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8
Typical Experimental Procedure for the Synthesis of 1,4-Dihydropyridine Derivatives
In a 25 mL round-bottomed flask, benzaldehyde (1 mmol), ethyl acetoacetate (2 mmol), NH4OAc (1 mmol), and PTSA (0.1 mmol) was added. To this an aqueous solution of SDS (3 mL, 0.1 M) was added. The reaction mixture was immersed in an ultrasonic bath and irradiated for 1 h. Then, the reaction mixture was diluted with brine and extracted with EtOAc. The organic layer was dried over anhyd Na2SO4 and concentrated to give a crude product. The pure product was obtained by crystallization of the crude material from MeOH; mp 158 °C. 1H NMR (200 MHz, CDCl3): δ = 1.21 (t, J = 7.7 Hz, 6 H), 2.29 (s, 6 H), 4.08 (q, J = 7.7 Hz, 4 H), 4.98 (s, 1 H), 6.00 (s, 1 H), 7.01-7.26 (m, 5 H). IR (KBr): 3322, 1676, 1633 cm-1. MS: m/z = 330 [M + H]+. Anal. Calcd for C19H23NO4: C, 69.28, H, 7.04, N, 4.25. Found: C, 69.12, H, 6.98, N, 4.14.
9
Typical Experimental Procedure for the Synthesis of Polyhydroquinoline Derivatives
In a 25 mL round-bottomed flask, dimedone (1 mmol), benzaldehyde (1 mmol), ethyl acetoacetate (1 mmol), NH4OAc (1 mmol), and PTSA (0.1 mmol) was added. To this an aqueous solution of SDS (3 mL, 0.1 M) was added. The reaction mixture was immersed in an ultrasonic bath and irradiated until reaction was complete (TLC monitoring, 1-3 h). The reaction mixture was diluted with brine and extracted with EtOAc. The organic layer was dried over anhyd Na2SO4 and concentrated to give a crude product. The pure product was obtained by crystallization from MeOH; mp 203-204 °C. 1H NMR (300 MHz, CDCl3): δ = 0.94 (s, 3 H), 1.07 (s, 3 H), 1.21 (t, J = 7.1 Hz, 3 H), 2.13-2.29 (m, 4 H), 2.35 (s, 3 H), 4.06 (q, J = 7.1 Hz, 2 H), 5.07 (s, 1 H), 6.64 (s, 1 H), 7.08-7.13 (m, 1 H), 7.18-7.23 (m, 2 H), 7.28-7.33 (m, 2 H). 13C NMR (75 MHz, CDCl3): δ = 12.92, 17.96, 25.84, 28.15, 31.38, 35.33, 39.65, 49.50, 58.52, 104.72, 110.70, 124.74, 126.59, 126.72, 142.41, 145.82, 147.47, 166.24, 194.43. IR (KBr): 3287, 3078, 2963, 1697, 1611
cm-1. MS: m/z = 340 [M + H]+. Anal. Calcd for C21H25NO3: C, 74.31, H, 7.42, N, 4.13. Found: C, 74.27, H, 7.39, N, 4.08.
