the n o protected optically active ketomethylene pseudopeptide derivatives are analyzed by optically active gas chromatography for optical purity a solution of the racemic ketomethylene pseudopeptide derivative in dichloromethane is separated into the two enantiomers by a 25 meter chirasil val iii capillary column with flame ionization detection after conditions for separation of the two enantiomers are established each optically active hydrogenation product is evaluated for the extent of optical purity generally the compound of the formula ii or ii 1 are prepared by the method shown in scheme 2 str7 the conditions of the treatment of formula iii or iii 1 by tertiary butyl hypochlorite are at a temperature of 0 c 50 u00b0 c in an inert solvent such as dichloromethane chloroform acetonitrile and the like the product of this treatment is then further treated with 1 4 diazabicyclo 2 2 21octane dabco at a temperature of 0 u00b0 c 50 u00b0 c in an inert solvent such as dichloromethane tetrahydrofuran chloroform acetonitrile and the like compounds of the formula iii or iii 1 are prepared by methods known in the art or by methods analogous to those known in the art from starting material which are known or which can be prepared by known methods variations in these conditions and evaluations for different compounds within the definitions of the formula i or i 1 are within the skill of an ordinarily skilled artisan the general procedure for removal of a protecting group such as the tert butyl ester is as follows a sample of the product i and i 1 is dissolved in dichloromethane and treated with an equal volume amount of trifluoroacetic acid at 0 u00b0 c the solution is allowed to warm to room temperature and the.