Biphenyl 5-bromo-2-nitro

Although the preparation has been repeated, there have been no other reports of the type of reaction, (described in 1923) in which carbazole in the presence of excess potassium hydroxide and nitrobenzene at only 50°C gave a good yield of 9-(4-nitrophenyl)-carbazole, presumably via an adduct such as 43 subsequently oxidized by excess nitrobenzene and/or air. More recent examples of N-arylation of carbazoles have involved copper catalysis in reaction of aryl halides with carbazoles. Thus, copper bronze and potassium carbonate heated with the carbazole and the appropriate aromatic halide have produced 9-(4-methoxyphenyl)- and 9-(2-tolyl)carbazoles 9-(4-phenylphenyl)carbazole, l,4-di(carbazol-9-yl)benzene, 4,4 -di(carbazol-9-yl)biphenyl, and 9-(2-pyridyl)- and 9-(2-quinolyl)carbazoles 9-[2-(2-phenylphenyl)phenyl]- and 9-[2-(4-methylphenyl)phenyl] carbazoles 9-(3-bromo-6-nitrophenyl)-, 9-[3-(carbazol-9-yl]-, 9-(2-nitrophenyl)-, 9-(4-methyl-2-nitrophenyl)-, 9-(4-methoxycarbonyl)-l-nitro-, and l-nitro-9-(4-tolyl)carbazoles 9-(2-methoxycarbonylphenyl)carbazole 9-[2- 2-... 

In CT, biphenyl and its p-fluoro-, chloro-, bromo-, iodo-, and nitro-derivatives are flat 2,2 - and 3,3 -dinitrodiphenyls in benzene are roughly orthogonal... 

Scope and Limitations. Carbonyl Component. For practice purposes this reaction is limited to aromatic aldehydes, of which a wide variety has been studied, and to a,/3-unsaturated aliphatic aldehydes. The sub-stitutents on the ring of the aromatic aldehydes include alkyl, fluoro, chloro, bromo, iodo, hydroxyl, alkoxy, acyloxy, carbethoxy, nitro, and various combinations of two or more of these groups. Aldehydes of the naphthalene, pyrene, biphenyl, thiophene, furmi, pyrrole, indole, chro-mane, coumarane, and thiazole series also have been employed. 

There are alternative routes to the 4- -alkoxybiphenyl-4 -carboxylic acids, but these usually involve acylation of an appropriate 4-n-alkoxybiphenyl with acetyl chloride. However, oxidation of the resulting 4-n-alkoxybiphenyl with hypobromite solution can result in some bromination of the biphenyl occurring. In the preparation of the 3-nitro-4-n-alkoxybiphenyl-4 -carboxylic acids small amounts of the 3-bromo-impur-ity can have adverse effects on transition temperatures and phase formation. Thus, in order to obtain materials suitable for physical studies, the intermediates need to be rigorously purified. 

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