Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D405/00—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom
  • C07D405/02—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom containing two hetero rings
  • C07D405/04—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom containing two hetero rings directly linked by a ring-member-to-ring-member bond
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P43/00—Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/10—Drugs for disorders of the cardiovascular system for treating ischaemic or atherosclerotic diseases, e.g. antianginal drugs, coronary vasodilators, drugs for myocardial infarction, retinopathy, cerebrovascula insufficiency, renal arteriosclerosis
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
  • C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
  • C07D233/66—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members 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
  • C07D233/84—Sulfur atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
  • C07D311/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings ortho- or peri-condensed with carbocyclic rings or ring systems
  • C07D311/04—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D487/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00
  • C07D487/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00 in which the condensed system contains two hetero rings
  • C07D487/04—Ortho-condensed systems

Definitions

• the present invention relates to an improved catalytic process for asymmetric hydrogenation.
• the present invention relates to a process for preparing intermediates useful in the synthesis of peripherally-selective inhibitors of dopamine- ⁇ - hydroxylase (D ⁇ H), the process involving catalytic asymmetric hydrogenation.
• D ⁇ H dopamine- ⁇ - hydroxylase
• (R)-6,8-difluorochroman-3-ylamine (compound Q) is a key intermediate in the synthesis of compound P.
• the stereochemistry at the carbon atom to which the amine is attached gives rise to the stereochemistry of compound P, so it is advantageous that compound Q is present in as pure a form as possible.
• the R enantiomer of compound Q should be in predominance, with little or no S enantiomer present.
• the process for preparing compound Q will advantageously produce compound Q with as high an enantiomeric excess (e.e) as possible.
• X is CUi, oxygen or sulphur
• Ri, R. and R3 are the same or different and signify hydrogens, halogens, alkyl, alkyloxy, hydroxy, nitro, alkylcarbonylamino, alkylamino or dialkylamino group
• R4 is alkyl or aryl, wherein: the term alkyl means hydrocarbon chains, straight or branched, containing from one to six carbon atoms, optionally substituted by aryl, alkoxy, halogen, alkoxycarbonyl or hydroxycarbonyl groups; the term aryl means a phenyl or naphthyl group, optionally substituted by alkyloxy, halogen or nitro group; and the term halogen means fluorine, chlorine, bromine or iodine.
• Compound B may be referred to as an ene-carbamate.
• the chiral catalyst comprises a ligand which is the S or R enantiomer of ToIBINAP and the reaction is carried out at a temperature from above 7O 0 C to 100 0 C and in the presence of an acid at a concentration of 0.05 to 0.2% .
• X is O.
• at least one of Ri, R2 and R3 is fluorine.
• compound A has the following formula:
• R4 is Ci to C4 alkyl.
• R4 is methyl (i.e. the methyl- substituted ene-carbamate), ethyl (i.e. the ethyl-substituted ene-carbamate) or tBu (i.e. the tBu-substituted ene-carbamate).
• R4 is methyl.
• R4 is benzyl (i.e. the benzyl-substituted ene-carbamate).
• the chiral catalyst preferably comprises a transition metal complex comprising the ToIBINAP ligand.
• the catalyst has the formula [(TolBINAP)Ru(arene)X']Y,
• R-ToIBINAP The preferrred ToIBINAP ligand to be used in the asymmetric hydrogenation of the present invention is designated R-ToIBINAP herein, and is shown in the structure below:
• the preferred catalyst has the formula:
• the most preferred catalysts are:
• [RuCl(R)-TolBINAP(p-cymene)]Cl can be prepared from (R)-ToIBINAP and dicMoro-(p-cymene)-ruthenium (H) dimer.
• [RUCI(R)-TOIBINAP(C 6 H 6 )ICI can be prepared from [Ru(C 6 H 6 )Ch] 2 and (R)- ToIBINAP in a 1:1 ethanol-dichloromethane mixture.
• Ru((R)-TolBINAP)Br2 can be prepared from from Ru(2-methylallyl)2COD, (R)-
• the catalyst is produced in situ i.e. the catalyst is not isolated prior to the hydrogenation reaction but is formed from its precursor ligands in the reaction pot.
• the hydrogenation is preferably carried out in the presence of an acid.
• the acid is HBF 4 , HCl, HBr, CF3SO3H, CHsCOOH or HsPO 4 .
• the acid is HaPO 4 at a concentration of 0.05% to 0.2%, preferably 0.1% .
• a concentration of 0.1% means that the weight of phosphoric acid in the mixture is equal to 0.1 % of the weight of methanol (i.e. 0.1 % w/w).
• the acid is present in a solvent.
• the acid solvent is water.
• the acid is HsPO 4 and the solvent is an inert solvent(s) such as water.
• the acid/solvent solution is 85% HsPO 4 in water.
• the compound B/acid molar ratio ranges from 20/1 to 70/1.
