- An efficient synthesis of imidazo[2,1-b][1,3,4]thiadiazol-7-ium hydroxides by a one-pot, three-component reaction in water
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An improved synthesis of 2-ethyl-5-(2-hydroxy-4-oxoquinolin-3(4H)-ylidene)-6-aryl-5,6-dihydroimidazo[2,1-b][1,3,4]thiadiazol-7-ium hydroxide derivatives 4a-k via the reaction of aryl glyoxal monohydrates 1a-k, quinoline-2,4-diol 2 and 2-amino-[1,3,4]thiadiazole (3) in the presence of Et3N/sulfamic acid in H2O is described. This green protocol is characterized by the use of the readily available catalyst and reactants, short reaction times, operational simplicity and high yields of products. The structures of all compounds were characterized by 1H NMR, 13C NMR and Fourier-transform infrared (FT-IR) spectral data and microanalyses.
- Khalafy, Jabbar,Etivand, Nasser,Khalillou, Neda
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p. 297 - 302
(2018/12/04)
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- Catalytic asymmetric Meerwein-Ponndorf-Verley reduction of glyoxylates induced by a chiral N,N′-dioxide/Y(OTf)3 complex
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An asymmetric Meerwein-Ponndorf-Verley (MPV) reduction of glyoxylates was for the first time accomplished via an N,N′-dioxide/Y(OTf)3 complex with aluminium alkoxide and molecular sieves (MSs) as crucial additives. A variety of optically active α-hydroxyesters were obtained with excellent results. A possible reaction mechanism was proposed based on the experiments.
- Wu, Wangbin,Zou, Sijia,Lin, Lili,Ji, Jie,Zhang, Yuheng,Ma, Baiwei,Liu, Xiaohua,Feng, Xiaoming
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supporting information
p. 3232 - 3235
(2017/03/20)
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- Naphthol synthesis: Annulation of nitrones with alkynes: Via rhodium(III)-catalyzed C-H activation
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An efficient and redox-neutral naphthol synthesis has been realized via rhodium(iii) catalyzed C-H activation of α-carbonyl nitrones and annulation with alkynes, where the nitrone group functioned as a traceless directing group.
- Wang, Qiang,Xu, Youwei,Yang, Xifa,Li, Yunyun,Li, Xingwei
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supporting information
p. 9640 - 9643
(2017/09/01)
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- Metal-free dual sp3 C-H functionalization: I2- promoted domino oxidative cyclization to construct 2,5-disubstituted oxazoles
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An I2-promoted sp3 C-H functionalization has been developed for the synthesis of 2,5-disubstituted oxazoles from easily available methyl ketones and benzylamines without any metal and peroxide catalyst. This domino oxidative cyclization process involves the cleavage of C-H bond and the formation of C-N, C-O bonds.
- Gao, Qing-He,Fei, Zhuan,Zhu, Yan-Ping,Lian, Mi,Jia, Feng-Cheng,Liu, Mei-Cai,She, Neng-Fang,Wu, An-Xin
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- Synthesis of α-ketothioamides via willgerodt-kindler reaction of arylglyoxals with amines and sulfur under solvent-free conditions
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Willgerodt-Kindler reaction of arylglyoxal hydrates with secondary amines and elemental sulfur under solvent-free conditions at 80 °C is developed, in which α-ketothioamides are obtained in 70-90% yield in 0.6-1 hour. The X-ray crystal-structure analysis for one compound was obtained. Georg Thieme Verlag Stuttgart . New York.
- Eftekhari-Sis, Bagher,Khajeh, Saleh Vahdati,Büyükgüng?r, Orhan
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p. 977 - 980
(2013/06/27)
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- Willgerodt-Kindler reaction of arylglyoxals with amines and sulfur in aqueous media: A simple and efficient synthesis of -ketothioamides
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A simple and efficient method for the synthesis of -ketothioamides via the Willgerodt-Kindler reaction is developed. Reactions were carried out between arylglyoxal hydrates, amines and elemental sulfur in water at 80°C to afford corresponding -ketothioamides in good to high yields in a short reaction time.
- Eftekhari-Sis, Bagher,Vahdati-Khajeh, Saleh,Amini, S. Motahhareh,Zirak, Maryam,Saraei, Mahnaz
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p. 464 - 473
(2013/10/21)
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- A highly efficient and enantioselective intramolecular cannizzaro reaction under TOX/Cu(II) catalysis
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An asymmetric intramolecular Cannizzaro reaction of aryl and alkyl glyoxals with alcohols has been realized with an unprecedented high level of enantioselectivity, on the basis of a newly developed congested TOX ligand and a gradual liberation protocol of active glyoxals from glyoxal monohydrates. Preliminary results suggested a mechanism of enantioselective addition of alcohols to glyoxals contributing most to the stereoselectivity, other than by the dynamic kinetic resolution of hemiacetal intermediates.
- Wang, Pan,Tao, Wen-Jie,Sun, Xiu-Li,Liao, Saihu,Tang, Yong
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supporting information
p. 16849 - 16852
(2013/12/04)
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- Catalytic oxidations of enolizable ketones using 2-alkylidene-4- oxothiazolidine vinyl bromide
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Direct oxidation of enolizable ketones to α-hydroxy derivatives, vicinal dicarbonyls or tricarbonyl compounds has been achieved by a catalytic amount of 2-alkylidene-4-oxothiazolidine vinyl bromide in DMSO as a solvent. The yields range from moderate to good.
- Baranac-Stojanovi?, Marija,Markovi?, Rade,Stojanovi?, Milovan
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experimental part
p. 8000 - 8008
(2011/11/06)
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- The Oxidation of Acetophenones to Arylglyoxals with Aqueous Hydrobromic Acid in Dimethyl Sulfoxide
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The reaction of acetophenones with aqueous hydrobromic acid (HBr) in dimethyl sulfoxide (Me2SO) leads to the formation of arylglyoxals in good yield.Evidence has been obtained which suggests that this oxidation is mediated by a low concentration of molecular bromine, with the consecutive intermediacy of the α-bromo- and α-hydroxyacetophenones.The reaction of α-bromoacetophenone 2 with Me2SO alone provides the arylglyoxal 4 with the glyoxylic acid 6 as the major products.The α-hydroxyacetophenone 3 and thiol ester 5 are intermediates leading to 4 and 6, respectively, and may be isolated as minor products.The presence of water in the medium suppresses the formation of 5 and 6 and results in a cleaner conversion to 4.Treatment of aryl aldehyde 13 with 14 followed by reaction of the resulting 15 with aqueous HBr in Me2SO gave arylglyoxal 4 in good yield.
- Floyd, M. Brawner,Du, Mila T.,Fabio, Paul F.,Jacob, Linda A.,Johnson, Bernard D.
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p. 5022 - 5027
(2007/10/02)
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