evaporated completed to get oily product (98g) and the crude product a compound of Formula IV was distilled to get pale yellow color product of 4-chloro methyl cyclohexane- 1-carboxylate (Formula IV,83g, molar yield 77%). Distilled product 4-chloro methyl cyclohexane- 1 -carboxylate was taken for further conversion. [0083] In one another example, the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.25g of 4- bromo methyl cyclohexane- 1 -carboxylic acid in toluene (Formula V) was dissolved in mixture of 125ml of Isopropyl alcohol and of toluene. To this mixture, sulphuric acid (35g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 15.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution. Toluene layer was evaporated completed to get oily product (32g) and the crude product a compound of Formula IVwas distilled to get pale yellow color product of 4-bromo methyl cyclohexane- 1-carboxylate (Formula IV,26.5g, molar yield 95%). Distilled product 4-bromo methyl cyclohexane- 1- iso propyl ester carboxylate was taken for further conversion.
[0084] In one more example, the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.lOOg of 4- bromo methyl cyclohexane- 1 -carboxylic acid in toluene (Formula V) was dissolved in mixture of 50ml of Ethanol . To this mixture, sulphuric acid (30g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 8.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution. Toluene layer was evaporated completed to get oily product (112g) and the crude product a compound of Formula IVwas distilled to get pale yellow color product of 4-bromo methyl cyclohexane- 1- ethyl carboxylate (Formula IV,106g, molar yield 94%). Distilled product 4-bromo methyl cyclohexane- 1 -ethyl carboxylate was taken for further conversion. [0085] In another more example, the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.50g of 4- bromo methyl cyclohexane- 1- carboxylic acid (Formula V)was dissolved in mixture of 25ml of Isobutanol . To this mixture, sulphuric acid (17g) was added at a temperature less than 40°C. This mixture was heated to about 70-75°C and maintained at the same temperature for 8.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 25ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution. Toluene layer was evaporated completed to get oily product (65g) and the crude product a compound of Formula IV was distilled to get pale yellow color product of 4-bromo methyl cyclohexane- 1- iso butyl ester carboxylate (Formula IV,58g, molar yield 92%). Distilled product 4-bromo methyl cyclohexane- 1 -iso butyl ester carboxylate was taken for further conversion. [0086] In yet another example, the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.50g of 4- bromo methyl cyclohexane- 1 -carboxylic acid (Formula V)was dissolved in mixture of 25ml of n-butanol and 75ml of toluene. To this mixture, sulphuric acid (17g) was added at a temperature less than 40°C. This mixture was heated to about 70-75°C and maintained at the same temperature for 8.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 25ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution. Toluene layer was evaporated completed to get oily product (60g) and the crude product a compound of Formula IVwas distilled to get pale yellow color product of 4-bromo methyl cyclohexane- 1 - butyl ester carboxylate (Formula IV,57g, molar yield 91%). Distilled product 4-bromo methyl cyclohexane- 1 -butyl ester carboxylate was taken for further conversion.
