ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Reactions with Diazoazoles, VIII1). - Syntheses of Azolo [5,1-d]-1,2,3,5,-tetrazin-4(3H-onesAzolo[5,1-d]-1,2,3,5-tetrazin-4(3H)-ones 4 and 5 are formed by cycloaddition reactions of α-diazoazoles 2 with aryl or alkyl isocyanates 3a-p, respectively, as well as with diisocyanates 3q, r (Method A). Alternative syntheses for 4 are presented by diazotization of N-alkyl(aryl)-5-amino-1H-pyrazole-1-carboxamides (6) and subsequent intramolecular coupling (Method B), by coupling of 3-diazo-5-methyl-4-phenyl-3H-pyrazole (2A) with primary amines 11 to give pyrazolyltriazenes 12A, and by their carbonylation reaction (Method C). The lability of azolotetrazinones against bases is exemplified with-methyl-3,8-diphenylpyrazolo-[5,1-d]-1,2,3,5-tetrazine-4(3H)-one (4Aa) in its reaction with hydroxide ions or morpholine.
Notes:
Azolo[5,1-d]-1,2,3,5-tetrazin-4(3H)-one 4 und 5 entstehen durch Cycloaddition von α-Diazoazolen 2 an Aryl- oder Alkylisocyanate 3a-p bzw. an Diisocyanate 3q, r (Methode A). Alternativsynthesen für 4 werden durch Diazotierung von N-Alkyl(Aryl)-5-amino-1H-pyrazol-1-carboxamiden 6 und nachfolgende intramolekulare Kupplung (Methode B) sowie durch Kupplung von 3-Diazo-5-methyl-4-phenyl-3H-pyrazol (2A) mit primären Aminen 11 zu Pyrazolyltriazenen 12A und deren Carbonylierung (Methode C) vorgestellt. Die Basenlabilität der Azolotetrazinone wird am Beispiel des 7-Methyl-3,8-diphenylpyrazolo[5,1-d]-1,2,3,5-tetrazin-4(3H)-ons (4Aa) in dessen Reaktion mit Hydroxidionen oder Morpholin aufgezeigt.
Additional Material:
9 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19871200816
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