Reactions of Pyrimidine-2-sulfenyl Chloride with Alkylvinyl and Allyl Ethers

The regioselective synthesis of novel thiazolo[3,2-a]pyrimidine derivatives in 52–92% yields was developed based on the reaction of pyrimidine-2-sulfenyl chloride with unsaturated ethers. The reaction with allylic and vinylic ethers proceed regioselectively, but with the opposite regiochemistry. The reaction with allylic ethers lead to 2-substituted thiazolo[3,2-a]pyrimidine derivatives whereas 3-organyloxy derivatives are formed in the reaction with vinylic ethers.