3-Mercapto-1,2,4-triazines

Triazine-3,5-dione, 6-mercapto-metal complexes, 3, 456 oxidation, 3, 411... 

Substituents in the 6-position (cf. 267) show appreciable reactivity. 6-Bromo-as-triazine-3,5(2j, 4j )-dione (316) undergoes 6-substitution with secondary amines or hydrazine, with mercaptide anions or thiourea (78°, 16 hr), with molten ammonium acetate (170°, 24 hr, 53% yield), and with chloride ion during phosphorous oxychloride treatment to form 3,5,6-trichloro-as-triazine. The latter was characterized as the chloro analog of 316 by treatment with methanol (20°, heat evolution) and hydrolysis (neutral or acid) to the dioxo compound. The mercapto substituent in 6-mercapto-as-triazine-3,5(2iI,4if)-dione is displaced by secondary... 

Aus 3-Hydroxy- (bzw. 3-Mercapto)-5,6-diphenyl-1,2,4-triazin wird ein Gemisch aus 1,4-Dihydro- (sehr oxidationsempfindlich) und 4,5-Dihydro-Dcrivat erhalten4 ... 

Ferricyanide oxidation of 1,5-disubstituted thiocarbazones (116) give the mesoionic tetrazolium salts (117) under mild conditions (Eq. 21).190 This is in contrast to the strongly alkaline oxidation of carbazides leading to mercapto formazans as shown in Eq. 8 (Section 7.3.1.4). The heterocyclic triazine (118), obtained by the action of a diazonium salt on 2-... 

Substituted aminotriazinones have proved to be important synthons in heterocyclic syntheses. 4-Amino-6-methyl-3-mercapto-[l,2,4]triazin-5-one 32 reacted with bromomalononitrile in the presence of sodium hydroxide to afford the... 

A series of 4//.8//-1,2-4-triazino[3,4-//]-l,3,4-thiadiazin-4-ones 17 <2001IJB475> has been reported and obtained by condensation of 4-amino-6-substituted-3-mercapto-l,2,4-triazin-5(4//)-ones 35 with various phenacyl bromides (Equation 2) <2001IJB475>. 

Triazinothiadiazines 24 and 25 <2002IJH287> containing sydnone and coumarin systems have also been prepared from 4-amino-3-mercapto-6-substituted-l,2,4-triazin-5-ones 38 as shown in Scheme 5. 

Several 3-mercapto-l,2,4-trizines have been synthesized through the condensation of thiosemicarbazide with diketones under microwave irradiation in a solventless system <06PS87>. The synthesis and cyclocondensation reactions of 3-substituted-5-(2-aminobenzyl)-l//-[l,2,4]triazin-6-ones have been reported <06JHC613>. 

Chiral 4-(l -arylpropyl)amino-3-mercapto-6-methyl-4//-1,2,4-triazin-5-ones were... 

Thus, 5-aryl-3-hydrazino[l,2,4]triazine 200 was reacted with acid chlorides to yield 201 <2004AF42>, and reaction of 5,6-diphenyl-3-hydrazino[l,2,4]triazine 202 with carbon disulfide yielded a 3-mercapto product 203 <2000PJS214>. 

Most of the cyclizations of the five-membered ring relating this type of fused [l,2,4]triazines concern the synthesis of [l,3,4]thiadiazolo[2,3-c][l,2,4]triazines. These synthetic approaches are similar in respect to the starting compound, which is a substituted 4-amino-3-mercapto[l,2,4]triazine-5(477)one 218 in each case. The ring-closure reactions can be classified into four related categories according to the reagent used aldehyde, isothiocyanate, carbon disulfide, or an acid. 

A third, not too widely used, approach is transformation of an iV-aminotriazine compound, as shown in Scheme 56. The 3-mercapto-4-amino[l,2,4]triazine derivative 361 was treated with an active methylene ketone and NBS in ethanol to yield the cyclized product 362 in moderate to excellent yield <2001JHC711>. A similar synthetic strategy was also applied in another case <2003KGS1844>. 

The reaction of 5-mercapto-6-amino-l,2,4-triazin-3-one 143 with a-haloketones gives the thiazino[2,3-r ]-l,2,4-triazines 144 shown in Equation (21), although the publication lacks further detail (yields, for example, are not given) and focuses upon the synthesis of other heterocyclic systems <2001PS205>. 

Many 1,2,4-triazines form complexes with metal ions and can be used for their determination. Thus, 3- and/or 5-(2-pyridyl)-substituted 1,2,4-triazines (e.g. 820) can be used for the determination of iron (II), cobalt(II), nickel(II), zinc(II) and copper(I) ions, thallium and palladium ions can be analyzed by 6-phenyl- (821a) and 5,6-diphenyl-l,2,4-triazine-3-thione (821b), while osmium can be determined by 3-thioxo-l,2,4-triazin-5-one (822), 3-thioxo-dihydro-l,2,4-triazin-5-one (823), 6-mercapto-l,2,4-triazine-3,5-dione (824a), 6-mercapto-5-thioxo-l,2,4-triazin-3-one (824b) and 3,5-dithioxo-l,2,4-triazine-6-carboxyl-ates (825) <78HC(33)189, p. 1004). 

The chemistry of the mercapto-l,3,5-triazines, thiocyanurates and isothiocyanurates will be discussed in this section. 

N -Cyanocarbamimides (112) may be condensed with chloromethyleniminium salts in a similar way (equation 58). Yields are good to excellent, and reaction conditions are mild (Table 12) (81S907). The synthesis provides an easy route to 4-aIkoxy-2-chloro-l,3,5-triazines (113) and the-corresponding mercapto derivatives. 

The dye C.I. Solubilised Sulphur Red 11 [90218-69-2] (25) contains neither thiolate groups nor their precursors. It is prepared by treating perylenetetracarboxylic dianhydride with l,4-diaminobenzene-2-sulfonic acid, then with cyanuric chloride and with NH3. It is not known whether the chlorine of the monochloro-triazine groups of the precursor is replaced by a mercapto group in dyeing. 

The reaction of 2-mercapto-5-(phenylazo)-4,6-dimethylpyridine-2-carbonitrile with appropriate halogeno compounds yields S-alkylated products which can be cyclised to yield pyridothieno-pyrimidines (61a) or -triazines (61b) [94PS(90)85]. Related reactions have been employed to yield further fused ring heterocycles [95PS(104)143]. 

Research on the metabolism of chloro-s-triazines is rapidly expanding, and significant gains are being made in several areas. However, much remains to be learned about the fate of these compounds in soils. Little is known, for example, about the metabolic fate of the 2-methoxy-and 2-methyI-mercapto-s-triazines in soils. 

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