- Direction of isomerization of 5-hydroxy-3-propargylthio-1,2,4-triazines according to 1H/15N heteronuclear multiple bond correlation (HMBC) spectra
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We have studied isomerization of 6-substituted 5-hydroxy-3-propargylthio-1, 2,4-triazines using base catalysis. We have used NMR correlation spectroscopy (1H/15N HMBC spectra) to prove the structure of the regioisomer formed. The typ
- Smutin,Gindin,Sablina
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- Deuterium studies in the cyclization and isomerization of 3-propargylmercapto-1,2,4-triazines to thiazolo[3,2-b]-[1,2,4] triazines
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Transformation of 3-propargylmercapto-1,2,4-triazin-5(2H)-one (2; R=H or Me) to the corresponding 2-dihydro-3-methylenethiazolo[3,2-b][1,2,4]triazin-7-one (3; R=H or Me) is performed in a dilute solution of triethylamine in MeOH. Compound (3; R=Me) was isomerized to 3,6-dimethyl-thiazolo[3,2-b][1,2,4]-triazin-5-one (4; R=Me) in 5% aqueous sodium hydroxide. Treatment of (3; R=Me) with 5% sodium deuteroxide gave 6-methyl-3-monodeuterated methyl-2-D-thiazolo[3,2-b][1,2,4]-triazin-7-one (5, R=Me).
- Heravi,Shafaie,Khosrofar,Ghassemzdeh
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- Regioselective acid-catalyzed cyclization reaction: Unique synthesis of condensed thiazoles and selenazole
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The facile and regioselective synthesis of condensed thiazoles 7-11 and selenazole 12 has been performed by the catalytic action of H2SO4 On corresponding propynylthio 1-5 and propynylseleno 6 derivatives respectively.
- Heravi, Majid M.,Aghapoor, Kioumars,Nooshabadi, Masood A.
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- A novel depropynylative cyclization of N-propynyl-3-propynylthio-1,2,4-triazin-5-one
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6-Methyl-2N-propynyl-3-propynylthia-1,2,4-triazin-5-one and sodium methoxide were refluxed in N,N-diethylaniline to afford 3,6-dimethyl thiazolo [3,2-b] triazin-7-one.
- Heravi,Kiakojoori,Mojtahedi
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- Heteropoly acid catalyzed selective cyclization of 6-alkyl-3- propargylmercapto-1,2,4-triazin-5(2H)-one
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Cyclization of 6-alkyl-3-propargylmercapto-1,2,4-triazin-5(2H)-one, derivatives (2) in the presence of Keggin heteropoly acids, H3PW 12O40, H3PMO12O40, H4SiW12O40 and lacunary Keggin structure (K 7PMO2W9O40) afforded 3 (3a = 6-dimethyl-7H-thiazolo[2,3-b][1,2,4]-triazin-7-one and 3b=6-ethyl-3-methyl-7H- thiazolo[2,3-b][1,2,4]-triazin-7-one) in high yields and short reaction times.
- Hakimi, Fatemeh,Tabatabaee, Masoumeh,Heravi, Majid M.,Roshani, Mina,Bamoharam, Fatemeh F.
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experimental part
p. 798 - 802
(2012/03/22)
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- Solid acid induced heterocyclization under microwave irradiation. Highly selective synthesis of condensed thiazole
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Condensed thiazoles are synthesized in satisfactory to good yields by the catalytic action of sulfuric acid adsorbed on silica gel under microwave irradiation in a solventless system.
- Heravi,Montazeri,Rahimizadeh,Bakavolia,Ghassemzadeh
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p. 464 - 465
(2007/10/03)
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- Ionic intermediates in the first stages of the reaction of 3,4-dihydro-6-methyl-3-thioxo-1,2,4-triazin-5(2H)-one with propargyl bromide
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Tautomerism of 3,4-dihydro-6-methyl-3-thioxo-1,2,4-triazin-5(2H)-one and its anion were studied by 6-31G* nonempirical calculations. Of the 13 possible tautomers of the former in the gas phase the only stable is the 2H,4H-thione tautomer, and of the 6 possible tautomers of the anion the least energies are characteristic of the 2H- and 4H-thione ones. According to IR and UV spectral data, in methanol the 2H-thione tautomer of the anion is only stabilized. This tautomer enters substitution reaction with propargyl bromide to give an S-propargyl derivative whose anion is an intermediate of heterocylization reaction. The alkylation and heterocyclization reactions are probably orbital-controlled.
- Vokin,Elokhina,Shulunova,Lopyrev,Kanitskaya,Nakhmanovich,Turchaninov
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p. 605 - 614
(2007/10/03)
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