Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D211/00—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings
  • C07D211/04—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D211/80—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having two double bonds between ring members or between ring members and non-ring members
  • C07D211/84—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having two double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen directly attached to ring carbon atoms
  • C07D211/90—Carbon atoms having three bonds to hetero atoms with at the most one bond to halogen
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C211/00—Compounds containing amino groups bound to a carbon skeleton
  • C07C211/01—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms
  • C07C211/26—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms of an unsaturated carbon skeleton containing at least one six-membered aromatic ring
  • C07C211/27—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to acyclic carbon atoms of an unsaturated carbon skeleton containing at least one six-membered aromatic ring having amino groups linked to the six-membered aromatic ring by saturated carbon chains

Definitions

• the present invention relates to new, improved and industrially viable process for the preparation of Lercanidipine or its pharmaceutically acceptable salts using novel derivatives of 2,N-dimethyl-N-(3,3-diphenylpropyl)-l -amino compounds and novel process for the preparation of amorphous Lercanidipine hydrochloride.
• Lercanidipine hydrochloride i.e., 3,5-Pyridinedicarboxylic acid, l,4-dihydro-2,6- dimethyl-4-(3-nitrophenyl)-,2-[(3,3-diphenylpropyl)methylamino]- 1 , 1 -dimethyl ester, hydrochloride having the formula (I)
• Lercanidipine hydrochloride (I) is disclosed in US4705797.
• crude lercanidipine is obtained as an oily residue that must be purified by flash chromatography using chloroform, containing increasing amounts of acetone, as the eluant.
• the solvent is then evaporated to dryness and remaining residue is dissolved in methanol adding a small excess of hydrochloric acid in ethanol.
• the hemi-hydrated hydrochloride salt is prepared by treatment with diluted hydrochloric acid in the presence of sodium chloride.
• US Patent No. 5912351 describes an alternate process for the preparation of lercanidipine hydrochloride. It involves reaction of 1, 4-dihydro-2, 6-dimethyl-5- methoxycarbonyl-4- (3-nitrophenyl) pyridine-3-carboxylic acid with thionyl chloride in dichloromethane and dimethylformamide at a temperature between -4° and +1 0 C and subsequent esterification of the obtained acid chloride with 2, N-dimethyl-N- (3, 3 diphenylpropyl)-l-arnino-2-propyl alcohol at a temperature between -10° and O 0 C.
• the disadvantage of the said process is the use of thionyl chloride as a reactant, which is difficult to handle on an industrial scale because of evolution of sulphur dioxide and hydrochloric gas from the reaction. Moreover it also requires special grade of equipment such as glass-lined reactor etc.
• the Applicant has found simpler and cost-effective process for synthesizing Lercanidipine, avoiding use of hazardous materials, which is industrially viable and gives better yields.
• WO/03/014084 discloses novel crystalline form I & II of Lercanidipine Hydrochloride and mixtures of Form I & II having predetermined and reproducible content of Form I & II & optionally other forms of Lercanidipine Hydrochloride such as amorphous.
• EP 1600441 discloses crystalline form I of Lercanidipine Hydrochloride and a mixture of form I with amorphous and optionally form II.
• these prior art don't describe pure amorphous form (anhydrous or hemihydrate) of Lercanidipine Hydrochloride and its preparation.
• WO2006089787A1 discloses process for the preparation of pure amorphous lercanidipine hydrochloride from crystalline lercanidipine hydrochloride.
• the present invention provides obvious benefits with respect to removing both the technical problems associated with prior art as well being simpler and economical, while at the same time achieving high purity and yield of the product with convenience to operate on a commercial scale.
• the present invention relates to new, improved and industrially viable process for the preparation of Lercanidipine hydrochloride using novel intermediate of amino phenyl derivatives of formula (III) with 1,4-dihydropyridine acid derivative.
• R is X OrOSO 2 R
• X Cl, F, Br or I ;
• R alkyl (C 1 to C 4) , phenyl, or 4-methyl phenyl.
• the object of the present invention is to provide a new and improved process for synthesis of Lercanidipine hydrochloride.
• the second object of the instant invention is to provide a simpler and cost-effective process for synthesis of Lercanidipine hydrochloride.
