Aniline hydrobromide

Anilines react with ct-haloacetophenones to give 2-arylindoles. In a typical procedure an W-phenacylaniline is heated with a tw o-fold excess of the aniline hydrobromide to 200-250°C[1]. The mechanism of the reaction was the subject of considerable investigation in the 1940s[2]. A crucial aspect of the reaction seems to be the formation of an imine of the acetophenone which can isomerize to an aldimine intermediate. This intermediate apparently undergoes cyclization more rapidly (path bl -> b2) than its precursor (Scheme 7.3). Only with very reactive rings, e.g, 3,5-dimethoxyaniline, has the alternative cydiz-ation (path al a2) to a 3-arylindole been observed and then only under modified reaction conditions[3],... 

Aniline hydrobromide [542-11-0] M 174.0, m 286". Crystd from water or EtOH and dried at 5mm over P2O5. Crystd four times from MeOH containing a few drops of cone HCl by addition of pet ether (b 60-70°), then dried to constant weight over paraffin chips, under vacuum [Gutbezahl and Grunwald J Am Chem Soc 75 559 795i]. It was ppted from EtOH soln by addition of Et20, and the filtered solid was recrystd from EtOH and dried in vacuo. [Buchanan et al. J Am Chem Soc 108 1537 1986.]... 

A larger amine such as aniline hydrobromide would be expected to substitute less completely. Only two molecules can be placed on a model of an Si ring, one above and one below the ring. This theoretical composition must have four radical positions on each ring. This composition was empirically confirmed, and so the equation can be written ... 

The A-substituted >-(bromoalkyl)cyanamide may be isolated by vacuum-distillation, or the crude product may be used for further reactions for instance, the Br may be replaced by N(Alkyl)2,1153 or the CN may be split off by boiling 48% HBr. An example of the last-mentioned reaction is the preparation of 7V-(5-bromopentyl)aniline hydrobromide by boiling for 48 h a mixture of 48 % HBr and the Br(CH2)4CH2-N(C6H5)-CN obtained from 1-phenyl-piperidine and BrCN.1158... 

Phenylindoles. The reagent reacts with aniline hydrobromide in the presence of N,N-diethylaniline to form 2-phenylindole (equation I). Actually, the... 

Aniline hydrobromide Aniline hydrochloride Aniline nitrate... 

The reaction of 3-hydroxyglutaronitrile with aniline hydrobromide yields 2,6-dianilinopyridine using thiophenol, hydrogen bromide, and acetic acid instead of aniline hydrobromide, 2-amino-6-phenylthiopyridine results. Interesting cases of ring formation have been reported, for example, the synthesis of 2-amino-3,S-dicyano-6-ethoxy-4-phenylpyridine (IX-4) frombenzal-malonitrile (IX-3) and ethanolic potassium hydroxide. The presence of... 

Condensation of 2,3 > 4-> 6-tetra-0-acetyl-1-thio- -D-glucopyranose with p-(2-bromoethyl)aniline hydrobromide followed by treatment with methanolic sodium methoxide led to the corresponding substituted ethyl /5-thioglycoside. 1-Thioglucosyl aminoacid esters trans-... 

Alternative method for the synthesis of tetrafluoroindole was described in 1968. Ketone 133 was heated under reflux with aniline in the presence of anhydrous zinc chloride in order to prepare the Schiff base 134. However, the only product isolated was A-phenyl-4,5,6,7-tetrafluoro-2-methylindole 136 (<10 %). The yield of 136 was increased up to 47 % by the addition of aniline hydrobromide to the reaction mixture. Thus, the improved synthesis of indole 136 includes heating of the ketone 133, aniline hydrobromide, anhydrous zinc chloride and aniline under reflux for 2 h [53]. 

Aniline Aniline-2-carboxylicacid Aniline-3-carboxylic acid Aniline-4-carboxylicacid Aniline hydrobromide Aniline hydrochloride Aniline nitrate Aniline sulfate (2 1)... 

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