5 -Mercaptotetrazole

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. 

Sodium l-methyl-5-mercaptotetrazolate reacts with species 194 to yield the neutral complex 195 (99P749). Similar species are known [96JGS(D)1011, 98IGG873)]. 

Sodium Mercaptotetrazole. NaCHN4S, mw 124.11, N 45.15% colorl needles. Can be prepd by adding to the prod of the reaction between methylmercaptotetrazole and aq hydriodic acid a sufficient amt of soda soln to make the reaction si alkaline (Ref 2). The resulting cryst compd cont 1.5 mols of w. It is sol in w and ale, less sol in abs ale, insol in eth. May be obtd in a very pure state by dissolving in w and pptg with eth. Such crysts would give pure 5-mercaptotetrazole on acidification with sulfuric acid Refs 1) Beil 26,409 2) M. Freund T. 

Several classes are known. Dimroth-type rearrangements occur by ring opening and reclosure so that one ring atom changes places with an exocyclic atom. The rearrangement of 5-phenylaminothiatriazole to l-phenyl-5-mercaptotetrazole in basic solution is reversible (Scheme 74). As the anion, the tetrazole system is the more stable whereas as the neutral species, the thiatriazole is more stable... 

The rearrangement of 5-phenylaminothiatriazole to l-phenyl-5-mercaptotetrazole in basic solution A58 has been shown to be reversible59 (Scheme 4). The mercaptotetrazole (11) rearranges rapidly in refluxing... 

Hydroxy- and 5-mercaptotetrazoles and their mono-N1 -substituted derivatives can be involved into keto-enol and thiol-thione tautomeric equilibria (Equation 7). This is the reason for significant differences in chemical and physical properties of these compounds from other 5R-tetrazoles. 

Oxygen-sulfur heteroatom exchange has been achieved with 3-methyl-benzene thiazole-2-thione in the presence of trifluoroacetic acid and with l-phenyl-5-mercaptotetrazole. Thiirane can be prepared from oxirane on a support impregnated with alkali metal salts, by decomposition of the dithiocarbon-ate formed with carbon disulfide. A macrocyclic ether, perhydrobenzo-18-crown-6, plays a role in the nucleophilic reaction of oxirane with KCNS, which leads to thiirane in good yield. ... 

Treatment of thionhydrazides, RC(==S)—NH—NH2 with nitrous acid should lead to thiocarbonyl azides, RC(=S)—N3, and it seems likely that these azides are indeed formed as short-lived intermediates. The isolated products are 1,2,3,4-thiatriazoles. When thiosemi-carbazides are nitrosated, 5-amino-l,2,3,4-thiatriazoles or/and 5-mercaptotetrazoles are obtained. Freundformulated his products as such in 1895, while Oliveri-Mandala considered them thiocarbamoyl azides on the basis of some chemical evidence. Lieber resolved this controversy by recording the infrared spectra of the compounds and demonstrating the absence of an azide band . He did the same for the 5-alkylmercapto-l,2,3,4-thiatriazoles , which had earlier been reported as azido-dithiocarbonates , and for the products from azide ion and thiophosgene and carbon disulphide , all of which possess thiatriazole structures. Lieber also demon-... 

Structures comprising Two Five-Membered Rings (5,5). - Thiazolo[3,2-dJ-tetrazoles [CN/ -C- S]. l-Aryl-5-mercaptotetrazoles react with 4-XCeH4-COCHaBr. The resulting derivatives are cyclized to l,5-diaryl-l -thiazolo[3,2-d tetrazol-4-ium perchlorates (218). ... 

Thiazolo[3,2-rf] tetrazolium salts (219) have been prepared by treatment of l-phenyl-5-mercaptotetrazole with a-bromoketones followed by cyclization (Scheme 25).464 Further aspects of the chemistry of tetrazolium salts are discussed in Sections II,D,4 and III,A,4. These compounds represent an area of study distinct from the tetrazoles, and a number of interesting reviews have been published on them separately.465-467... 

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