Alumina, for column chromatography

With regard to the selectivity of N- (9n(9methylation to N,N-di-methylation, KY, CsY, and KX showed good results. Neutral alumina for column chromatography also promoted the reaction, but the selectivity was very low. 

A heterogeneous mixture of solid potassium cyanide (0.651 g, 10 mmol), solid methylamine hydrochloride (0.753 g, 11 mmol) and neutral alumina (for column chromatography, 1.5 g) in acetonitrile (4 mL) is placed in a Pyrex test tube (25 mm diameter, 150 mm) with a Teflon -lined screw cap. The mixture is subjected to preliminary sonication at 50°C for 10 min in a thermostated Branson cleaner (100 W, 45 kHz). Benzaldehyde (0.531 g, 5 mmol) was then added and sonication was continued for 5 h. Solid materials were filtered off through a Celite pad and the filtrate was concentrated on a rotary evaporator. The crude product was purified by short column chromatography to give a-methylamino-phenyl-acetonitrile. IR (neat) 3380, 3320, 2225 cm-1. iR NMR (CDCI3, TMS) 6 7.45 (m, 5H), 4.80 (s, IH), 2.65 (s, 3H), 1.65 (br. s, IH) ppm. 

Ultrasonic pretreatment of KMn04 in benzene before the addition of the substrate decreases the reaction time. The addition of alumina (for column chromatography) assists the sonochemical reaction. 

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