Methylamine → Ammonia

Participants

Reaction Steps

(R)-5-Formyl-3-(N-isopropyl-N-n-propylamino)chroman (0.4 g, 1.5 mmol) was dissolved in methanol (15 mL), saturated with methylamine. Some molcular sieves (3Å) were added. The solvent was removed in vacuo. The residue was dissolved in methanol (30 mL) under nitrogen atmosphere. Tosylmethylisocyanide (0.36 g, 1.8 mmol) and K2CO3 (0.25 g, 1.8 mmol) were added and the reaction mixture was reluxed for 1 hour. Additionally tosylmethylisocyanide (0.36 g, 1.8 mmol) and K2CO3 (0.25 g, 1.8 mmol) were added and the reflux was continued for 3 hours. Tosylmethylisocyanide (0.1 g, 5.2 mmol) was added once more and the reflux was continued for 12 hours. The solvent was removed in vacuo. The residue was dissolved in diethyl ether/2M NH3. The layers were separated and the water-phase was extracted once more with ether. The organic layers were combined and dried (Na2SO4). The solvent was removed in vacuo to give a brown oily residue which was purified by flash chromatography (SiO2, first CH2Cl2 /EtOAc, 5:1, also containing 0.5% of NH3 and then EtOAc/EtOH, 50:1+0.5% of NH3) to give 200 mg of the title compound (42 yield). [α]D21 -37° (c 30 mg/mL, MeOH). The HCl-salt was precipitated from diethyl ether at 0° C. and recrystallized from ethanol/diethyl ether. mp 159°-161° C. (dec).

Provenance & Evidence