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

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).

1. customIn a 500 mL volume flask, was combined
2. customwas placed into an 80° C.
3. additionpoured onto ice water
4. customtransferred to a separatory funnel
5. extractionThe reaction mixture —H2O solution was then extracted twice with 150 mL of CH2Cl2
6. customto remove the acids and neutrals (the starting material)
7. extractionextracted 4 times with 150 mL of ethyl acetate
8. extractionThe ethyl acetate extract
9. dry with materialwas dried over MgSO4
10. concentrationconcentrated

ORD record

ord-5fb638d9147140e6b0875cb03fd43705

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09255273B2