Dimethylformamide → 9-Methyl-9H-carbazole-3-carbaldehyde

HRID 1774069Notes

Reaction equation

Br[C:2]1[CH:3]=[CH:4][C:5]2[N:6]([CH3:15])[C:7]3[C:12]([C:13]=2[CH:14]=1)=[CH:11][CH:10]=[CH:9][CH:8]=3.[Li]CCCC.CN([CH:24]=[O:25])C>C1COCC1>[CH3:15][N:6]1[C:5]2[CH:4]=[CH:3][C:2]([CH:24]=[O:25])=[CH:14][C:13]=2[C:12]2[C:7]1=[CH:8][CH:9]=[CH:10][CH:11]=2

Participants

Conditions

Temperature: -78 °C

Procedure

To a solution of 2b (1.8 g, 6.9 mmol) in dried THF (45 mL) was added n-BuLi (3.3 mL 8.3 mmol) at −78° C. The resulting mixture was stirred at −78° C. for 1 h and then added with dried DMF (8 mL). The reaction mixture was allowed to warm to room temperature and stirred overnight before quenched with aqueous ammonia chloride solution. Water was added and extracted with ethyl acetate three times. The combined organic phase was washed with brine and dried over anhydrous sodium sulfate. After removing the solvent, the residue was purified by silica gel chromatography using ethyl acetate and petroleum ether (EA:PE=1:4) as eluent to afford 3b (0.86 g) in 60% yield. 1H NMR (400 MHz, CDCl3) δ 9.58 (s, 1H), 7.79 (s, 1H), 7.49 (d, J=7.6 Hz, 1H), 7.41 (d, J=8.8 Hz, 1H), 7.09 (t, J=7.6 Hz,), 6.90 (t, J=7.6 Hz, 1H), 6.77 (d, J=8.0 Hz, 1H), 6.61 (d, J=8.4 Hz, 1H), 3.00 (s, 3H). 13C NMR (400 MHz, CDCl3) δ 190.9, 143.2, 140.5, 127.4, 125.8, 122.7, 121.7, 119.6, 119.4, 108.3, 107.6, 28.0.

Workup

temperatureto warm to room temperature
stirringstirred overnight
custombefore quenched with aqueous ammonia chloride solution
additionWater was added
extractionextracted with ethyl acetate three times
washThe combined organic phase was washed with brine
dry with materialdried over anhydrous sodium sulfate
customAfter removing the solvent
customthe residue was purified by silica gel chromatography

Sources & evidence

ORD record: ord-2c22ee579c0f47438c9617ff30e1a01b
Source dataset: uspto-grants-2016_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09255933B2

Reaction notes

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