Thio Derivatives

6 Thio Derivatives. - The p-CD derivative having per 2,3-di-0-acetyl-6-thiocyanato-D-glucose components, by treatment with trimethyl(tri- 

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Some specific thio-derivatives of thiazoles have been synthesized for pharmacodynamic, pesticidal, or rubber industry studies they are shown in Tables VII-13 and VII-14 described in Section III. Their chemistry has... 

If greater activation is desired the methyl- or aryl-thio derivatives may be oxidized to the sulfoxides/sulfones (Section 2.15.4.1), which may then be aminated (64JOC2903, 80JOC3746, 77JOC997). 

The rather low values for the methylene groups of barbituric acid and its 2-thio derivative indicated a particularly easy adduct formation (84) which proceeds in water in excellent yield. 

Alkylation reactions were recently performed with all the thio derivatives of 6-azauraciI and 6-azathymine. In agreement with previous findings, the methylmercapto derivatives were obtained by alkylation of all these substances in alkaline solution. Thus, e.g., 3-ihethylmercapto-5-oxo-2,5-dihydro-1,2,4-triazine (96), 5-methylmer-capto-3-oxo-2,3-dihydro-l,2,4-triazine (90), and 3,5-dimethylmer-capto-1,2,4-triazine (91) were obtained. The last-named of these was... 

The course of methylation of all the thio derivatives with diazomethane was then investigated. These mcthylations generally result in mixtures of substances it may be deduced from the products isolated, however, that this reaction proceeds first at the nitrogen atom (in contrast with alkaline methylation) and only then at the sulfur one. The methylation of the 3-methylmercapto derivative to 4-methyl-3-methylmercapto-5-oxo-4,5-dihydro-l,2,4-triazine (95) is of interest in this connection. 

Sorm et a/. prepared azacytidine and some of its derivatives in a similar way. The 4-thio derivative was obtained from 2, 3, 5 -tri-0-acetyl- or 2, 3, 5 -tri-0-benzoyl-6-azauridine by treatment with phosphorus pentasulfide this liberated 4-thio-6-azauridine (126) which was identified with 4-thio-6-azauracil on comparing the UV spectra. Treatment with ammonia produced 6-azacytidine (127) treatment with hydrazine, hydroxylamine, and n-butylamine yielded the corresponding derivatives. 

Alkylation of these mercapto compounds in alkaline solution gives only the S-methyl derivatives. Of the four isomeric A-methyl derivatives, the 4-thioquinazolines, (28) and (29), have been obtained from the corresponding oxo compounds with phosphorus pentasulfide but the corresponding 2-thio derivatives (30) and (31) are not known. However, derivatives of substance (31) with methyl replaced by... 

Preliminary studies with a thio derivative of isatin (indole-2-thione-3-phenylhydrazone) also showed the hydrazone structure to be the favored tautomeric form (81JOC2764). 

Functionalized thiols react with 3-amino-4-nitrofurazan in the presence of a base to form various thio derivatives (Scheme 144) (99MI3, 99MI4). 

I. Hargittai and I. C. Paul, in The Chemistry of Cyanates and their Thio Derivatives (Ed. S. Patai), Part 1, Chap. 2, John Wiley and Sons, Chichester, 1977, pp. 69-129. 

The chemistry of amidines and imidates The chemistry of cyanates and their thio derivatives (2 parts)... 

The Chemistry of Cyanates and their Thio Derivatives (two parts)... 

Table 1—3. Rate constants and half-life times t1/2 [min] for hydrolysis of NJJ -carbonylbisazoles and their benzo and thio derivatives in THF/water (40 1 27°C) and IR frequencies V(C=o> in CHC13.

V. Laine, A. Coste-Sarguet, A. Gadelle, J. Defaye, B. Perly, and F. Djedaini-Pilard, Inclusion and solubilisation properties of 6-S-glycosyl-6-thio-derivatives of /1-cyclodextrin, J. Chem. Soc. Perkin Trans., 2 (1995) 1479-1487. 

The most convenient method of preparing thio derivatives of 1,2,4-thiadiazoles is by a type E synthesis. Treating dipotassium cyanodithioiminocarbonate with chlorine gas affords 5-thio-substituted 1,2,4-thiadiazoles. Alternatively, treatment with sulfur followed by chlorine gas affords 3,5-bisthio-substituted 1,2,4-thiadiazoles <1996CHEC-II(4)307>. 

Dipolarophiles (178) containing this fragment can easily be generated by irradiation of thio derivatives of acetophenone 177 (Scheme 3.137). (Special... 

Fits for the La3 +-catalyzed methanolysis of /xnitrophenyl acetate (2),7 paraoxon (1), its thio derivative, 0,0-Diethyl. S -p-nitrophcnyl phosphorothioate (3)10b and IV-p-nitrophenyl /1-lactam (4)32 have also been computed, with the various ky" the values being given in Table 4. 

The most widely used method for the preparation of [l,2,4]triazolo[3,4-A][l,3,4]thiadiazoles 85 employs 4-amino-5-thio-4/7-[l,2,4]triazoles 83 or 4-amino[l,2,4]-triazole-5(47T)-thiones 84 as starting materials. The reaction of the triazoles 83 or 84 with carbonic acid derivatives furnishes [l,2,4]triazolo[3,4-4][l,3,4]thiadiazoles with a heteroatom substituent (N, O, S) at position 6 the O- and S-functions are formulated as 6-hydroxy and 6-thio derivatives 85a or as thiadiazol-(5/7)6-ones and -thiadiazole-(577)6-thiones 85b, respectively reaction with carboxylic acid derivatives provides the 6-substituted-[l,2,4]triazolo[3,4-4][l,3,4]-thiadiazoles 85c (Equation 20 Table 3). 

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