The Thermal Decomposition of N-Nitrosoamides

White and Aufdermarsh (1958, 1961), by the use of an oxygen-18 tracer technique, added considerable knowledge to the mechanism of the reaction. Thus a series of N-alkyl-N-nitroso-2-naphthamides (105) 

Collins and his co-workers (1961) studied the thermal decomposition of N-acetyl-N-nitroso-l,2,2-triphenylethylamine (111) by means of a combined isotopic-stereochemical technique. Their original interest in 

Unlabeled acetoxyl from solvent, however, should attack the cation with predominant inversion of configuration. Since the ( + )-l,2,2-triphenylethyl acetate (63) yields (+)-carbinol (62) upon treatment with lithium aluminum hydride, the configurations of the ( + )-amine (64), (— )-nitrosoamide (111), (+)-acetate (63) and ( + )-carbinol (62) all possess the same configuration, and are related to d-( — )-mandelic acid, whose absolute configuration has been established (Mislow, 1951). 

The extent of rearrangement of the carbon-14 label in products with both retained [( + )-63ab] and inverted [( —)-63ab) configuration from the thermal decomposition of ( —)-lll was somewhat greater than observed for the deamination of (+)- or (— )-64a in either aqueous solution or in glacial acetic acid [see run 4, Table 4], The data were nicely reproducible, and seemed to indicate that the two reactions were mechanistically similar. The application of equations (19)-(22) to these data in order to calculate and kjk, and the fm ther recalculation of m-values from the ratios of the rate constants so obtained have been discussed earlier, and the results have already been presented in Table 5. The implications of these results (run no. 4, Table 5) clearly are that the deamination of 64 and the thermal decomposition, in acetic acid, of 111 both proceed through similar, open carbonium ion intermediates shown in Chart VI. 

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