Water → HCID 20283281, compound

HRID 1447480Notes

Reaction equation

[OH:1][C:2]1([C:16]([O:18][CH3:19])=[O:17])[CH2:11][CH2:10][C:9]2[C:4](=[C:5]([O:14][CH3:15])[CH:6]=[CH:7][C:8]=2[O:12][CH3:13])[CH2:3]1.[C:20](OC(=O)C)(=[O:22])[CH3:21].O>N1C=CC=CC=1.CN(C)C1C=CN=CC=1>[C:20]([O:1][C:2]1([C:16]([O:18][CH3:19])=[O:17])[CH2:11][CH2:10][C:9]2[C:4](=[C:5]([O:14][CH3:15])[CH:6]=[CH:7][C:8]=2[O:12][CH3:13])[CH2:3]1)(=[O:22])[CH3:21]

Participants

Conditions

Temperature: 0 °C

Procedure

5.0 g of methyl rac-1,2,3,4-tetrahydro-2-hydroxy-5,8-dimethoxynaphthalene-2-carboxylate were dissolved in 50 ml of pyridine. The solution was cooled to 0° C. and 10 ml of acetic anhydride and 150 mg of 4-dimethylaminopyridine were added. After standing at 0° C. for 24 hours, the mixture was poured into 250 ml of water. The mixture obtained was extracted with three 100 ml portions of ethyl acetate and the combined ethyl acetate extracts were washed with 2-N hydrochloric acid until the washings were acidic, then with 200 ml of water, 200 ml of dilute aqueous potassium hydrogen carbonate and 200 ml of brine. After drying, the solvent was evaporated to give a white crystalline residue. Recrystallisation from diethyl ether gave 5.6 g (96.5%) of methyl rac-2-acetoxy-1,2,3,4-tetrahydro-5,8-dimethoxynaphthalene-2-carboxylate in the form of colourless crystals of melting point 155.5°-156° C.

Workup

customThe mixture obtained
extractionwas extracted with three 100 ml portions of ethyl acetate
washthe combined ethyl acetate extracts were washed with 2-N hydrochloric acid until the washings
customAfter drying
customthe solvent was evaporated
customto give a white crystalline residue
customRecrystallisation from diethyl ether

Sources & evidence

ORD record: ord-7346c1b9a5614f468400e9d3b2388109
Source dataset: uspto-grants-1982_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04316985

Reaction notes

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