Synthesis
Preparation of Example (Compound 22a): 29.4 g of o-bromobenzaldehyde and 81 mL of 40% aqueous methylamine were mixed with 238 mL of tetrahydrofuran (THF). At room temperature, 19 g of sodium borohydride (NaBH4) was added in batches over 25 minutes. The reaction mixture was stirred overnight at room temperature and then concentrated using a rotary evaporator. The residue was stirred into ice water and the aqueous phase was extracted twice with ether. The combined ether phases were concentrated by evaporation under reduced pressure. The product was purified by silica gel column chromatography using ethyl acetate or ethyl acetate/methanol (4:1) as eluent to give 18.5 g of N-methyl-2-bromobenzylamine (22a) in yellow liquid form. Yield: 58%.
References
[1] Patent: US6232468, 2001, B1
[2] Tetrahedron, 2003, vol. 59, # 40, p. 8049 - 8056
