Hydrochloric Acid → 1-ethyl-5-methyl-1H-[1,2,4]triazole-3-carbaldehyde

Participants

Reaction Steps

A mixture of 3-(diethoxymethyl)-1-ethyl-5-methyl-1H-[1,2,4]triazole from step 1 (56.86 g, 0.267 mol) and H2O (300 mL) was treated slowly with 35% aqueous HCl (55.61 g, 0.534 mol), and the reaction was stirred at room temperature for 24 h. The mixture was washed with DCM (2×200 mL). The aqueous phase was basified to pH 13 with NaOH, and washed with DCM (3×200 mL). The combined DCM extracts were discarded. The aqueous phase was neutralized to pH 7 with HCl, and extracted with DCM (3×200 mL). The organic phase from this last extraction, containing the product, was dried over Na2SO4, and the solvent was removed under vacuum, affording 9.8 g (26%) of 1-ethyl-5-methyl-1H-[1,2,4]triazole-3-carbaldehyde which was 96% pure by NMR. 1H NMR (500 MHz, CDCl3): δ 1.49 (t, J=7.5 Hz, 3H), 2.51 (s, 3H), 4.20 (q, J=7.5 Hz, 2H), 9.91 (s, 1H). 13C NMR (125 MHz, CDCl3): δ 12.1, 14.9, 44.4, 154.0, 159.2, 184.0. LC-MS (APCI) calcd for C6H9N3O: 139.07, found (M+H+): 140.1 m/z. Anal calcd for C6H9N3O: C, 51.79; H, 6.52; N, 30.20. Found: C, 51.5; H, 6.38; N, 29.98.

Provenance & Evidence