Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D213/62—Oxygen or sulfur atoms
  • C07D213/69—Two or more oxygen atoms
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/55—Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups

Definitions

• Disclosed herein is a process for preparing N-benzyl-3-hydroxypyridin-2-(lH)-ones that are substituted at the pyridine ring 4-position with a 4-carbamoylpiperazin-l-yl moiety.
• the antecedent "about” indicates that the values are approximate.
• the range of “about 1 equivalent (equiv.) to about 50 equivalents” indicates that the values are approximate values.
• the range of "about 1 equivalent to about 50 equivalents” includes approximate and specific values, e.g., the range includes about 1 equivalent, 1 equivalent, about 50 equivalent and 50 equivalents.
• the range includes both the endpoints of the range as well as all numbers in between. For example, “between 1 equiv. and 10 equiv.” includes 1 equiv., 10 equiv. and all amounts between 1 equiv. and 10 equiv. Likewise, “from 1 equiv. to 10 equiv.” includes 1 equiv., 10 equiv. and all amounts between 1 equiv. and 10 equiv.
• Y is a 4-carbamoylpiperazin-l-yl unit having the formula:
• R 1 is defined herein.
• Z is a substituted or unsubstituted phenyl ring having formula:
• n is an integer from 0 to 5.
• R units when present represent from 1 to 5 substitutions for a hydrogen atom on the indicated phenyl ring.
• the index n is an integer from 1 to 5 when one or more substitutions are present.
• R is absent and therefore there are no substitutions for hydrogen and the resulting subgenus is represented by the formula:
• R units are independently chosen from:
• C1-C6 linear, C3-C6 branched or C3-C6 cyclic alkyl Non-limiting examples of C1-C4 linear alkyl units include methyl (Ci), ethyl (C2), n-propyl (C3), n- butyl (C 4 ), n-pentyl (Cs) and n-hexyl (Ce).
• Non-limiting examples of C3-C6 branched and C3-C6 cyclic alkyl units include z ' so-propyl (C3), cyclopropyl (C3), sec-butyl (C 4 ), z ' sobutyl (C 4 ), tert-butyl (C 4 ), cyclobutyl (C 4 ), neo- pentyl (Cs), cyclopentyl (Cs), iso-hexyl (C6), cyclohexyl (C6), and the like; ii) C1-C6 linear, C3-C6 branched or C3-C6 cyclic alkoxy.
• Non-limiting examples of C1-C4 linear alkoxy units include methoxy (Ci), ethoxy (C2), n-propoxy (C3), n-butoxy (C 4 ), n-pentyloxy (Cs) and n-hexyloxy (C6).
• Non-limiting examples of C3-C6 branched and C3-C6 cyclic alkoxy units include iso- propoxy (C3), cyclopropoxy (C3), sec-butoxy (C 4 ), z ' sobutoxy (C 4 ), tert- butoxy (C 4 ), cyclobutoxy (C 4 ), neopentyloxy (Cs), cyclopentyloxy (Cs), iso- hexyloxy (Ce), cyclohexyloxy (Ce), and the like;
• each R unit comprising a halogen is independently chosen from fluoro, chloro, bromo or iodo; or
• One aspect of the disclosure relates to compounds wherein the index n is equal to 0 and therefore R unit substitutions are absent therefore resulting in a subgenus having the formula:
• Another aspect of the disclosure relates to compounds wherein the index n is equal to 1.
• R is a halogen.
• Z units are chosen from 2- fluorophenyl, 3 -fluorophenyl, 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4- chlorophenyl, 2-bromophenyl, 3-bromophenyl, 4-bromophenyl, 2-iodophenyl, 3- iodophenyl, and 4-iodophenyl.
• Z is 4-chlorophenyl.
• R is chosen from one or more C1-C6 linear alkyl units.