[0087] In further example, the compound of Formula V from Example 1.2 was esterified to obtain the compound of Formula IV.40g of 4- bromo methyl cyclohexane- 1 -carboxylic acid (Formula V)was dissolved in mixture of 50ml of methanol and 150 ml of toluene. To this mixture, sulphuric acid (35g) was added at a temperature less than 40°C. This mixture was heated to about 70°C and maintained at the same temperature for 8.0hours for the completion of reaction. After the completion of reaction, the organic layer was separated. The organic toluene layer was washed twice with 50ml of water followed by addition of 7.0%of aqueous sodium bicarbonate solution. Toluene layer was evaporated completed to get oily product (44g) and the crude product a compound of Formula IVwas distilled to get pale yellow color product of 4-bromo methyl cyclohexane- 1-carboxylate (Formula IV,33g, molar yield 77%). Distilled product 4-bromo methyl cyclohexane- 1 -carboxylate was taken for further conversion^
Example 1.4.1
Azidation of methyl 4-bromomethylcyclohexane-l-carboxylate to methyl 4- azidomethylcyclohexane-l-carboxylate (without base)
Figure imgf000040_0001
[0088] The compound of Formula IV from Example 1.3 was subjected to azidation as described below to obtain the compound of Formula III. 27.7g of sodium azide (1.0 mol) in water was mixed with 33 g of tetra butyl ammonium bromide, to this mixture 100 g of methyl 4-bromomethylcyclohexane- 1 -carboxylate (Formula IV) was added at less than 40°C and then heated to 80-90°C. The reaction was maintained at the same temperature for about 24 hours. After the completion of reaction, the reaction mass was diluted with 100ml of toluene. Three layer formation was observed, top toluene layer had the product compound of Formula IV and middle layer had tetra butyl ammonium bromide and then the aqueous layer. The top organic layer was washed with water and the toluene layer was evaporated completely to obtain the compound of Formula III of methyl 4-azidomethylcyclohexane- 1-carboxylate (molar yield 103%). The product of Formula III along with residual toluene was taken for further stages.
[0089] In another example, the compound of Formula IV from Example 1.3 was subjected to azidation as described below to obtain the compound of Formula III. 16g of sodium azide (l.Omole) in water was mixed with 16.2g of tetra butyl ammonium bromide, to this mixture 58g of 4-chloro methyl cyclohexane- 1 -carboxylate (Formula IV) was added at less than 40°C and then heated to 80-90°C. The reaction was maintained at the same temperature for about 24hours. After the completion of reaction, the reaction mass was diluted with 44ml of toluene. Three layer formation was observed, top toluene layer has the product compound of Formula IV and middle layer had tetra butyl ammonium bromide and then aqueous layer. The top organic layer was washed with water and the toluene layer was evaporated completely to obtain the compound of Formula III of 4-azido methyl cyclohexane- 1- carboxylate (molar yield as crude 87%). The product of Formula III along with residual toluene was taken for further stages. [0090] In yet another example, the compound of Formula IV from Example 1.3 was subjected to azidation as described below to obtain the compound of Formula III. 8.3g of sodium azide (l.Omole) in water was mixed with 8.4g of tetra butyl ammonium bromide, to this mixture 30g of 4-bromo methyl cyclohexane- 1 -iso propyl ester carboxylate was added at less than 40°C and then heated to 80-90°C. The reaction was maintained at the same temperature for about 24hours. After the completion of reaction, the reaction mass was diluted with 100ml of toluene. Three layer formation was observed, top toluene layer has the product compound of Formula IV and middle layer had tetra butyl ammonium bromide and then aqueous layer. The top organic layer was washed with water and the toluene layer was evaporated completely to obtain the compound of Formula III of 4-azido methyl cyclohexane- 1 -iso propyl ester carboxylate (molar yield as crude 100%). The product of
Formula III along with residual toluene was taken for further stages. [0091] In one more example, the compound of Formula V from Example 1.2 was subjected to azidation as described below to obtain the compound of Formula II .30g (0.13 mol) of 4- bromo methyl cyclohexane -1- carboxylic acid dissolved with (0.13 mol) of Potassium hydroxide solution added to the sodium azide (0.13 mol) with water maintaining 24 hours After reaction completed pH adjust to 1-2 by using hydrochloric acid solid filtered dry solid 21.5g of 4-azido methyl cyclohexane - 1 -carboxylic acid (molar yield-87%)
[0092] The solvent for the process as explained in example 1.4 was changed and the difference in yield was observed. The other solvents attempted were water, dimethylsulphoxide (DMSO), dimethylformamide (DMF) and dimethylacetamide (DMA). Example 1.4.2
Azidation of 4-bromomethylcyclohexane-l-carboxylate to Potassium salt of 4- azidomethylcyclohexane-l-carboxylate (with base)
[0093] In an example, the compound of Formula IV from Example 1.3 was subjected to azidation as described below to obtain the compound of Formula III, sodium azide (22.4 g, 0.49 mol) was dissolved in 80 ml of water and heated to about 80°C. To this solution, 100 g
(0.49 mol) of methyl 4-bromomethylcyclohexane-l-carboxylate (Formula IV) in dilute NaOH solution (200 ml of water containing 19.9 g of sodium hydroxide (0.49moles)) was added for over 4.0 hours at 80- 90°C. The reaction mass maintained further at 80- 90°C for about 15.0 hours. After the completion of reaction, the reaction mass was diluted with 150 ml of toluene and was acidified with sulphuric acid. Organic layer containing product was separated. The aqueous layer was extracted with 50 ml of toluene and the combined toluene layer was re-extracted with 300ml water containing potassium hydroxide (32.79g of KOH of assay 85%). Potassium salt of 4- azido methyl cyclohexane carboxylic acid (Formula Ila) in water was taken for further stages. [0094] The azidation process as explained in Example 1.4.2 was carried out by varying the base as sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium hydroxide, triethyl amine and Ammonia. Sodium carbonate and sodium bicarbonate was preferably used.