• the compound B/acid molar ratio ranges from 31/1 to 64/1.
• the compound B/acid molar ratio ranges from 50/1 to 64/1. More preferably, the compound B/acid molar ratio is 64/1.
• the improvements in the process according to the invention make it possible to obtain acceptable conversion and e.e. using a molar ratio of compound B/catalyst of 100/1 up to 2000/1.
• the molar ratio is 250/1 or greater, more preferably, 500/1 or greater, still more preferably 750/1 or greater.
• the molar ratio is most preferably in the range 1000/1, or greater, for example about 2000/1.
• the hydrogenation may be carried out in the presence of a solvent.
• the hydrogenation solvent is selected from a substituted or unsubstituted straight- or branched- chain Ci to Ce alcohol, an arene or mixtures thereof.
• the solvent is selected from MeOH, EtOH, 1 PrOH, 1-PrOH, 1-BuOH, 2-BuOH, CF3CH2OH, DCM (dichloromethane), DCE (dichloroethane), THF (tetrahydrofuran), toluene or a 1:1 mixture of MeOH and DCM.
• the hydrogenation takes place in a pre- distilled methanol solvent.
• the methanol is distilled before the catalyst is added to the hydrogenation reaction mass.
• the distillation may take place under a slow stream of an inert gas. It is thought that the distillation of the methanol, rather than degassing of the methanol, removes oxygen from the reaction vessel.
• the hydrogenation may be carried out at a temperature ranging from above 70° C to 100 0 C.
• the hydrogenation is carried out at a temperature ranging from 75° C to 90° C, more preferably at a temperature ranging from 75 0 C to 85 0 C, and most preferably at a temperature of about 80 0 C.
• these particular temperature ranges are important for obtaining high yield and e.e.
• the hydrogenation may be carried out at a pressure ranging from 10 bars to 30 bars.
• the hydrogenation is carried out at a pressure ranging from 20 bars to 30 bars.
• the hydrogenation is carried out at a pressure of 30 bars.
• the catalyst is formed in-situ. This means that the catalyst is formed from its ligands and is used in the process to convert compound B to compound A without an intervening purification step. Formation of the catalyst in DCM/EtOH has been found to provide a catalyst which produces the best conversion and e.e.
• the process further comprises subsequently recrystallising the compound of formula A.
• the recrystallisation may be carried out in a DCM/hexane mixture, in a particularly advantageous aspect of the invention, the recrystallisation is carried out in a 2-propanol/water mixture.
• recrystallisation in a 2-propanol/water mixture makes it possible to produce the product in a higher yield and with a higher e.e.
• the recrystallisation results in an e.e. ranging from 95 to 100%, preferably from 97 to 100% , more preferably from 99 to 100% .
• the 2-propanol/water mixture preferably comprises 40-50 vol% 2-propanol and 50- 60 vol% water, most preferably 45 vol% 2-propanol and 55 vol% water.
• the compound of formula A is preferably refluxed with the solvent, then cooled to 25-35 0 C, preferably 3O 0 C, then cooled to approximately 5-10 0 C, preferably 5 0 C.
• the suspension may be filtered and the filter cake washed with a suitable solvent, for example a mixture of 2- ⁇ ropanol/water. This washing step is advantageous in achieving high optical purity.
• compound A is in the form of the S enantiomer. In an alternative embodiment, compound A is in the form of the R enantiomer.
• the process further comprises converting the R or S enantiomer of compound A to the respective R or S enantiomer of a compound of formula C, or a salt thereof
• X is CH2, oxygen or sulphur; Ri, Rz and Rs are the same or different and signify hydrogens, halogens, alkyl, alkyloxy, hydroxy, nitro, alkylcarbonylamino, alkylamino or dialkylamino group; and R4 is alkyl or aryl, wherein: the term alkyl means hydrocarbon chains, straight or branched, containing from one to six carbon atoms, optionally substituted by aryl, alkoxy, halogen, alkoxycarbonyl or hydroxycarbonyl groups; the term aryl means a phenyl or naphthyl group, optionally substituted by alkyloxy, halogen or nitro group; and the term halogen means fluorine, chlorine, bromine or iodine.
• X is O.
• at least one of Ri, R> and R3 is fluorine.
• the compound of formula C is:
• the R or S enantiomer of compound A is converted to the respective R or S enantiomer of the compound of formula C by hydrolysis.
• Hydrolysis may be carried out using 40% potassium hydroxide in methanol, followed by isolation of the crude amine and crystallisation of the amine as a salt with L-tartaric acid.
• the process further comprises reacting the R or S enantiomer of the compound of formula C, or a salt thereof, to produce the respective R or S enantiomer of a compound of formula E or a salt thereof.
