2-(Dimethylamino)ethanol → HCID 16113118, compound

In a 500 mL dry round bottom flask with reflux condenser and magnetic stirrer was placed 2-chloro-3-ethyl nicotinate (40.0 g, 215.5 mmol) in methanol (200 mL), and CH3ONa (65 mL, 301.7 mmol, 25% in methanol) was added slowly and the reaction mixture was refluxed for 16 hour. The reaction mixture was cooled to room temperature, quenched by addition of saturated NH4Cl solution and extracted by ethyl acetate. The combined organic layer was washed well with water, brine, dried over Na2SO4 and concentrated to give 2-methoxy-3-methyl nicotinate (35 g, 970% yield). In a dry 500 mL round bottom flask sodium hydride (9.21 g, 230.3 mmol, 60%) was added in DMF (100 mL). 4-Methoxyacetophenone (31.5 g, 209 mmol) in dry DMF (50 mL) was added dropwise at 0° C. over 30 min. The reaction mixture was stirred for 1 h at room temperature. 2-Methoxynicotinic acid methyl ester (35 g, 209 mmol) dissolved in dry DMF (50 mL) was added slowly on cooling. After addition the mixture was stirred for 16 h at room temperature. The reaction mixture was quenched by addition of a saturated aqueous NH4Cl solution and diluted with water. The solids were filtered off, washed with water and dried to give the diketo product (56.7 g, 95%). The above diketo compound (56.7 g, 199 mmol) and pyridinium hydrochloride (345 g) were placed in a 1000 mL round bottom flask and the mixture was heated at 190° C. for 5 hours. The reaction mixture was cooled to room temperature and diluted with water. The solids were separated by filtration and purified by column chromatography using 5% methanol in CH2Cl2 to give 2-(4-Hydroxy-phenyl)-pyrano[2,3-b]pyridin-4-one (23.25 g, 48.8%). 2-(4-Hydroxy-phenyl)-pyrano[2,3-b]pyridin-4-one (0.48 g, 2.0 mmol) was suspended in anhydrous THF (25 mL). Triphenyl phosphene (0.577 g, 2.2 mmol), N,N-dimethylaminoethanol (0.213 g, 2.4 mmol) and N,N-diisopropylethylamine (0.37 g, 3.0 mmol), were added. To the stirred solution was added diethylazodicarboxylate (0.383 g, 2.2 mmol). After the addition of DEAD, the reaction mixture became a clear solution. The reaction mixture was stirred at room temperature overnight. Additional triphenyl phosphene (0.288 g, 1.1 mmol), N,N-dimethylaminoethanol (0.107 g, 1.2 mmol), N,N-diisopropylethylamine (0.185 g, 1.5 mmol), and diethylazodicarboxylate (0.191 g, 11.1 mmol) were added and stirring was continued for 15 hours. The solvent was removed under vacuum. The crude material was purified by column chromatography (Silica Gel 230-400 mesh; 2-5% methanol in CH2Cl2 as eluent) to give 2-[4-(2-dimethylamino ethoxy)phenyl]pyrano[2,3-b]pyridine-4-one as white solid (0.445 g, 72%). The above compound (0.2 g, 0.644 mmol) was dissolved in anhydrous Dichloromethane (10 mL). HCl in ether (3 mL, 1.0 M) was added dropwise. A yellow precipitate was formed. The reaction mixture was stirred at room temperature for 30 min. under nitrogen. The solvent was removed and the crude compound was triturated with ether to give 2-(4-(2-(dimethylamino)ethoxy)phenyl)-4H-pyrano[2,3-b]pyridinone dihydrochloride (0.24 g, 97%) as a pale yellow solid. MS (ES) m/z: 311.98 (M+1), 310.94 (M); MP 236-238° C.

1. stirringstirring
2. waitwas continued for 15 hours
3. customThe solvent was removed under vacuum
4. customThe crude material was purified by column chromatography (Silica Gel 230-400 mesh; 2-5% methanol in CH2Cl2 as eluent)

ORD record

ord-e5def4cd0253402d8f84963afbe699a8

Source dataset

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08410109B2