Hydrochloric Acid → Furo[2,3-c]pyridine, 4,5,6,7-tetrahydro-6-methyl-

To 6-(t-butoxycarbonyl)-4,5,6,7-tetrahydrofuro[2,3-c]pyridine (1.05 g), a saturated solution of hydrochloride in ethanol (30 ml) was added at room temperature. After stirring for 2 hours, the reaction mixture was concentrated. The residue thus obtained was suspended in methylene chloride (20 ml), followed by the addition of methanol (20 ml), triethylamine (1.31 ml), acetic acid (810 μl), formaldehyde (a 37% aqueous solution, 610 μl) and sodium triacetoxyborohydride (1.51 g) at room temperature. The resulting mixture was stirred for 1 hour. To the reaction mixture, a saturated aqueous solution (100 ml) of sodium bicarbonate and methylene chloride (20 ml) were added to cause separation. The water layer was extracted with methylene chloride (3×10 ml). The organic layers were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue thus obtained was purified by chromatography on a silica gel column (50 g of silica gel, methylene chloride:acetone=1:1→1:2→methylene chloride:methanol=10:1), whereby the title compound (434 mg) was obtained as a colorless transparent oil.

1. concentrationthe reaction mixture was concentrated
2. customThe residue thus obtained
3. stirringThe resulting mixture was stirred for 1 hour
4. customseparation
5. extractionThe water layer was extracted with methylene chloride (3×10 ml)
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residue thus obtained
9. customwas purified by chromatography on a silica gel column (50 g of silica gel, methylene chloride:acetone=1:1→1:2→methylene chloride:methanol=10:1), whereby the title compound (434 mg)
10. customwas obtained as a colorless transparent oil

ORD record

ord-c2ff7b28513e414981f5a625693a2876

Source dataset

uspto-grants-2004_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06747023B1