Folate antagonists. 6. Synthesis and antimalarial effects of fused 2,4‐diaminothieno[2,3‐d]pyrimidines

Abstract
2,4‐Diamino‐5,7‐dihydro‐6H‐thiopyrano[4′,3′:4,5]thieno[2,3‐d]pyrirnidine, 2,4‐diamino‐9H‐mdeno[1′,2′:4,5]thieno[2,3‐d]pyrimidine, 2,4‐diamino‐5H‐indeno[2′,1′:4,5]thieno[2,3‐d]pyrimidine, 9,11‐diamino‐5,6‐dihydronaphtho[1′,2′:4,5]thieno[2,3‐d]pyrimidine, 7,9‐diamino‐5,6‐dihydronaphtho[2′,1′:4,5]thieno[2,3‐d]pyrimidine, 2,4‐diamino‐7‐benzy]‐5,6,7,8‐tetrahydropyrido[4′,3′:4,5]thieno[2,3‐d]pyrimidine, and various 2,4‐diamino‐5,6,7,8‐tetrahydro‐[1]benzothieno[2,3‐d]pyrimidines were synthesized by cyclization of the requisite fused 2‐aminothio‐phenene‐3‐carbonitriles utilizing chloroformamidine hydrochloride in diglyme. Several compounds exhibited strong inhibitory effects againstStreptococcus faecalis(MGH‐2),Staphylococcus aureus(UC‐76),Streptococcus faecium(ATCC 8043),Lactobacillus casei(ATCC 7469), andPediococcus cerevisiae(ATCC 8081)in vitro, and three compounds displayed antimalarial activity againstPlasmodium bergheiin mice andP. falciparum(Uganda I)in vitro.