Thiones azole

Azolinone derivatives and the corresponding thiones and imines are listed in Table 18 only substituted derivatives have been measured frequently. The chemical shifts of non-aromatic azole derivatives are given in Tables 19-21 relatively few data are available and these are generally for substituted derivatives rather than for the parent compounds. 

For hydroxy- and mercaptoazoles, hydroxy-oxo and thiol-thione tautomeric equilibria depend strongly on the orientation of the substituents and heteroatoms. Most 2- and 5-hydroxy(mercapto)azoles exist mainly as 0X0 (thione) tautomers, but the corresponding 3- and 4-isomers often prefer the hydroxy (mdrcapto) forms. 

Figure 5-3. Biocides bromo-2-nitropropane, 1-N-hexadecyl-1,2,4-tri-azole bromide, 3-hydroxy-4-methylthiazol-2(3H)-thione, 3-hydroxy-4-phenylthiazol-2(3H)-thione, 2,3-dibromo-1-chloro-4-thiocyanato-2-butene, 1,2-dibromo-2,4-dicyanobutane, 2,2-dibromo-2-nitroethanol.

The reaction of 5-aryl-3-(chloromethyl)[l,3,4]oxadiazole-2(3//)-thiones 100 with hydrazine or methylhydrazine yields the corresponding 2,3-dihydro[l,2,4]triazolo[3,4-A][l,3,4]oxadiazole derivatives 102 <1984JCED477>. By analogy, hydrazine and phenylhydrazine convert the [l,2,4]triazole-2(3//)-thiones 101 into 3,7-dihydro-2//-[l,2,4 tria-zolo[4,3-r][ 1,2,4] triazoles 103 <1992PS99, 2002JCCS1035>. Finally, the azole-2(3//)-thiones 101 react with hydroxylamine to form the 3,7-dihydro[l,2,4]triazolo[5,l-d[l,2,4]oxadiazoles 104 (Scheme 8) <1992PS99>. 

It has been demonstrated that the reaction of azole A -oxides with cycloalkane thiones offers a simple and efficient route to azole-thiones. The described reaction sequence has subsequently been found to constitute a useful synthesis of imidazole-2(3//)-thiones (see Scheme 16). 

The product Ci4Hn,N4S, obtained from the meso-ionic 1,3,4-thiadi-azole-2-thione (251, R = R = Ph) and dimethylazodicarboxylate was initially regarded as the six-membered meso-ionic heterocycle 259. However, subsequent studies have established that the product is, in fact, 2-phenyl-5-phenylazo-l,3,4-thiadiazole (260). ... 

Thiazoles, vinyl-radical polymerization, 6, 278 Thiazole-5-sulfonic acid, 2-amino-synthesis, 6, 255-256 Thiazole-2-sulfonic acids reactions, 5, 104 6, 291 Thiazole-5-sulfonic acids synthesis, 6, 255 Thiazole-5-thione, 2-phenyl-tautomerism, 6, 249 Thiazolethiones reactivity, 6, 250 Thi azole-2-thiones reactions, 5, 102 tautomerism, 5, 367 Thiazolidine, 2-alkyl-occurrence, 6, 327 Thiazolidine, 2-arylimino-X-ray analysis, 6, 238 Thiazolidine, 4-imino-mesoionic didehydro derivative nomenclature, 1, 34 nomenclature, 1, 34... 

Thieno[2,3 -6]selenophenes lithiation, 4, 950 Thienospirans synthesis, 4, 760 Thieno[3,4-c][l,2,5]thiadiazoles cycloaddition reactions, 6, 534 reactions, 6, 1036 synthesis, 6, 1042, 1044 Thieno[2,3-d]thiazole, 2-acylamino-synthesis, 6, 1010 Thieno[2,3-d]thiazoles synthesis, 5, 116 6, 988, 994 Thieno[3,2-d]thi azoles synthesis, 5, 135 6, 1015 Thieno[3,4-d]thiazolidine-2-thione, perhydro-... 

The tautomers of azole and azine derivatives, stabilized as a result of complex formation, are widely found [11,15,16,18,261-269]. Thus, the metal-cyclic structures with anionic ligands are formed in chelates of 2-hydroxy- 436, 438) and 2-mercapto-substituted (484, 485) derivatives of these nitrogen-containing heterocycles described above. At the same time, the ketone (thion) isomers are stabilized in molecular adducts. In this respect, the syntheses (4.64) [266], (4.65) [267], and (4.66) [269] are quite representative for this group ... 

Oxidative functionalization of imidazoles is typically not preparatively useful. However, an optimized procedure for direct peracid oxidation of azoles to N-hydroxyazoles was reported [95JCS(P1)243], with imidazoles affording dioxygenated products. In contrast, imidazoles are conveniently converted to imidazole-2-thiones with phenyl chlorothionoformate [95SL239]. 

Formylpyrazoline-5-thiones undergo cyclo-condensation with compounds containing an active methyl or methylene group to give thieno[2,3-c]pyr azoles (74TL4069). The addition of 0.5 molar equivalent of dibenzoyl peroxide increases the yield from 29 to 77% (equation 59). 

Relatively few data are available on the 1H NMR spectra of azolinones and related thiones and imines (Table 13). Some available data on 1H NMR spectra of nonaromatic azoles containing two ring double bonds are given in Table 14. Here there is no ring current effect and the chemical shifts are consequently more upfield. 

Amino-5-hydrazino-3>inercapto-4H-s-triazole, or 4- Am i no 5-hyd ra zi no-4H 1,2,4-tri azol e-3-thione (Called in Beil 4 Amino-5-hydrazono-3-thion- 1,2,4-triazolidin) (Called 4-Amino-... 

Hot aqueous base brings abont hydrolytic cleavage of the heterocyclic ring of benzo-l,3-azol-2-ones giving the corresponding ortfto-disnbstitnted benzene." Alkylation in basic medinm generally leads to N-and 0-substitution thiones alkylate on the thione snlfnr." ... 

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