J.-P. Anselme

N-nitrosamines via the phase-transfer mediated nitrosation of secondary amines with sodium nitrite and n-haloamides

Abstract Secondary amines are cleanly and readily converted to the corresponding N-nitrosamines in high yield under phase-transfer conditions by means of soduim nitrite and N-halo-amides; the active nitrosating agent is presumed to be dinitrogen tetroxide.

The photolysis of diphenylcarbamoyl azide

Abstract In contrast to the thermal decomposition which produces 1-phenylindazolone in 90% yield, the photolysis of diphenylcarbamoyl azide in alcohols (and other solvents) gives 1-phenylbenzimidazolone, diphenylamine and the corresponding carbazates (except in t-amyl alcohol where no carbazate is formed), In no case could 1-phenylindazolone be isolated. The formation of 1-phenylbenzimidazolone is shown to proceed via the singlet diphenylcarbamoyl nitrene while the generation of diphenylamine is believed to occur by radical abstraction of the triplet nitrene. The carbazates arise by the Curtius rearrangement of the H bonded azide.

Oxidation of 1,2-bis-(benzenesulfonyl)hydrazine to 1,2-diphenyldisulfone

Abstract The oxidation of 1,2-bis(benzenesulfonyl)hydrazine yields diphenyldisulfone and not 1,2-bis(benzenesulfonyl)dimide as previously reported.

N-nitrosohydroxylamines I. Acetolysis and acid-catalyzed hydrolysis of N,O-dibenzyl-N-nitrosohydroxylamines. Reaction with potassium t-butoxide

Abstract The major products of the hydrolysis of N,O-dibenzyl-N-nitrosohydroxylamines (3) are the denitrosated parent hydroxylamines (6); under more forcing conditions, products of the further hydrolysis of 6 are obtained. Acetolysis in acetic acid gives the benzyl acetates derived from both N- and O-substituents. With potassium tert-butoxide, the major path is abstraction of an O-benzyl hydrogen followed by fragmentation to the aldehyde and the benzyldiazotate ion. Possible mechanisms for the formation of the products are discussed.

AN UNPRECEDENTED FAVORSKI-LIKE RING CONTRACTION OF THE 1,3,4-OXADIAZINONE RING TO A BIMANE

Abstract The reaction of oxadiazinone 5 with sodium hydride in THF leads to an unprecedented Favorski-like ring contraction to the diazacyclopentadienone 1 which then dimerizes with loss of one molecule of nitrogen to give the observed bimane 3.

N-Nitrosamines from carbamoyl chlorides

Abstract The action of sodium nitrite on disubstituted carbamoyl chlorides provides the corresponding N-nitrosamines in excellent yields.

The oxidation of hydrazine derivatives with 4-phenyl-1,2,4-triazoline-3,5-dione

Abstract The oxidation of benzophenone hydrazone with 4-phenyl-1,2,4-triazoline-3,5-dione (PTD) yields benzophenone azine which is also formed from the reaction of the hydrazone with the ylid obtained from diphenyldiazomethane and PTD; the ylid forms a stable addition product with ethanol. With PTD, carbohydrazides are converted to 1,2-diacylhydrazines and small amounts of the corresponding azides; in contrast, p-toluenesulfonylhydrazine yields p-toluenesulfinic acid, isolated as its adduct with PTD, 1-(p-toluenesulfonyl)-4-phenylurazole. Possible mechanisms to rationalize the formation of these products are discussed.

N-nitrosohydroxylamines. III: Reaction of N,O-dibenzyl-N-nitrosohydroxylamines with acetic anhydride

Abstract The major path of the reaction of N,O-dibenzyl-N-nitrosohydroxylamines ( 3 ) with acetic anhydride appears to proceed by initial radical cleavage of the NN bond with loss of nitric oxide. The formation of the main products ( 5 ) may be rationalized by subsequent transformation of the resulting hydroxylamino radicals.

An unexpected cyclization path to some pyrazoles

Abstract The treatment of ketal hydrazones of arylglyoxals (2) with 75% sulfuric acid leads to 3-aroyl-4-phenyl-1-methylpyrazoles (6) as well as 4-phenyl-1-methylpyrazole (7) and the corresponding benzoic acids. Possible mechanisms are discussed.

Oxidation of 1-nitroso-1-alkylhydrazines

Abstract Oxidation of 1-nitroso-1-alkylhydrazines with a variety of oxidizing agents yields the product of coupling of the radical fragments generated by extrusion of nitrogen from the putative N-Nitrene intermediate.