SYNTHESIS OF 4-VALEROLACTONE AND 4-BROMOVALERIC ACID.
4-Valerolactone has been obtained by the liquid-phase oxidation of 2,3-dihydropyran with pyridinium chlorochromate. The yields of 4-valerolactone at the liquid-phase oxidation stage reach 90-96% at 90% conversion of the starting material. The isolation of 4-valerolactone is complicated by resinification and condensation. Yields of up to 54% of valerolactone were obtained. 4-Bromovaleric acid was obtained by hydrobrominating 4-valerolactone in dioxane solution, yields of up to 64% of 4-bromovaleric acid being obtained. A by-product of the reaction was beta -( beta prime -bromoethoxy)ethyl 4-bromovalerate.