Substituted-amino-l,2,3,4-thiatriazoles

Accordingly, 5-substituted-amino-l,2,3,4-thiatriazoles (Tables III and IV) are formed quite generally from 4-substituted-thiosemicarb-azides. When the substituent is an aryl group these initial products are isomerized to 5-mercaptotetrazoles on treatment with alkali whereas this is not the case when the substituent is an alkyl group. 

The most characteristic feature of the infrared spectra of all 5-mono- and -di-substituted-amino-l,2,3,4-thiatriazoles is a strong band in the 1540-1590 cm range, which without doubt is due to the C=N and N=N stretching vibrations of the heteroaromatic ring system. Various infrared bands between 889 and 1122 cm have been assigned to skeletal vibrations of the thiatriazole ring and a band... 

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... 

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... 

It appears quite probable that this reaction occurs by the same mechanism as the reaction of nitrous acid with thiosemicarbazides and of sodium azide with isothiocyanates. The primary reaction product is a thiocarbamoyl azide (CCXIII) to which, however, the cyclic structure of a 5-amino-l,2,3,4-thiatriazole (CCXIV) is attributed. In alkaline medium these compounds rearrange to the corresponding 1 -substituted-Zla-tetrazoline-5-thiones (CCXII) 236, 237). A survey of these compounds, prepared from the dithiocarbamic acid esters, is given in Table 33. 

N3NH4 Ammonium azide, 2 136 NsNa Sodium azide, 1 79 2 139 NsRb Rubidium azide, 1 79 (Ns)2CO Carbonyl azide, 4 35 N3SCNHC6H5 5-Anilino-l,2,3,4-thiatriazole, 6 45 NsSCNH2 5-Amino-l,2,3,4-thia-triazole, 6 42 5-(substituted)-amino derivatives, 6 44 (N3SCS)2 Azido-carbon disulfide, 1 81, 82... 

Alkylation with triethyloxonium tetrafluoroborate of a 1,2,3,4-thiatriazole substituted in the 5-position with an aryl or an alkylthio group gives a thiatriazolium salt (81 equation 52) (76AHC(20)145). With an alkyl- or aryl-amino group in the 5-position, however, a 4,5-disubstituted thiatriazoline is formed (see Section 4.28.2.5.2). Under similar alkylation conditions 5-ethoxythiatriazoles decompose completely to nitrogen, sulfur and ethyl cyanate. This is the normal thermal decomposition reaction of 5-alkoxythiatriazoles (see Section 4.28.2.3.l(i)) <76AHC(20)145). 

The reactivity of electrophilic isothiocyanates towards inorganic and organic azides is well known. The conversion of hydrazoic acid with aryl isothiocyanates 175 provides 5-amino-substituted 1,2,3,4-thiatriazoles 177 by addition of hydrazoic acid to the C=S bond of the isothiocyanate moiety, probably via unstable thiocarbamoyl azides 176 [132]. Benzoyl isothiocyanate (179, R = CeHs), for example, reacts with hydrazoic acid to benzoylcyanamide (180, R = CeHs). hi contrast, the reaction of sodium azide with isothiocyanates 175 occurs at the C=N bond of the isothiocyanate moiety and gives l-substituted-A -tetrazoHne-5-thiones, also known as l-substituted-5-mercaptotetrazoles 178 (Scheme 35) [133-135]. 

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