- A metal-free and recyclable synthesis of benzothiazoles using thiourea as a sulfur surrogate
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Using odorless thiourea as the S source, benzothiazoles and asymmetric disulfides could be obtained from thioformanilides through the tandem cyclization/nucleophilic addition/hydrolysis/nucleophilic substitution reaction. Furthermore, the obtained asymmetric disulfides could readily transfer to benzothiazoles after nitro-reduction and amide formation reaction. This metal-free and recyclable synthetic methodology offered a time-efficient, less expensive, and environmentally friendly alternative to multifunctional benzothiazoles.
- Yin, Yan,Zhou, Hong,Liu, Xichen,Chen, Haiying,Wu, Fanhong,Zhang, Heng,Tao, Ruiheng,Cheng, Fengkai,Feng, Yangbo
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p. 1709 - 1712
(2015/03/14)
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- A new synthesis of chloroheterocycles via metal-halogen exchange between trichloroacetyl derivatives and heteroaromatic lithium and Grignard reagents
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The reaction between 2-lithio derivatives of aromatic azaheterocycles and trichlorocetyl derivatives rapidly produces the corresponding 2-chloro derivatives in high yields through a metal-halogen exchange mechanism. The use of ethyl trichloroacetate can give better results with respect to those obtained with trichloroacetyl chloride, which probably involves dichloroketene formation. The reaction with Grignard reagents is more complex: in fact, 2-benzothiazolylmagnesium chloride with ethyl trichloroacetate or trichloroacetyl chloride gives 2-chlorobenzothiazole together with considerable amounts of ethyl 1,3-benzothiazole-2-carboxylate or 2-benzothiazolyl dichloromethyl ketone, respectively.
- Boga, Carla,Del Vecchio, Erminia,Forlani, Luciano,Milanesi, Lilia,Edgardo Todesco, Paolo
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p. 155 - 159
(2007/10/03)
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- A New and Facile Iodine(III) Mediated Method for the Cleavage of Hydrazides
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Hypervalent iodine oxidation of the various hydrazides 1a-h using iodobenzene diacetate (IBD) in methanol, ethanol, and water in acetonitrile, leads to facile cleavage of hydrazino moiety with the formation of corresponding methyl, ethyl esters and carboxylic acids, respectively (Scheme 1).
- Prakash, Om,Sharma, Vijay,Sadana, Anil
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p. 100 - 101
(2007/10/03)
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- ETHYL CARBOETHOXYFORMIMIDATE IN HETEROCYCLIC CHEMISTRY
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The reactions of ethyl carboethoxyformimidate with various bidentate reagents illustrate its usefulness as a reagent in heterocyclic chemistry.
- Gomez, E.,Avendano, C.,McKillop, A.
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p. 2625 - 2634
(2007/10/02)
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