Synthesis of 2-methylene-2,3-dihydro-and 2-methyl-5H-thiazolo[3.2-a]thieno[2.3-d]pyrimidines

Article abstract of DOI:10.1007/BF00912986

The title substances and their [1]benzothieno analogues were synthesized by reaction of 3-allyl-2-mercapto-([1]benzo)thieno-[2.3-d]pyrimidine-4(3 H)-ones with Br₂ to 2-bromomethyl-2.3-dihydro-thiazolo[3.2-a]([1]benzo-)thieno[2.3-d]pyrimidine-5-ones, which on treatment with morpholine did not give the corresponding morpholine derivatives but elimination to the exocyclic double bond. These 2-methylene-2.3-dihydro-products were isomerized by H₂SO₄ to the corresponding 2-methyl compounds.