5-Amino-l,2,3,4-thiatriazole

CN3S s N N N — 5-Phenyl-l,2,3,4-thiatriazole 5-amino-l,2,3,4-thiatriazole 5-phenyl-1,2,3,4-thiatriazole 3-oxide... 

An analogous decomposition of 5-amino-l,2,3,4-thiatriazole or 5-alkylamino-1,2,3,4-thiatriazoles gives cyanamide or an alkyl-cyanamide. ... 

On treatment of 5-amino-l,2,3,4-thiatriazole with concentrated hydrochloric acid Freund and Schander obtained a hydrochloride of a sulfur-containing substance which was thought to be a three-membered ring compound [cf. Eq. (19)]. The possibility that it might be a dimer with a six-membered ring was, however, left open. 

Only amino tautomeric forms were also observed for the derivatives of 5-amino-l,2,3,4-thiatriazole 97 [76AHC(S1), p. 440 84CHEC-I(6)579]. 

Acetyl-4-(4/-sulfophenyl)-3-tetrazene, 2982 Aluminium azide, 0082 Aluminium tetraazidoborate, 0059 Amino guanidine, 0507 1-Amino-3-nitroguanidine, 0495 5-Aminotetrazole, 0461 5-Amino-l,2,3,4-thiatriazole, 0413... 

Amino-l,2,3,4-thiatriazole (207) when acylated with 0-aryl chlorothioformate (208) transforms into an unstable 5-aryloxy-3-imino-l,2,4-dithiazole hydrochloride (209). Acylation of this compound produces 2,5-bis(aryloxy)-l,6,6aA -trithia-3,4-diazapentalene ([210), which may be obtained more conveniently by acylating (207) with two equivalents of (208) (Scheme 44) <89M( 120)997, 90JPR208>. 

Amino-l, 2,3,4-thiatriazoles (13) have attracted considerable interest as potential precursors for other heterocycles. The reaction of the nucleophilic amino group with different electrophilic centers has been studied by several groups. 

Charges were calculated using natural population analysis <1988CRV899> with the objective of obtaining a better knowledge of the reactivity of the 5-amino-l,2,3,4-thiatriazole system (see Table 3). Except for the N-3 atom, all... 

Amino-l,2,3,4-thiatriazoles are readily available starting materials and can be transformed into a number of N,S-containing heterocycles. 

According to the calculated data, the 4-amino-l,2,3,5-thiatriazole molecule is planar <2004JMT83>. In comparison with the isomeric 5-amino-l,2,3,4-thiatriazole, 4AT is less polar and the dipole moment is only half as large as that of the 5AT isomer <2005JMT61>. The energy gap for 4-amino-l,2,3,5-thiatriazole is less than that for the isomeric thiatriazole. Based on these data, it was concluded that the 1,2,3,5-triazole should be more effective as a corrosion inhibitor <2005JMT61>. One may conclude from these data that 4AT is more prone to react with electrophiles than 5AT and that the aromaticity of 4AT is higher (see Section 6.10.2.2). 

A solution of 91 g. (1 mol) of thiosemicarbazide4 in 350 ml. of 3 N HC1 (1 mol) is prepared. A clear solution is obtained at 30°. The solution is placed in a 1-1., threenecked flask equipped with a mechanical stirrer, thermometer, and dropping funnel and cooled in an ice-salt bath to 10°. A portion of the dissolved thiosemicarbazide precipitates at this stage. A solution of sodium nitrite, 69 g. (1 mol) in 150 ml. of water, is placed in the dropping funnel. The total volume of the solution is 180 ml. The sodium nitrite solution is added dropwise to the stirred mixture, while the temperature is maintained at 10°. When about 130 ml. of the solution has been added (45 minutes), the addition is stopped and the fine white crystalline precipitate filtered off. The filtrate, which is pale blue in color, is put back into the reaction flask and the addition of the sodium nitrite solution continued. The temperature of the reaction mixture should be maintained at 10 to 15° throughout the addition of the sodium nitrite. When about 40 ml. more of the sodium nitrite solution has been added (15 minutes), the reaction mixture tends to assume a very pale yellow color. Addition of the sodium nitrite is stopped at this stage and the rest of the precipitate filtered off. The addition of even a few drops of the sodium nitrite solution to the filtrate causes an intense yellow color. The filtrate is discarded at this stage. The combined precipitates of 5-amino-l,2,3,4-thiatriazole is washed three times with small amounts of ice-cold distilled water and dried under vacuum over sulfuric acid. The yield is 81.5 g. or 80% of theory, f... 

The procedure is essentially similar to that described for the preparation of 5-amino-l,2,3,4-thiatriazole. Freund and Hempel6,7 have reported observing that the initial diazotization products of 4-aryl-substituted thiosemicarba-zides lead to the formation of tetrazoles, while the corresponding 4-alkyl-substituted thiosemicarbazides were considered by Freund and Schwarz8 to be thiatriazoles. However, Oliveri-Mandala,9 on the basis of his study of the reaction of alkyl and aryl isothiocyanates with hydrazoic acid, concluded that the initial diazotization product of either 4-aryl or 4-alkyl thiosemicarbazides were open-chain thiocarbamyl azides, RNHC( S)N3. Lieber, Pillai, and Hites10 have recently clarified this situation and have shown... 

The procedure described for 5-anilino-l,2,3,4-thiatriazole is typical. To a stirred and cooled mixture of 16.7 g. (0.10 mol) of 4-phenylthiosemicarbazide (Eastman-Kodak number 5426) and 76 ml. of 15% hydrochloric acid was added 6.9 g. (0.1 mol) of sodium nitrite in 50 ml. of water. The mode of addition of the sodium nitrite used for the preparation of 5-amino-l,2,3,4-thiatriazole was followed. The white powdery material was recovered by filtration. The yield was 16 g. or 89% of theory. Recrystallization from methanol yields the pure product. 

IR and mass spectra of 5-substituted 1,2,3,4-thiatriazoles have been reviewed (76AHC(20)145). Recently, in-plane normal vibration modes of 5-amino-l,2,3,4-thiatriazole and 5-mercapto-l,2,3,4-thiatriazole have been tentatively assigned in the solid state on the basis of a normal coordinate analysis, transferring force constants from related molecules... 

UV spectra of 5-phenyl-l,2,3,4-thiatriazole (Amax = 280 nm, e = 10 800) (60CB2353) and of some 5-amino-l,2,3,4-thiatriazoles have been recorded (77JOC3725,80CCC2329). 

Cyclohexylamino-l,2,3,4-selenatriazole (29) dissociated into hydrazoic acid and isoselenocyanate on attempted isolation (equation 13) (82UP42800). Monosubstituted 5-amino-l,2,3,4-thiatriazoles also undergo this type of ring cleavage, although only in the presence of base (see Section 4.28.2.4.1). 

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