Dimethylformamide diethylacetal → 3,4-dihydro-6,7-dimethoxy-2-(dimethylaminomethylene)-1(2H)-naphthalenone

HRID 1106550Notes

Reaction equation

[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][C:12]=1[O:13][CH3:14])[C:9](=[O:15])[CH2:8][CH2:7][CH2:6]2.C(O[CH:19](OCC)[N:20]([CH3:22])[CH3:21])C>>[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][C:12]=1[O:13][CH3:14])[C:9](=[O:15])[C:8](=[CH:19][N:20]([CH3:22])[CH3:21])[CH2:7][CH2:6]2

Participants

Reactant 2

HCID 70913Dimethylformamide diethylacetal

HCID 2668163,4-Dihydro-6,7-dimethoxy-1(2H)-naphthalenone

Product 1

HCID 541518493,4-dihydro-6,7-dimethoxy-2-(dimethylaminomethylene)-1(2H)-naphthalenone

Procedure

From 3,4,5-trimethoxyphenylguanidinium nitrate (1.14 g, 4.0 mmol), 3,4-dihydro-6,7-dimethoxy-2-(dimethylaminomethylene)-1(2H)-naphthalenone (1.04 g, 4,0 mmol) and sodium hydroxide (176 mg, 4.4 mmol). The crude product was purified by chromatography on silica (3% methanol in dichloromethane) and recrystallised from ethyl acetate-hexane to give the title compound as pale yellow crystals (354 mg) m.p. 179-182°. δH (CDCl3) 8.22 (1H, s), 7.83 (1H, s), 7.12 (1H, br s), 6.99 (2H, s), 6.75 (1H, s), 3.96 (3H, s), 3.94 (3H, s), 3.88 (6H, s), 3.83 (3H, s) and 2.89-2.81 (4H, m). MS (ES+) 424 (MH+, 100%). The 3,4-dihydro-6,7-dimethoxy-2-(dimethylaminomethylene)-1(2H)-naphthalenone starting material was prepared from 6,7-dimethoxy-1-tetralone (4.12 g, 20 mmol) and N,N-dimethyl formamide diethyl acetal (10.3 ml, 60 mmol) to give the product as red-brown crystals (3.26 g) m.p. 138-140°. MS (ES+) 284 (MNa+, 12%), 262 (MH+, 100%), 189 (28%).

Sources & evidence

ORD record: ord-0698c814a8c64726a8c89bb9ee469fca
Source dataset: uspto-grants-2000_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06057329

Reaction notes

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