Example 1.5
Hydrolysis of methyl 4-azidomethylcyclohexane-l-carboxylate to potassium salt of 4- azidomethylcyclohexane-l-carboxylic acid
[0095] The compound of Formula III as obtained from Example 1.4.1 was hydrolyzed to obtain the compound of Formula Ila. An aqueous solution of potassium hydroxide (35.1 lg, 0.53moles) was stirred at 20-50°C and then cooled to 25- 35°C. methyl 4- azidomethylcyclohexane-l-carboxylate (100 g, 0.50moles) was added to the diluted potassium hydroxide solution at 25- 35°C, over 1.0 hour. Reaction mass was stirred at 30- 40°C for 5.0 hours. After completion of reaction, the reaction mass was diluted with 50ml of toluene and stirred for 15 minutes. The toluene layer was separated and product potassium salt of 4- azidomethylcyclohexane- 1 -carboxylic acid (Formula II) in dilute potassium hydroxide solution was used for further reaction. [0096] In another example, the compound of Formula III from Example 1.4.1 was hydrolyzed as per the below said process to result in the compound of Formula Ila. An aqueous solution of sodium hydroxide flakes (21.5g, 0.53moles) was added and stirred at 20- 50°C and then cooled to 25- 35°C. 4-azido methyl cyclohexane- 1 -methanol (lOOg, 0.50moles) was added to the diluted sodium hydroxide solution at 25- 35°C, over l.Ohour. Reaction mass was stirred at 30- 40°C for 5.0hours. After completion of reaction, the reaction mass was diluted with 50ml of toluene and stirred for 15 minutes. The toluene layer was separated and product sodium salt of 4- azido methyl cyclohexane- 1 -carboxylate (Formula II) in dilute sodium hydroxide solution was used for further conversions.
[0097] The hydrolysis process was carried out in the presence of other bases such as sodium hydroxide, barium hydroxide, ammonia and triethyl amine. The process was preferably carried out using potassium hydroxide. Example 1.6
Reduction of Potassium salt of 4-azidomethylcyclohexane-l-carboxylic acid to Tranexamic acid
Figure imgf000044_0001
[0098] The compound of Formula I was obtained by reducing either the compound of
Formula Ila from Example 1.5 or the compound of Formula III from Example 1.4.2. Potassium salt of 4- azidomethylcyclohexane- 1 -carboxylic acid was diluted with water (400 ml) and to that 10 g of dry Raney nickel was added. The slurry was heated to 40- 50°C and then hydrogen gas was bubbled through the reaction mass for 12.0 hours at temperature in the range of 45-50°C and then increased the temperature to 70°C. The reaction temperature was maintained at 70°C for 2.0 hours. After the completion of reaction, the Raney nickel was removed by filtration. The reaction mass was neutralized with acetic acid to pH of 6-7. The reaction was concentrated using charcoal treatment. The residue was treated with 400 ml of methanol at a temperature of about 65 °C. The product was then filtered and the wet product of compound of Formula I (60 g) was dissolved in 240 ml of water and 60 ml of ammonia. The solution was filtered using the micron filter and the clear filtrate was concentrated to a volume of 150 ml and then diluted with 125ml of IP A (isopropyl alcohol) and heated to reflux (about 80°C for 1.0 hour) and then cooled to 25- 30°C. The obtained solution was then filtered and washed with IPA (30ml). The product was dried under vacuum at 80- 90°C. The final product obtained was 52 g of pure tranexamic acid with total impurity less than 0.2%. The potassium acetate from this process was reused in the conversion of 1 ,4-dibromomethyl cyclohexane conversion to 1 ,4-cyclohexane dimethanol. [0099] The potassium acetate from this process can be reused in the conversion of 1,4- dibromo methyl cyclohexane conversion to 1,4-cyclohexane dimethanol.
