Beckmann rearrangement abnormal

Abnormal Beckmann rearrangement is when the migrating substituent fragment (e.g., R ) departs from the intermediate, leaving a nitrile as a stable produet. 

Vanitha, K. A. Balasubramanian, M. Beckmann rearrangement. In Name Reactions for Homologations-Part II Li, J. J., Corey, E. J., Eds. WUey Sons Hoboken, NJ, 2009, pp 274-292. (Review). 

Synthesis of quinoxaline-1,4-dioxides from benzofurazan oxide. 

Name Reactions A Collection of Detailed Mechanisms and Synthetic Applications, DOI 10.1007/978-3-319-03979-4 20, Springer International Publishing Switzerland 2014 

Haddadin, M. I Issidorides, C. H. Heterocycles 1976, 4, 767-816. The authors named the reaction after the city where it was discovered, Beirut, the capital of Lebanon. 

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Not only do oximes undergo the Beckmann rearrangement, but so also do esters of oximes with many acids, organic and inorganic. A side reaction with many substrates is the formation of nitriles (the abnormal Beckmann rearrangement, 17-31). Cyclic ketones can be converted directly to lactams in one laboratory step by... 

The most important route is the conversion of pyrimidines into 1,3,5-triazines. The first one-step transformation was effected by Taylor and Jefford (62JA3744) by heating the pyrimidine (179) with benzenesulfonyl chloride in pyridine (equation 106). The reaction may be considered as an example of an abnormal Beckmann rearrangement. The mechanism of the reaction of the 4-aminopyrimidine (180) is probably dependent on the nature of the 2-substituent (180, R). If R is an electron-releasing moiety, pathway B seems more likely (Scheme 109). The 4-hydroxypyrimidine (179 R = OH) behaves similarly. Many 2-cyano-1,3,5-triazines may be synthesized by this method. 

The abnormal Beckmann rearrangement displayed by the oxime of 17-oxo-5a-androstan-3/3-yl acetate (248) to yield the 13,17-seco-nitrile (249) has provided the key step in a synthetic route to 17-oxo-18-nor-5a,13/8-androstan-3/S-yl acetate and its 13a-epimer.114 The reaction sequence is shown in Scheme 12. The 17-ketone (248) was converted via its oxime into the seco-nitrile in a yield of 52%. Treatment of the oxime by the more conventional toluene-p-sulphonyl chloride reagent... 

Conley, R. T., Ghosh, S. "Abnormal" Beckmann rearrangements. Mechanisms of Molecular Migrations 1971,4, 197-308. 

The reaction of ketone 62 with hydroxylamine hydrochloride and sodium acetate afforded the oxime 63, which upon treatment with CH(0CH3)3/THA underwent an abnormal Beckmann rearrangement furnishing the carbonitrile 64. " ... 

Poly phosphoric acid Abnormal Beckmann rearrangement... 

Abnormal Beckmann rearrangement s. 15, 175 2,6-Piperazinediones from a-(carbalkoxymethylamino)nitriles... 

Normal and abnormal Beckmann rearrangement 1,2,4-Oxadiazoles from glyoximes Nitriles from oximes... 

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