Sodium Hydroxide → 3-dipropylamino-5-chloroformylchroman-HCL

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Reaction Steps

3-Dipropylamino-5-methyloxychroman (Example 2; 400 mg, 1.37 mmol) was dissolved in 10 ml methanol and NaOH (60 mg, 1.5 mmol) in 2 mL H2O was added. The mixture was refluxed for 5 hours, cooled, filtered through Celite and evaporated to dryness. The residue was refluxed in SOCl2 (5 mL, 68 mmol) for 30 minutes. The excess SOCl2 was then removed in vacuo to give 3-dipropylamino-5-chloroformylchroman-HCL as a gum. The pale brown gum was dissolved in CH2Cl2 (50 mL), and a stream of NH3 (g) was introduced during 2 minutes. The solution was washed with aqueous NaHCO3, dried with Na2SO4 and evaporated to dryness. The oil was purified by flash chromatography (silica gel) by elution with ethyl acetate/hexane 1:4. Yield 80%, 13C-NMR: 172.0 154.9 136.5 126.9 120.4 119.1 118.6 67.8 53.0 52.6 26.1 22.4 21.9 14.1 11.7.

Provenance & Evidence