反应详情

3,4-Diethylpyrrole (Sessler, J. L.; Mozaffari, A.; Johnson, M. R. submitted to Organic Syntheses) (7) (0.62 g, 5.0 mmol), benzyl 5-(acetoxymethyl)-3-ethoxycarbonylmethyl-4-methylpyrrole-2-carboxylate (10) (3.94 g, 10.6 mmol), and p-toluenesulfonic acid monohydrate (152 mg) were dissolved in 50 ml of absolute ethanol and heated at reflux for 4 hours under N2. The resulting suspension was reduced in volume to 30 ml and placed in the freezer for several hours. The product was then collected by filtration, washed with a small amount of cold ethanol, and recrystallized from CH2Cl2 /ethanol to afford compound 11 as a fine, off-white powder (2.13 g, 50%); m.p. 127°-128° C.; 1H NMR (CDCl3) delta 1.28 (6 H, t, J=7.47 HZ, CH2CH3), 1.20 (6 H, t, J=7.07 Hz, OCH2CH3), 2.26 (6 H, s, CH3), 2.48 (4 H, q, J-7.34 HZ, CH2CH3), 3.31 (4 H, s, CH2CO2Et), 3.70 (4 H, s, pyrrole2 --CH2), 4.05 (4 H, q, J=7.09 Hz, OCH2CH3), 4.75 (4 H, br s, CH2Ph), 7.14-7.32 (10 H, m, aromatic), 8.83 (1 H, s, NH), 11.5 (2 H, br s, NH); CIMS, (M+H)+ 778.6; HRMS, 749.3689 (calcd for C44H51N3O8 : 749.3676).

1. temperatureheated
2. temperatureat reflux for 4 hours under N2
3. waitplaced in the freezer for several hours
4. filtrationThe product was then collected by filtration
5. washwashed with a small amount of cold ethanol
6. customrecrystallized from CH2Cl2 /ethanol