Secondary amine synthesis (aldehyde versus primary amine):
To a solution of 1-[3-(4-methylpiperazin-l-yl)-2,3,4,5-tetrahydrooxepin-3-yl]methanamine (250 mg, 1.109 mmole) in 1,2-dichloroethane (4 ml) was added AcOH (290 μL, 5.07 mmole) then 1-methyl-2-oxo-1,2-dihydroquinoline-3-carbaldehyde (190 mg, 1.015 mmole). After 20 min sodium triacetoxyborohydride (323 mg, 1.522 mmole) was added. After 16 hr the mixture was diluted with IM aqueous NaOH and extracted with CH2Cl2 (3x). The combined organic layers were dried (MgSO4), filtered, and concentrated. Flash column chromatography (gradient, 0-10% MeOH/CH2Cl2) gave the title compound as a pale yellow oil (279 mg, 69%).
Patent reference: WO2010056564 (Merck)