synthesis of 4-(N,N-Dimethylamino)butanal dimethyl acetal: 4- Chlorobutanal dimethyl acetal (2) (100 g, 0.655 mol) was dissolved in aqueous dimethyl amine solution (200 mL) and the solution is stirred for 15 min at ambient temperature. The reaction mixture was then warmed to 50 oC and stirred for 3 h. After the reaction mixture was cooled to room temperature, the product was extracted with methylene chloride (2 × 250 mL). The combined organic layers were washed with 5 % NaHCO3 solution (2 × 100 mL) and brine solution (2 × 100 mL). The organic layer was evaporated and the residue was distilled to afford 88 g (84 %) of 4-(N,Ndimethylamino)butanal dimethyl acetal as a colourless liquid with 99.6 % purity by GC: b.p. 40 oC/1 mm Hg.
(a) (i) Sodium carbonate, dichloromethane, 5 oC, 0.5 h (ii) Methanol, conc. H2SO4, room temperature, 3 h, 87 %. (b) Aqueous dimethyl amine solution (30 %), 50 oC, 3 h, 76.0 %
1H NMR (CDCl3, 200 MHz): δ 1.47-1.63 (m, 4H), 2.21 (s, 6H), 2.24 (t, J = 7.0 Hz, 2H), 3.31 (s, 6H), 4.37 (t, J = 5.4 Hz, 2H). IR (cm-1): 2945 (-CH2-), 2816 (-CH-), 1464 (C-N), 1074 (-C-O-). Mass: m/z 162.5 (M+1).
