Background and overview of the preparation method of 1-pyridin-2-yl-piperazin-2-one dihydrochloride
1-Pyridin-2-yl-piperazin-2-one dihydrochloride can be used as a pharmaceutical synthesis intermediate. If 4-bromoquinoline-6-carboxylic acid is inhaled, move the patient to fresh air; if there is skin contact, take off contaminated clothing, rinse the skin thoroughly with soap and water, and seek medical attention if you feel unwell; if In case of eye contact, the eyelids should be separated, rinsed with flowing clear methylpyridine water or normal saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately.
Preparation method of 1-pyridin-2-yl-piperazin-2-one dihydrochloride
The preparation of 1-pyridin-2-yl-piperazin-2-one dihydrochloride is as follows: 4-benzyloxycarbonyl-1-methyl-pyrazin-2(1H)-one (3.0g , 12.8mmol), 2-bromopyridine (2.02g, 12.8mmol), palladium acetate (0.29g, 1.28mmol), xantphos (1.11g, 1.92mmol) and cesium carbonate (6.26g, 19.2mmol) in anhydrous dioxygen The mixture in heterocyclohexane (13 mL) was heated in a sealed tetrahydrofuran vessel at 110°C in an oil bath for 6 hours. The resulting reaction mixture was cooled to room temperature, diluted with dichloromethane, filtered, and concentrated in vacuo. The residual solid was purified by silica gel column chromatography, eluting with an ethyl acetate-hexane gradient. The appropriate fractions were concentrated to obtain the pyridine intermediate. A mixture of 4-benzyloxycarbonyl-1-pyridin-2-ylpiperazin-2-one (1.50 g, 4.94 mmol) and Pearlmans catalyst (0.7 g) in ethanol (50 mL) was placed under a hydrogen atmosphere (1 atm). Stir at room temperature for 1 hour. The product mixture was filtered through a pad of celite and concentrated in vacuo to afford the title compound 1-pyridin-2-yl-piperazin-2-one dihydrochloride.
HNMR (MHz, CDCl3) δ8.43 (dd, J=1.8, 4.9Hz, 1H), 7.93 (d, J=8.3Hz, 1H), 7.69 (m, 1H), 7.10 (dd , J=4.9, 7.3Hz, 1H), 4.00 (t, J=5.5Hz, 2H), 3.72 (s, 2H), 3.23 (t, J=5.5Hz, 2H).
