- Preparation method of zolpidem
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The invention discloses a preparation method of a zolpidem intermediate. In the process of preparing the zolpidem intermediate N, N, 6-trimethyl-2-(4-methylphenyl)-imidazo [1, 2-alpha] pyridine-3-acetamide hydrochloride by reducing N, N, 6-trimethyl-2-(4-methylphenyl)-imidazo [1, 2-alpha] pyridine-3-acetamide hydrochloride, through process optimization and parameter adjustment, by using a 10% palladium-carbon catalyst and combining the reaction condition of hydrogen pressure of 0.02-0.09 MPa, the conversion effect of the N, N, 6-trimethyl-2-(4-methylphenyl)-imidazo [1, 2-alpha] pyridine-3-chloroacetamide hydrochloride is promoted, side reactions and impurities are reduced, the product yield is increased, the problem of low product synthesis yield in the process of preparing N, N, 6-trimethyl-2-(4-methylphenyl)-imidazo [1, 2-alpha] pyridine-3-acetamide hydrochloride through reduction reaction in zolpidem production is solved, and the production cost of zolpidem tartrate is reduced.
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Paragraph 0019; 0028-0031
(2021/08/19)
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- PROCESS FOR THE PREPARATION OF 4,4-DIFLUORO-3-OXOBUTANOIC ACID ESTERS
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The present invention relates to a process for the preparation of a compound of the formula (I), wherein R is C1-12 alkyl, by the contact of a compound of the general formula (II) , wherein R1 and R2 are each, independently, C1-12 alkyl; or R1 and R2 join together with the nitrogen atom to which they are attached to form an alicyclic amine ring containing 4 to 7 carbon atoms or a morpholine ring, with an acetic acid ester of the general formula (III) CH3COOR, wherein R is as defined under formula (I), in the presence of a base.
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Page/Page column 6
(2010/02/15)
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- Enantioselective Oxidation of Thioethers: Synthesis of trans-2-N,N-Dialkylacetamide-1,3-dithiolanes-S-oxide and Their Use in Asymmetric Aldol-Type Reactions
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(-)-trans-2-N,N-dialkylacetamide-1,3-dithiolanes-S-oxide 2 have been obtained in high d.e. (>99:1) and e.e.(up to 94percent, >98percent after crystallization) by enantioselective oxidation .The aldol-type addition of the magnesium enolate of the N,N-diethyl derivative (-)-2b to iso-butyraldehyde afforded good chemical yields of a single diastereomer.Key Words: Enantioselective oxidation; Asymmetric aldol-type addition, trans-(-)-2-N,N-Diethylacetamide-1,3-dithiolane-S-oxide.
- Corich, Martina,Furia, Fulvio Di,Licini, Giulia,Modena, Giorgio
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p. 3043 - 3044
(2007/10/02)
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- Process for the preparation of imidazopyridines
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A process for the preparation of an imidazopyridine which is a compound of formula (I) STR1 in which: Y denotes hydrogen, a halogen or a C1-4 alkyl group; X1 and X2 denote, independently of each other, hydrogen, a halogen or a C1-4 alkoxy, C1-6 alkyl, CF3, CH3 S, CH3 SO2 or NO2 group; and R1 and R2 denote, independently of each other, hydrogen or a C1-5 alkyl group, with the proviso that R1 and R2 do not both denote hydrogen, or a salt thereof; which process comprises reacting a compound of formula (V) STR2 wherein Y, X1, X2, R1 and R2 are as defined above, with a reducing agent and if desired converting the resulting compound of formula (I) into a salt, together with intermediates of formulae: STR3 The final products have useful pharmacological properties, e.g. as anxiolytics.
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