Hydrochloric Acid → 5-Methyl-2,3-dihydro-1,4-benzodioxine-6-carbohydrazide

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Reaction Steps

In a 500 mL volume flask, was combined 18.6 g (0.0499 moles) of N′-(5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazinecarboxylic acid 4-methoxy-benzyl ester, 72 mL of concentrated HCl, and 108 mL of dioxane. The flask was placed into an 80° C. oil bath and mechanically stirred for 2 hours. The reaction mixture was cooled with ice water, then poured onto ice water and transferred to a separatory funnel. The reaction mixture—H2O solution was then extracted twice with 150 mL of CH2Cl2 to remove the acids and neutrals (the starting material). The aqueous phase was made basic (pH 12) with a 20% NaOH solution and extracted 4 times with 150 mL of ethyl acetate. The ethyl acetate extract was dried over MgSO4 and concentrated to yield 4.5 g of 5-methyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid hydrazide. 1H NMR (CDCL3, 300 MHz) δ (ppm): 7.0 (s, 1H), 6.85 (d, 1H), 6.74 (d, 1H), 4.28 (m, 4H), 2.781 (s, 3H).

Provenance & Evidence