Hydrogen Bromide → 6-(2-bromoethyl)-2,3,7-trimethyl-5H-thiazolo[3,2-a]pyrimidin-5-one monohydrobromide

Participants

Reaction Conditions

Reaction Steps

A mixture of 30 parts of 4-hydroxy-2-mercapto-6-methyl-5-pyrimidineethanol, 6.8 parts of sodium hydroxide, 15 parts of sodium hydrogen carbonate and 100 parts of 2-propanone was stirred at room temperature and there were added 180 parts of tetrahydrofuran and 170 parts of water. Then there were added at once 25 parts of 3-chloro-2-butanone and 0.2 parts of N,N,N-triethylbenzenemethanaminium chloride and the whole was stirred and heated for 1 hour at 60° C. Stirring was continued overnight at room temperature. The reaction mixture was filtered and the filtrate was salted out. The organic phase was separated, dried, filtered and evaporated, yielding 36 parts of 5-(2-hydroxyethyl)-6-methyl-2-[(1-methyl-2-oxopropyl)thio]-4(3H)-pyrimidinone as an oily residue (intermediate 6). A mixture of 36 parts of 5-(2-hydroxyethyl)-6-methyl-2-[(1-methyl-2-oxopropyl)thio]-4(3H)-pyrimidinone and 240 parts of a hydrobromic acid solution 60% in acetic acid was stirred and heated for 4 hours at 90° C. The reaction mixture was evaporated and the residue was suspended in 400 parts of 2-propanone. The solid product was filtered off, washed with 2-propanone and dried, yielding 44 parts of 6-(2-bromoethyl)-2,3,7-trimethyl-5H-thiazolo[3,2-a]pyrimidin-5-one monohydrobromide; mp. 172° C. (intermediate 7).

Provenance & Evidence