Acetic Anhydride → N-(2,2-Dimethyl-2H-1-benzopyran-7-yl)acetamide

HRID 1589217Notes

Reaction equation

[CH3:1][C:2]1([CH3:15])[O:7][C:6]2[CH:8]=[C:9]([N+:12]([O-])=O)[CH:10]=[CH:11][C:5]=2[CH:4]=[CH:3]1.[C:16](OC(=O)C)(=[O:18])[CH3:17]>[Fe].C(O)(=O)C>[C:16]([NH:12][C:9]1[CH:10]=[CH:11][C:5]2[CH:4]=[CH:3][C:2]([CH3:15])([CH3:1])[O:7][C:6]=2[CH:8]=1)(=[O:18])[CH3:17]

Participants

Conditions

Temperature: 120 °C

Procedure

2,2-Dimethyl-7-nitro-2H-benzo[b]pyran (40.00 g, the preparation of which is disclosed in British Pat. No. 1,548,222), glacial acetic acid (200 ml), acetic anhydride (120 ml) and electrolytic iron powder (88 g) were stirred and heated at 120° C. for 16 hours. Dilution with water, extraction via chloroform followed by washing of the organic layer with water and sodium bicarbonate solution, drying evaporation etc., gave a crude gum which was chromatographed on a silica gel column using ethyl acetate--60°-80° petroleum ether mixtures in a gradient elution technique. Fractions homogeneous by TLC were combined and recrystallised from 60°-80° petroleum ether to give 7-acetamido-2-,2-dimethyl-2H-benzo[b]pyran (5.27 g) as white needles of mp 80°-81° C.; nmr (CDCl3) 1.39 (6H), 2.12 (3H), 5.48 (1H, d, J=10), 6.21 (1H, d, J=10), 6.76-7.34 (3H, m), 8.95 (1H). Anal. Calcd for C13H15NO2 ; C, 71.87; H, 696; N, 6.45. Found: C, 72.00; H, 7.11; N, 6.23%.

Workup

extractionDilution with water, extraction via chloroform
washby washing of the organic layer with water and sodium bicarbonate solution
customdrying
customevaporation etc.
customgave a crude gum which
customwas chromatographed on a silica gel column
customethyl acetate--60°-80° petroleum ether
washmixtures in a gradient elution technique
customrecrystallised from 60°-80° petroleum ether

Sources & evidence

ORD record: ord-e094197b69ec48c0a9531a578d8d6c7f
Source dataset: uspto-grants-1986_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04568692

Reaction notes

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