2- 2-nitro-4- benzoyl

In extending this direct method of synthesis, we next investigated the possibility of preparing similarly constituted halides from 2-deoxy-D-arabino-hexose (2-deoxy-D-glucose) (21). The hexose was subjected to a partial anomerization procedure described by Bergmann and co-workers (1). The solid material obtained by this procedure is a mixture of the anomeric forms of 2-deoxy-D-arabino-hexose low temperature p-nitro-benzoylation of the latter in pyridine resulted in a mixture of crystalline, anomeric tetrakis-p-nitrobenzoates in a ratio of approximately 1 1. They were readily separable by fractional recrystallization, and treatment of either with an excess of hydrogen bromide in dichloromethane, or with... 

Azobenzol wird in fast quantitativer Ausbeute zu Hydrazobenzol reduziert (s.Bd. X/2, S. 716). Die Reduktion von l-Aryl-2-(4-nitro-benzoyl)-diazenen fiihrt unter Erhalt der Nitro-Gruppe zu2-Aryl-l-(4-nitro-benzoyl)-hydrazinen (s.Bd. XI/1, S. 453). In 4-Amino-azobenzol dagegen wird die Azo-Gruppe zum Amin reduziert, so daB 1,4-Diamino-benzol isolicrt wird (s.Bd. XI/1, S. 592). 

Aryl-(2-nitro-benzoyl)- 568 Bis-[alkoxycarbonyl-methyl]- 523 Bis-[2-chIor-phenyl]- 687, 688 Bis-[3-cyan-phenyl]- 687... 

By a procedure similar to that described for />-nitrobenzoyl peroxide, the following peroxides have been prepared w-nitro-benzoyl peroxide (m.p. 136-137°) in 90 per cent yield anisoyl peroxide (m.p. 126-127°) in 86-89 per cent yields -bromoben-zoyl peroxide (m.p. 144°) in 73 per cent yield and 3,4,5-tribromo-benzoyl peroxide (m.p. 186°) in 40 per cent yield.1 The procedure is not satisfactory for preparation of acetylsalicylyl peroxide, which is more conveniently prepared by action of hydrogen peroxide upon an acetone solution of the acid chloride. 

There is considerable overlap in the effective range of the initiators, but this is less troublesome than it might seem since the various mechanisms can be expected to differ in their response to inhibitors. And if the alternatives are free radical and ion-pair with one of the possible ions not very reactive, decision is easy. For example, the polar decomposition of >-methoxy-/> -nitro benzoyl peroxide in acrylonitrile initiates... 

A viable iron carbonyl-mediated reduction process converts acid chlorides and bromoalkanes into aldehydes [3, 6]. Yields are high, with the exception of nitro-benzoyl chloride, and the procedure is generally applicable for the synthesis of alkyl, aryl and a,(i-unsaturated aldehydes from the acid chlorides. The reduction proceeds via the initial formation of the acyl iron complex, followed by hydride transfer and extrusion of the aldehyde (cf. Chapter 8). 

Eine Mischung von 9,06 g (50,0 mmol) (2-Nitro-benzoyl)-hydrazin und 4-Chlor-phenylisothiocyanat er-hitzt man in 200 ml Benzol 30 min unter RuckfluB. Dann gibt man 15,5g (75,0 mmol) Dicyclohexylcarbodiimid in 50 ml Benzol hinzu und erhitzt 7 h znm Sieden. Man kiihlt, filtriert, wascht die erhaltene Substanz mit Benzol, trocknet und kristallisiert aus DMF/Wasser um Ausbeute 13,0g (82%) Schmp. 225 . 

Ein spezielles Beispiel fur leichte Ersetzbarkeit einer Acyloxy-Gruppe durch die Amino-Gruppe ist die Reaktion der O-Benzoyl- bzw. 0-(4-Nitro-benzoyl)-Derivate von tertiaren Cyclopropylcarbinolen mit wasserfreiem Ammoniak im Druckrohr bei 20°2. 

Other syrupy, benzylated bromides bearing O-acetyl or O-p-nitro-benzoyl groups were also prepared and characterized,86-84 as well as a partially benzylated chloride.85 Acid hydrolysis of 22 gave crystalline 2-O-benzyl-a-L-fucose, which was acylated with p-nitrobenzoyl chloride-pyridine. Treatment84 of the resulting tris(p-nitrobenzoate) with hydrogen bromide-dichloromethane led to precipitation of p-nitrobenzoic acid and formation of syrupy 2-0-benzyl-3,4-di-0-(p-nitro-benzoyl)-a-L-fucopyranosyl bromide (33). 

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