- An efficient and chemoselective Cbz-protection of amines using silica-sulfuric acid at room temperature
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A simple, facile, and chemoselective N-benzyloxycarbonylation of amines using silica-sulfuric acid that proceeds under solvent-free conditions at room temperature has been achieved. These reactions are applicable to a wide variety of primary (aliphatic and cyclic) secondary amines, amino alcohols, and heterocyclic amines.
- Gawande, Manoj B.,Polshettiwar, Vivek,Varma, Rajender S.,Jayaram, Radha V.
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- A facile protocol for N-Cbz protection of amines in PEG-600
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An efficient and eco-friendly protocol for the chemoselective N-benzyloxycarbonylation of amines was described. The reaction of amines with benzyl chloroformate (Cbz-Cl) in the presence of PEG-600 at room temperature afforded the corresponding N-Cbz derivatives in excellent yields. The method is applicable to the N-Cbz protection of aliphatic (acyclic and cyclic) and aromatic amines.
- Zhang, Chun Lin,Zhang, Dong Feng,Zhao, Hong Yi,Lin, Zi Yun,Huang, Hai Hong
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- A Simple, efficient, Catalyst-Free and Solvent-Less Microwave-Assisted process for N-Cbz Protection of Several amines
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A simple, green and chemo-selective method for the N-benzyloxycarbonylation of amines, β-amino alcohols, α-amino esters and sulfonamides has been developed under microwave irradiation. Good to excellent yields of the N-benzyloxy-carbamates compounds were obtained in short times without any side products.
- Aouf, Zineb,Mansouri, Rachida,Lakrout, Salah,Berredjem, Malika,Aouf, Nour-Eddine
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p. 151 - 156
(2017/08/02)
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- Convenient method for the preparation of carbamates, carbonates, and thiocarbonates
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(Chemical Equation Presented) A convenient, rapid, and efficient method for the preparation of carbamates from amines with 1-alkoxycarbonyl-3-nitro-1,2,4- triazole transfer reagents is reported. Reactions of newly synthesized stable crystalline reagents with alkyl amines were completed in a few minutes without any additional base, and highly pure carbamates were obtained without chromatographic purification. These highly active reagents are also useful for the selective protection of nucleobases and preparation of carbonates and thiocarbonates.
- Shimizu, Mamoru,Sodeoka, Mikiko
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p. 5231 - 5234
(2008/09/17)
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- New classes of antimuscarinic agents endowed with selective antispasmodic properties. 1-Arylsulfonyl pyrrolidin-2-ones and 2-thiones, 1-arylsulfonyl piperidin-2-ones and 2-thiones and 1-arylsulfonyl hexahydro-2H-azepin-2-one
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A series of 1-arylsulfonylpyrrolidin-2-ones (and 2-thiones), 1-aryl sulfonylpiperidin-2-ones (and 2-thiones) and 1-arylsulfonyl hexahydro-2H-azepin-2-one were synthesized and submitted to a battery of binding assays. The compounds showed little or no affinity for the receptors tested other than muscarinic receptors labelled either with [3H]pirenzepine or with [3H]quinuclidinyl benzilate. When tested in the isolated guinea pig ileum, they antagonized the contractions induced by acetylcholine and behaved as competitive muscarinic antagonists. After parenteral administration in mice, most compounds inhibited carbachol-induced diarrhoea but were less effective in counteracting salivation and lacrimation and showed little or no mydriatic action, thus displaying selectivity at the intestinal level. The reference drugs tested, atropine, butyl scopolamine and cimetropium bromide were far less selective. Maximal in vivo activity was obtained by introducing diethylamino or 1-piperidino or 1-hexahydroazepinyl groups in the 4-position of the phenyl ring while the enlargement of a 5- to a 6-membered lactam ring or its conversion into a thiolactam had a less marked effect. The most interesting compounds were further evaluated for their ability to antagonize carbachol-induced colonic hypermotility in the rat and arecoline-induced analgesia in mice. The effect on gastric acid secretion in the rat was also investigated. The overall in vivo data showed that compounds 14, 15, 26 and 27, i.e. those bearing a 1-hexahydroazepinyl group in the 4-position of the phenyl ring, were the most potent and selective compounds. Unlike the reference drugs, they antagonized carbachol-induced diarrhoea and colonic hypermotility at doses (0.6-4 mg/kg i.p.) 1-2 orders of magnitude lower than those needed to counteract carbachol-induced salivation and lacrimation or to induce mydriatic and antisecretory effects. The novelty of these structures and their selectivity of action on smooth muscle are the two key features of this class of antimuscarinics.
- Toja,Parini,Bonetti,Hunt,Fortin,Barzaghi,Cesana,Maggioni,Nencioni,Galliani
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p. 501 - 509
(2007/10/02)
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- Derivatives of 1-arylsulphonyl-2-pyrrolidinone and their use as medicaments
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Compounds useful for the treatment of patients suffering from muscle spasms of the formula (I) STR1 in which R represents the radical STR2 in which R1, in any position on the phenyl nucleus, represents a linear, branched or cyclic alkyl, alkeny
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