Synthesis of 3-hydroxy-3-(hydroxymethyl)-5-methyl-1,2-cyclohexanedione, a hydrolytic product of leucogenenol

Abstract

One of the hydrolytic products of leucogenenol was synthesized, thereby confirming a part of its structure. The monoethoxy derivative of 5-methyl-1,3-cyclohexanedione was reduced with lithium aluminum hydride to 5-methyl-2-cyclohexen-1-one ( 2), which was then hydroxylated with permanganate, and the product condensed with acetone to yield the 2,3- O-isopropylidene derivative ( 3) of 2,3-dihydroxy-5-methylcyclohexanone; this was treated with diazomethane to form the corresponding 3-oxirane ( 4) of the 1,2-isopropylidene acetal of 5-methyl-1,2-cyclohexanediol. The oxirane ring was hydrolyzed in the presence of alkali to yield the 1,2- O-isopropylidene derivative of 3-(hydroxymethyl)-5-methyl-1,2,3-cyclohexanetriol, which formed a diacetate and a dibenzoate, both of which showed four compounds in t.l.c. and g.l.c. Two of the components of the diacetates and dibenzoates had the same retention times and R F values as the corresponding derivatives obtained by the reduction and condensation with acetone of the diacetoxy and dibenzoxy derivatives from the dione isolated from leucogenenol. In addition, the 1,2-isopropylidene acetal of 3-acetoxy-3-(acetoxymethyl)- and 3-benzoxy-3-(benzoxymethyl)-5-methyl-1,2-cyclohexanediol prepared from the dione isolated from leucogenenol had i.r. and n.m.r. spectra that were indistinguishable from the spectra of the corresponding synthetic compounds having the same R F values. Oxidation, with ammonium vanadate in dilute sulfuric acid, of a mixture of two of the isomers of synthetic 3-acetoxy-3-(acetoxymethyl)- and 3-benzoxy-3-(benzoxymethyl)-5-methyl-1,2-cyclohexanediol yielded diones whose i.r. and n.m.r. spectra, and m.p. of the bis(phenylhydrazone) of the benzoxy derivative, were indistinguishable from those of the corresponding derivatives of the dione prepared from leucogenenol.