A- -/V- heterocycle

LMe,ff r2]y[ni(THF) is soluble in THF and toluene and sparingly soluble in Et20 and ra-pentane. The bound THF ligand may be readily removed by refluxing in toluene (see below) and may be displaced by other Lewis bases such as a /V-heterocyclic carbene ligand.1... 

Heterocyclic p-enaminoesters, versatile synthons in heterocyclic synthesis , Wamhoff, H., A /v. Heterocycl. Chem., 1985, 38, 299. 

The possibility that certain metal complexes of a-(/V)-heterocyclic carbox-aldehyde thiosemicarbazones may be cytotoxic to tumour cells has been exam ined [58,60-62],... 

CHE937 V. G. Andrianov and A. V. Eremeev, Cheni. Heterocycl. Conipd. (Engl. 

Kitajima, andT. Keumi, Bull. Ghent. Soc. Jpn. 67, 757 (1994). 94CHE370 V. G. Andrianov and A. V. Eremeev, Ghent. Heterocycl. Gonipd. (Engl. 

V-Heterocyclic carbenes (NHCs) have become an incontrovertible class of mole-cnles for transition-metal- (TM) and organo-catalysis. Inception of the field dates back almost a centnry ago when Tschngajeff (Chugaev) and co-workers reacted... 

CDI and the other A /V -carbonylbisazoles of sufficiently high reactivity react with alcohols ROH to produce diesters of carbonic acid RO-CO-OR, and with amines R R2NH to give diamides of carbonic acid (ureas) R N-CO-NR 2. By use of corresponding bifunctional partners, heterocyclic systems are accessible through insertion of the carbonyl group between two heteroatoms (see Chapter 7). 

A, A /-Carbonylbis[2(3//)-benzoxazolethione], obtained from mercaptobenzoxazole and dimeric phosgene as the more thermodynamically stable A-acyl product, also represents a reactive heterocyclic diamide of carbonic acid, and is therefore used in the same way for ester syntheses as A /V -carbonyldibenzimidazole.c 1321... 

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