反应详情

To 79.6 parts of 2,3-dihydro-6-(2-hydroxyethyl)-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one were added dropwise successively 95 parts of acetic acid and 303 parts of a hydrobromic acid solution 30% in acetic acid at a temperature below 45° C. Upon completion, the whole was heated to reflux and stirring was continued for 17.25 hours at reflux temperature. The reaction mixture was cooled to room temperature. The precipitated product was filtered off and stirred in 152 parts of 2-propanol. The product was filtered off, washed with 40 parts of 2-propanol, dried in vacuo at 50° C. and recrystallized from methanol, yielding 102.3 parts of 6-(2-bromoethyl)-2,3-dihydro-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one monohydrobromide; mp. 237.2° C. (intermediate 4).

1. temperatureUpon completion, the whole was heated
2. temperatureto reflux
3. temperatureat reflux temperature
4. filtrationThe precipitated product was filtered off
5. stirringstirred in 152 parts of 2-propanol
6. filtrationThe product was filtered off
7. washwashed with 40 parts of 2-propanol
8. customdried in vacuo at 50° C.
9. customrecrystallized from methanol