Abstract: A process of preparing lactam derivatives of pilocarpine is disclosed. The process involves condensation of a dihydroxybutene and alkyl orthoester to form a lactone intermediate which is oxidized to trans-pilopic acid. This lactone ring is reacted with a benzylamine and the benzyl group removed with a novel dissolving metal reduction mixture to yield the key intermediate IV ##STR1## which can be elaborated to pilolactam through a known sequence of steps.

Abstract: The present invention relates to new carbonyl 3R, 4R-ethyl-[(1-methyl-1H-imidzaol-5-yl)methyl]-2-pyrrolidinone derivatives carrying a carboxyester-type lipophilic moiety on the pyrrolidinone nitrogenand are valuable antiglaucoma agents and targeted for use in the treatment of so-called dry eye.More particularly, the present invention concerns new N-substituted carbonyl-3R, 4R-ethyl-[(1-methyl-1H-imidazol-5-7)methyl]-2-pyrrolidinone derivatives of the formula (I): ##STR1## wherein R is selected from the group consisting of ##STR2## wherein R.sup.1 is a halo radical, e.g. a chloro radical, or a lower alkyl radical, e.g. a methyl or ethyl radical, with the proviso that when m is 1, R.sup.1 is not methyl or t-butyl, m is an integer of 1 or 2, n is 0 or an integer of 1 or 2 and X is O or S, and pharmaceutically-acceptable acid addition salts thereof.