A total of 93 kinds of compound were synthesized in order to clarify the relationship between the chemical structure of phenylthiourea derivatives and their antibacterial action against human-type tubercle bacilli H37Rv.
1) Carboxyl group introduced into the benzene ring, irrespective of their position of ortho, meta, or para, does not show any antibacterial activity.
2) Esteriflcation of the carboxyl group introduced into the benzene ring showed no antibacterial action when a substituent is in the ortho-position, when R in R-NH-CSNH COOEt is an aryl, but showed antibacterial action when the substituent is in the para-position and when R is an alkyl group, although no great difference in the antibacterial action was observed with increasing number of carbon atoms in the alkyl group from 3, 4, to 6.
3) Thiocarbanilide with substituents in para- and para-prime positions showed antibacterial activity, while those with substituents in the two ortho or ortho and meta-prime positions had no such activity. Although the number of compounds examined was small, those with substituents in ortho and para-prime, two meta positions, or meta and para-prime positions seem to acquire antibacterial activity.
4) Some of the compounds of R-NHCSNH- show antibacterial activity according to the kind and position of the substituent R′, although no great difference was found by the change of carbon number from 3, 4, to 6 in the alkyl group R.
5) Phenylthiourea derivatives have no cross-resistance with INAH, PAS, or streptomycin.
