Hydrazinecarboxylic acid, (2-ethoxy-2-oxoethylidene)-, 1,1-dimethylethyl ester synthesis

Yield:188262-96-6 13.8%

Reaction Conditions:

in 1,4-dioxane at 25 - 60; for 0.25 h;

Steps:

6-1

Synthesis of (tert-butoxycarbonyl-hydrazono)-acetic acid ethyl ester (115) Ethyl glyoxylate (13.9 mL, 61.3 mmol) was added to a solution of hydrazine carboxylic acid tert-butyl ester (7.35 g, 55.6 mmol) in anhydrous 1,4-dioxane (75 mL) at 25° C. under a nitrogen atmosphere. The resulting mixture was stirred at 60° C. for 15 min. The mixture was cooled to 25° C. and concentrated. The residue was purified by flash chromatography on silica gel to afford the desired product (115) (9.38 g, 13.8% yield) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ: 8.34 (s, 1H), 7.55 (s, 1H), 4.33 (q, 2H, J=7.2 Hz), 1.54 (s, 9H), 1.36 (t, H, J=7.2 Hz).

References:

US2008/292588,2008,A1 Location in patent:Page/Page column 61-62