82626-48-0

The crystal structure of zolpidem hemitartrate hemihydrate (I, Form E) has been solved from high-resolution laboratory powder diffraction data. It crystallizes in the orthorhombic P212121 space group with a=22.4664(6)?, b=26.0420(7)?, and c=7.4391(1)?. Protonation of zolpidem molecules could not be unambiguously determined. Thermal stability of Form E has been investigated by TG-DTA and in situ by temperature resolved X-ray powder diffraction. Water loss occurs between 508C≤t≤1008C while structure decomposition commences at approximately 120°C yielding zolpidem tartrate (II) and pure zolpidem base (III) in approximately equimolar amounts. Crystal structures of II and III have been solved simultaneously from a single powder pattern of thermally decomposed I. Zolpidem tartrate crystallizes in the orthorhombic P212121 space group with a=19.9278(8)?, b=15.1345(8)?, and c=7.6246(2)? (at 140°C). Zolpidem base crystallizes in the orthorhombic Pcab space group with a=9.9296(4)?, b=18.4412(9)?, and c=18.6807(9)? (at 140°C). In the reported crystal structures zolpidem molecules form stacks through π-π interaction or dipole-dipole interactions while tartrate moieties, if present, form hydrogen bonded chains. Water molecule in I forms a hydrogen bond to the imidazole nitrogen atom of the zolpidem molecule. Free space in the crystal structure of I could allow for the additional water molecules and thus a variable water content.

An improved and scalable method for the synthesis of zolpidem (1), a hypnotic drug, was developed. A two-step sequence involving imine formation and subsequent tandem reaction between an imine and propiolamide in the presence of CuI/BINOL, an efficient promoter for the tandem reaction, is described. Zolpidem was efficiently prepared in a 54% isolated yield and the hemitartrate salt of zolpidem was produced in 37% yield by simple crystallization, without tedious column chromatography. The procedure can be scaled up to >10 g. The yield of 1 increased to 83% following isolation of the intermediate imine 5.

The invention belongs to the technical field of drug synthesis, and provides a zolpidem preparation method which comprises the following steps: by taking SM-1 as a starting material, Rh (trop2N) (PPh3) as a catalyst and MMA as a hydrogen acceptor, carrying out catalytic dehydrogenation coupling reaction on the starting material, the catalyst and dimethylamine, and carrying out acid dissolution and alkali precipitation refining to obtain a product with higher purity. Compared with the prior art, the zolpidem preparation process has the advantages that the process route can be obviously shortened, and the preparation process is suitable for industrial production.

An efficient synthesis of C3-cyanomethylated imidazo[1,2-α]pyridines via ultrasound-promoted three-component reaction under catalyst-free, oxidant-free, and mild conditions has been developed. A series of C3-cyanomethylated imidazo[1,2-α]pyridines were rapidly prepared with satisfactory yields and good functional group compatibility. This strategy cloud also be applied to the synthesis of zolpidem and alpidem in short steps.

A convenient strategy is presented for the synthesis of C3-alkylated imidazopyridines through one pot condensation and alkylation of α-bromocarbonyl compounds with 2-aminopyridines. A series of C3-alkylated imidazopyridines were obtained in moderate to hi

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.

-

The invention belongs to the field of pharmacy, and relates to a method for preparing zolpidem. The preparation method comprises the following steps: taking maleic anhydride and 2-amino-4-methylpyridine as raw materials, and carrying out a series of react

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.

An efficient and environment-friendly C3-ethoxycarbonylmethylation of imidazo[1,2-a]pyridines with ethyl diazoacetate in the presence of a Rh(II) catalyst was developed. Such strategy not only enables the synthesis of zolpidem, but also provides a way to

The invention provides a preparation method of zolpidem. The method comprises the following steps: malononitrile and 2-methacrolein which are used as raw materials undergo a 1,4-addition reaction to prepare 2-methyl-4,4-dicyano-n-butyraldehyde, the 2-meth

A novel efficient approach towards Zolpidem, Alpidem and their analogues was elaborated. The corresponding amides derived from imidazopyridine and imidazothiazole were prepared by the reaction of amines with previously unknown dibromoalkenes having these heterocyclic fragments. Amination of dibromoalkenes in the presence of water led directly to target drugs and their analogues in up to 95 % yield.

Practical and scalable procedures for Minodronic acid and Zolpidem are developed with short reaction sequences from 2-aminopyridines and maleic anhydride, respectively. The new procedures avoid column chromatography for the purification in all synthetic steps. Key aspects of this development involve reductive hydrodechlorination and Suzuki coupling reaction of 2-chloroimidazole[1,2-a]pyridines, and their application towards synthesis of the two drugs is also addressed.

