반응 #67930

반응 방정식

N′-(5-ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazinecarboxylic acid tert-butyl ester

trifluoroacetic acid

NaOH H2O

→

5-ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid hydrazide

수율 129.9%

용매

water

반응 조건

후처리

1. 1
   workup.STIRRINGwith stirring, until the acid
2. 2
   기타The reaction mixture was transferred to a separatory funnel
3. 3
   추출extracted with ethyl acetate
4. 4
   workup.STIRRINGby shaking gently (caution: gas evolution)
5. 5
   추출The ethyl acetate extract
6. 6
   기타was dried
7. 7
   기타evaporated
8. 8
   기타to yield 5.51 g of a pale, viscous yellow semi-solid
9. 9
   기타was then placed in a 50° C.
10. 10
    기타for about 1 hour

실험 절차

5.15 g (16 mmol) of N′-(5-ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carbonyl)-hydrazinecarboxylic acid tert-butyl ester were added to a 200 mL round bottom flask. About 20 mL of trifluoroacetic acid were added and the reaction mixture was stirred at room temperature for 24 hours. Then about 40 mL of water were added, followed by the slow addition of cold 10% NaOH/H2O, with stirring, until the acid was neutralized (pH ˜14). The reaction mixture was transferred to a separatory funnel and extracted with ethyl acetate by shaking gently (caution: gas evolution). The ethyl acetate extract was dried and evaporated to yield 5.51 g of a pale, viscous yellow semi-solid. The material was then placed in a 50° C. vacuum oven for about 1 hour to yield 4.62 g of 5-ethyl-2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid hydrazide. The t-Boc cleavage is best accomplished with neat trifluoroacetic acid; use of adjunctive solvents always resulted in much lower yields. 1H NMR (CDCl3, 500 MHz) δ (ppm): 7.0 (br, 1H), 6.83 (m, 1H), 6.71 (m, 1H), 4.28 (br s, 4H), 2.76 (m, 2H), 1.6 (br, 2H), 1.17 (t, 3H).

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