Hydrochloric Acid → 6-(2-Chloroethyl)-3,7-dimethyl-5H-[1,3]thiazolo[3,2-a]pyrimidin-5-one

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Reaction Steps

A mixture of 40 parts of 4-methyl-2-thiazolamine, 30 parts of 3-acetyl-4,5-dihydro-2(3H)-furanone and 225 parts of methylbenzene was stirred and refluxed for 2.50 hours with 0.6 parts of hydrochloric acid. After cooling to room temperature, 170 parts of phosphoryl chloride were added. The whole was heated slowly to about 110° C. and stirring was continued for 2 hours at this temperature. The reaction mixture was evaporated and the residue was poured onto crushed ice. Ammonium hydroxide was added till a pH of 8 was reached. The product was extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column-chromatography over silica gel using a mixture of trichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of 2,2'-oxybispropane and 2-propanol, yielding 19.3 parts of 6-(2-chloroethyl)-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidin-5 -one (intermediate 1).

Provenance & Evidence