Water → 2-Methoxy-8-hydroxy-11,12-dihydro-5H-benzo[b]naphtho[2,1-d]pyran-5-one

HRID 1709

Reaction equation

HRID 1709 reaction equation
[C:1]([CH:5]1[C:14]2[C:9](=[CH:10][C:11]([O:15][CH3:16])=[CH:12][CH:13]=2)[CH2:8][CH2:7][C:6]1=O)([O:3][CH3:4])=[O:2].[C:18]1([CH:25]=C[CH:23]=[C:21](O)[CH:20]=1)[OH:19].P(Cl)(Cl)(Cl)=O.O>C1(C)C=CC=CC=1>[CH3:16][O:15][C:11]1[CH:10]=[C:9]2[C:14](=[CH:13][CH:12]=1)[C:5]1[C:1](=[O:2])[O:3][C:4]3[CH:25]=[C:18]([OH:19])[CH:20]=[CH:21][C:23]=3[C:6]=1[CH2:7][CH2:8]2

Participants

6

Reactant 4

HCID 962WaterHCID 5054ResorcinolHCID 24813Phosphorus oxychlorideHCID 109554821-Carbomethoxy-6-methoxy-2-tetralone

Product 1

HCID 106614352-Methoxy-8-hydroxy-11,12-dihydro-5H-benzo[b]naphtho[2,1-d]pyran-5-oneYield 70.8%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
80 °C

Procedure

To a solution of 1-carbomethoxy-6-methoxy-2-tetralone (see, Colvin, Martin, and Shroot, Chemistry and Industry, 2130 (1966)) (18.0 g, 76.8 mmol) and resorcinol (8.9 g, 80.7 mmol) stirring at ambient temperature in toluene (450 mL) was added phosphorus oxychloride (12.0 g, 7.3 mL, 18.3 mmol) dropwise, and the mixture warmed to 80° C. for 12 h. After cooling to room temperature, the mixture was poured into water (500 mL) and filtered, rinsing the precipitate with ether. The filtrate layers were separated, the aqueous layer was extracted with ethyl acetate (3×500 mL), and the combined organic layers were dried (sodium sulfate) and concentrated. Recrystallization of the residue from methanol provided 16.0 g of the title compound as a yellow solid, mp 244-249 d°C.: 1 H NMR (300 MHz, DMSO-d6) d 10.55 (br s, 1H), 8.24 (d, J=8.6 Hz, 1H), 7.75 (d, J=8.7 Hz, 1H), 6.6-7.0 (m, 4H), 3.76 (s, 3H), 2.8-3.0 (m, 4H); 13C NMR (125 MHz, DMSO-d6) d 170.3, 160.3, 158.3, 158.1, 153.3, 147.7, 137.5, 127.4, 125.8, 122.5, 114.5, 112.6, 112.4, 110.9, 101.4, 54.6, 26.3, 22.7; IR (KBr) 3250, 1676, 1618 cm-1 ; MS (FD+) m/e 294 (M+); Anal. calc'd. for C18H14O4 : C, 73.45; H, 4.80. Found: C, 73.15; H, 4.86.

Workup

  1. temperatureAfter cooling to room temperature
  2. filtrationfiltered
  3. washrinsing the precipitate with ether
  4. customThe filtrate layers were separated
  5. extractionthe aqueous layer was extracted with ethyl acetate (3×500 mL)
  6. dry with materialthe combined organic layers were dried (sodium sulfate)
  7. concentrationconcentrated
  8. customRecrystallization of the residue from methanol

Sources & evidence

ORD record
ord-2e1c1509e9854bccbce85b7561bd70a2
Source dataset
uspto-grants-1998_03
Patent number
US05726186

Linked notes

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