反应详情

A mixture of 20 parts of 3,4-dihydro-7-(2-hydroxyethyl)-8-methyl-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, 50 parts of acetic acid and 180 parts of a hydrobromic acid solution 67% in acetic acid was stirred and heated to reflux. Stirring was continued overnight at reflux temperature. The reaction mixture was evaporated and the solid residue was triturated in 2-propanone. The product was filtered off and dried, yielding 24 parts (100%) of 7-(2-bromoethyl)-3,4-dihydro-8-methyl-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one monohydrobromide; mp. 215° C. (intermediate 10).

1. temperatureheated to reflux
2. stirringStirring
3. temperatureat reflux temperature
4. customThe reaction mixture was evaporated
5. customthe solid residue was triturated in 2-propanone
6. filtrationThe product was filtered off
7. customdried