Ethyl 8-methoxy-3-nitronaphthalene-2-carboxylate → Ethyl 3-amino-8-methoxynaphthalene-2-carboxylate
Reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:15]([N+:16]([O-])=O)=[CH:14][C:13]2[C:8](=[C:9]([O:19][CH3:20])[CH:10]=[CH:11][CH:12]=2)[CH:7]=1)=[O:5])[CH3:2].[H][H]>CCO.[Pd]>[CH2:1]([O:3][C:4]([C:6]1[C:15]([NH2:16])=[CH:14][C:13]2[C:8](=[C:9]([O:19][CH3:20])[CH:10]=[CH:11][CH:12]=2)[CH:7]=1)=[O:5])[CH3:2]Participants
Procedure
Palladium-on-carbon (10%, 1.281 g, 1.204 mol, 0.1 equiv) was added under an atmosphere of argon to a solution of 8-methoxy-3-nitro-naphthalene-2-carboxylic acid ethyl ester (3.313 g, 12.04 mmol) in EtOH (50 ml). The atmosphere was replaced by hydrogen gas, and the mixture was stirred at room temperature for 3 hours (hydrogen balloon). The atmosphere was changed back to argon, the catalyst was filtered off and the filtrate was concentrated in vacuo to afford the title compound (2.820 g, 96%, inseparable 1:1.15 mixture of regioisomers A:B) of adequate purity for direct use in the next transformation. 1H NMR (400 MHz, CDCl3): δ=8.88 (s, 1H isomer B), 8.44 (s, 1H isomer A), 7.36 (s, 1H isomer A), 7.32-7.26 (m, 1H isomer A+1H isomer B), 6.91 (s, 1H isomer B), 6.73 (d, J=7.4 Hz, 1H isomer A), 6.50 (d, J=7.6 Hz, 1H isomer B), 4.41 (q, J=7.0 Hz, 2H isomer B), 4.40 (q, J=7.1 Hz, 2H isomer A), 3.97 (s, 3H isomer B), 3.96 (s, 3H isomer A), 1.44 (t, J=7.1 Hz, 3H isomer B), 1.44 (t, J=7.0 Hz, 3H isomer A). MS (ES+): 246 (M+H)+.
Workup
- filtrationthe catalyst was filtered off
- concentrationthe filtrate was concentrated in vacuo
Sources & evidence
- ORD record
- ord-f270e96b93cb4d23b2b28500013ffe66
- Source dataset
- uspto-grants-2010_08
- Patent number
- US07781438B2
Reaction notes
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