- 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 0017; 0028; 0034-0035
(2021/08/19)
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- Preparation method of zolpidem impurities
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The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of zolpidem impurities. The method is a brand-new zolpidem impurity preparation method. According to the method, a compound II (N, N, 6-trimethyl-2-(4-methylphenyl)-imidazo[1, 2-alpha]pyridin-3-alpha-hydroxyacetamide) is used as a raw material and is combined with a specific polyphosphoric acid, concentrated sulfuric acid and aluminum trichloride acid catalysis system, and the mixture undergoes a reaction at the temperature of 80-140 DEG C. The product yield is high, the operation is simple, the method is suitable for the large-scale industrial production of the zolpidem impurity compound I, and the impurity detection monitoring during the zolpidem synthesis process is easily achieved.
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Paragraph 0044-0047
(2020/04/17)
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- Study on a three-step rapid assembly of zolpidem and its fluorinated analogues employing microwave-assisted chemistry
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We developed an efficient microwave-assisted three-step synthesis of zolpidem and its fluorinated analogues 1-3. The procedure relays on the utilization of easily accessible and inexpensive starting materials. Our protocol shows superior performance in terms of yield and purity of products, compared to conventional heating systems. Notably, the total time needed for reaction accomplishment is significantly lower comparing to oil bath heating systems. Finally, we have performed a detailed study on the preparation of zolpidem tartrate salt I, and we assessed its particle-sizes using a polarizing microscope. Our goal was to select the appropriate method that generates the acceptable particle-size, since the solid-size directly influences solubility in biological fluids and further bioavailability. We believe that the disclosed procedure will help to produce a lab-scale quantity of zolpidem and its fluorinated derivatives 1-3, as well as zolpidem tartrate salt I, with suitable fine-particle size for further biological experimentation.
- Fajkis, Nikola,Gryzlo, Beata,Kolaczkowski, Marcin,Krupa, Anna,Marcinkowska, Monika
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- Process for the preparation imidazo[1,2-A]pyridine-3-acetamides
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The present invention relates to an improved synthesis of imidazo[1,2-a]pyridine-3-N,N-dialkylacetamides, including zolpidem tartrate.
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- SYNTHESIS OF HETEROARYL ACETAMIDES
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An improved process for the preparation of a heteroaryl acetamide from a heteroaryl α-hydroxyacetamide is provied. The process comprises directly hydrogenating the heteroaryl α-hydroxyacetamide in the presence of a strong acid, a halide and a catalyst. In
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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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