1455-91-0Relevant articles and documents
Clean photodecomposition of 1-methyl-4-phenyl-1 H-tetrazole-5(4 H)-thiones to carbodiimides proceeds via a biradical
Alawode, Olajide E.,Robinson, Colette,Rayat, Sundeep
, p. 216 - 222 (2011/03/18)
The photochemistry of 1-methyl-4-phenyl-1H-tetrazole-5(4H)-thione (1a) and 1-(3-methoxyphenyl)-4-methyl-1H-tetrazole-5(4H)-thione (1b) was studied in acetonitrile at 254 and 300 nm, which involves expulsion of dinitrogen and sulfur to form the respective carbodiimides 5a,b as sole photoproducts. Photolysis of the title compounds in the presence of 1,4-cyclohexadiene trap led to the formation of respective thioureas, providing strong evidence for the intermediacy of a 1,3-biradical formed by the loss of dinitrogen. In contrast, a trapping experiment with cyclohexene provided no evidence to support an alternative pathway of photodecomposition involving initial desulfurization followed by loss of dinitrogen via the intermediacy of a carbene. Triplet sensitization and triplet quenching studies argue against the involvement of a triplet excited state. While the quantum yields for the formation of the carbodiimides 5a,b were modest and showed little change on going from a C 6H5 (1a) to mOMeC6H4 (1b) substituent on the tetrazolethione ring, the highly clean photodecomposition of these compounds to a photostable end product makes them promising lead structures for industrial, agricultural, and medicinal applications.
Electronic properties of 1-methyl-4-phenyl-1H-tetrazole-5(4H)-thiones: An experimental and theoretical study
Rayat, Sundeep,Chhabra, Radhika,Alawode, Olajide,Gundugola, Aditya S.
experimental part, p. 38 - 45 (2010/02/16)
The syntheses of 1-(4-methoxyphenyl)-4-methyl-1H-tetrazol-5(4H)-thione 1a, 1-methyl-4-phenyl-1H-tetrazole-5(4H)-thione 1b, 1-(4-chlorophenyl)-4-methyl-1H-tetrazol-5(4H)-thione 1c, 1-methyl-4-(4-nitrophenyl)-1H-tetrazol-5(4H)-thione 1d were carried out and their electronic absorption spectra were obtained in cyclohexane, THF, and acetonitrile. The UV spectra of 1a-d showed a modest dependence on the polarity of the solvent. The change of substituent on the tetrazolethione ring from a strongly electron donating group (p-C6H4OMe, 1a), to a moderately electron donating (C6H5, 1b) to a weakly electron withdrawing group (p-C6H4Cl, 1c) also produced minimal effect on the electronic properties of 1a-c. However, the presence of a strongly electron withdrawing group (p-C6H4NO2, 1d) on the heterocyclic ring produced a marked change in the UV spectrum. Time-dependent density functional calculations revealed that all the bands result from π → π* excitations with some degree of intramolecular charge transfer (ICT) within the molecules. Our studies further showed that as the acceptor strength is increased in the order: 1a (p-C6H4OMe) 6H5) 6H4Cl) 6H4NO2), the ICT also increases. In accordance with the experimental observations, the calculated transitions also showed modest dependence on the polarity of the solvent.
Photoextrusion of Nitrogen from 1,4-Dihydro-1-phenyl-5H-tetrazol-5-ones and -thiones. Benzimidazolones and Carbodiimides
Quast, Helmut,Nahr, Uwe
, p. 526 - 540 (2007/10/02)
Alkylation of 1-phenyltetrazolone 10a with 2-cyclohexen-1-yl bromide followed by dehydrogenation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone permits introduction of a phenyl group at N-4 of the tetrazole ring via the sequence 10a -> 10f -> 10g.The photoextrusion of molecular nitrogen from the (N-4)-substituted 1-phenyltetrazolones, 10a (hydrogen), 10b (methyl), 10d,e (propenyl), and 10g (phenyl) produces essentially quantitative yields of the corresponding benzimidazolones 14a,b,d,e,g.On irradiation of the 1-phenyltetrazolethiones 8b,f,g the carbodiimides 22b,f,g are obtained together with molecular nitrogen and sulfur, while 8a affords phenylcyanamide (25).In contrast to the thermolysis, which is known to give 2-(methylamino)benzothiazole (21b), photolysis of the (phenylimino)-1,2,3,4-thiatriazole 24, an isomer of methylphenyltetrazolethione 8b, also yields molecular nitrogen, sulfur, and methylphenylcarbodiimide (22b).
