Water → HCID 19922029, compound

HRID 328036Notes

Reaction equation

HRID 328036 reaction equation
C[O:2][C:3]1[CH:16]=[C:15]2[C:6]([CH:7]=[CH:8][C:9]3[O:10][C:11](=[O:17])[CH2:12][CH2:13][C:14]=32)=[CH:5][CH:4]=1.Cl.N1C=CC=CC=1.O.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1.C(OCC)(=O)C>[OH:2][C:3]1[CH:16]=[C:15]2[C:6]([CH:7]=[CH:8][C:9]3[O:10][C:11](=[O:17])[CH2:12][CH2:13][C:14]=32)=[CH:5][CH:4]=1

Participants

7

Reactant 4

HCID 962Water2×HCID 521998p-Toluenesulfonic acid monohydrateHCID 10176127Pyridinium chlorideHCID 199219889-Methoxy-1,2-dihydro-3H-naphtho[2,1-b]pyran-3-one

Product 1

HCID 19922029HCID 19922029, compound

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent2×

Procedure

A mixture of 2.57 g (11.3 mmol) of 1,2-dihydro-9-methoxy-3H-naphtho[2,1-b]pyran-3-one from the preceding example and 7.86 g (68.0 mol) of pyridine hydrochloride was heated at 200°-230° C. for 2.5 hr. After being cooled to room temperature, the reaction mixture was treated with 100 mL of water and worked-up with ethyl acetate in the usual manner. The crude product (2.52 g) was dissolved in 150 mL of toluene, treated with 0.31 g (1.63 mmol) of p-toluenesulfonic acid monohydrate, and the resulting solution was stirred at reflux for 3.5 hr, with removal of water using a Dean-Stark trap. The solution was diluted with 300 mL of ethyl acetate, washed three times with saturated sodium bicarbonate solution, and work-up was completed in the usual manner. The crude product was purified by flash chromatography on 300 g of silica gel, eluting with hexane-ethyl acetate (3:1) to give 2.06 g (85.3%) of the title compound as a light-brown solid, mp 194°-202° C. (recrystallized from ethyl acetate).

Workup

  1. temperaturewas heated at 200°-230° C. for 2.5 hr
  2. washwashed three times with saturated sodium bicarbonate solution
  3. customThe crude product was purified by flash chromatography on 300 g of silica gel
  4. washeluting with hexane-ethyl acetate (3:1)
  5. customto give
  6. custom2.06 g (85.3%) of the title compound as a light-brown solid, mp 194°-202° C. (recrystallized from ethyl acetate)

Sources & evidence

ORD record
ord-71531ca0140047b9aa455d5bfe326dd4
Source dataset
uspto-grants-1993_12
Patent number
US05273999

Reaction notes

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