2-Methylresorcinol → 2,4-Dihydroxy-3-methylbenzaldehyde

Reaction equation

P(Cl)(Cl)(Cl)=O.CN([CH:14]=[O:15])C1C=CC=CC=1.[CH3:16][C:17]1[C:23]([OH:24])=[CH:22][CH:21]=[CH:20][C:18]=1[OH:19]>CCOCC>[OH:19][C:18]1[C:17]([CH3:16])=[C:23]([OH:24])[CH:22]=[CH:21][C:20]=1[CH:14]=[O:15]

Participants

Procedure

Phosphorus oxychloride (80 mL, 0.86 mol) was added to a stirred mixture of N-methylformanilide (102 mL, 0.82 mol) in ether (250 mL). The mixture was stirred for 1 hour at room temperature and then cooled in ice. 2-Methyl resorcinol (Aldrich, 100 g, 0.81 mol) was added and the mixture was allowed to warm to room temperature while stirring overnight. The precipitated intermediate product was collected by filtration and rinsed with ether (3×). the intermediate was hydrolyzed by dissolving in a mixture of acetone (250 mL) and water (250 mL) and stirring for 30 minutes. Water (2 L) was added, the mixture was brought to a boil, and then allowed to cool and deposit crystalline product. This was recrystallized a second time from water (4 L) to afford pure product (70 g, 57%). M.p. 150° C. (Lit. 152°-3° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949). ]. NMR (DMSO-d6): δ 1.973 (s, 3H), 6.551 (d, J=8.5 hz, 1H), 7.428 (d, J-8.5 hz, 1H), 9.703 (s, 1H), 10.745 (s, 1H), and 11.592 (s, 1H).