Objectives: Anxiolytic drug zolpidem was incorporated into the microcontainers based on mesoporous calcium carbonate particles modified by diethylaminoethyl-dextran/hyaluronic acid shell. The release of zolpidem in saline solution and in polymer film modelling nasal mucosa was investigated. The anxiolytic effect of zolpidem upon intranasal administration of microcontainers and free medicine was determined by in?vivo experiments on mice. Methods: The structures of all compounds during zolpidem synthesis were established using nuclear magnetic resonance spectroscopy. The loading efficacy and release kinetics of zolpidem were analysed by spectrophotometry. Surface morphology of formulation was investigated by scanning electron microscopy. To determine the effect of zolpidem-loaded containers administration by the intranasal route in?vivo experiments was carried out applying the open field test. Key findings: Nasal administration of zolpidem in the form of the microcontainers based on mesoporous calcium carbonate particles modified by diethylaminoethyl-dextran/hyaluronic acid shell has a pronounced anxiolytic effect on the behaviour of the animals in the open field test. Conclusions: The polyelectrolyte shell deposited together with zolpidem enhances the loading efficacy of the microcontainers. In vivo experiments on mice demonstrate increase in anxiolytic effect of zolpidem in microcontainers compared with upon intranasal administration of free medicine.

An iron-catalyzed dehydrogenative sp3-sp2 coupling of acetonitrile and 2-arylimidazo[1,2-a]pyridine has been realized, which can serve as a novel approach toward heteroarylacetonitriles. The merit of this strategy is illustrated by the breadth of functional groups tolerated in the transformation and the fast access to pharmaceuticals (such as zolpidem) directly from the heteroarylacetonitriles.

The invention relates to a preparation method of zolpidem tartrate and an intermediate thereof. According to the preparation method, the ratio of starting materials is adjusted, solvent screening is carried out, investment on raw materials is low, the cost is reduced, the yield is improved, impurity contents of prepared zolpidic acid and the prepared zolpidem tartrate are low, purification can be avoided, organic solvents and excessive raw materials in a reaction process can be recycled, and therefore, the preparation method is suitable for industrial production and is considerable in application prospect.

The invention discloses a method for preparing zolpidem. The method comprises the step of subjecting 6-methyl-2-(4-methylphenyl)-imidazo[1,2-a]pyridine, which serves as a raw material, to a reaction with 2-bromo-N,N-dimethylacetamide under the action of photocatalysis, thereby obtaining the zolpidem. Compared with the prior art, the method has the advantages that environment-friendly and pollution-free LED light serves as an energy source, so that an environment-friendly sustainable development idea is embodied; and during the preparation of the zolpidem, five steps in the prior art are shortened to one step. According to the method, the preparation route is short, the preparation method is simple, the production cost is low, the product yield is high, the consumption of a solvent and the pollution to environments during blowdown are reduced, the implementation is easy, and thus, the industrialization is facilitated.

The invention relates to a preparation method of N,N,6-trimethyl-2-(4-methylphenyl)imidazo[1,2-alpha]pyridine-3-acetamide. The method is characterized by comprising the following steps: enabling the 6-methyl-2-(4-methylphenyl)imidazo[1,2-alpha]pyridine-3-acetic acid (2) to perform amidation reaction with dimethylamine under the effect of a condensing agent to obtain N,N,6-trimethyl-2-(4-methylphenyl)imidazo[1,2-alpha]pyridine-3-acetamide (1). The preparation method disclosed by the invention adopts the easily obtained dimethylamine with low market price as the raw material to prepare the high-purity N,N,6-trimethyl-2-(4-methylphenyl)imidazo[1,2-alpha]pyridine-3-acetamide (1) with one-step high yield; the feeding amount of the dimethylamine approaches theoretical amount, the raw material is saved, and the environment pollution is avoided; any environmental harmful acid gas cannot be discharged in the reaction, the reaction step is short, the operation is simple, the process is stable, safe and controllable; the unique waste solid DCU produced in the reaction can be sufficiently recycled, and cleaner production can be realized.

A metal-free process for the C-3 alkylation of imidazopyridines has been developed. Various alkylation products including alkyl ester-, cyano-, ketone- and amide-substituted imidazopyridines were prepared in good yields. With this method, a highly efficie

The invention belongs to the field of chemical synthesis, and relates to a method for preparing a compound zolpidem. The invention provides an effective new method for preparing zolpidem by a trimaceral serially reaction. The method for preparing the zolpidem provided by the invention has the advantages that the reaction step is short, the condition is moderate, atom economy and environmentally friendly are achieved, the yield is high, the cost is low, industrialized production is applicable, and the defects in the prior art that the synthetic route is long and the cost is high are overcome.

The flow of information between chemical and biological research can present a bottleneck in pharmaceutical research. Tools that bridge these disciplines and aid information exchange have therefore clear value. Over the last few years, both synthetic chemistry and biological screening have benefited from automation, and a seamless chemistry-biology interface is now possible. We report here on the use of flow processes to perform synthesis and biological evaluation in an integrated manner. As proof of concept, a flow synthesis of a series of imidazo[1,2-a]pyridines, including zolpidem and alpidem, was developed and connected to a Frontal Affinity Chromatography screening assay to investigate their interaction with Human Serum Albumin (HSA). The Royal Society of Chemistry 2013.

