Ethylene adduct of conjugated octadecadienoic acids: II. Ozonization products

Methyl 8-(4-n-hexylcyclohex-2-enyl) octanoate obtained by esterifying the adduct of ethylene andtrans,trans-9,11-octadecadienoic acid was ozonized in methanol as a participating solvent. The resultant cyclic methoxyhemiperacetal was reduced with powdered zinc to the dialdehyde, methyl 9,12-diformylstearate, which was isolated as the tetramethyldiacetal. This dialdehyde readily air-oxidizes to give methyl 9,12-dicarboxystearate. Heating the cyclic methoxyhemiperacetal slowly from 25 to 100 C in vacuo results in an unusual decomposition reaction which gives hydrogen and methyl 9 (12)-carbomethoxy-12(9)-carboxystearate as the primary products and methyl 9 (12)-carbomethoxystearate as the major by-product. Treatment of the cyclic hemiperacetal with hydrogen peroxide in formic acid gave unexpectedly dihydroxystearic acid as one of the products. Presented in part at the AOCS-AACC Meeting, Washington, D. C., April 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.