Ready Conversion of Sugar Derived 5,6-Dihydro-2-pyrones into 3-Acyloxy- and 3-Acylamido-2-Pyrones
作者:Alejandro Nin、Oscar Varela、Rosa M. de Lederkremer
DOI:10.1055/s-1991-26383
日期:——
5-Acyloxy-6-acyloxymethyl-5,6-dihydro-2-pyrone derivatives (1a, b and 3b and 5-acyloxy-6-methyl-5,6-dihydro-2-pyrone (3a), obtained by acylation of 2-amino-2-deoxy-D-gluconic acid or L-rhamono- and D-glucono-1,5-lactones, react with tin(IV) chloride to give 3-acylamido- and 3-acyloxy-6-acyloxymethyl-2-pyrones (2a,b and 4b, respectively) and 3-benzoyloxy-6-methyl-2-pyrone (4a), in excellent yield. On prolonged reaction time (5h), the pyrone 4b underwent substitution of the allylic benzoate by chlorine to afford the corresponding 6-chloromethyl derivative 4c.