• Another object of the present invention is to provide an industrially viable process for synthesis of Lercanidipine hydrochloride.
• Still another object of the present invention is to provide an improved process for synthesis of Lercanidipine hydrochloride, which gives better yield.
• Yet another object of the present invention is to provide novel polymorphic forms of Lercanidipine hydrochloride and process for the preparation thereof.
• Yet another object of the present invention is to provide novel process for amorphous form of Lercanidipine hydrochloride.
• the present invention provides a process for the preparation of lercanidipine hydrochloride of formula (I) as described herein below:
• Fig. 1 This figure indicates X-ray diffraction pattern of amorphous Form Tl of Lercanidipine hydrochloride obtained according to the present invention.
• Fig. 2 This figure indicates Infrared Spectrum of amorphous Form Tl Lercanidipine hydrochloride obtained according to the present invention.
• Fig. 3 This figure indicates Differential Scaning Calorimetry of amorphous Form Tl Lercanidipine hydrochloride obtained according to the present invention.
• an efficient process for the preparation of Lercanidipine which provides obvious benefits with respect to economics, generation of minimal effluents, lesser number of process steps, less reactor occupancy, higher purity of the product with convenience to operate on a commercial scale.
• the present invention provides an improved process for preparing Lercanidipine Hydrochloride (I) as discussed herein: -
• Reaction B -(a) (a') Reacting 2,N-Dimethyl-N-(3,3-diphenyl propyl)-l-amino-2-propanol Formula ( II ) with Halogenating agent in suitable solvent or mixture thereof to obtained, of N- Dimethyl-N- (3,3-diphenyl propyl)- l-amino-2-halide compound (IHB)
• X Cl, Br, F, or I.
• X chloride
• R" thionyl chloride, Phosphorous oxychloride, Oxaloylchloride, phosphorous trichloride or phosphorous pentachloride.
• Reaction B-(a) can be carried out using by methane sulphonyl halide, p-toluene sulphonyl chloride, or benzene sulphonyl chloride using base selected from the group comprising of organic base, inorganic bases.
• organic and inorganic bases are triethylamine, pyridine, sodium hydroxide and potassium hydroxide, sodium carbonates, and the like, at temperature ranging from about -15°C. to 60°C, preferably between -5°C. to 25 0 C, more preferably between 5°C. to 2O 0 C, optionally in an inert gas atmosphere.
• the duration of the esterification reaction may be from 15 minutes to 5 hours depending on reagents used and measuring end point of reaction by analytical method such as TLC, HPLC and the like.
• Reaction B-(a') can be carried out by using thionyl chloride, Phosphorous oxichloride, oxalylchloride, phosphorous trichloride or phosphorous pentachloride at temperature ranging from about 15 0 C. to 60°C, preferably between 2O 0 C. to 45°C, more preferably between 25 0 C. to 40°C, optionally in an inert gas atmosphere. The duration of the reaction may be from 15 minutes to 5 hours.
• Reaction (C) as per the present invention can be carried out using in general by reacting compound (IIIB) with 2,6-dimethyl-5-methoxy carbonyl-4-(3-nitrophenyl)- l,4-dihydropyridine-3-carboxylic acid of formula (IV) using base selected from the group comprising of organic base, inorganic bases.
• organic and inorganic bases are triethylamine, pyridine, sodium hydroxide and potassium hydroxide, sodium carbonates, and the like, preferably potassium hydroxide, in a solvent to obtained compound (I) at temperature ranging from about -15 0 C to 90°C, preferably ranging from O 0 C.
• the duration of the condensation reaction may be from 15 minutes to 5 hours depending on reagents used and measuring end point of reaction by analytical method such as TLC, HPLC and the like.
• the suitable solvent used in Reaction B is selected from the group comprising of ethers, esters, aromatic hydrocarbon, chlorinated or non-chlorinated Aprotic solvents or mixtures thereof.
• the ethers that can be used as solvent are selected from the group comprising of diethyl ether, tetrahydrofuran, petroleum ether (60-80 0 C.) or mixtures thereof.
• the esters that can be used as solvent are selected from the group comprising of methyl acetate, ethyl acetate, n-butyl acetate, n-propyl acetate or mixtures thereof.
