Nitrodibromoacetonitrile: an agent for bromination and for the formation of adducts formally derived from cyanonitrocarbene

Abstract

The reactions of nitrodibromoacetonitrile (N DBA) with alkenes, aromatic compounds, amines, and sulphides have been studied. Products were formally derived from bromine or nitrocyanocarbene except for bis(2-bromocyclohexyl)nitroacetonitrile (1 3), an adduct (2: 1 ) obtained from cyclohexene and N D BA. 2,3-Dimet hyl but -2-ene was converted into 3-cyano-4,4,5,5tetra met hyl-4,5-di hydroisoxazole 2-oxide (1 5) and 2,3-dibromo-2,3-dimethylbutane (I 6). meso-I ,2-Dibromo-I ,2-diphenylethane was obtained from trans-stilbene. In a reaction catalysed by copper, benzene and NDBA gave benzoyl cyanide. From anthracene, phenol, and cupric acetylacetonate, 9,1O-dibromoanthracene, 4bromophenol, and cupric bromoacetylacetonate were obtained respectively. Dimethyl sulphide, tetrahydrothiophene, and triethylamine afforded the corresponding sulphonium-(30) and (31 ) and ammonium cyanomethylide-(33) t derivatives and, with the latter, co-formation of triethylammonium bromide.Rationales for the reactions are discussed.Abstraction of a 'positive' substituent from bromotrinitromethane,' iodotrinitromethane,2 trinitr~acetonitrile,~ and tetra-nitromethane4 by an alkene lead to the formation of nitronate esters (4) [isolated as isoxazolidine derivatives (6) and polynitro compounds (5)J5 Carbenium nitronates (1'2) t--+ polynitromethanides (1 , 3) have been proposed as intermediates (Scheme 1).Certain metal trinitromethanide salts reacted with cyclohexene in aprotic solvents at 20-50 "C to give 3a,4,5,6,7,7ahexahydro-3-nitro-1,2-benzisoxazole 2-oxide (7),5 Scheme 2. Polynitromethanide salts and alkenes generally gave similar reactions. 5 3 6 The intermediacy of dinitrocarbene (8) was considered; ' however, it was not established that ejection of * We are indebted to Dr.

Fluoreszenzchemosensoren auf Basis des Anthracen-Fluorophors

“…3 h 52 % [47] 1998 Bu 4 NBr 3 Essigsäure 30 Min. 55 % [48] 1989 O 2 NBr 2 CCN CH 2 Cl 2 3 h 65 % [49] Werden zur Bromierung große Überschüsse an Brom verwendet und die Reaktionszeiten deutlich verlängert, kommt es zu einer weiteren Bromierung eines der äußeren Ringe des Anthracengerüsts.…”