4- Bromo-2,6-dinitrophenol

The absolute stereochemistry of the aromatic Erythrina alkaloids has been determined. An X-ray analysis of the 2-bromo-4,6-dinitrophenolate... 

With the aid of decoupling experiments and the INDOR technique, it was possible to define completely the structure and stereochemistry of erythristemine (1) with the exception of the configuration at C-11." In order to obtain the latter information, recourse was taken to A-ray analysis on the 2-bromo-4,6-dinitrophenolate salt of (1). This constitutes a new method and may be applicable elsewhere. Details of the structural and stereochemical elucidation of the interesting insecticidal alkaloid (2), which may be regarded as a ring-D degraded erythroidine structure, have appeared. ... 

C6Ds02f Resorcinol (a form), 46B, 97 C6Dg02, Resorcinol ip form), 46B, 97 CeHClsO, Pentachlorophenol, 27, 903 CsH2Cla02, Tetrachlorohydroquinone, 27, 901 32B, CeH3BrN205, 2-Bromo-4,6-dinitrophenol, 41B, 129 C6H3CIN2O5, 2-Chloro-4,6-dinitrophenol, 41B, 130 C6H, C1N03, 2-Nitro-4-chlorophenol, 42B, 85 C6H Cl20, 2,3-Dichlorophenol, 42B, 85... 

C26H2eBrN309, Erythristemine 2-bromo-4,6-dinitrophenolate, 42B, 463 C26H29NOB, Colchicine 0,N-diacetate, 45B, 647... 

Photolytic. A carbon dioxide yield of 19.7% was achieved when bromobenzene adsorbed on silica gel was irradiated with light (X >290 nm) for 17 h (Freitag et al., 1985). Irradiation of bromobenzene in air containing nitrogen oxides gave phenol, 4-nitrophenol, 2,4-dinitrophenol, 4-bromophenol, 3-bromonitrobenzene, 3-bromo-2-nitrophenol, 3-bromo-4-nitrophenol, 3-bromo-6-... 

The reduction of 2-bromo-4,6-dinitroaniline (BDNA), an important intermediate in the preparation of textile dyes that has been detected in river waters (Maguire and Tkacz, 1991), in anaerobic sediment-water systems occurred in an analogous manner to that of 2,4-dinitroaniline and 2,4-dinitrophenol (Equation 3.27). 

Aromatic nucleophilic substitution by superoxide occurs by a mechanism different from that encountered in aliphatic nucleophilic substitution reactions of this ion. Thus, reaction of enriched potassium superoxide with l-bromo-2,4-dinitro-benzene catalyzed by dicyclohexyl-18-crown-6 in benzene saturated with unlabeled oxygen results in 2,4-dinitrophenol almost devoid of label. The loss of label in this reaction rules out a direct displacement mechanism. This result is consistent with electron transfer from superoxide anion to the arene to form an intermediate aromatic anion radical which reacts with oxygen (from all sources) to yield phenol. This mechanism is formulated in equation 8.12. Examples of this reaction are presented in Table 8.7. 

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