Synthesis and Thermal Decomposition of 4‐Azidoisoxazoles

Abstract

ABSTRACT.give a-cyanodiazoketones 2 . L and, in the case of fi, also the N- We will also discuss the mechanism of decomposition of REACTION PRODUCTS When the aminoisoxazoles &,b were diazotized with sodium nitrite in hydrochloric acid at 0 -5OC, and then treated with sodium azide, the expected azidoisoxazoles 2 , p were obtained in only small amounts (ranging from 0 to 8 % ) .The major products of the reactions were found to be the a-cyanodiazoketones -3a,b and, in the case of 2, also the N-hydroxytriazole 1.In order to optimize the yields of &,a the reaction conditions were varied, including a change of solvent, nitrosation reagent and temperature. The best results were obtained when the diazotization was carried out at a temperature between -15 and -lO°C, yielding 30% of &,k under the conditions described in the Experimental Section (Method B).-229 -

Photolysis of 5-Azido-3-Phenylisoxazole at Cryogenic Temperature: Formation and Direct Detection of a Nitrosoalkene

“…However, for azidoisoxazole derivatives, another type of organic azide, the thermal decomposition behavior has been studied but the photochemistry has not been reported extensively. Kumar et al and later L'Abbé and Godts studied the thermal decomposition of 4-azidoisoxazole derivatives and demonstrated that they undergo facile cleavage to form cyano products, as shown in Scheme 1 [9,10], presumably through a concerted reaction mechanism. In comparison, the thermal activation of 3-azidoisoxazole derivatives results in the formation of both isoxazoloisoxazole and hydroxypyrrole products (Scheme 2) [11,12].…”