反应详情

The bromoacid 3 (11.8 g) was added in portions over 0.5 hour to 100 ml of 90% HNO3 (white fumming) at -10° C. The suspension was stirred at -10° for an additional 2 hours when the solution became clear orange. This solution was poured onto crushed ice. The product was collected by filtration, washed with ice cold H2O (3 × 50 ml) until the washings were neutral. Drying in vacuo followed by crystallization twice from CH2Cl2 /hexane gave pure nitro acid 4 (11.02 g, 85%): m.p. 125-126, i.r. (Nujol) 2800-2300, 1690, 1610 (COOH), 1600 (Aromatic), 1540, 1300 cm-1 (NO2); nmr (CDCl3, DMSO-d6) 4.9 (S,2), 7.8 (d,1), 8.2 (dd,1), 8.6 (d,1) 10.8 (s,1); Rf(5) 0.55; Rf (1) 0.82; UVmax (CH3OH) 227 mμ (t = 2.13 104) 305 mμ (t 4.1 × 103).

1. additionThis solution was poured
2. customonto crushed ice
3. filtrationThe product was collected by filtration
4. washwashed with ice cold H2O (3 × 50 ml) until the washings
5. customDrying in vacuo
6. customfollowed by crystallization twice from CH2Cl2 /hexane