13349-82-1Relevant articles and documents
Base-Mediated 1,6-Aza-Michael Addition of Heterocyclic Amines and Amides to para-Quinone Methides Leading to Meclizine-, Hydroxyzine-and Cetirizine-like Architectures
Panda, Gautam,Roy, Deblina
, p. 4434 - 4442 (2019)
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.
New method for preparing quetiapine
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Paragraph 0020-0021, (2018/04/21)
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.