MICROWAVE-INDUCED ORGANIC-REACTION ENHANCEMENT (MORE) CHEMISTRY - TECHNIQUES FOR RAPID, SAFE AND INEXPENSIVE SYNTHESIS

Synthetic organic reactions have been conducted under microwave irradi ation in open vessels in unaltered domestic microwave ovens. Reaction times vary from a few seconds for sub-milligram reactions to about 15 minutes for reactions carried out on a scale of hundreds of grams. Pro mising results have been obtained for several condensations, as well a s the Bischler-Napieralski reaction, the Wolff-Kishner reduction, free radical dehalogenation reactions, and other standard synthetic operat ions. Rapid catalytic transfer hydrogenation using ammonium formate as the source of hydrogen has been conducted at about 100-130 OC under m icrowave irradiation. Meaningful, safe and inexpensive synthetic exper iments for undergraduate and precollege students have been developed a nd tested. The MORE chemistry techniques make it possible to use simpl e apparatus and very short reaction times. Commercial microwave ovens are now essential equipment in our research and teaching laboratories [1-3]. These ovens are relatively inexpensive, easy to move from one l aboratory and set up in another, and safe to operate. Glass, plastics, and ceramics are essentially transparent to microwaves whereas many o rganic compounds are dipolar in nature and absorb microwave energy rea dily. We have found that untraditional experimental arrangements are p ossible for conducting a wide variety of organic reactions in open ves sels inside domestic microwave ovens. Depending on the quantity of rea ctants, most reactions (on a scale of milligrams to several grams) can be completed in minutes instead of hours. One important element of ou r ''Microwave-induced Organic Reaction Enhancement'' (MORE) chemistry is the proper choice of a microwave energy transfer agent as the react ion medium.