Chemistry of chelocardin. IV. C(2)-acylation and alkylation of 2-deacetylchelocardin

The properties of the 1,3-cyclohexanedione system in 2-deacetylchelocardin (2) and N-carbobenzoxy-2-deacetylchelocardin (3) are found to be significantly different from those of ordinary 1,3-cyclohexanediones. Acylation and alkylation of (2) or (3) generally gives O-acylation or O-alkylation products. However, reaction of N-carbobenzoxy-2-deacetylchelocardin (3) with methyl orthoformate or N,N-dimethylformamide dimethyl acetal leads exclusively to C-acylation products.