• the aromatic hydrocarbons that can be used as solvent are selected from the group comprising of benzene, toluene, xylene or mixtures thereof.
• Chlorinated aprotic solvents that can be used as solvent are selected from the group comprising of Chloroform, chlorobenzene, Dichloromethane, Dichloroethane, 1,1,1-trichloroethane, or any mixture thereof.
• Non-chlorinated aprotic polar solvent that can be used as solvent are selected from the group comprising of dimethylformatnide, dimethylsulphoxide and dimethyl acetamide or any mixture thereof.
• the solvent used in Reaction B is dichloromethane.
• the solvent used in C can be selected from the group comprising of protic or aprotic solvents or mixtures thereof.
• Protic solvents that can be used as solvent are selected from the group comprising of ethanol, methanol, isopropyl alcohol, and tertbutanol or any mixture thereof.
• Aprotic solvents that can be used as solvent are selected from the group comprising of chloroform, tetrahydrofuran, and dioxane, dimethylformamide.
• the solvent used in Reaction C is isopropyl alcohol.
• the present invention provides a process for preparing the Lercanidipine Hydrochloride (I) as discussed herein: -
• Reaction (B') halogenation can be carried out by using methane sulphonyl chloride, thionyl chloride, Phosphorous oxichloride, oxalylchloride, phosphorous trichloride or phosphorous pentachloride at temperature ranging from about 15°C. to 60°C preferably between 20°C. to 45 0 C, more preferably between 25°C. to 40 0 C, optionally in an inert gas atmosphere. The duration of the reaction may be from 15 minutes to 5 hours.
• reactant used is methane sulphonyl chloride or Thionyl chloride. In a more preferred embodiment, reactant used is methane sulphonyl chloride.
• the solvent used in reaction B' is selected from the group comprising of ethers, esters, aromatic hydrocarbon, chlorinated or non-chlorinated aprotic solvents or mixtures thereof.
• the ethers that can be used as solvent are selected from the group comprising of diethyl ether, tetrahydrofuran, petroleum ether (60-80°C.) or mixtures thereof.
• the esters that can be used as solvent are selected from the group comprising of methyl acetate, ethyl acetate, n-butyl acetate, n-propyl acetate or mixtures thereof.
• the aromatic hydrocarbons that can be used as solvent are selected from the group comprising of benzene, toluene, xylene or mixtures thereof.
• Chlorinated aprotic solvents that can be used as solvent are selected from the group comprising of chloroform, chlorobenzene, dichloromethane, dichloroethane, 1,1,1-trichloroethane, or any mixture thereof.
• Non-chlorinated aprotic polar solvent that can be used as solvent are selected from the group comprising of dimethylformamide, dimethylsulphoxide and dimethyl acetamide or any mixture thereof.
• the solvent used in Reaction ( B') is dichloromethane.
• compound (I) is optionally purified in alcohol followed by treatment in ester in presence of anhydrous hydrochloric acid then the content of hydrochloric acid in ester may vary from about 0.01% w/w to about 0.5%. In a preferred embodiment it may vary from 0.05 to 0.3%. hi a more preferred embodiment it may vary from 0.05% to 0.25%.
• Polymorphic forms can be distinguished from each other by various analytical techniques, for example, by x-ray diffraction and infrared spectroscopic techniques.
• the present invention provides a method for preparing amorphous Lercanidipine hydrochloride comprising the steps of: (1) dissolving Lercanidipine hydrochloride in an organic solvent to prepare a solution and optionally distilled out the organic solvent (2) forming precipitates by adding an organic solvent selected from the group consisting of cyclohexane, cyclopentane, n-hexane, and ether; and (3) Isolating amorphous Lercanidipine hydrochloride
• the organic solvent of step-1 is used to dissolve Lercanidipine hydrochloride.
• the suitable solvent used for dissolving Lercanidipine hydrochloride are chlorohydrocarbon such as methylene chloride; alcohol such as methanol, ethanol, isopropyl alcohol and t-butyl alcohol; or a mixture of organic solvent may be used.
• step (2) of the present invention the addition of another organic solvent may be carried out at 10°C-30°C.