• Non-limiting examples of this embodiment are Z units chosen from 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3- ethylphenyl, 4-ethylphenyl, 2-(n-propyl)phenyl, 3-(n-propyl)phenyl, 4-(n-propyl)phenyl, 2- (n-butyl)phenyl, 3-(n-butyl)phenyl, 4-(n-butyl)phenyl, 2-(n-pentyl)phenyl, 3-(n- pentyl)phenyl, 4-(n-pentyl)phenyl, 2-(n-hexyl)phenyl, 3-(n-hexyl)phenyl, and 4-(n- hexyl)phenyl.
• a further embodiment of this aspect relates to compounds wherein R is chosen from one or more C3-C6 branched alkyl units.
• Non-limiting examples of this embodiment are Z unis chosen from 2-(z ' so-propyl)phenyl, 3-(z ' sopropyl)phenyl, 4-(z ' so-propyl)phenyl, 2-(iso- butyl)phenyl, 3-( «o-butyl)phenyl, 4-(3 ⁇ 4o-butyl)phenyl, 2-(sec-butyl)phenyl, 3-(sec- butyl)phenyl, 4-(sec-butyl)phenyl, 2-(tert-butyl)phenyl, 3-(tert-butyl)phenyl, 4-(tert- butyl)phenyl, 2-( «o-pentyl)phenyl, 3-(z ' so-pentyl)phenyl, 4-(3 ⁇ 4o-pentyl)phenyl, 2-
• a still further embodiment of this aspect relates to compounds wherein R is chosen from one or more C1-C6 linear alkoxy units.
• Non-limiting examples of this embodiment are Z unis chosen from 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2- ethoxyphenyl, 3-ethoxyphenyl, 4-ethoxyphenyl, 2-(n-propoxy)phenyl, 3-(n- propoxy)phenyl, 4-(n-propoxy)phenyl, 2-(n-butoxy)phenyl, 3-(n-butoxy)phenyl, 4-(n- butoxy)phenyl, 2-(n-pentyloxy)phenyl, 3-(n-pentyloxy)phenyl, 4-(n-pentyloxy)phenyl, 2-(n- hexyloxy)phenyl, 3-(n-hexyloxy)phenyl, and 4-(n-hexyloxy)phenyl.
• a yet further embodiment of this aspect relates to compounds wherein R is chosen from one or more C3-C6 branched alkoxy units.
• Non-limiting examples of this embodiment are Z unis chosen from 2-(3 ⁇ 4o-propoxy)phenyl, 3-(zso-propoxy)phenyl, 4-(iso- propoxy)phenyl, 2-(zso-butoxy)phenyl, 3-(3 ⁇ 4o-butoxy)phenyl, 4-(zso-butoxy)phenyl, 2-(sec- butoxy)phenyl, 3-(sec-butoxy)phenyl, 4-(sec-butoxy)phenyl, 2-(tert-butoxy)phenyl, 3-(tert- butoxy)phenyl, 4-(tert-butoxy)phenyl, 2-(zsopentyloxy)phenyl, 3-(zsopentyloxy)phenyl, 4- (wo-pentyloxy)phenyl, 2-(z ' sohexyloxy)phenyl
• a further aspect of the disclosure relates to compounds wherein the index n is greater than 1.
• R is a halogen.
• Z units are chosen from 2,3-difluorophenyl, 2,4-difluorophenyl, 2,5-difluorophenyl, 2,6- difluorophenyl, 3,4-difluorophenyl, 3,5-difluorophenyl, 2,3,4-trifluorophenyl, 2,3,5- trifluorophenyl, 2,4,6-trifluorophenyl, 3,4,5-trifluorophenyl, 2,3,4,5-tetrafluorophenyl, 2,3,4,6-tetra-fluorophenyl, 2,3,4,5,6-pentafluorophenyl, 2,3-dichlorophenyl, 2,4- dichlorophenyl, 2,5-dichlorophenyl, 2,6-d
• R is a C1-C6 linear alkyl.
