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

HRID 363259Notes

Reaction equation

HRID 363259 reaction equation
[OH:1][C:2]1[CH:11]=[C:10]([OH:12])[C:9]([C:13](=[O:16])[CH2:14][CH3:15])=[C:8]2[C:3]=1[C:4]([CH2:18][CH2:19][CH3:20])=[CH:5][C:6](=[O:17])[O:7]2.CO[CH:23](OC)[CH2:24][C:25]([CH3:28])(O)[CH3:26]>N1C=CC=CC=1>[CH3:26][C:25]1([CH3:28])[O:1][C:2]2[C:3]3[C:4]([CH2:18][CH2:19][CH3:20])=[CH:5][C:6](=[O:17])[O:7][C:8]=3[C:9]([C:13](=[O:16])[CH2:14][CH3:15])=[C:10]([OH:12])[C:11]=2[CH:23]=[CH:24]1

Participants

4

Reactant 2

HCID 44399804,4-Dimethoxy-2-methylbutan-2-olHCID 54948785,7-Dihydroxy-8-propionyl-4-propyl-2H-chromen-2-one

Product 1

HCID 54948815-Hydroxy-2,2-dimethyl-6-propionyl-10-propyl-2H,8H-pyrano[2,3-f]chromen-8-oneYield 79.1%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

A mixture of 3 (2.60 g, 9.42 mmol) and 4,4-dimethoxy-2-methylbutan-2-ol (5.54 g, 37.7 mmol) were dissolved in anhydrous pyridine (6.5 mL). The mixture was ref luxed under nitrogen for three days. After removal of the solvent in vacuo, the residue was dissolved in ethyl acetate. The ethyl acetate was washed several times with 1N HCl and brine. It was then dried over Na2SO4. The crude product obtained by evaporation in vacuo was purified by silica gel column chromatography, eluting with 25% ethyl acetate/hexane to afford 2.55 g of 4 in 78.6% yield, mp 96°-98° C. 1H-NMR (CDCl3) δ 1.05 (3H, t, J=7.3 Hz, CH3); 1.22 (3H, t, J=7.5 Hz, CH3); 1.53 (6H, s, 2 CH3); 1.75 (2H, m, CH2); 2.92 (2H, t, J=7.1 Hz, CH2); 3.35 (2H, q, J=7.1 Hz, CH2); 5.56 (1H, d, J=10.0 Hz, H3); 5.98 (1H, s, H9); 6.72 (1H, d, J=10.0 Hz, H4); MS (EI): 343 (5.7, M+1); 342 (22.5, M+); 327 (100, M-CH3); IR (KBr): 1728 (vs, C=O) cm-1 ; Anal. calcd. for C20H22O5 : C, 70.16; H, 6.48; Found: C, 70.45; H, 6.92.

Workup

  1. customAfter removal of the solvent in vacuo
  2. dissolutionthe residue was dissolved in ethyl acetate
  3. washThe ethyl acetate was washed several times with 1N HCl and brine
  4. dry with materialIt was then dried over Na2SO4
  5. customThe crude product obtained by evaporation in vacuo
  6. customwas purified by silica gel column chromatography
  7. washeluting with 25% ethyl acetate/hexane

Sources & evidence

ORD record
ord-9e2160bdd41644dd9a288c7a56053c9d
Source dataset
uspto-grants-1999_02
Patent number
US05872264

Reaction notes

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