Synthesis of heterocycles on the basis of products of arylation of unsaturated compounds 22.* 3-Aryl-2-chloropropanal in the synthesis of N-Aryl-5-(R-benzyl)-1,3-thiazole-2-amines

Abstract

Derivatives of 2-aminothiazole cover a wide spectrum of biological activity [2][3][4][5][6][7][8] and are also used in various fields of technology [9,10]. One of the most suitable methods for the synthesis of 2-aminothiazole is the interaction of α-halocarbonyl compounds with thioamides and thioureas [11][12][13]. 5-Substituted 2-aminothiazoles have been obtained by this method, using α-halo aldehydes, the range of which is limited. The development of a preparative method for the synthesis of 3-aryl-2-chloropropanal [14,15] provided the possibility to easily obtain 2-amino-5-(R-benzyl)thiazoles.In this paper a method is proposed for the synthesis of N-aryl-5-(R-benzyl)-1,3-thiazole-2-amines 5a-o by the interaction of chloro aldehydes 3a-f with arylthioureas 4a-e and N-(2-pyridyl)thioureas 4f,g. The aldehyde starting materials 3a-e were obtained by chloroarylation of acrolein 1 with the aryldiazonium salts 2a-e. We note that compounds 3 can also be obtained from 3-arylpropanols which, in their turn, were synthesized from the corresponding cinnamic acids [16]. However this method is preparatively less suitable and the overall yields of the aldehydes 3 are not large.It was established that cyclization of the chloro aldehydes 3a-e with arylthioureas 4 occurs on boiling in ethanol, and the presence of bases is not required (method A).2-Chloro-3-(1-naphthyl)propanal 3f, prepared by the interaction of naphthyldiazonium tetrachlorocuprate (2f) with acrolein 1 [8,14], was used in the synthesis of compounds 5n,o.

Antineoplastic activity of novel thiazole derivatives

“…3-Aryl-2-chloropropanals (2a-d) react with the thiourea in ethanol at refluxing and form 2-amino-5-R-benzyl-1,3-thiazoles (3a-d) with good yield [22,23]. Previously, we have discussed the synthetic possibilities of 5-benzyl-2-aminothiazoles during the synthesis of 2-[(5-benzyl-1,3-thiazol-2-yl)imino]-1,3-thiazolidin-4-ones as potential biologically active compounds [24,25]. In this paper, we described N-acylated 2-amino-5-benzyl-1,3-thiazoles (5a-d) obtained by the reaction of 2-amino-5-R-benzyl-1,3-thiazoles 3a-d with acid chlorides 4a-d in the presence of trietylamine in the dioxane medium.…”

A simple non-extractive green method for the spectrophotometric sequential injection determination of copper(ii) with novel thiazolylazo dyes

“…34 The synthetic possibilities of 5-benzyl-2-aminothiazoles during the synthesis of 2-[(5-benzyl-1,3-thiazol-2-yl)imino]-1,3thiazolidin-4-ones as potential biologically active compounds have been previously discussed. 35,36 Herein, the novel advantages of 2-amino-4-methyl-5-(4-sulfonamidobenzyl)thiazole diazotization and the application of the obtained diazonium salt in diazocoupling are described. 5-Benzyl-2-aminothiazole was a mild base; therefore, efficient diazotization could be achieved only by using nitrosylsulfuric acid obtained from NaNO 2 and concentrated H 2 SO 4 .…”