3-(Substituted phenyl) imidazolidine-2-thiones (SPITs) and related compounds were synthesized by cyclizing monoethanolamine hydrogen sulfate with arylisothiocyanates in the presence of sodium hydroxide. The activity for stimulating adenylate cyclase prepared from thoracic nerve cords of the American cockroach, Periplaneta americana L., was examined with these compounds. A SPIT with a 2, 6-diethylphenyl group (48) was the only full ...