Abstract: A process is provided for preparing (trans)-4-phenyl-DL-proline derivatives, which are useful in preparing certain angiotensin converting enzyme inhibitors, which process involves reacting an ester of the structure ##STR1## wherein X is a leaving group such as tosylate, R.sup.3 is lower alkyl, R is cyclohexyl, phenyl or substituted phenyl, and R.sup.1a is a protecting group, with a potassium amide base such as potassium hexamethyldisilazide under reduced temperatures to form the trans-4-substituted proline ester derivative of the structure ##STR2## then hydrolyzing the proline ester to the acid of the structure ##STR3## and removing the R.sup.

Abstract: Methyl-D-ribofuranoside is p-nitrobenzoylated to yield crystalline methyl 2,3,5-tri-O-(p-nitrobenzoyl)-.beta.-D-ribofuranoside which can be used to prepare a stable, crystalline 2,3,5-tri-O-(p-nitrobenzoyl)-.beta.-D-ribofuranosyl bromide which in turn is useful as a precursor of natural or synthetic purine and pyrimidine nucleosides, as well as of glycosides. This bromide can also be cyanated to yield crystalline 2,5-anhydro-3,4,6-tri-O-(p-nitrobenzoyl)-D-allononitrile which in turn can be hydrolyzed and subsequently reacted with polyamino pyrimidines to yield nucleoside analogs such as 8-.beta.-D-ribofuranosyl adenine. This bromide also can by hydrolyzed to yield crystalline 2,3,5-tri-O-(p-nitrobenzoyl)-D-ribofuranose which in turn can be p-nitrobenzolated to yield crystalline 1,2,3,5-tetra-O-(p-nitrobenzoyl)-.beta.-D-ribofuranose. This latter compound can be brominated to produce an alphabromide derivative which is useful as a precursor of nucleosides.

Abstract: An improved method of 3-O-demethylating fortimicin B or a 4-N-alkylfortimicin B derivative comprising the steps of reacting fortimicin B with lithium in the presence of ethylenediamine and thereafter isolating 3-O-demethylfortimicin B from the reaction mixture.