• Isolating lercanidipine hydrochloride includes filteration, washing and drying of the isolated product at appropriate condition wherein filtration should preferably be carried out after the formation of precipitates in step (2), more preferably be carried out within about 1-3 hours. Further, drying of the isolated product can be preferably carried out under vacuum at 20 ⁇ 80°C, preferably at 30 ⁇ 32°C, for 6 - 12 hours.
• Alternative method for preparing amorphous Lercanidipine hydrochloride comprising the steps of: (1) dissolving Lercanidipine hydrochloride in alcohol such as methanol, ethanol, isopropyl alcohol and t-butyl alcohol or MDC or in a mixed organic solvent of methylene chloride and alcohol to form a solution (2) forming precipitates by adding water or by adding solution of step (1) into the water and (3) Isolating amorphous Lercanidipine hydrochloride.
• step (2) of the alternative method the addition of water may be carried out at 10°C-30°C.
• step (2) of the alternative method when solution is added into the water, it may optionally contain NaCl or KCl. Addition time may vary from 1 to 3 hour at 0 ⁇ 5 0 C.
• the present invention provides still another method for preparing amorphous Lercanidipine hydrochloride comprising the steps of: (1) dissolving Lercanidipine hydrochloride in alcohol such as methanol, ethanol, isopropyl alcohol and t-butyl alcohol or MDC or in a mixed organic solvent of methylene chloride and alcohol to form a solution; (2) the solvent removed from the solution by concentrating the solution under reduced pressure or spray drying to obtain amorphous Lercanidipine hydrochloride.
• alcohol such as methanol, ethanol, isopropyl alcohol and t-butyl alcohol or MDC
• Lercanidipine hydrochloride (10.0 g) is dissolved in methanol (30.0 ml) with stirring for 20 minutes at 25-30 0 C. Filter the solution over hyflow bed and washed hyflow bed with methanol (20.0 ml). Distilled out methanol completely under vacuum below 40-45 0 C and kept the mass with stirring under vacuum at 40-45 0 C for 2 hours. Charge water (100.0 ml) at 25-30 0 C and stirred for 1 hour. Filtered the solution and wash the bed with 30.0 ml of water and finally dried the material under vacuum at 30-32 0 C for 12 hrs. (Dry Wt. 9.5 gm; Yield: 95%).
• Lercanidipine hydrochloride (10.0 g) is dissolved in methanol (50.0 ml) with stirring for 20 minutes at RT. Filter the solution over hyflow bed and washed hyflow bed with methanol (20.0 ml). Distilled out methanol completely under vacuum below 40- 45°C and kept the mass with stirring under vacuum at 40-45°C for 2 hours. Charge diisopropyl ether (100.0 ml) at 25-3O 0 C and stirred for 1 hour. Filtered the solution and wash the bed with 20.0 ml of diisopropyl ether and finally dried the material under vacuum at 30-32°C for 6 hrs. (Dry Wt. 9.4 gm; Yield: 95%).
• NaCl (2.5 g) is dissolved in water (500 ml) at 25-30 °C and cooled the solution at 0-5 °C.
• Lercanidipine hydrochloride (20.0 g) is dissolved in methanol (35.0 ml) with stirring at 40-45 0 C. Filter the solution over hyflow bed and washed hyflow bed with methanol (5.0 ml) and add this filtrate to the NaCl solution at 0-5 °C within 1 hour. Stir the solution at 0-5 0 C for 1 hour and filter the solution over hyflow bed and washed hyflow bed with water (50.0 ml). Charge 200 ml water to the wet-cake and keep it under stirring for 30 min.
• Lercanidipine hydrochloride (30.0 g) is dissolved in methanol (450.0 ml) with stirring for 15 minutes at 30-35 °C. Filter the solution over hyflow bed and washed hyflow bed with methanol (50.0 ml). Spray dried the material on spray drier (Input temp: 90 0 C, exhaust temp: 67 0 C, blanket nitrogen pressure: 1 kg/cm 2 , blanket nitrogen pressure: 1 kg/cm 2 ). Unload the material under nitrogen atmosphere and finally dried the material under vacuum at 30-32°C for 24 hrs. (Dry Wt. 15 gm; Yield: 50%).

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• Hydrogenated Pyridines (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

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