Cyclopropane Compounds of Biological Interest

The cyclopropane ring is a relative newcomer to be recognized in natural products of biological interest, and to be applied synthetically to prospective biologically active compounds. The syntheses of biologically active cyclopropane derivatives have been studied only during the last 25 years. Ideas concerning the biosynthesis of naturally occurring cyclopropane compounds have been formulated still more recently. Although cyclopropane itself has been used as a general anesthetic in the clinic since 1930, more than 30 years passed before the first cyclopropane derivative, trans -2-phenylcyclopropylamine, became available in medicine. A number of cyclopropane fatty acids had turned up as constituents of certain lipids, but their origin and function did not become understood until much later. These slow developments contrast with the high level of activity in the purely chemical study of cyclopropane and its derivatives. Here the formation of such compounds from olefins or by photochemical reactions, and their ability to rearrange, have had high priority among organic chemists. Kinetic, theoretical, orbital-overlap, and bond-strain studies have also received considerably more attention than medicinal and biological investigations. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.