反应详情

To a 3-necked RB flask equipped with overhead mechanical stirrer, condenser, addition funnel, N2 inlet line with bubbler was added N-methylformanilide (Aldrich, 89.21 g, 0.66 mol, 81 mL) and o-dichlorobenzene (Aldrich, 200 mL). The mixture was cooled to 10° with an ice bath. Phosphorus oxychloride (Aldrich, 101.21 g, 0.66 mol, 60 mL) was then added dropwise to the solution not allowing the reaction temperature to rise above 10°. The reaction mixture was then allowed to warm to RT. Solid naphthacene (Cambridge Chemical, Inc., 50 g, 0.22 mol) was then added in five portions over 5 min. The reaction mixture was warmed slowly to 80° (the mixture turns from purple to an almost black color). The reaction was stirred at 80° for 12 h, cooled, poured into ice water (2 L) and stirred an additional 12 h at RT. The mixture was then filtered. The organic layer in the filtrate was dried (Na2SO4) and applied to a plug of SiO2 (500 g) and eluted first with PhCH3 followed by CH2Cl2. The appropriate fractions were combined and the solvent removed by rotary evaporation. Recrystallization (CH2Cl2 /EtOAc) gave 17.5 g (31.1% yield) of naphthacene-5-carbaldehyde, mp 163°-164° (Lit. 164°, N.P. Buu-Hoi et al., Recueil 76 674 (1957)), (C, H). The solid from the filtration of the crude reaction mixture was washed with a large volume of CH 3 OH (5×200 mL), dissolved in THF (4 L) and passed through a plug of SiO2 (500 g) using an additional 2 L of THF as eluting solvent. The solvent was reduced to a volume of 300 mL and then diluted to 800 mL with EtOAc. The solvent volume was reduced to 250 mL. After filtration and drying 10.90 g (17.4% yield) of naphthacene-5,11-dicarbaldehyde, mp 247°-250°, (C, H).

1. customTo a 3-necked RB flask equipped with overhead mechanical stirrer, condenser, addition funnel, N2 inlet line with bubbler
2. temperatureThe mixture was cooled to 10° with an ice bath
3. customto rise above 10°
4. temperatureThe reaction mixture was warmed slowly to 80° (the mixture
5. temperaturecooled
6. stirringstirred an additional 12 h at RT
7. filtrationThe mixture was then filtered
8. dry with materialThe organic layer in the filtrate was dried (Na2SO4)
9. washeluted first with PhCH3
10. customthe solvent removed by rotary evaporation
11. customRecrystallization (CH2Cl2 /EtOAc)