A synthesis of tetronic acid [furan-2(3H),4(5H)-dione] and three analogues

Abstract

A synthesis of four tetronic acids [furan-2(3H),4(5H)-diones] is described. On treatment with triethylamine the readily prepared diethyl α-(chloroacetyl)malonate yielded ethyl 2-ethoxy-4,5-dihydro-4-oxofuran-3-carboxylate (ca. 50%), which was converted into tetronic acid by alkali, and into 3-ethoxycarbonyltetronic acid by water, in high yields. 5-Methyl-, 5-phenyl-, and 5-ethyl-tetronic acids were prepared analogously. The last compound was also obtained by hydrogenation of 5-ethylidenetetronic acid.