• Z units are chosen from 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethyl- phenyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, 2,3,4-trimethylphenyl, 2,3,5-trimethyl- phenyl, 2,4,6-trimethylphenyl, 3,4,5-trimethylphenyl, 2,3,4,5-tetramethylphenyl, 2,3,4,6- tetra-methylphenyl, 2,3,4,5,6-pentamethylphenyl, 2,3-diethylphenyl, 2,4-diethylphenyl, 2,5- diethylphenyl, 2,6-diethylphenyl, 3,4-diethylphenyl, 3,5-diethylphenyl, 2,3,4-tri
• a still further aspect of the disclosure relates to compounds wherein the index n is greater than 1 and wherein at least one R is chosen from C1-C6 linear, C3-C6 branched or C3- Ce cyclic alkyl and at least one R is chosen from halogen.
• a yet further aspect of the disclosure relates to compounds wherein the index n is greater than 1 and wherein at least one R is chosen from C1-C6 linear, C3-C6 branched or C3- Ce cyclic alkoxy and at least one R is chosen from halogen.
• a still yet further aspect of the disclosure relates to compounds wherein the index n is greater than 1 and wherein at least one R is chosen from C1-C6 linear, C3-C6 branched or C3-C6 cyclic alkyl and at least one R is chosen from C1-C6 linear, C3-C6 branched or C3-C6 cyclic alkoxy.
• R 1 units are C1-C4 linear or C3-C4 branched alkyl.
• C1-C4 linear alkyl units include methyl (Ci), ethyl (C 2 ), n-propyl (C3), and n-butyl (C 4 ).
• C3-C6 branched alkyl units include z ' so-propyl (C3), sec-butyl (C 4 ), iso- butyl (C 4 ) and tert-butyl (C 4 ).
• R 1 is tert-butyl
• R 1 is methyl
• R 1 is ethyl
• Step A relates to the benzylation of 3-hydroxypyridin-2(lH)-one (2,3-dihydroxy- pyridine) at the pyridin-2(lH)-one ring nitrogen with a benzylating agent having the formula:
• X is a leaving group.
• leaving groups include chloro, bromo, iodo, tosyl, mesyl and the like.
• R and the index n are defined herein above.
• step A is carried out under modified Silyl-Hilbert-Johnson conditions.
• the reaction depicted in Step A includes formation of di-silylated intermediate.
• This di-protected intermediate prevents undesired O-benzylation of the 3-hydroxy and 2-hydroxy units of the pyridine tautomeric form 3-hydroxypyridin-2(lH)-one by the benzylating agent A-l.
• the resulting bis-silyl protected intermediate has the formula: wherein P represents a silyl protecting group.
• Scheme II below summarizes a non-limiting example of Step A wherein two equivalents of hexamethyldisilazane are used to form intermediate A-i.
• Step A(i) relates to the addition of at least about 2 equivalents of a silylating reagent to form a bis-O-silyl intermediate or a least one equivalent of a silylating reagent that can provide two equivalents of a silyl protecting group to form an intermediate such as A-i as depicted in the example set forth in Scheme II.
• this intermediate can be formed by the reaction of bis(trimethylsilyl)amine (HMDS) with 3- hydroxypyridin-2(lH)-one.
• HMDS bis(trimethylsilyl)amine
• product A-ii is also not isolated.
• Aqueous work-up removes the silyl protecting groups allowing the pyridinium salt A-ii to collapse and tautomerize to the 3-hydroxy-pyridin-2(lH)-one form and thereby liberate N-benzyl-3-hydroxypyridin-2(lH)- ones having the formula A-2.
• Step A can be conducted with any a silylating reagent in an amount wherein the agent provides two or more equivalents of protecting group.
• the agent provides two or more equivalents of protecting group.
• one equivalent of hexamethyldisilazane provides two equivalents of a silyl protecting group.
• hexamethyldisilazane is used as the silylating reagent.
