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 1637976Notes

Reaction equation

HRID 1637976 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 refluxed 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 1 N 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. temperatureThe mixture was refluxed under nitrogen for three days
  2. customAfter removal of the solvent in vacuo
  3. dissolutionthe residue was dissolved in ethyl acetate
  4. washThe ethyl acetate was washed several times with 1 N HCl and brine
  5. dry with materialIt was then dried over Na2SO4
  6. customThe crude product obtained by evaporation in vacuo
  7. customwas purified by silica gel column chromatography
  8. washeluting with 25% ethyl acetate/hexane

Sources & evidence

ORD record
ord-864c5afb45214cc481ff0237008bcaca
Source dataset
uspto-grants-2000_03
Patent number
US06043271

Reaction notes

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