Amlodipine maleate

A long-acting dihydropyridine calcium channel blocker. It is effective in the treatment of ANGINA PECTORIS and HYPERTENSION.

1.00 g (2.4 mmol) 4-(2-chloro-phenyl)-2-(2-hydroxyimino-ethoxymethyl)-6-methyl-1, 4-dihydro-pyridine-3, 5-dicarboxylic acid 3-ethyl ester 5-methyl ester (5) was dissolved in 20 ml glacial acetic acid and hydrogenated for four hours at atmospheric pressure and room temperature using 0.062 g palladium 10percent on carbon as catalyst. The catalyst was filtered off after which the acetic acid was evaporated off. The residue was dissolved in ether and washed successively with 10percent sodium bicarbonate solution and water. After drying with MgSO4 the ether was evaporated off and the residue was dissolved in a small volume of ethanol. To the resulting solution 0.28 g (2.4 mmol) of maleic acid was added with cooling. The maleate salt precipitated after a while and was then filtered off and washed with diethyl ether and dried in vacuo, giving 0.9 g of the product as a fine white powder. By addition of a small amount of ether to the mother liquor further 270 mg of product was obtained. Combined yield: 1.17 g = 92.9 percent mp. 170-172 °C [] Elemental analysis: CalculatedC 54.9percentH 5.6percentN 5.3percentCl 6.8percentFoundC 53.86percentH 5.6percentN 5.11percentCl 6.9percentIR: 3392 cm-1; 2946 cm-1; 1688 cm-1; 1648 cm-1;1603 cm-1; 1479 cm-1; 1283 cm-1; 1206 cm-1; 1100 cm-1; 759 cm-1; (KBr) FAB-MS: 409 [MH+], 408 [M+], 297 [M+-C6H4Cl] NMR: 500 MHz 1H-NMR (D6-DMSO) (δ ppm) : 8.37 (s, 1H, NH); 7.87 (br. s, 3H, NH); 7.10-7.35 (m, 4H, ArH); 6.06 (s, 2H, CH); 5.31 (s, 1H, CH); 4.66 (d. d., 2H, CH2); 3.97 (q, 2H, CH2); 3.66 (t, 2H, CH2); 3.50 (s, 3H, CH3); 3.09 (t, 2H, CH3); 2.3 (t, 3H, CH3); 1.12 (t, 3H, CH3).0.5 g (1.2 mmol) 4-(2-chloro-phenyl)-2-(2-hydroxyimino-ethoxymethyl)-6-methyl-1, 4-dihydro-pyridine--3, 5-dicarboxylic acid 3-ethyl ester 5-methyl ester (5) and 0.56 g (2.4 mmol) nickel chloride hydrate was dissolved in 35 ml methanol and cooled to -30 °C. 0.454 g (0.012 mol) sodium borohydride was added in small portions over 30 minutes whereafter the mixture was stirred for 1 hour at room temperature. The mixture was evaporated to dryness and 20 ml of 6N hydrochloric acid was added with stirring. The mixture was filtered and then made alkaline with conc. ammonium hydroxide (pH > 8.5). The filtrate was extracted twice with dichloromethane, and then dried with MgSO4. The organic phase was evaporated to give 0.274 g (56.7 percent) of the crude base. The product was dissolved in a small amount of ethanol. To the resulting solution 0.08 g (0.7 mmol) maleic acid was added with cooling. After a while the maleate salt precipitated and was then filtered off and washed with diethyl ether and dried in vacuo, giving the product as a fine white powder. yield: 0.21 g = 33.4 percent mp. 170-172 °C [] Elemental analysis: CalculatedC 54.9percentH 5.6percentN 5.3percentCl 6.8percentFoundC 54.94percentH 5.65percentN 5.23percentCl 7.05percentIR: 3392 cm-1; 2946 cm-1; 1688 cm-1; 1648 cm-1; 1603 cm-1; 1479 cm-1; 1283 cm-1; 1206 cm-1; 1100 cm-1; 759 cm-1; (KBr) FAB-MS: 409 [MH+], 408 [M+], 297 [M+-C6H4Cl]Into the reactor add 290kg of methylamine solution, under stirring add 59 kg of Phthaloyl Amlodipine, stirring at a temperature of 25 ° C for more than 20 hours, cool down to 20 ° C, filter, wash the filter residue with drinking water until the pH of the water is ≤10, the filter residue is rinsed with purified water, dried, and dried at 60 ° C, until the water is ≤1.5percent, cool down at normal temperature, discharge, obtained Amlodipine: 10g of Amlodipine and 100ml of water add into 250ml eggplant bottle, stir at room temperature, and dissolve 3.9 g of maleic acid into 40 ml of water, at a constant temperature of 30 ° C, drip into the Amlodipine solution into the eggplant-shaped bottle by using the dropping funnel, after the addition, continue to stir for 4 hours, filter by suction, wash the filter cake twice with water, and vacuum dry at 65 ° C for more than 8 hours, obtained white block of Amlodipine Maleate crude, yield 91percent, purity 99.2percent; Take 10g crude Amlodipine Maleate, adds into 250ml eggplant shaped bottle, and then add 80ml methanol into the eggplant shaped bottle, heat at 60 ° C, stir to completely dissolve the material, cool at 50 ° C, add 1g of activated carbon, stir to warm at 65 ° C, stir for 30min, heat filtration, remove activated carbon, and add 20ml of methanol to clean the eggplant shaped bottle, distill it under reduced pressure, and steam to a volume of 40ml, add 120 ml of ethyl acetate, azeotropic distillation is carried out, the volume is distilled off to 50 ml, the temperature is lowered at room temperature, then lowered at 0 ° C, stirred for 2 h, suction filtered, and dried under reduced pressure, obtained Amlodipine Maleate, the yield is 91.5 percent, and the purity is 99.5 percent;Preparation of 3-Ethyl, 5-methyl (4RS) 2-[(2-AMINOETHOXY) METHYLL-4-(2-CHLOROPHENYL)-6-METHYL 1, 4- dihydropyridine-3, 5-dicarboxylate maleate (I) Amlodipine base (80. 0 g, 0.196 mol) was added into toluene (552 mL) at 21-24 °C. To dissolve the base methanol (65 ML) was added to above solution. Maleic acid (22.7 g, 0.196 mol) was disolved in MEOH (67 mL) and was added to above solution at 21-24 °C. The solution was stirred for Ih at this temperature and the salt was filtered off. The crystals were washed with diethylether (100 ML) and ethyl acetate (100 mL) and dried to give 93.7 g of AMLODIPINE maleate as a white solid in 91. 2percent YIELD. 1H-NMR (DMSO) 8 8.37 (s, 1H), 7. 79 (s, 3H), 7.20 (m, 4H), 6.00 (s, 2H), 5.38 (s, 1H) 4.68 (d, 1H), 4. 55 (d, IH), 3.95 (m, 2H), 3.60 (m, 2H), 3. 48 (S, 3H), 2.95 (M, 2H), 2.28 (s, 3H), 1.08 (t, 3H). 13C-NMR (DMSO) 8 167.8, 167.7, 166.9, 146.3, 145.9, 145.2, 136.4, 131.8, 131. 6, 129.7, 128.5, 128.1, 102.9, 102.6, 67.3, 67. 2, 60.1, 51. 2, 40. 3, 37. 3, 19. 0, 14. 7.

Used as an antihypertensive drug

Molecular Weight:524.9
Hydrogen Bond Donor Count:4
Hydrogen Bond Acceptor Count:11
Rotatable Bond Count:12
Exact Mass:524.1561582
Monoisotopic Mass:524.1561582
Topological Polar Surface Area:175
Heavy Atom Count:36
Complexity:766
Undefined Atom Stereocenter Count:1
Defined Bond Stereocenter Count:1
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes