This book is devoted to heterocyclizations of aliphatic and aromatic , -unsaturated carbonyls with various binucleophiles leading to three-, five-, six and seven-membered partially hydrogenated nitrogen-containing heterocycles. During the last decade interest in these classes of organic c- pounds has been experiencing a scientific renaissance owing to their significant role in biological processes in living cells and diverse effects on physiological activities. In addition, such compounds are also more prevalent from the vi- point of "classical" problems of organic chemistry, among them reactivity, chemo- and regioselectivity, tautomerism, conformational analysis and features of their electronic structure. The character of these problems in the case of partially hydrogenated heterocycles differs sufficiently from that for hetero- omatized and perhydrogenated heterocyclic compounds and investigations in this field very often lead to interesting and unusual results. Extensively characterized cyclocondensations of , -unsaturated carbonyls, their synthetic equivalents and their precursors are the most widespread, facile and generally valid pathway to dihydroazaheterocycles. The popularity and significance of this synthetic approach is based on the high reactivity and availability of unsaturated carbonyl compounds and the precise selectivity of the heterocyclization reactions in comparison with that involving -dicarbonyls. The recent development of combinatorial high-throughput methods and the use of new energy sources such as microwaves and ultrasound to enhance reactions have also increased interest in , -unsaturated carbonyls and their reactions.
"A lucky strike by a pair of prospectors turns into a nightmare when crooked politicians attempt to steal their claim. Loaded with action and romance, this 1906 bestseller recaptures the excitement of the Gold Rush era, when thousands of prospectors headed to Alaska in hopes of finding riches. Miners, gamblers, and fortune-hunters of every description populate these pages, chasing their dreams among the rowdy camps and boom towns of the frozen north. Author Rex Beach, known as the Victor Hugo of the North, based this novel on a true series of events involving the theft of Yukon gold mines by corrupt politicians. Beach seasoned the dramatic tale with incidents from his own experiences prospecting for gold in Nome at the beginning of the twentieth century. Five different movie versions of The Spoilers include versions with John Wayne and Gary Cooper in the role of the rugged hero."