AN IMPROVED PROCESS FOR THE PREPARATION OF ARMODAFINIL

摘要

The invention encompasses processes for preparing intermediates, such as (R)-modafinic acid and its C_1-2 alkyl ester, and the conversion of the intermediates into armodafinil. In particular, the invention concerns: (i) a process for the optical resolution of modafinic acid with (R)-a-naphthylethylamine and its conversion into armodafinil; (ii) (R)-modafinic acid containing less than 2% area by HPLC of (S)-modifinic acid; (iii) a process for the preparation of C_1-2 alkyl ester of (R)-modafinic acid from (R)-modafinic acid by reaction with methanol or ethanol in the presence of at least one acidic reagent and its conversion into armodafinil; (iv) armodafinil with less than 0.5% area by HPLC of (S)-modafinil entantiomer, a pharmaceutical composition containing it and process for the preparation of this composition; (v) armodafinil with less than 0.1% area by HPLC of modafinic acid, a pharmaceutical composition containing it and process for the preparation of this composition; (vi) a process for the reduction of modafinic acid content in armodafjnil by contacting a solution with activated basic or neutral alumina; (vii) armodafinil with less than 0.2% area by HPLC of bis(diphenylmethyl) disulphide (R-MDF-DS), a pharmaceutical composition containing it and process for the preparation of this composition; (viii) a process for the preparation of R-MDF-DS from diphenylmethanethiol acetate; and (ix) a process for the reduction of R-MDF-DS content in armodafinil by suspending it in a C_5-10 hydrocarbon.