- Base-Mediated 1,6-Aza-Michael Addition of Heterocyclic Amines and Amides to para-Quinone Methides Leading to Meclizine-, Hydroxyzine-and Cetirizine-like Architectures
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An expeditious, cost-effective synthetic methodology for a wide range of nitrogen-containing unsymmetrical trisubstituted methanes (TRSMs) is reported. The synthesis involves base-mediated 1,6-conjugate addition of heterocyclic amines and amides to substituted para-quinone methides, giving the unsymmetrical TRSMs in moderate to very good yields (up to 83percent) in one pot. The low cost, mild temperature, high atom economy and yields, easy scale-up and broad substrate scope are some of the salient features of this protocol. Further, the methodology could be extended for the synthesis of meclizine-, -hydroxyzine-and cetirizine-like molecules. The structure of one such compound, 2,6-di-tert-butyl-4-((4-chlorophenyl)(4-methylpiperazin-1-yl)methyl)phenol, was determined by single crystal X-ray analysis.
- Panda, Gautam,Roy, Deblina
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Read Online
- Preparation method of 1-[2-(2-hydroxyethoxy) ethyl] piperazine
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The invention discloses a preparation method of 1-[2-(2-hydroxyethoxy) ethyl] piperazine in the technical field of organic chemical material synthesis, which comprises the following steps of: carryingout condensation reaction in a solvent to prepare an intermediate by using 1, 1'-methylene thio dipiperazine and chlorodiethylene glycol as starting materials and sodium carbonate as an acid-bindingagent; and adding an oxidant, and carrying out cracking reaction to obtain 1-[2-(2-hydroxyethoxy) ethyl] piperazine. The method has the advantages of short reaction steps, mild reaction conditions andhigh product yield, and a new method is provided for preparing 1-[2-(2-hydroxyethoxy) ethyl] piperazine. The target product provided by the invention has huge application value in the aspects of chemical pharmacy, organic synthesis and the like.
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Paragraph 0031-0064
(2021/02/06)
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- New method for preparing quetiapine
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The invention provides an efficient and concise method for preparing highly-pure 1-[2-(2-hydroxyethoxy)ethyl]piperazine hydrochloride, and a method for preparing quetiapine through directly reacting 11-chloro-dibenzo[b,f][(1,4)]thiazepine with 1-[2-(2-hydroxyethoxy)ethyl]piperazine hydrochloride which substitutes the free alkali form. A low-temperature recrystallization technology adopted to purify the 1-[2-(2-hydroxyethoxy)ethyl]piperazine hydrochloride avoids the residual of unknown tiny piperazine impurities in the product during high-temperature purification, so the highly-pure quetiapineis obtained in subsequent reactions.
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Paragraph 0020-0021
(2018/04/21)
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- A method for preparing [...]
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The invention discloses a preparation method of quetiapine hemifumarate. The preparation method of quetiapine hemifumarate comprises the following steps: etherifying, hydrogenating, condensing and carrying out chlorination by taking o-chloronitrobenzene and thiophenol as raw materials, and finally salifying with fumaric acid, thereby obtaining quetiapine hemifumarate. The production technology is simple to operate and convenient for large-scale production, the cost is saved and the high-purity high-yield quetiapine hemifumarate can be obtained.
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Paragraph 0039; 0040
(2017/03/14)
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- A method of manufacturing a mono-N-alkyl-piperazinecarboxylic
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The invention relates to a method for producing a mono-N-alkyl piperazine of formula (I), where R1 represents C1 to C5 alkyl or 2-(2-hydroxy-ethoxy) ethyl, by reacting diethanolamine (DEOA) of formula (II) with a primary amine of formula H2N-R1 (III) in the presence of hydrogen and a supported catalyst containing metal. The catalytically active mass of the catalyst, before reduction of the latter using hydrogen, contains oxygenic compounds of aluminum, copper, nickel and cobalt and between 0.2 and 5.0 wt. % oxygenic compounds of tin, calculated as SnO, and the reaction is carried out in the liquid phase at an absolute pressure ranging from 95 to 145 bar.
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Paragraph 0090-0091
(2018/11/22)
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- Process for the Preparation of a Mono-N-Alkypiperazine
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Process for the preparation of a mono-N-alkylpiperazine of the formula I in which R1 is C1- to C5-alkyl or 2-(2-hydroxyethoxy)ethyl, by reacting diethanolamine (DEOA) of the formula II with a primary amine of the formula H2N—R1 (III) in the presence of hydrogen and a supported, metal-containing catalyst, where the catalytically active mass of the catalyst, prior to its reduction with hydrogen, comprises oxygen-containing compounds of aluminum, copper, nickel and cobalt and, in the range from 0.2 to 5.0% by weight, oxygen-containing compounds of tin, calculated as SnO, and the reaction is carried out in the liquid phase at an absolute pressure in the range from 95 to 145 bar.
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Paragraph 0094; 0095
(2014/01/07)
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- PROCESS FOR THE PREPARATION OF A MONO-N-ALKYLPIPERAZINE
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Process for the preparation of a mono-N-alkylpiperazine of the formula I in which R1 is C1- to C5-alkyl or 2-(2-hydroxyethoxy)ethyl, by reacting diethanolamine (DEOA) of the formula II with a primary amine of the formula H2N—R1 (III) in the presence of hydrogen and a catalyst molding, where the reaction is carried out in the liquid phase at an absolute pressure in the range from 150 to 250 bar and the amination is carried out by means of a catalyst molding, the precursor of which can be prepared according to a process in which (i) an oxidic material comprising copper oxide, aluminum oxide and lanthanum oxide is provided,(ii) pulverulent metallic copper and/or copper flakes and optionally graphite is added to the oxidic material,(iii) the mixture resulting from step ii is shaped to give a molding, where the oxidic material is obtainable by simultaneous or successive precipitation of the component copper oxide, of the component aluminum oxide and of the component lanthanum oxide and subsequent drying and calcination and, after the shaping according to step iii, the catalyst molding is calcined again.
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Paragraph 0096
(2014/01/07)
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- A study of photodegradation of quetiapine by the use of LC-MS/MS method
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Photodegradation of quetiapine under UVC irradiation in methanol solution was investigated and structural elucidation of its photodegradation products was performed with the use of the reversed phase UHPLC system coupled with accurate mass hybrid ESI-Q-TO
- Skibinski, Robert
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experimental part
p. 232 - 240
(2012/04/10)
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