1-Methyl-5-nitro-1,2,3-triazole synthesis

Yield:107945-66-4 35% ，1204736-25-3 60%

Reaction Conditions:

Stage #1: 4⁽⁵⁾-nitro-1,2,3-triazolewith sodium hydride in tetrahydrofuran;mineral oil at 0; for 0.25 h;
Stage #2: methyl iodide in tetrahydrofuran;acetone;mineral oil at 20; for 2 h;

Steps:

149.a 1-Methyl-4-nitro-1H-1,2,3-triazole 149a

Example 149a
1-Methyl-4-nitro-1H-1,2,3-triazole 149a
To a 100-mL single-neck round-bottomed containing 4-nitro-2H-1,2,3-triazole (2.0 g, 17.5 mmol) and THF (10 mL) at 0° C. was added NaH (1.7 g, 35.0 mmol, 2.0 eq.).
The mixture was stirred at 0° C. for 15 min.
A solution of CH₃I (3.68 g, 26.3 mmol, 1.5 eq.) in acetone (40 mL) was added and the resulting reaction mixture was stirred at room temperature for 2 h.
After this time, the reaction was quenched by water (20 mL) at 0° C. and concentrated under reduced pressure.
The residue was diluted with dichloromethane (100 mL).
It was then washed with brine, dried over anhydrous Na₂SO₄, and concentrated under reduced pressure.The residue was purified by silica-gel column chromatography eluting with 6:1 petroleum ether/ethyl acetate to afford 1-methyl-5-nitro-1H-1,2,3-triazole (1.34 g, 60%) as a white solid and 149a (800 mg, 35%) as a slightly yellow solid. ¹H NMR (500 MHz, CDCl₃) δ 8.34 (s, 1H), 4.26 (s, 3H). 1-Methyl-5-nitro-1H-1,2,3-triazole: ¹H NMR (500 MHz, CDCl₃) δ 8.16 (s, 1H), 4.31 (s, 3H).

References:

US2013/116246,2013,A1 Location in patent:Paragraph 0500