2-Cyclopropyl-7,8-dimethoxy-2H-chromene-5-carboxylic acid methyl ester → 2-Cyclopropyl-7,8-dimethoxy-2H-1-benzopyran-5-methanol

HRID 1367635Notes

Reaction equation

C[O:2][C:3]([C:5]1[C:6]2[CH:7]=[CH:8][CH:9]([CH:19]3[CH2:21][CH2:20]3)[O:10][C:11]=2[C:12]([O:17][CH3:18])=[C:13]([O:15][CH3:16])[CH:14]=1)=O.COCCO[AlH2-]OCCOC.[Na+]>O1CCCC1.CC(OC)(C)C>[CH:19]1([CH:9]2[CH:8]=[CH:7][C:6]3[C:11](=[C:12]([O:17][CH3:18])[C:13]([O:15][CH3:16])=[CH:14][C:5]=3[CH2:3][OH:2])[O:10]2)[CH2:20][CH2:21]1

Participants

Conditions

Temperature: 40 °C

Procedure

Methyl ester 2 (2 g, 6.2 mmol) was dissolved in 30 ml tetrahydrofurane and 2.7 ml of a 3.5-M solution of Red-Al (9.4 mmol) was added. The mixture was stirred at 40° C. for 3 hours. The solution was diluted with 100 ml of TBME and slowly quenched by addition of 50 ml of a 30% potassium-tartrate solution. The layers were separated and the organic solution was washed with brine (2 times 30 ml), dried over magnesium sulfate and concentrated. The pure alcohol 4 (1.34 g, 5.1 mmol) was obtained as a white-yellow solid.

Workup

customslowly quenched by addition of 50 ml of a 30% potassium-tartrate solution
customThe layers were separated
washthe organic solution was washed with brine (2 times 30 ml)
dry with materialdried over magnesium sulfate
concentrationconcentrated

Sources & evidence

ORD record: ord-365dde01fbf14fa9bffb9d6163b257d4
Source dataset: uspto-grants-2011_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07893262B2

Reaction notes

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