[0100] The compound of Formula I was obtained by reducing the compound of Formula Ila from Example 1.5. .4- azido methyl cyclohexane- 1 -carboxylic acid was diluted with 34g (0.37 mole) of Aqueous ammonia solution and then add water (600ml) and to that lOg of dry Raney nickel was added at 30-40°C and then hydrogen gas was bubbled through the reaction mass for 12.0hours by maintaining the reaction . After the completion of reaction, the Raney nickel was removed by filtration. The reaction mass was distilled out water for ammonia traces remove add water and n-Butanol heated to 80-85°C maintain 30 mints and then cooled to 0-5 maintain and filtered it dry solid 22.4g (molar yield-52%).
[0101] lOOg of 4- azido methyl cyclohexane- 1 -carboxylic acid (Formula Ila) was diluted to methanol and add lOg of (5% Pd/C) heated to 70-75°C applied hydrogen pressure 8kg/cm2 maintaining 20hrs.After reaction completed cooled to 40°C add water removed Pd/C by filtration Filtrate concentrate compiled add methanol heated to 70-75°C maintain lhr and then cooled to 30-35°C crude product isolated. The crude product is dissolved in part of water and 0.5 part of ammonia solution in water ( 25% w/w ) , then the solution was charcoalized and filtered . the clear filtered was evaporated to almost dryness and then was diluted with 2part of Isopropanol. The product is isolated from water and IPA mixture. The final product obtained was 35g (molar yield 40.74%) of pure tranexamic acid. [0102] Methyl 4- azido methyl cyclohexane- 1-carboylate (25g )was dissolved in methanol and hydrogenated using Palladium on carbon at 90-95°C at 8.0Kg/cm2 of hydrogen pressure over 24.0h .After the completion of reaction by TLC , the Palladium carbon was removed by filtration . The reaction was evaporated under vacuum and then was diluted with water (75ml) to obtain the compound of Formula lib. Then the compound of Formula lib was hydrolysed by the process described below. Potassium hydroxide ( 11.5g) was added to the mass and heated to 90- 95°C to complete the hydrolysis. Tranexamic acid was isolated by neutralization ( pH -6.5) using acetic acid followed by evaporation. The concentrated mass was diluted with methanol (100ml) and heated to about 70°C.Then the crude tranexamic acid (12g ) was isolated at 25- 30°C. The crude product is dissolved in part of water and 0.5 part of ammonia solution in water ( 25% w/w ) , then the solution was charcoalized and filtered . The clear filtered was evaporated to almost dryness and then was diluted with 2part of Isopropanol. The product is isolated from water and IPA mixture . .The final product obtained was 8g (molar yield 40%) of pure tranexamic acid.
