- Preparation method of azelastine key intermediate N-methylhexahydroazepine-4-ketone hydrochloride
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The invention belongs to the technical field of medicine synthesis, and particularly relates to a preparation method of an azelastine key intermediate N-methylhexahydroepine-4-ketone hydrochloride. Aiming at the problems that in the prior art, a synthetic route of N-methylhexahydroepine-4-ketone hydrochloride uses more organic raw materials, so that the cost is increased, the environmental protection is not facilitated, and the impurity content in a product is increased, the technical scheme of the invention is as follows: N-methyl-2-pyrrolidone is used as an initial raw material and is subjected to alkaline hydrolysis, and substitution addition and esterification are sequentially carried out, and then cyclization is carried out to synthesize the azelastine key intermediate. The method issuitable for industrial production of the azelastine key intermediate N-methylhexahydroepine-4-ketone hydrochloride.
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Paragraph 0050-0055; 0068-0071; 0094-0098
(2020/12/30)
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- Preparation method for 4-thiophenyl-thiophenol
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The invention discloses a preparation method for 4-thiophenyl-thiophenol. The preparation method comprises the following steps: with diphenyl sulfide as a raw material, subjecting the diphenyl sulfideto a halogenation reaction so as to obtain 4-halogeno diphenyl sulfide; subjecting the 4-halogeno diphenyl sulfide to a mercapto substitution reaction so as to obtain 4-thiophenyl-thiophenol salt; and subjecting the 4-thiophenyl-thiophenol salt to acidification. The preparation method provided by the invention avoids the use of substances like benzenethiol with pollution to the environment, and realizes highly-efficient cyclic recovery and utilization of reaction materials, solvents, water, etc. The preparation method provided by the invention does not discharge organic wastes, waste acid andwaste alkaline water, and is a green process for synthesis of the 4-thiophenyl-thiophenol.
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Paragraph 0079; 0101; 0104; 0105
(2018/07/06)
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- Selective conversion of glycerol to lactic acid with iron pincer precatalysts
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A family of iron complexes of PNP pincer ligands are active catalysts for the conversion of glycerol to lactic acid with high activity and selectivity. These complexes also catalyse transfer hydrogenation reactions using glycerol as the hydrogen source.
- Sharninghausen, Liam S.,Mercado, Brandon Q.,Crabtree, Robert H.,Hazari, Nilay
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supporting information
p. 16201 - 16204
(2015/11/16)
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- Reactions of Carbonyl Compounds in Basic Solutions. Part 15. The Alkaline Hydrolysis of N-Methyl, N-Phenyl and Bicyclo Lactams, Penicillins and N-Alkyl-N-methylacetamides
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The rate coefficients for the alkaline hydrolysis of a series of N-methyl, N-phenyl and bicyclo lactams, penicillins and N-alkyl-N-methylacetamides in water or in aqueous dimethyl sulphoxide have been measured at several temperatures.The reactions were first order in both substrates and base.The reactivities are related to the structures of the substrates, especially N-substitution, ring size and fused ring effects.The reactivities, as well as the activation parameters, kinetic solvent and solvent isotope effects, are used to suggest the detailed mechanisms.All the β-lactams appear to react with rate-determining addition of hydroxide anion; while the N-alkyl γ- and δ-lactams and N-alkyl-N-methylacetamides have rate-determining ring fission of the tetrahedral adduct, assisted by water-catalysis.The reactivity of penicillin in alkaline hydrolysis has been analysed by studies of model compounds.These show that the increased reactivity of the penicillin β-lactam ring arises from the direct action of the fused ring structure and the acetylamino side chain.
- Bowden, Keith,Bromley, Keith
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p. 2111 - 2116
(2007/10/02)
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