Hydrochloric Acid → 4,5-Dimethoxy-2-(1-methyl-2-phenyl-ethyl)-benzoic acid methyl ester

HRID 38318Notes

Reaction equation

[I-].[CH3:2][O:3][C:4]1[C:9]([O:10][CH3:11])=[CH:8][C:7]([C:12]2[O:13][CH2:14]C(C)(C)[N+]=2C)=[C:6]([CH:20]([CH3:28])[CH2:21][C:22]2[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=2)[CH:5]=1.[OH-:29].[Na+].Cl.C[Si](C=[N+]=[N-])(C)C>CO.C1C=CC=CC=1>[CH3:14][O:13][C:12](=[O:29])[C:7]1[CH:8]=[C:9]([O:10][CH3:11])[C:4]([O:3][CH3:2])=[CH:5][C:6]=1[CH:20]([CH3:28])[CH2:21][C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 2-[4,5-dimethoxy-2-(1-methyl-2-phenyl-ethyl)-phenyl]-3,4,4-trimethyl-4,5-dihydro-oxazolium iodide (5.132 g, 10.4 mmol) in 52 mL methanol was added 4 M NaOH (5.2 mL, 20.7 mmol). The solution was warmed to reflux. After 16 hours the solution was cooled to 0° C. and acidified to pH=1 with concentrated HCl. The mixture was extracted with ethyl acetate, washed with H2O and washed with brine. The combined organics were dried over Na2SO4, filtered and concentrated in vacuo to give a crude acid (3.228 g). A portion of this acid (2.919 g, 9.73 mmol) was dissolved in a mixture of 70 mL benzene and 20 mL MeOH. Trimethylsilyldiazomethane (6.3 mL, 2.0 M in hexanes) was added drop-wise. After 30 minutes the solution was concentrated in vacuo to give 4,5-dimethoxy-2-(1-methyl-2-phenyl-ethyl)-benzoic acid methyl ester as an oil (2.886 g).

Workup

temperatureThe solution was warmed to reflux
extractionThe mixture was extracted with ethyl acetate
washwashed with H2O
washwashed with brine
dry with materialThe combined organics were dried over Na2SO4
filtrationfiltered
concentrationconcentrated in vacuo
customto give a crude acid (3.228 g)
concentrationAfter 30 minutes the solution was concentrated in vacuo

Sources & evidence

ORD record: ord-e50f689a9216437790543befda201bd0
Source dataset: uspto-grants-2013_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08524725B2

Reaction notes

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