Example 2.1
Single pot preparation process of Tranexamic acid
[0103] 100 g of trans- 1 ,4-cyclohexane dimethanol (Formula Vll-content of trans isomer minimum 95%) was dissolved in hydrobromic acid (about 50% w/w, 0.76moles, 1.1 equivalent) at 20- 40°C. This mixture was added to pre -heated chlorobenzene (at 105- 110°C) over 4-12 hours and water was removed from the reaction mixture. The reaction mass was maintained at about 110°C for 2-5hours. The reaction mass was concentrated completely to get an oily product (Formula VI) (138 g). The compound of Formula VI obtained was as such added to pre-cooled nitric acid (276 g, 2.92moles) containing 5g of sodium nitrite and 75 ml of chloroform over 4-8hours. The reaction was stirred for 4-8hours at 10-20°C. The completed reaction mass was extracted twice with 100 ml of chloroform. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30 g of NaOH in 150 ml of water), the aqueous layer had the compound of Formula V and the dilute sodium hydroxide layer was acidified with hydrochloric acid(90 g) at 20-35 °C and extracted with toluene (200 ml).Toluene layer was distilled to remove residual water, then 50 ml of methanol was added followed by the addition of sulphuric acid (25 g) and heated to about 70°C for 10 hours. The top toluene layer containing methyl 4-bromomethylcyclohexane-l-carboxylate (Formula IV) was washed with dilute sodium carbonate solution (2x50ml). Toluene layer was removed completely and the crude product (100 g) was purified by flash high vacuum distillation. The distilled product (Formula IV) was added to 70ml of water containing 25g of sodium azide and tetra butyl ammonium bromide at 30-40°C and was stirred for over lhour and then the reaction mass was heated to 85-90°C. The reaction was maintained at the same temperature for about 24 hours. After the completion of reaction, the reaction mass was diluted with 200ml of toluene, then the toluene layer was separated, washed with water. Toluene layer was evaporated completely. The residue of Formula III (80 g) was added to 1 0ml of water containing potassium hydroxide (32 g) at 10-20°C over 30 minutes. Then reaction temperature was raised to 35-45°C and maintained at the same temperature for about 5hours. After the completion of reaction, the mass was diluted with 50ml of toluene and stirred for 15 minutes. Toluene layer was removed and 8 g of Raney Nickel on dry basis was added to the aqueous product layer containing the compound of Formula II and then hydrogen gas was bubbled into the reaction mass. The reaction mass temperature was raised to 45-55°C under hydrogen bubbling condition and maintained at the same temperature for 12 hours and then raised to 70-75°C, maintained for 2 hours and then the reaction mass was cooled to about 40°C. Raney nickel was removed by filtration. The reaction mass was neutralized with acetic acid to pH of 6-7. The reaction was concentrated using charcoal treatment. The residue was treated with methanol (300 ml) at about 65 °C and then cooled to 30°C. The crude product of Formula I was filtered and then crystallized from IPA and water as explained in Example 1.6 resulting in 44.2g (40% yield starting from cyclohexane dimethanol) of pure tranexamic acid. Example 2.2
Single pot preparation process of Tranexamic acid [0104] lOOg of trans- 1,4-cyclohexane dim ethanol (Formula VII) (content of trans isomer minimum 95%) was dissolved in hydrobromic acid (about 50% w/w, 0.76moles, 1.1 equivalent) at 20- 40°C. This mixture was added to pre -heated chlorobenzene (at 105- 110°C) over 4-12 hours and water was removed from the reaction mixture. The reaction mass was maintained at about 110°C for 2-5hours. The reaction mass was concentrated completely to get an oily product (Formula VI) (138 g). The compound of Formula VI obtained, was as such added to pre-cooled nitric acid (276g, 2.92moles) containing 5 g of sodium nitrite and 75 ml of chloroform over 4-8 hours. The reaction was stirred for 4-8 hours at 10-20°C. The completed reaction mass was extracted twice with 100ml of chloroform. The chloroform layers were combined and was extracted with dilute sodium hydroxide (30 g of NaOH in 150ml of water), the aqueous layer had the compound of Formula V and the dilute sodium hydroxide layer was acidified with hydrochloric acid (90g) at 20-35 °C and extracted with toluene (200ml). Toluene layer was extracted with diluted potassium hydroxide solution (40g of potassium hydroxide in 500ml of water ). This solution was added to a solution containing 