5-Hydroxy-2,2-dimethyl-6-propionyl-10-propyl-2H,8H-pyrano[2,3-f]chromen-8-one → 5-Hydroxy-2,2-dimethyl-6-propanoyl-10-propyl-3,4-dihydropyrano[2,3-f]chromen-8-one

Beteiligte Stoffe

Reaktionsschritte

A mixture of 5-hydroxy-2,2-dimethyl-6-propionyl-10-propyl-2H-pyrano[2,3-f]chromen-8-one (30) (5 g, 14.60 mmol) and sulfided platinum (5% on carbon, 1 g) in toluene/isopropyl alcohol (200/50 mL) was hydrogenated 16 h at room temperature under atmospheric pressure of hydrogen. The catalyst was filtered off and the filtrate concentrated under vacuum. The solid residue was crystallized from ethanol and re-crystallized from acetone to provide 2.66 g of 44a (53% yield). 1H NMR (CDCl3): 1.03 (t, J=7.5 Hz, 3H), 1.23 (t, J=7.5 Hz, 3H), 1.42 (s, 6H), 1.64 (m, 2H), 1.84 (t, J=6.5 Hz, 2H), 2.70 (t, J=6.5 Hz, 2H), 2.90 (m, 2H), 3.34 (q, J=7.0 Hz, 2H), 5.98 (s, 1H), 14.61 (s, 1H); 13C NMR (CDCl3): 8.45, 13.89, 16.42, 23.37, 26.62, 31.20, 38.13, 39.38, 77.60, 102.77, 103.43, 105.30, 110.22, 156.41, 157.29, 158.94, 159.76, 165.77, 206.67; IR: 1730 cm−1; MS (ACPI+): 345 (M+1); Anal. Calcd. for C20H24O5: C 69.75, H 7.02; Found C 70.03, H 7.18.

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