The Behaviour of Nitrilimines Towards Ethyl Isocyanoacetate |
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Authors: | Dietrich Moderhack Ali Daoud Peter G Jones |
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Institution: | Institut für Pharmazeutische Chemie der Technischen Universit?t Braunschweig, D-38106 Braunschweig, Germany, DE Institut für Anorganische und Analytische Chemie der Technischen Universit?t Braunschweig, D-38106 Braunschweig, Germany, DE
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Abstract: | Summary. Interactions between nitrilimines and the title isocyanide afford, through two competing pathways, 2,3-dihydro-1,2,4-triazines
and 1,3-oxazoles. In situ cycloaddition of unreacted nitrilimine with the triazines gives rise to a third class of products, the bicyclic 1,5,6,8a-tetrahydro1,2,4]triazolo4,3-d]1,2,4]triazines. Acceptor-free representatives of the latter are prone to triazine ring cleavage, yielding triazolyl ketone
hydrazones which served as a structure proof. Substituent effects became apparent upon employment of N-(4-methoxyphenyl)- and N-(4-nitrophenyl)nitrilimines: whereas the former afforded a quinoxaline as the fourth product, triazine formation was totally
blocked with the latter, the corresponding oxazole being the sole product. The constitution of acceptor-substituted bicyclic
compounds (which failed to give the structure-revealing hydrazones) was established by an X-ray diffraction analysis.
Corresponding author. E-mail: d.moderhack@tu-bs.de
Received March 5, 2002; accepted March 19, 2002 |
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Keywords: | ,Cyclizations, Heterocycles, Isocyanides, Nitrilimines, X-Ray structure determination |
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