1,4-Dioxane → 6-Chloroquinoline-4-carbaldehyde
Reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[N:8]=[CH:7][CH:6]=[C:5]2[CH3:12].[O:13]1CCOCC1>>[Cl:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[N:8]=[CH:7][CH:6]=[C:5]2[CH:12]=[O:13]Participants
3
Procedure
A solution of 2 (16.04 g, 90.6 mmol) and SeO2 (13.0 g, 117.3 mmol) in 5% aq. 1,4-dioxane (200 mL) was refluxed for 2 h. The precipitated selenium was filtered off and the filtrate was evaporated to dryness in vacuo. The residue was taken into CH2Cl2, and filtered through a short plug of silica gel. The filtrate was concentrated to give a light brown solid. Further purification by crystallization (EtOAc/Hexanes) gave 1 (11.6 g, 61%) as a pale yellow solid Mp 152-153° C. (lit.2 153-154° C). 1H NMR (300 MHz, CDCl3): δ 10.43 (s, 1H), 9.20 (d, 4.4 Hz, 1H), 9.10 (d, 2.2 Hz, 1H), 8.16 (d, 9.1 Hz, 1H), 7.82 (d, 4.4 Hz, 1H), 7.77 (dd, 9.1, 2.2 Hz, 1H). MS m/z: 192 (M+1). Analysis calcd. for C10H6ClNO; C, 62.68; H, 3.16; N, 7.31; Cl, 18.50; found, C, 62.92; H, 3.33; N, 7.23; Cl, 18.60.2