Sulfuric acid magnesium salt (1:1) → N-(5-bromo-2,3-dichlorobenzyl)cyclopropanamine

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Reaction Steps

5-Bromo-2,3-dichlorobenzaldehyde (1 eq.) from the previous step and cyclopropylamine (2 eq.) were combined in CH2Cl2 (0.1 M). To this was then added MgSO4 (1 eq.) and the resulting suspension was stirred at RT for 18 h. The insolubles were then removed via filtration through a pad of celite and the filtrate was concentrated in vacuo. The crude imine thus obtained was then re-taken up in a 2:1 (v/v) mixture of THF:MeOH (0.17 M). To this solution was added sodium borohydride (10 eq.) portionwise and the resulting mixture was stirred at RT for 48 h. The reaction was quenched with 1 N aq. HCl, neutralized with 1 N aq. NaOH and extracted with ether. The combined organic extracts were then washed with water and brine, dried over Na2SO4, filtered and the filtrate concentrated in vacuo. Purification of the crude product thus obtained by way of flash chromatography (SiO2, Hex→1:1 (v/v) Hex:EtOAc) afforded the title compound as a colorless oil.

Provenance & Evidence