[H-].[Al+3].[Li+].[H-].[H-].[H-].[CH3:7][O:8][C:9]1[C:18]2[C:13](=[CH:14][CH:15]=[CH:16][CH:17]=2)[C:12]([O:19][CH3:20])=[CH:11][C:10]=1[C:21](OC)=[O:22].[NH4+].[Cl-].Cl>CCOCC.C1COCC1.CO>[CH3:7][O:8][C:9]1[C:18]2[C:13](=[CH:14][CH:15]=[CH:16][CH:17]=2)[C:12]([O:19][CH3:20])=[CH:11][C:10]=1[CH2:21][OH:22]
A solution of lithium aluminum hydride (29.2 mL, 29.2 mmol, 1 M in ether) in ether (30 mL) was heated to reflux under argon. A solution of ester 22 (7.18 g, 29.2 mmol) in ether (30 mL) and THF (8 mL) was added dropwise over 35 min via an addition funnel. The milky yellow mixture was refluxed for 3 h and then cooled to 0° C. Methanol (10 mL) was added dropwise and the resulting clear yellow solution was stirred for 1 h. Saturated NH4Cl (20 mL) and aqueous HCl (5 mL, 10%) were added and the mixture was extracted with ether (6×). The combined organic layers were washed with saturated Na2CO3 (2×) and H2O (2×), dried (MgSO4), filtered and evaporated. Column chromatography of the crude product (35:65 EtOAc:hexanes) afforded 23a (5.82 g, 92%) as a pink solid; Rf=0.48 (35:65 EtOAc:hexanes); mp=69-70° C.; lit mp=68-70° C.25; 1H NMR (CDCl3): δ 8.23 (dd, 1H), 8.03 (dd, 1H), 7.52 (m, 2H), 6.82 (s, 1H), 4.89 (s, 2H), 3.99 (s, 3H), 3.92 (s, 3H), 1.95 (bs, 1H).
Wird geladen…
