Farmitalia Carlo Erba

Franco Dallatomasina

Pietro Giardino

Ernesto Oppici

Stefano Cambiaghi

Pietro Cesti

Franco Francalanci

Marco Foa'

Marcello Marchi

Maria Altamura

Roberto Ortica

Enzo Murador

Gaspare Spreafico

A process for preparing a compound of formula I: ##STR1## wherein R.sub.1 represents a hydroxy protecting group and R.sub.2 represents a carboxy protecting group, which comprises:

Process for preparing penems

The invention describes a process for preparing peptides. More particularly, a process for preparing L-.alpha.-aspartyl-L-phenylalanine C.sub.1 -C.sub.4 lower alkyl ester is described and claimed by enzymatic hydrolysis of a suitable N-acyl-derivative.

Process for preparing peptides

A process for the preparation of the N-L-.alpha.-aspartyl-L-phenylalanine 1-methyl ester (aspartame) which is characterized by adding phosphoric acid and a lower alkyl alcohol to the reaction mixture containing N-formyl .alpha.-L-aspartyl- and .beta.-L-aspartyl-L-phenyl-alanine methyl ester and only one of the resultant deformylated isomers, i.e. aspartame phosphate precipitates. The .alpha.-isomer phosphate is collected by filtration and converted to free aspartame by treatment with a base.

Aspartame synthesis

A process for deformylation and separation of N-formyl-L- .alpha.-aspartyl-L-phenylalanine methyl ester from a mixture containing both .alpha. and .beta. isomers thereof, which comprises admixing with said isomeric mixture hydrogen peroxide and an organic acid.

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Segrate, Italy

Franco Dallatomasina