70ml of water with 25g of sodium azide at 80- 90°C for 5.0 hours and maintained at the same temperature for 10.0 hours. After the completion of reaction, the mass was acidified using sulphuric acid. The extracted product using toluene (IX 200ml and lXlOOml) and the combine toluene layer was extracted with dilute potassium hydroxide solution (500ml of water containing 32g of potassium hydroxide) and trace of toluene was removed by distilling water under vacuum. Raney Nickel (10 g) on dry basis was added to the reaction mass containing the compound of Formula II and then hydrogen gas was bubbled into the reaction mass. The reaction mass temperature was raised to 45-55°C under hydrogen bubbling condition and maintained at the same temperature for 12hours and then raised to 70-75°C, maintained for 2hours and then the reaction mass was cooled to about 40°C. Raney nickel was removed by filtration. The reaction mass was neutralized with acetic acid to pH of 6-7. The reaction was concentrated using charcoal treatment. The residue was treated with methanol (300ml) at about 65 °C and then cooled to 30°C. The crude product of Formula I was filtered. Wet product (65g) was then crystallized from IPA and water as explained in Example 1.6 resulting in 48.2g (43.6% yield starting from cyclohexane dimethanol) of pure tranexamic acid.
[0105] The process as explained in Examples 1.6, 2.1 and 2.2, the reaction attempted using various catalysts such as Raney Nickel, Palladium on charcoal, Ruthenium on charcoal, Platinum on charcoal/ammonia, Rhodium on charcoal, gave similar results. Advantages of the present invention
Current commercial process for preparing tranexamic acid involves high pressure and temperature for hydrogenation and high temperature isomerization reaction with higher level of inorganic matter during isolation of Tranexamic acid and needs to be eliminated in subsequent purification which resulted lower yield.
The process provided in the present disclosure is a simple efficient preparation process for pure Tranexamic acid from commercially available raw materials. The process yields higher purity of the product Tranexamic acid. The process involves effective recycling of all the minor products and the reagents used which makes the process more environment friendly. The reagents used, and the reaction conditions are milder, hence the process is an enhanced process which is industrially applicable and cost effective. The single pot preparation process reduces cycle time and is economically competent.

Claims

I/We claim:
1. A process for preparing Tranexamic acid of Formula I,
Figure imgf000050_0001
Formula-I said process comprising steps: a) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III;
Figure imgf000050_0002
Formula iV Formula III wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; A is selected from the group consisting of chlorine, bromine and iodine; and b) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I
Figure imgf000051_0001
Formula Ila Formula lib wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; and R of Formula lib is selected from Ci-io alkyl.
2. The process as claimed in claim 1 in which the compound of Formula IV is prepared by a process comprising: a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI;
Figure imgf000052_0001
Formula Vi I Formula VI wherein A, A’ is independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; and
Figure imgf000052_0002
Formula V c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV, wherein R is selected from Ci- io alkyl .
3. The process as claimed in claim 1 , wherein the at least one azidating agent is selected from the group consisting of sodium azide, potassium azide, trimethylsilyl azide, quaternary salts of azide and combinations thereof and the first solvent is selected from the group consisting of sodium bromide, tetra butyl ammonium bromide, dimethyl formamide, dimethyl sulphoxide, dimethyl acetamide, water and combinations thereof.
4. The process as claimed in claim 1, wherein the step la carried out in the presence of at least one second base selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal.
5. The process as claimed in claim 1 , wherein the at least one first base is selected from hydroxide or carbonate or bicarbonate of alkali or alkaline earth metal.
6. The process as claimed in claim 1, wherein the at least one metal catalyst is selected from the group consisting of raney nickel, palladium on charcoal, rhodium, ruthenium, platinum, and combinations thereof.
7. The process as claimed in claim 1 , wherein the at least one hydrogen source is selected from the group consisting of hydrogen gas, ammonium formate, cyclohexene, hydrazine hydrate, or combinations thereof; and the second solvent is selected from water, methanol, ethanol, ethyl acetate or combinations thereof.
8. The process as claimed in claim 1 , wherein reduction is carried out at hydrogen pressure in the range of 1 to 10 kg/cm2.
9. The process as claimed in claim 2, wherein the at least one halogenating agent is selected from the group consisting of sodium halide in sulphuric acid, hydrohalic acid in acetic acid, gaseous hydrohalic acid, hydrohalic acid in water and combinations thereof and the third solvent is selected from toluene, xylene, chlorobenzene, dichlorobenzene, halogenated benzene or halogenated aromatic compound.
10. The process as claimed in claim 2, wherein the step 2a is carried out in the presence of metallic zinc or zinc halide or sulphuric acid.
11. The process as claimed in claim 2, wherein the at least one oxidizing agent is selected from the group consisting of nitric acid, sodium nitrite, alkali or alkaline earth metal nitrite, N-hydroxy phthalimide, TEMPO((2, 2,6,6- Tetramethylpiperidin-l-yl)oxyl, (2,2,6,6-tetramethylpiperidin-l-yl)oxidanyl), N- hydroxy 3,4,5,6-tetrachlorophthalimide and combinations thereof.
12. The process as claimed in claim 2, wherein the esterifying agent is selected from Ci-io aliphatic alcohol; and the at least one acidic source is selected from the group consisting of sulphuric acid, phosphoric acid, dry hydrochloric acid, acidic resin, clay and combinations thereof.
13. A single pot process for preparing tranexamic acid of Formula I, the process comprising: a) reacting a compound of Formula VII with at least one halogenating agent in the presence of a third solvent at a temperature in the range of 100-120°C to obtain compound(s) of Formula VI having A, A’ independently selected from group consisting of chlorine, bromine, iodine, hydroxyl, and combinations thereof; b) reacting the compound(s) of Formula VI with at least one oxidizing agent at a temperature in the range of 0-30°C to obtain a compound of Formula V having A selected from chlorine, bromine, or iodine; c) optionally esterifying the compound of Formula V in the presence of an esterifying agent with at least one acidic source at a temperature in the range of 30-90°C to obtain the compound of Formula IV having R selected from Ci- io alkyl ; d) reacting a compound of Formula IV with at least one azidating agent in the presence of a first solvent at a temperature in the range of 70-120°C to obtain a compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium, amine or Ci-io alkyl; and A is selected from the group consisting of chlorine, bromine and iodine; e) reducing the compound of Formula III, wherein R is selected from H, alkali metals, alkaline earth metals, ammonium or amine to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at a temperature in the range of 10 to 80°C; or hydrolyzing the compound of Formula III wherein R is selected from Ci-io alkyl to a compound of Formula Ila in the presence of at least one first base at a temperature in the range of 15- 60°C, followed by reducing the compound of Formula Ila to the compound of Formula I in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C, wherein Y of Formula Ila is selected from alkali metals, alkaline earth metals, ammonium or amine; or reducing the compound of Formula III wherein R is selected from Ci-io alkyl in the presence of at least one metal catalyst, at least one hydrogen source and a second solvent at temperature in the range of 30 to 80°C to obtain a compound of Formula lib, followed by hydrolyzing the compound of Formula lib in the presence of at least one first base at a temperature in the range of 15- 60°C to obtain the compound of Formula I, wherein R of Formula lib is selected from Ci-io alkyl.
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WO2025052151A1 (en) 2023-09-08 2025-03-13 Galen Limited Pharmaceutical compositions

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CN116730856A (en) * 2023-06-19 2023-09-12 浙江竹子制药有限公司 Synthesis method of tranexamic acid
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WO2025052151A1 (en) 2023-09-08 2025-03-13 Galen Limited Pharmaceutical compositions

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