• X is CEb, oxygen or sulphur
• Ri, R2 and Rs are the same or different and signify hydrogens, halogens, alkyl, alkyloxy, hydroxy, nitro, alkylcarbonylamino, alkylamino or dialkylamino group
• R12 signifies hydrogen, alkyl or alkylaryl group, wherein: the term alkyl means hydrocarbon chains, straight or branched, containing from one to six carbon atoms, optionally substituted by aryl, alkoxy, halogen, alkoxycarbonyl or hydroxycarbonyl groups; the term aryl means a phenyl or naphthyl group, optionally substituted by alkyloxy, halogen or nitro group; and the term halogen means fluorine, chlorine, bromine or iodine.
• X is O.
• at least one of Ri, R2 and R3 is fluorine.
• the compound C can be converted to the compound E by using the compound C as an amino component to build the N(I) moiety of the substituted imidazole-2- thione ring of compound E. More specifically, the amino group on the compound C may be converted to a 5-substituted imidazole-2-thione ring, and the group substituted at the 5 position may be converted to the group -(CHz) n -NHRu. In one embodiment, the R or S enantiomer of the compound of formula C, or a salt thereof, is reacted with a compound of formula Dl
• Ri, R. and R3 are the same or different and signify hydrogens, halogens, alkyl, alkyloxy, hydroxy, nitro, alkylcarbonylamino, alkylamino or dialkylamino group;
• X is O, S or CH2;
• n signifies 1, 2 or 3;
• R12 signifies hydrogen, alkyl or alkylaryl group,
• Rn signifies a hydroxyl protecting group and
• R13 signifies an amino protecting group, or Rn is defined as above but R12 and R13 taken together represent a phthalimido group; with a water soluble thiocyanate salt in the presence of an organic acid in a substantially inert solvent, followed by subsequent deprotection of the intermediate products F to I:
• the water soluble thiocyanate salt is an alkali metal thiocyanate salt or a tetraalkylammonium thiocyanate salt.
• the solvent is an organic solvent. Further details e.g. suitable reaction conditions may be found in WO2004/033447.
• X is O. In another embodiment, n is 2 or 3. Preferably X is O and n is 2 or 3. In a further embodiment, at least one of Ri, R2 and R3 is fluorine.
• the product of the reaction of the R or S enantiomer of the compound of formula C and the compound of formula D is fSj-5-(2-aminoethyl)-l-(l,2,3,4-tetrahydronaphthalen- 2-yl)- 1 , 3-dihydroimidazole-2-thione; (S)-5-(2-arninoethyl)- 1-(5 ,7-difluoro- 1,2,3,4- tetrahydronaphthaIen-2-yl)-l,3-dihydroimidazole-2-thione; f/?j-5-(2-aminoethyl)-l-chroman- 3-yl-l ,3-dihydroimidazole-2-
• the product of the reaction of the R or S enantiomer of the compound of formula C and the compound of formula D may also be a salt of (5j-5-(2-aminoethyl)-l-(l, 2,3,4- tetrahydronaphthalen-2-yl)-l,3-dihydroimidazole-2-thione; ( ' 5)-5-(2-aminoethyl)-l-(5,7- difluoro-l,2,3,4-tetrahydronaphthalen-2-yl)-l,3-dihydroimidazole-2-thione; (R)-5-(2- aminoethyl)-l-chroman-3-yl-l,3-dihydroimidazole-2-thione; (R)-5-(2-aminoethyl)-l-(6- hydroxychroman-3-yl)- 1 ,3-dihydroimidazole-2-thione; (K)-5-(2-amin
• EtOH was the most promising and was repeated 3 times to demonstrate reproducibility. All experiments gave 100% conversion and 89-89.4% ee.
• the substrate (50 g, 207 mmol) ( ⁇ . ⁇ -difluoro ⁇ H-clnomen-S-yOcarbamic acid methyl ester) and MeOH (400 ml, not distilled) were charged in a 500 mL stainless steel autoclave, the autoclave was sealed and 40 ml of methanol was distilled off via the outlet tube with magnetic stirring. The outlet was closed without removal of the heating, the hydrogen pressure (7 bar) was applied and the solution was allowed to cool down to 25 0 C with stirring. 1 % (w/w) H3PO4 in MeOH (40 ml, prepared from 85% aq H3PO4) was added via syringe with slow stream of hydrogen.
• the solution was degassed 5 times by applying and releasing the hydrogen pressure (20 bar) with stirring at 20-25 0 C and the catalyst solution was added via syringe with a slow stream of hydrogen.
• the autoclave was closed, charged with hydrogen (30 bar) and heated at 8O 0 C (internal, thermocouple) with magnetic stirring for 20 h.
• the pressure was released after cooling to 20-25 0 C, 0,025 mL of the solution was diluted to 10 mL, the resulting solution was analysed directly by chiral HPLC.

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• 2009
  • 2009-05-05 AR ARP090101613A patent/AR071632A1/es unknown
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