Heterocyclic Chemistry at a Glance
Furans and Thiophenes 105 Ring synthesis – disconnections Various routes for the ring synthesis of furans and thiophenes have be ...
106 Furans and Thiophenes A route to thiophenes, which certainly mirrors the biosynthesis of naturally occurring thiophenes, is ...
Heterocyclic Chemistry at a Glance, Second Edition. John A. Joule and Keith Mills. © 2013 John Wiley & Sons, Ltd. Published ...
108 1,2-Azoles and 1,3-Azoles To understand the N-alkylation of imidazole and pyrazole, we need fi rstly to be aware of the taut ...
1,2-Azoles and 1,3-Azoles 109 Electrophilic substitution at C In the sense that the azoles have a fi ve-membered heteroaromatic ...
110 1,2-Azoles and 1,3-Azoles 4-Halopyrazoles are accessible directly from the heterocycle, as are 4-bromoisothiazole and 4-brom ...
1,2-Azoles and 1,3-Azoles 111 TheseN-anions provide the means for the controlled introduction of substituents onto the nitrogen ...
112 1,2-Azoles and 1,3-Azoles Organolithium, and in some cases Grignard, reagents are available from azole halides. The relative ...
1,2-Azoles and 1,3-Azoles 113 Palladium(0)-catalysed reactions Extensive use has been made of palladium(0)-catalysed cross-coupl ...
114 1,2-Azoles and 1,3-Azoles Highly hindered analogues of these products, which have become known as ‘N-heterocyclic carbenes’ ...
1,2-Azoles and 1,3-Azoles 115 Oxazoles can be converted into pyridines by reaction with, for example, acrylic acid, the initial ...
116 1,2-Azoles and 1,3-Azoles If the nitrogen of the starting amide also carries an alkyl group, cyclisation can only lead to an ...
1,2-Azoles and 1,3-Azoles 117 is utilised in lieu of chloroethanal and the heteroatoms derive from thiourea; these are typical e ...
118 1,2-Azoles and 1,3-Azoles As a fi nal example in this category we show the synthesis of 2-formylimidazole. An imino-ether (n ...
1,2-Azoles and 1,3-Azoles 119 1,2-Azoles ring synthesis – disconnections There are two important disconnections for the construc ...
120 1,2-Azoles and 1,3-Azoles Regiocontrol can also be achieved by using a 1,3-dicarbonyl equivalent, for example an alkynyl-ket ...
1,2-Azoles and 1,3-Azoles 121 Diazoalkanes will also add to alkynes. Synthesis of isothiazoles from -amino,-unsaturated carbo ...
Heterocyclic Chemistry at a Glance, Second Edition. John A. Joule and Keith Mills. © 2013 John Wiley & Sons, Ltd. Published ...
Purines 123 Adenosine nucleotides are at the heart of energy transfer in many metabolic systems, via the interconversion of aden ...
124 Purines compounds to be isolated as a pure substance – by the Swedish chemist Carl Scheele in 1776. When there is excess uri ...
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