抄録
Tammet al., Folkerset al. (1951, 1953) examined extensively an antiinfluenza virus action of 2-substituted benzimidazole derivatives and reported a marked effect of isopropyl and n-butyl derivatives among 2-alkylsubstituted benzimidazole. They did not report the effect of the higher alkyl substitution. They considered at first these substances as an antimetabolite against vitamin B12 (N-α-D-ribofuranoside) and finally reported that 5, 6-dichloro-N-β-ribo-furanoside was the most effective (Tammet al., 1954, 1956) . Allfreyet al. (1957) described that this substance was an antimetabolite of RNA inhibiting a labelled amino acid incorporation into the nucleus of calf thymus tissue.
Antitumor effect of benzimidazole is not so marked (Skipperet al., 1950; Bieseleet al., 1951; Mantegazzaet al., 1951; Flintet al., 1953) . However, we intended to synthesize the derivatives of benzimidazole which can possibly be a purine antimetabolite. Therefore, we did not consider 5, 6- but 4, 6-substituted derivatives and N-β-riboside instead of α-riboside aiming at the adenosine and guanosine which contain N-β-riboside.
The present paper deals with the results testing the antitumor effect of 2-substituted benzimidazole and of its 6-nitro derivatives newly synthesized by us. Nucleosides analogues are now being synthesized.
