p-Toluenesulfonic acid → 1,3-Bis[(2-ethoxycarbonylethyl)thio]acetone ethoxycarbonylhydrazone

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Reaction Steps

A solution of 1,3-bis[(2-ethoxycarbonylethyl)thio]acetone (6.22 g, 19.3 mmol), ethyl carbazate (2.40 g, 23.1 mmol) and a catalytic amount of p-toluenesulfonic acid in anhydrous acetonitrile (50 mL) containing molecular sieve was stirred for 2 days at room temperature. The reaction was quenched with water/ethyl acetate and filtered. The filtrate was extracted with ethyl acetate. The organic extract was washed with aqueous sodium bicarbonate, dried over sodium sulfate, and concentrated. The residue was triturated with hexane, affording 7.2 g of 1,3-bis[(2-ethoxycarbonylethyl)thio]acetone ethoxycarbonylhydrazone. 1H NMR (CDCl3) δ 2.2-2.4 (m, 9H), 2.6-2.8 (m, 8H), 3.42 (s, 2H), 3.54 (s, 2H), 4.1-4.3 (m, 6H), 8.82 (br s, 1H).

Provenance & Evidence