V. Velezheva, A. Y. Lepeshkin, O. Fedotova
Oct 1, 1996
Citations
0
Influential Citations
3
Citations
Journal
Pharmaceutical Chemistry Journal
Abstract
Previously we have demonstrated that 1-acetyl-2-bromo3-indolinone (I, bromindoxyl) is a convenient intermediate for the passage from l-acetylindoxyl to 2-alkyl(aryl)-3ethoxycarbonylpyrrolo[3,2-b] indoles [1] and 2-mercapto(methylthio)irnidazo[4,5-b]indoles [2, 3]. Some of these derivatives exhibited pharmacological (in particular, antihypoxic) activity. This study is a continuation of the series of works devoted to the development of general preparative methods for obtaining azolo[4,5-b]indoles, in particular, thiazolo[5, 4-b]indoles and imidazo[4,5-b]indoles, with various substituents in the azole cycle. In the literature, the series of thiazolo[5,4-b]indoles is represented only by 2-methyl derivatives (7-H, 7-OCH3) synthesized proceeding from isatin oximes [4, 5]. Thiazolo[5,4-b]indoles were obtained via the Gunch reaction from bromindoxyl (I) and primary thioamides ( I Iallc). It was found that the result was significantly dependent on the substituent connected to the thioamide group. For example, reactions involving thioamides of phenylacetic (IIa), phenylpropionic (lib), and cyanoacetic ((IIc) acids led to the formation of thiazoloindoles ( I l ia Illc) with yields varying within 41 78% (Table l). It was established that thiazoloindoles llla and lllb separate from the reaction mass in the form of stable hydrobromides, while cyanomethylthiazoloindole lllc does not form salts under the same conditions.