Cyclopentadiene → 5-Nitro-1,4-dihydro-1,4-methanonaphthalene

HRID 2098363Notes

Reaction equation

HRID 2098363 reaction equation
N(O[CH2:4][CH2:5][CH2:6][CH3:7])=O.N[C:9]1[CH:17]=[CH:16][CH:15]=[C:14]([N+:18]([O-:20])=[O:19])[C:10]=1[C:11](O)=O.C1CC=CC=1>ClCCl.CC(C)=O>[N+:18]([C:14]1[CH:15]=[CH:16][CH:17]=[C:9]2[C:10]=1[CH:11]1[CH2:7][CH:6]2[CH:5]=[CH:4]1)([O-:20])=[O:19]

Participants

6

Reactant 3

HCID 7612CyclopentadieneHCID 10996Butyl nitriteHCID 957952-Amino-6-nitro-benzoic acid

Product 1

HCID 1435695-Nitro-1,4-dihydro-1,4-methanonaphthaleneYield 58.3%

Reagents, catalysts & solvents 2

HCID 180AcetoneSolventHCID 6344DichloromethaneSolvent

Procedure

In a three necked flask equipped with thermometer, dropping funnel and cooler with a bubbler, tertio-butyl nitrite (5.77 ml, 1.77 eq, 48.6 mmol) is dissolved in dichloromethane (30 ml) and heated to reflux while a solution of cold 2-amino-6-nitro-benzoic acid (5 g, 1 eq, 27.5 mmol) and cyclopentadiene (40.7 ml, 18 eq, 0.49 mol) in acetone (20 ml) is added dropwise. Care should be taken regarding gas evolution. After refluxing for 18 hours, the reaction is cooled down to ambient temperature before being filtrated through a silica pad and evaporated. The crude mixture is purified by chromatography column (silica gel, elution with a gradient from pure cyclohexane to a mixture of ethyl acetate:cyclohexane 1:12. 3 grams of 5-nitro-1,4-dihydro-1,4-methano-naphthalene are then obtained (58% yield). 1H NMR (CDCl3) 7.7 ppm, 1H, dd, J=0.7 and 8.4 Hz; 7.45 ppm, 1H, dt, J=7.3 and 0.7 Hz; 7.07 ppm, 1H, dd, J=7.3 and 8.4 Hz; 6.9-6.86 ppm, 2H, m; 4.86 ppm, 1H, bs; 4.02 ppm, 1H, bs; 2.38 ppm, 1H, dt, J=7.7 and 1.5 Hz; 2.3 ppm, 1H, dt, J=7.4 and 1.5 Hz.

Workup

  1. customIn a three necked flask equipped with thermometer
  2. temperatureheated
  3. additionis added dropwise
  4. temperatureAfter refluxing for 18 hours
  5. filtrationbefore being filtrated through a silica pad
  6. customevaporated
  7. customThe crude mixture is purified by chromatography column (
  8. washsilica gel, elution with a gradient from pure cyclohexane
  9. additionto a mixture of ethyl acetate:cyclohexane 1:12

Sources & evidence

ORD record
ord-bd0cf58c913c4ba59ec823965c19292f
Source dataset
uspto-grants-2013_05
Patent number
US08450499B2

Reaction notes

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