- Novel synthesis of 2-thiazolines
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The synthesis of a series of 2-thiazolines was carried out under mild conditions from the corresponding thiazolidines, by a Ru-catalyzed/TBHP oxidation reaction conditions. The reaction was chemoselective towards the amine-imine oxidation and was also regioselective, affording the unsaturation at the 2-position of the heterocycle, even with thiazolidine substrates bearing ester groups at the 4-position. (C) 2000 Elsevier Science Ltd.
- Fernandez, Xavier,Fellous, Roland,Du?ach, Elisabet
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- Additive-free pd-catalyzed α-allylation of imine-containing heterocycles
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An additive-free Pd-catalyzed α-allylation of different imino-group-ontaining heterocycles is reported. The activation of α-CH pronucleophiles (pKa (DMSO) > 25) occurs without the addition of strong bases or Lewis acids using only the Pd/Xantphos catalyst system. The reaction scope has been studied for various 5- and 6-membered nitrogen-containing heterocycles (yields up to 96%). Mechanistic investigations suggest an initial allylation of the imine-N followed by a Pd-catalyzed formal aza-Claisen rearrangement.
- Kljajic, Marko,Puschnig, Johannes G.,Weber, Hansj?rg,Breinbauer, Rolf
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supporting information
p. 126 - 129
(2017/11/27)
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- Easy access to 2-alkyl and 2-arylthiazolines using a modified heteropolyacid catalysis: Application to the synthesis of bacillamide A
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A straightforward access to 2-alkyl and 2-arylthiazolines by condensation of-aminothiols on nitriles, catalyzed by phosphotungstic acid (2%) under microwave irradiation, is described. This method has been directly applied to a short and efficient synthesi
- Fache,Cros,Piva,Lefebvre
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experimental part
p. 2098 - 2109
(2012/06/04)
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- A general method for the synthesis of the most powerful naturally?occurring Maillard flavors
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The natural flavors 2-acetyl-1-pyrroline 1a, 2-propionyl-1-pyrroline 1b, 2-acetyl-3,4,5,6-tetrahydropyridine 1c, 2-acetyl-2-thiazoline 1d, 2-propionyl-2-thiazoline 1e, and the artificial flavor 2-acetyl-5,6-dihydro-4H-1,3-thiazine 1f have been prepared by catalytic SeO2 oxidation of the corresponding cyclic imines 6a-c and sulfur cyclic imines 7a-c using TBHP as co-oxidant. The oxidation of the pyrrolines 1a and b is completely regioselective. Professional olfactory evaluation together with the odor threshold of the new flavor 1f is reported.
- Fuganti, Claudio,Gatti, Francesco G.,Serra, Stefano
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p. 4762 - 4767
(2007/10/03)
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- Routes of photocatalytic destruction of chemical warfare agent simulants
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Selected imitants of chemical warfare agents such as dimethyl methylphosphonate (DMMP), diethyl phosphoramidate (DEPA), pinacolyl methylphosphonate (PMP), butylaminoethanethiol (BAET) were subjected to photocatalytic and sonophotocatalytic treatment in aqueous suspensions of TiO2. Complete conversion of the same mass of imitants to inorganic products was obtained within 600 min for DMMP, DEPA, PMP, but required a longer time for BAET. Sonolysis accelerated photodegradation of DMMP. No degradation was observed without ultraviolet illumination. Final products of degradation were PO43-, CO2 for DMMP and PMP, PO43-, NO3- (25%), NH4+ (75%), CO2 for DEPA, and SO42-, NH4+, CO2 for BAET. The number of main detected intermediate products increases in the order DMMP (7), DEPA (9), PMP (21), and exceeds 34 for BAET. Degradation of DMMP mainly proceeds through consecutive oxidation of methoxy groups and then the methyl group. Dimethyl hydroxymethylphosphonate and dimethylphosphate testify to the parallel oxidation of the methyl group. Destruction of DEPA mainly starts with cleavage of the P-NH2 bond to form diethyl phosphate, which transforms further into ethyl phosphate. Oxidation of α and β carbons of ethoxy groups to form ethylphosphonoamidate, hydroxyethyl ethylphosphonoamidate and other products also contributes to the destruction. Photocatalytic degradation of PMP mainly starts with oxidation of the pinacolyl fragment, methylphosphonic acid and acetone being the major products. Oxidation of BAET begins with dark dimerization to disulfide, which undergoes oxidation of sulfur forming sulfinic and sulfonic acids as well as oxidation of carbons to form butanal, aminobutane, etc., and cyclic products such as 2-propylthiazole. A scheme of degradation was proposed for DMMP and DEPA, and starting routes for PMP and BAET. Quantum efficiencies of complete mineralization calculated as reaction rate to photon flux ratio approximate 10-3%.
- Vorontsov, Alexandre V.,Davydov, Lev,Reddy, Ettireddy P.,Lion, Claude,Savinov, Eugenii N.,Smirniotis, Panagiotis G.
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p. 732 - 744
(2007/10/03)
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- Mechanistic Studies on Thiazolidine Formation in Aldehyde/Cysteamine Model Systems
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A mechanism was proposed to elucidate the formation of a thiazolidine in aldehyde/cysteamine model systems. Buffer dramatically promotes thiazolidine formation from formaldehyde and cysteamine. Phosphate tends to stabilize the primary carbocation formed, and this may lead to completion of the cyclization by attack of the amino nitrogen on the activated carbon. Protic solvent, by removing the water molecule, further enhances thiazolidine formation. Redox reaction catalyzed by phosphate ions results in the conversion of thiazolidine to the corresponding thiazoline through hydride transfer.
- Huang, Tzou-Chi,Huang, Lee-Zen,Ho, Chi-Tang
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p. 224 - 227
(2007/10/03)
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- Research on radioprotective agents: Δ-2 Thiazolines and homologous derivatives
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Compounds derived from Δ-2 thiazoline, Δ-2 thiazolinium iodoalkylate and 4,5-dihydro-1,3 thiazine have been prepared and evaluated as potential antiradiation agents in mice. They generally have a low toxicity and significant radioprotective activity.
- Robbe,Fernandez,Chapat,et al.
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