Potassium Nitrate → 1-Methoxy-2-nitro-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-one

HRID 523497Notes

Reaction equation

HRID 523497 reaction equation
[N+:1]([O-:4])([O-])=[O:2].[K+].[CH3:6][O:7][C:8]1[C:13]2[CH2:14][CH2:15][CH2:16][C:17](=[O:19])[CH2:18][C:12]=2[CH:11]=[CH:10][CH:9]=1>C(#N)C.FC(F)(F)C(OC(=O)C(F)(F)F)=O>[CH3:6][O:7][C:8]1[C:13]2[CH2:14][CH2:15][CH2:16][C:17](=[O:19])[CH2:18][C:12]=2[CH:11]=[CH:10][C:9]=1[N+:1]([O-:4])=[O:2]

Participants

5

Reactant 2

HCID 24434Potassium NitrateHCID 127282361-methoxy-6,7,8,9-tetrahydro-5H-benzo[7]annulen-6-one

Product 1

HCID 1177782541-Methoxy-2-nitro-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-oneYield 34.6%

Reagents, catalysts & solvents 2

HCID 6342AcetonitrileSolvent2×HCID 9845Trifluoroacetic anhydrideSolvent

Procedure

To potassium nitrate in acetonitrile (50 mL) and trifluoroacetic anhydride (100 mL) at 0° C. was added dropwise 1-methoxy-5,7,8,9-tetrahydro-benzocyclohepten-6-one (25 g, 0.131 mol) in 50 mL acetonitrile. The reaction was stirred for 2.5 hours while warming to RT. The reaction was concentrated without heat on a rotary evaporator. MeOH was added and stirred briefly. Reconcentrated and worked-up by partitioning between dichloromethane and sat. sq. sodium bicarbonate solution. The organic layer was separated and dried (Mg2SO4), concentrated and purified by chromatography ISCO (330 g silica cartridge: gradient elution−10 to 50% EA:HEX over 60 minutes) affording two isomers. The title compound was the later eluting (10.7 grams, 34.6% yield). 1H-NMR (400 MHz, CDCl3) 7.70 (d, J=8.3 Hz, 1H), 7.06 (d, J=8.3 Hz, 1H), 3.92 (s, 3H), 3.80 (s, 2H), 3.13-3.09 (m, 2H), 2.60 (t, J=7.0 Hz, 2H), 2.10-2.03 (m, 2H).

Workup

  1. concentrationThe reaction was concentrated
  2. temperaturewithout heat on a rotary evaporator
  3. additionMeOH was added
  4. stirringstirred briefly
  5. customby partitioning between dichloromethane
  6. customThe organic layer was separated
  7. dry with materialdried (Mg2SO4)
  8. concentrationconcentrated
  9. custompurified by chromatography ISCO (330 g silica cartridge: gradient elution−10 to 50% EA:HEX over 60 minutes)
  10. customaffording two isomers

Sources & evidence

ORD record
ord-efec7f15a7da453587df16fe7dd347ee
Source dataset
uspto-grants-2016_05
Patent number
US09339502B2

Reaction notes

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