Abstract: The present invention provides a new and efficient process for the preparation of the dexmethylphenidate hydrochloride with high optical purity, the process comprising: (a) reacting a solution of threo-N-Boc-ritalinic acid with (S)-1-phenylethylamine, separating precipitated solid salt of (R,R)-enriched N-Boc-ritalinic acid with (S)-1-phenylethylamnine from the reaction mixture and recrystallizing, reslurring and/or trituring of said salt; (b) mixing the solid salt of (R,R)-N-Boc-ritalinic acid and (S)-1-phenylethylamine obtained in step (a) with aqueous acid and separating (R,R)-N-Boc-ritalinic acid from the mixture; and (c) reacting the (R,R)-N-Boc-ritalinic acid prepared in step (b) with hydrogen chloride and methanol to give dexmethylphenidate hydrochloride with optical purity of at least 99% ee. The present invention further provides salt of (R,R)-N-Boc-ritalinic acid with (S)-1-phenylethylamine as new intermediate in the preparation of dexmethylphenidate hydrochloride.

Abstract: The present invention provides a process for the preparation of threo-methylphenidate hydrochloride. According to a preferred embodiment, the process comprises the following steps: (a) contacting 1-(phenylglyoxylyl)piperidine arenesulfonylhydrazone of the formula wherein Ar denotes an aryl group, where the aryl group may be substituted by a C1–C6 alkyl, halo or nitro group; with an inorganic base in the presence of a water immiscible organic solvent and a phase transfer catalyst to obtain (R*,R*)-enriched 7-phenyl-1-azabicyclo [4.2.0]octan-8-one of the formula: (b) reacting the (R*,R*)-enriched 7-phenyl-1-azabicyclo[4.2.0]octan-8-one prepared in step (a) with a solution of hydrogen chloride in methanol to obtain threo-enriched methylphenidate hydrochloride; (c) crystallizing the threo-enriched methylphenidate hydrochloride prepared in step (b) to give the desired threo-methylphenidate hydrochloride.

Abstract: The present invention provides a novel process for the preparation of alkyl (1-alkylindol-3-ylmethyl)benzoate derivatives which process comprises the steps of: (a) reacting of an alkyl (halomethyl)benzoate with excess of an indole, said indole being unsubstituted at positions 1-, 2- and 3-, under conditions promoting alkylation at the 3-position of the indole to yield a mixture comprising alkyl (indol-3-ylmethyl)benzoate and unreacted starting indole, (b) treating the mixture obtained in step (a) with base to yield a mixture, comprising the salt of (indol-3-ylmethyl)benzoic acid and the unreacted indole, (c) recovering the unreacted indole from the mixture obtained in step (b), and recycling the indole as starting material to step (a), (d) isolating the salt of (indol-3-ylmethyl)benzoic acid and/or acidifying the salt to form (indol-3-ylmethyl)benzoic acid, (e) reacting the (indol-3-ylmethyl)benzoic acid or it's salt with alkylating agent in the presence of base to form the desired alkyl (1-alkylindol-3-ylmet

Abstract: The present invention provides a new and efficient process for the preparation of the dexmethylphenidate hydrochloride with high optical purity, the process comprising:

Abstract: The present invention provides a process for the preparation of threo-methylphenidate hydrochloride.

Abstract: A novel, crystalline ethanolate solvate form of zafirlukast is disclosed as well as methods for preparing it. Pharmaceutical compositions containing this novel form of zafirlukast are also disclosed. The compositions are useful in the treatment of diseases in which leukotrienes are implicated for example in the treatment of asthma.