4-Methylthio-7- thieno pyrimidine reactions

Thienopyrimidyl-2-thioacetamido)cephalosporanic acid derivatives 170 were prepared by reaction of the appropriate 7/3-chloroacetamidoceph-alosporanic acids 169 with the thieno[2,3-d]pyrimidine potassium salts 168 (87PHA160). The 4-methylthio group of quaternized thieno[2,3-d]pyrimi-dine 172 was displaced by the 3-aminomethyl group of cephalosporins 171 to afford cephalosporin derivatives 173 (89AUP584898). 

The reaction of the salt 308 with alkyl halides in base gave the corresponding 2-alkylthiothieno[3,4-d]pyrimidin-4(3//)-ones 369. Heating the latter with ammonia or amines afforded 2-amino(or substituted amino)thieno[3,4-d]pyrimidin-4(3//)-ones 370 (90EUP404356). When 2-methylthiothieno[3,4-d]pyrimidin-4(3//)-one 360 was heated with o-tolu-idine at 200°C, displacement of the 2-methylthio group afforded compound 372 (91MIP1). 

---