Diastereomeric 4,4-di:substd.-2-imidazolin-5-one derivs. - prepd. by asymmetric induction, intermediates for optically pure aminoacid(s) such as methyl-DOPA

摘要

Imidazoline-5-one derivs. of formula (I) are new: R1 is the optical active residue of a primary amine or aminoacid. R2 is H, 1-4C alkyl, benzyl or phenyl. R3 is 1-4C alkyl (opt. substd. by alkoxy, alkylthio or dialkyamino (all 1-4C alkyl), benzyloxy, benzylthio, 1-4C acyloxy, CN, 2-5C carbalkoxy, benzoyl or phenyl (the rings opt. substd. by 103 halo, NO2, 1-4C alkyl, alkoxy, or alkylthio, benzyloxy, 1-4C acyloxy or acylamino, or by one phenoxy (itself opt. substd by 1-4C alkoxy or acyloxy), CF3 or methylenedioxy), or R3 is allyl or phenyl. R4 is 1-6C alkyl opt. substd. by alkoxy, alkylthio or dialkylamino (all 1-4C alkyl), piperidino, pyrrolidino, benzyloxy, benzylthio, CN, 2-5C carbalkoxy, benzoyl or phenyl (both opt. substd. as for corresp. gps. R3), or R4 is ClCH2 or allyl. Q is pyridyl, furyl, thienyl, naphthyl, benzothienyl or bromobenzofuran. Where R3 and R4 are different, (I) are intermediates (by conventional hydrolysis) for optically active alpha-e ethyl-arylalanines, e.g. alpha-methyl-dopa (an antihypertensive) and alpha-methyltyrosine (a tranquilliser). (I) are prepd. by alkylation of corresp. cpds. (I) where R4 is H alkylation at the 4-posn. proceeds with nearly 100% asymmetric induction (the nature of R1 determines the configuration at this position) and practically no O-alkylation occurs. In an example, 1-L-alpha-phenylethyl-4-methyl-4-benzyl-2-imidazoline-5-one was prepd. from the L-alpha-phenylethylamide of alpha-isocyanopropionic acid/n-BuLi and benzyl bromide.