Udo F. Axen

N,N'-carbonyldiimidazole as coupling reagent for the preparation of bovine serum albumin conjugates.

Abstract This note describes the use of N,N′-carbonyldiimidazole for the coupling of prostaglandins and other carboxylic acids to the amino groups of bovine serum albumin.

Chapter 27. Synthetic Approaches to Prostaglandins

Publisher Summary This chapter presents the synthetic approaches to prostaglandins. Bioconversion of unsaturated fatty acids, the natural precursors of prostaglandins, yields prostaglandins in reasonable amounts. Starting with 3-ethoxy-2-cyclopentenone XIII d,l-dihydro-prostaglandin E 1 ethyl ester XVII was obtained as one isomer of a complex mixture of isomeric racemates. Structure and stereochemistry or XVII was proved by a number of physical, chemical and biological methods, comparison with the ester of hydrogenated natural PGE 1 , and unambiguously confirmed by radioisotope dilution. An interesting feature of this synthesis is the large number of highly selective reductions and hydrogenations. Each of the two side chains is introduced into the five membered rings through a formylation followed by a modified Wittig reaction. A Diels–Alder reaction was utilized for the introduction of both side chains which led to a synthetic prostaglandin analog with cis configuration of the alkyl side chains. The nitrite cleavage of bicycloketone XXXII to oxime XXXIII followed by mild conversion to d,l-pGE 1 is also elaborated.