New anticancer agents: chiral isomers of ethyl 5-amino-1,2-dihydro-2-methyl-3-phenylpyrido[3,4-b]pyrazine-7-car bamate .

Racemic ethyl 5-amino-1,2-dihydro-2-methyl-3-phenylpyrido[3,4-b]pyrazine-7- carbamate (1a) has shown antitumor activity in a variety of in vivo experiments. The preparation of the R and S isomers gave compounds with significant differences in potency in several biological tests.