Methotrexate analogs. 12. Synthesis and biological properties of some aza homologs

Abstract
Methotrexate analogs, in which an additional N atom is inserted between the phenyl ring and the carbonyl group of the side chain were prepared by photochemical methods. The compounds were less inhibitory toward dihydrofolate reductase and thymidylate synthetase derived from Lactobacillus casei than was methotrexate. They were less cytotoxic against human lymphoblastic leukemia cells (CCRF-CEM). In vivo against L-1210 leukemia in mice the aza homolog of methotrexate showed significant antitumor activity (% ILS [100 times median survival time treated per median survival time control minus 1] = 55%) compared to methotrexate (%ILS = 88%).