The action o [" salt.; of N-monosubstituted ['4-methyl-3-methyl(ao,l)-2-thiooxy-l,3-thiazolyl-5-carboxylic acids, which can be converted to the corresponding acid, acid chloride, and anilide.

We have studied the temperature dependence of the 1 H NMR spectra of some 2,4,6-trisubstituted 1,3,5-triazines having an NHAlk or NAlk 2 group or groups at the position 2 or 2 and 4 of the heterocycle. We have shown that rotation of these groups about the C-N bond is hindered. We have calculated the free energies of activation for the rotation processes.Keywords: 2,4,6-trisubstituted 1,3,5-triazines, hindered internal rotation, isomers, free energy of activation.In the 1 H NMR spectra of triazine derivatives containing NHAlk or NAlk 2 substituents at the positions 2 and 4 of the heterocycle, we observed two or more sets of signals from protons of the N-alkyl and NH groups which may be connected with the presence in the solutions of different isomeric forms of the indicated compounds [1]. In order to study this question, we recorded the 1 H NMR spectra of trisubstituted triazines 1-3 in the temperature range 20-90°C. 1 a R 1 = R 2 = NMe 2 , R 3 = Cl; b R 1 = NMe 2 , R 2 = OMe, R 3 = Cl; c R 1 = NHMe, R 2 = OMe, R 3 = Cl; d R 1 = R 2 = NHEt, R 3 = CN; e R 1 = R 2 = NHCHMe 2 , R 3 = CN; f R 1 = NHEt, R 2 = NHCMe 3 , R 3 = Cl; g R 1 = NMe 2 , R 2 = OMe, R 3 = OC 6 H 4 COOEt-p; h R 1 = NHEt, R 2 = SMe, R 3 = OC 6 H 4 COOEt-p; i R 1 = R 2 = NHCHMe 2 , R 3 = OC 6 H 4 COOMe-p; 2 a R 1 = R 2 = NMe 2 , R 3 = OH; b R 1 = NMe 2 , R 2 = OMe, R 3 = OH; c R 1 = NHEt, R 2 = OMe, R 3 = OH; d R 1 = NHEt, R 2 = OMe, R 3 = OCHMe 2 ; e R 1 = R 2 = NHEt, R 3 = OH; f R 1 = R 2 = NHEt, R 3 = OEt; g R 1 = R 2 = NHCHMe 2 , R 3 = OH; h R 1 = R 2 = NHCHMe 2 , R 3 = OMe; 3 a R 1 = R 2 = NMe 2 ; b R 1 = NMe 2 , R 2 = OMe; c R 1 = NHEt, R 2 = OMe; d R 1 = R 2 = NHEt; e R 1 = R 2 = NHCHMe 2 ; a-e R 3 = Me __________________________________________________________________________________________ Armenian Agricultural Academy, Yerevan 375009;

Treatment of 3,4-dimethyl-2-thioxothiazoline-5-carboxylic acid hydrazide with NH 4 SCN and PhCONCSgave the corresponding thiosemicarbazides, arylsulfochlorides yielded the arylsulfonylhydrazides, and diazotization conditions gave the corresponding azide. The interactions of the latter with different nucleophiles have been studied and a series of novel carbamic acid, urea, and semicarbazide derivatives containing a thiazoline fragment have been prepared.In continuation of our search for a novel series of biologically active substances based on the previously reported 3,4-dimethyl-2-thioxothiazoline-5-carboxylic acid hydrazide (1) [1] we now report the preparation of its arylsulfonyl and thiocarbamoyl derivatives 2a-e and 3, 4 respectively as well as the azide product of its diazotization 5. Compounds 2a-e are related in structure to known sulfonylamides [2] or thiourea derivatives [3] and hence attract particular interest as potential medicinal agents and pesticides. The azide 5, being a thiazolineisocyanate donor under Curtius reaction conditions can serve as a valuable starting compound for the development of novel routes to functionalize a thiazoline system and this has been demonstrated in a series of examples.When treated with arylsulfochlorides in pyridine medium at 20°C the hydrazide 1 gave high yields (80-90%) of the arylsulfonylhydrazides 2a-e and when refluxed with ammonium thiocyanate in ethanol or with benzoylisothiocyanate in dioxane the thiosemicarbazide 3 (yield 61%) or benzoylthiosemicarbazide 4 (yield 78%) respectively (Scheme 1).A single unsuccessful attempt to carry out the reaction of thiazolecarboxylic acid hydrazides to the corresponding azide has been reported in the literature. In [3] it was shown that 2-substituted 5-phenylthiazolecarboxylic acid hydrazides in excess acetic acid and the presence of NaNO 2 underwent a more extensive reaction and, in place of the expected azides, gave the N,N'-bis(2-substituted-5-phenyl)thiazolylureas.Despite this data we have found in our work that hydrazide 1 readily forms the azide 5 when treated with an equimolar amount of HNO 2 in aqueous medium in 91% yield. The reactions of the azide with various nucleophiles have been studied. It was found that, at 100-120°C in absolute toluene, the azide indicated underwent a Curtius rearrangement reaction to the corresponding isocyanate which reacts with alcohols, amines, and hydrazides to form novel derivatives of carbamic acid 6a-g, urea 7a-k, and semicarbazide 8a-d containing a thiazoline fragment.

A convenient, accessible, and high yield method for preparing of 6-methyl-2-thioxo-2,3-dihydropyrimidin-4(1H)-one (1) by treatment of acetoacetic acid ethyl ester with thiourea in sodium methylate was developed. The alkylation of the latter with 3-chloro-pentane-2,4-dione and further regioselective cyclization of intermediate compound (2) in high yield afforded 2-acetyl-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidin-5-one (3). The halogenation and some transformations of synthesized thiazolo[3,2-a]pyrimidine (3) due to its ketone group were carried out to obtain the corresponding carboxamide, carbothioamide, sulfonohydrazide, and oxime and its alkylated derivatives (5). At preliminary biological studies the synthesized compounds have shown growth stimulant properties. The activity of four of them was higher than 70%, compared with heteroauxin.

ABSTRACT:By means of regioselective