Ethanol → Ethyl 6-nitroquinoxaline-2-carboxylate
Reaction equation
[N+:1]([C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[N:10]=[C:9]([C:14]([OH:16])=[O:15])[CH:8]=[N:7]2)([O-:3])=[O:2].S(=O)(=O)(O)O.C(=O)([O-])[O-].[Na+].[Na+].[CH2:28](O)[CH3:29]>>[N+:1]([C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[N:10]=[C:9]([C:14]([O:16][CH2:28][CH3:29])=[O:15])[CH:8]=[N:7]2)([O-:3])=[O:2]Participants
Procedure
To a solution of 6-nitroquinoxaline-2-carboxylic acid (6) (5.00 g, 22.8 mmol) (Higashida, S.; Sakurai, M.; Yabe, Y.; Nishihgaki, T.; Komai, T.; Handa, H. Preparation of peptide inhibitors of HIV protease, peptides capable of inhibiting the activity of HIV protease, their preparation and their therapeutic use. European Patent, EP 0 587 311, 1994) in dry ethanol (50 mL), was added under argon, concentrated sulfuric acid (750 μL). After being stirred at reflux for 7 h, the reaction mixture was cooled to room temperature and a saturated aqueous sodium carbonate solution (50 mL) was added. The solution was extracted with dichloromethane (3×30 mL) and the combined organic layers were dried on magnesium sulfate, filtered and evaporated to dryness to afford ester 7 (3.79 g, 15.3 mmol) as a brown solid. Yield 67%; mp 221-223° C.; IR (KBr) ν 1282, 1347, 1531, 1741 cm−1; 1H NMR (200 MHz, CDCl3) δ 1.58 (t, 3H, J=7 Hz), 4.68 (q, 2H, J=7 Hz), 8.53 (d, 1H, J=9 Hz), 8.68 (dd, 1H, J=2.5, 9 Hz), 9.14 (d, 1H, J=2.5 Hz), 9.72 (s, 1H); MS m/z 248 (M+1, 4), 203 (36), 175 (100), 128 (23), 101 (32), 75 (24).
Workup
- customthe activity of HIV protease, their preparation and their therapeutic use
- temperatureat reflux for 7 h
- extractionThe solution was extracted with dichloromethane (3×30 mL)
- customthe combined organic layers were dried on magnesium sulfate
- filtrationfiltered
- customevaporated to dryness
Sources & evidence
- ORD record
- ord-f93cea9766ca449f930129314bcb684b
- Source dataset
- uspto-grants-2015_09
- Patent number
- US09125937B2
Reaction notes
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