- 4,4'-Azopyridine as an easily prepared and recyclable oxidant for synthesis of symmetrical disulfides from thiols or alkyl halides(tosylates)/thiourea
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Heterocyclic azo compounds, prepared from corresponding amines in one step, are used as effective oxidants for the conversion of thiols into symmetrical disulfides in high yields. Among the studied azo compounds, 4,4'-azopyridine was found to be very efficient for the odorless conversion of alkyl halides into disulfides in the presence of thiourea. An attractive feature of this azo compound is that its obtained solid side product hydrazine is easily separated by filtration and can be recycled to its azo compound for further use.
- Khalili, Dariush,Iranpoor, Nasser,Firouzabadi, Habib
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p. 544 - 555
(2015/10/19)
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- 5,5′-Dimethyl-3,3′-azoisoxazole as a new heterogeneous azo reagent for esterification of phenols and selective esterification of benzylic alcohols under Mitsunobu conditions
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5,5′-Dimethyl-3,3′-azoisoxazole is used as a new efficient heterogeneous azo reagent for the highly selective esterification of primary and secondary benzylic alcohols and phenols with aliphatic and aromatic carboxylic acids via Mitsunobu protocols. The reaction is highly selective for primary benzylic alcohols versus secondary ones, aliphatic alcohols and also phenols. The isoxazole hydrazine byproduct can be simply isolated by filtration and recycled to its azoisoxazole by oxidation.
- Iranpoor, Nasser,Firouzabadi, Habib,Khalili, Dariush
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supporting information; experimental part
p. 4436 - 4443
(2010/11/05)
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- Electrochemical oxidation of 2-aminobenzimidazole at pyrolytic graphite electrode
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The electrochemical oxidation of 2-aminobenzimidazole (2-ABT) has been studied in aqueous solution in a wide pH range of 3.0 to 10.8 using a pyrolytic graphite electrode.The initial step in the oxidation at physiological pH involves a 1e, 1H+ reaction leading to the formation of a free radical species, which rapidly dimerizes to give hydrazo intermediate.Further oxidation of hydrazo species in a 2e, 2H+ reaction leads to the formation of azobenzimidazole.Alternatively, the 1e, 1H+ oxidation of protonated 2-ABT gives a cation free radical, which on loss of proton followed by disproportionation gives s-tetrazine derivative of 2-ABT.Both the products have been isolated and characterized. keywords: oxidation / 2-aminobenzimidazole / electrochemistry
- Goyal, R. N.,Kamaluddin,Srivastava, A.
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p. 654 - 660
(2007/10/02)
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