[Mg].[CH2:2](Br)[CH:3]([CH3:5])[CH3:4].[N:7]1([C:13]2[CH:20]=[CH:19][CH:18]=[CH:17][C:14]=2[CH:15]=[O:16])[CH2:12][CH2:11][CH2:10][CH2:9][CH2:8]1>CCOCC>[CH3:4][CH:3]([CH3:5])[CH2:2][CH:15]([OH:16])[C:14]1[CH:17]=[CH:18][CH:19]=[CH:20][C:13]=1[N:7]1[CH2:12][CH2:11][CH2:10][CH2:9][CH2:8]1In a 3 necked round bottom flask (25 ml), equipped with a dropping funnel, reflux condenser and thermometer pocket, placed magnesium turnings (0.254 gm, 10.47 mmol) and flame dried the apparatus. Dry diethyl ether (10 ml.) was added to Mg. Turning, Isobutyl bromide (1.13 ml, 1.45 gm, 10.58 mmol) was taken in 2 ml of dry ether and added drop wise to the Mg turnings. As soon as ether starts boiling (in a few minutes) the reaction was cooled using ice-salt and continued the addition of isobutyl bromide. After complete addition of isobutyl bromide continued for another 20 minutes. o-piperidino benzaldehyde 8 (1.0 gm, 5.29 mmol) in 2 ml of ether was added drop wise at −10° C. After the completion of addition of 8 continued the stirring for 1 hr and the reaction was quenched with ice-cooled saturated ammonium chloride solution (5 ml), the solid separated is filtered off, the filtrate is extracted with ethyl acetate (10×2 ml) dried over sodium sulphate and concentrated to yield 1.36 gm of crude product. The crude product was chromatographed and obtained pure 9 (54.2%).
Loading…
