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

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.

1. washThe mixture was washed with DCM (2×200 mL)
2. washwashed with DCM (3×200 mL)
3. extractionextracted with DCM (3×200 mL)
4. extractionThe organic phase from this last extraction
5. additioncontaining the product
6. dry with materialwas dried over Na2SO4
7. customthe solvent was removed under vacuum

ORD record

ord-77455d4f67c94a1d812f6feadf55d2f9

Source dataset

uspto-grants-2006_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07151105B2