Microwave-induced organic reaction enhancement (more) chemistry: Techniques for rapid, safe and inexpensive synthesis

Research on Chemical Intermediates (Impact Factor: 0.88). 20(1):1-11. DOI: 10.1163/156856794X00027

ABSTRACT Synthetic organic reactions have been conducted under microwave irradiation 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. Promising results have been obtained for several condensations, as well as the Bischler-Napieralski
reaction, the Wolff-Kishner reduction, free radical dehalogenation reactions, and other standard synthetic operations. Rapid
catalytic transfer hydrogenation using ammonium formate as the source of hydrogen has been conducted at about 100-130 °C under
microwave irradiation.

Meaningful, safe and inexpensive synthetic experiments for undergraduate and pre-college students have been developed and
tested. The MORE chemistry techniques make it possible to use simple 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 laboratory and set up in another, and safe to operate. Glass, plastics, and ceramics are
essentially transparent to microwaves whereas many organic compounds are dipolar in nature and absorb microwave energy readily.
We have found that untraditional experimental arrangements are possible for conducting a wide variety of organic reactions
in open vessels inside domestic microwave ovens. Depending on the quantity of reactants, most reactions (on a scale of milligrams
to several grams) can be completed in minutes instead of hours. One important element of our “Microwave-induced Organic Reaction
Enhancement” (MORE) chemistry is the proper choice of a microwave energy transfer agent as the reaction medium.