A variety of functionalized imidazo[1,2-a]pyridines have been synthesized through a one-pot, room temperature, and reagent-free reaction between MBH acetates of nitroalkenes and 2-aminopyridines. The reaction involves a cascade inter-intramolecular double aza-Michael addition of 2-aminopyridines to MBH acetates. Our methodology is marked by excellent yield, regioselectivity and, above all, adaptability to synthesize imidazopyridine-based drug molecules such as Alpidem and Zolpidem.

-

(Figure Presented) Three is not a crowd: A method for the construction of Imidazopyridine, imidazoquinoline, and imidazoisoquinoline frameworks has been developed. The synthetic utility of this method was demonstrated in a highly efficient one-pot synthesis of the drugs alpidem and Zolpidem (see scheme).

The present invention relates to an improved process for the preparation of 6- methyl-2-[4-methylphenyl]imidazo[l,2-a]pyridine-3-N,N-dimethyl acetamide having formula (1). The compound of formula (1) has adopted name "Zolpidem". The present invention also relates to novel intermediate of the formula (2) and a process for its preparation.Wherein R represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl or tertiary butyl group. The novel intermediate of formula (2) is used in preparation of Zolpidem having formula (1). Zolpidem is useful in the treatment of anxiety, sleep disorders and convulsion.

The invention relates to the preparation of a non-hygroscopic polymorphic form of zolpidem hemitartrate, designated as Form I, and pharmaceutical compositions including it. The invention also relates to use of the compositions for treating anxiety, sleep

A method for preparing a polymorph of a hemitartrate salt of a compound having the structure: comprising dissolving a free base form of the compound in a liquid medium comprising an alcohol and a tartrate derivative to form a solution comprising the compound, the alcohol, and the tartrate derivative; heating the solution to a temperature sufficient to dissolve the compound and the tartrate derivative; and cooling the solution to a temperature sufficient to precipitate the hemitartrate salt of the compound.

A process for preparing zolpidem.

An improved process for the preparation of a heteroaryl acetamide from a heteroaryl α-hydroxyacetamide is provided. The process comprises directly hydrogenating the heteroaryl α-hydroxyacetamide in the presence of a strong acid, a halide and a catalyst wh

A process for the preparation of imidazo[1,2-a]pyridine derivatives of the formula I: wherein R is hydrogen, halogen or a C1-C4 alkyl group; R1 and R2 are independently hydrogen, a straight or branched C1/

The invention relates to processes for the preparation of a polymorph of zolpidem hemitartrate. More particularly, it relates to the preparation of a non-hygroscopic polymorphic form of zolpidem hemitartrate and pharmaceutical compositions that include th

-

The present invention relates to processes for the preparation of zolpidem of Formula V as shown in the accompanying drawings or pharmaceutically acceptable salts thereof from N, N-dimethyl-3-(4-methyl) benzoyl propionamide of Formula II. The process incl

A process for the preparation of N,N,6-trimethyl-2-(4-methylphenyl)-imidazo [1,2-a]pyridine-3-acetamide, compound of formula (I), comprising reacting mixed anhydride, compound of formula (III), with dimethylamine; wherein R is selected from C1 to C6 linear or branched alkyl groups and substituted phenyl groups.

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

-

The present invention relates to an improved synthesis of imidazo[1,2-a]pyridine-3-N,N-dialkylacetamides, including zolpidem tartrate.

The invention relates to a process for preparing a compound of formula (I) wherein a compound of formula (II), wherein R1 denotes chlorine, bromine, iodine, —O—COCH3, tosylate or mesylate, is reacted with a compound of formula (III),

The present invention provides for novel polymorphs of zolpidem hemitartrate and the preparation of the polymorphs.

It comprises reducing the hydroxy ester of formula (X) by reacting it in DMF and then with an iminium salt of formula (XIII) formed in situ with thionyl chloride and dimethylformamide, and subsequent reduction with an appropriate reducing agent to form the ester of formula (XII), which is then reacted with dimethylamine in a polyhydroxylated solvent medium at an appropriate

A series of 6-substituted 2-aryl-N,N-dimethylimidazol [1,2-a]pyridine-3-acetamides, congeners of zolpidem and alpidem, was synthesized and tested in vitro for binding with the benzodiazepine receptor in the competition with 3H-zolpidem as an ω1-selective radioligand. Molecular electrostatic potential (MEP) and the HOMO and LUMO energies were calculated for the compounds by semi-empirical quantum chemistry methods. The lipophilicity parameter of the compounds, expressed as the logarithm of the octanol-water partition coefficient (log P), was calculated; alternatively, standard values of the Hansch hydrophobic substituent constants π were used. In agreement with earlier investigations on the benzodiazepine receptor ligands with a high preference for the ω1-subtype, a quantitative correlation of the biological data with molecular parameters has revealed a significant dependence (r=0.954) of the binding affinity (IC50) on the deepest MEP minimum, in this case associated with the amide carbonyl oxygen atom. The lipophilicity parameters were found to be of lower significance.

-

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.