• Non-limiting examples of silylating reagents include trimethylsilyl chloride, tert-butyl dimethylsilyl chloride, trimethylsilylimidazole, N,0-bis(trimethylsilyl)acetamide, ⁇ , ⁇ '- bis(trimethylsilyl)urea, N,0-bis(trimethylsilyl)trifluoroacetamide, heptamethyldisilazane, l, l,3,3,-tetramethyl-l,3-divinyl-disilizane, and the like.
• Step A is conducted in the presence of a source of proton, i.e., a strong or weak protic acid as well as some salts of strong mineral acids.
• a source of proton i.e., a strong or weak protic acid as well as some salts of strong mineral acids.
• the acid is present in a catalytic amount.
• the source of proton is ammonium sulfate,
• the acid is hydroiodic, HI, or hydrobromic acid, HBr.
• the acid is phosphoric acid, H3PO4, or sulfuric acid, H2SO4.
• Step A can be conducted in the presence of any compatible solvent or mixture of compatible solvents.
• solvents includes acetonitrile,
• acetonitrile is used as the solvent.
• the reactant A-l is activated toward nucleophilic attack by 3-hydroxypyridin-2(lH)-one. This is accomplished by replacing the original leaving group X with a leaving group X 1 which is more labile to attack by the 3- hydroxypyridin-2(lH)-one nitrogen.
• an in situ Finkelstein reaction is used to activate the leaving group.
• a non-limiting example of the formation of an activated benzylating agent is depicted herein below in Scheme III.
• Step B relates to a Mannich Reaction between the N-benzyl-3-hydroxypyridin- 2(lH)-one formed in Step A and a 4-carbamoylpiperazine, B-1. Step B is depicted in Scheme IV below.
• Step B of the disclosed process involves the condensation of A-2 with B-1 in the presence of formaldehyde under standard Mannich Reaction conditions.
• the in situ generated imine of B-1 reacts with intermediate A-2 according to the proposed Scheme V herein below.
• Intermediate A-2 and adduct B-1 are combined together with a source of formaldehyde and a protic acid.
• the reaction can be conducted at room temperature or at any temperature at or below reflux depending upon the choice of an optional solvent.
• the reaction can be conducted in the presence of a compatible solvent.
• solvents include water, formic acid, acetic acid; alcohols, for example, methanol, ethanol, 2,2,2-trichlorethanol, propanol, isopropanol, butanol, tert-butanol, and the like; esters, for example, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, and the like; ethers, for example, diethyl ether, methyl tert-butyl ether, tetrahydrofuran, dimethoxyethane, bis(2-methoxyethyl) ether (diglyme), l,4-dioxane,and the like; alkanes, for example, pentane, isopentane, petroleum ether, hexane, mixtures of hexanes, cyclohexane, heptanes, is
• the solvent is an alcohol, for example, methanol, ethanol, n-propanol or z ' so-propanol.
• ethanol is used as a solvent.
• the formulator can choose different alcohols depending upon the desired temperature to which the reaction is heated, for example, the temperature of reflux.
• the source of formaldehyde is a 37% weight percent solution in water.
• Other reagents which form or release formaldehyde or a formaldehyde equivalent can be used.
• Hexamethyldisilazane (1 16.2 g, 0.72 mol, 2 equiv.) is added dropwise. The resulting suspension was heated to reflux for 4 hours. The solution was then cooled to room temperature followed by the addition of a solution of 4-chlorobenzyl chloride (63.8 g, 0.4 mol, 1.1 equiv.) in acetonitrile (40 mL, 1 part v/w). Potassium iodide (59.8 g, 0.36 mol, 1 equiv.) is then added. The solution was then brought to reflux for 16 hours. The solution was cooled to 5 °C and water (240 mL) was slowly added over 15 minutes.

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• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

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• 2015
  • 2015-02-18 CN CN201580020246.8A patent/CN106232120B/zh not_active Expired - Fee Related
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