Nitric Acid → 5-Chloro-2-ethoxycarbonyl-2,3-dihydro-2-methyl-7-nitrobenzofuran

HRID 440708Notes

Reaction equation

HRID 440708 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([C:11]([O:13][CH2:14][CH3:15])=[O:12])([CH3:10])[CH2:7][C:6]=2[CH:16]=1.[N+:17]([O-])([OH:19])=[O:18].C(=O)(O)[O-].[Na+]>S(=O)(=O)(O)O>[Cl:1][C:2]1[CH:3]=[C:4]([N+:17]([O-:19])=[O:18])[C:5]2[O:9][C:8]([C:11]([O:13][CH2:14][CH3:15])=[O:12])([CH3:10])[CH2:7][C:6]=2[CH:16]=1

Participants

5

Reactant 3

HCID 944Nitric AcidHCID 516892Sodium BicarbonateHCID 224047405-Chloro-2-ethoxycarbonyl-2,3-dihydro-2-methylbenzofuran

Product 1

HCID 224047575-Chloro-2-ethoxycarbonyl-2,3-dihydro-2-methyl-7-nitrobenzofuranYield 37.8%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent2×

Procedure

Stirred concentrated sulfuric acid, 50 mL, was cooled in an ice-water bath, and 9.0 grams (0.037 mole) of 5-chloro-2-ethoxycarbonyl-2,3-dihydro-2-methylbenzofuran was added. To this solution was added dropwise a solution of 2.6 grams (0.041 mole) of 90% nitric acid in 2 mL of concentrated sulfuric acid, while maintaining the reaction mixture temperature at 10°-16° C. Upon completion of the addition, the reaction mixture was stirred at the ice-water bath temperature for 30 minutes, then allowed to warm to ambient temperature where it stirred for one hour. The reaction mixture was poured into ice and neutralized with sodium bicarbonate and extracted with three portions of methylene chloride. The combined extracts were dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to a residual oil. The oil was subjected to column chromatography on silica gel, with 3:7 ethyl acetate:heptane as the eluant. The product-containing fractions were combined and concentrated under reduced pressure, yielding 4.0 grams of 5-chloro-2-ethoxycarbonyl-2,3-dihydro-2-methyl- 7-nitrobenzofuran, mp 69°-72.5° C. The NMR spectrum was consistent with the proposed structure. This reaction was repeated.

Workup

  1. temperaturewas cooled in an ice-water bath
  2. temperaturewhile maintaining the reaction mixture temperature at 10°-16° C
  3. additionUpon completion of the addition
  4. extractionextracted with three portions of methylene chloride
  5. dry with materialThe combined extracts were dried with magnesium sulfate
  6. filtrationfiltered
  7. concentrationThe filtrate was concentrated under reduced pressure to a residual oil
  8. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-7d030ec170b046a896d8c657da254ae8
Source dataset
uspto-grants-1996_05
Patent number
US05521147

Reaction notes

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