Development of an optimized synthetic approach for synthesis of caffeine-8-thioglycolic acid and its ester derivatives

personАвтори: Al. Zlatkov, J. Mitkov, M. Georgieva


dified and optimized methods for synthesis of 8-bromocaffeine, caffeine-8-thioglycolic acid and its ester derivatives were developed. The modification of 8-bromocaffeine synthesis included a change in the brominating agent, which resulted in cost reduction. Some investigations were performed on the influence of the catalyst type and concentration, using a modеl reaction of esterification of caffeine-8-thioglycolic acid with methanol. It was established that the application of the ion-exchane resign Wofatit P as catalyst resulted into significant increase of the ester yields and facilitation of its isolation. Thus the optimal parameters of the caffeine-8-thioglycolic acid esterification were: 35 fold excess of methanol, temperature of 65 °C and catalyst Wofatit P at 4 wt. % of total acid weight. Thus four other caffeine-8-thioglycolates were synthesized with high yields (78-98%) and purity and their structures were confirmed.

Етикети: , ,