Lithium Hydroxide → 1-ethyl-4-(3-methoxy-phenylethynyl)-1H-pyrrole-2-carboxylic acid
Reaction equation
C([O:3][C:4]([C:6]1[N:7]([CH2:21][CH3:22])[CH:8]=[C:9]([C:11]#[C:12][C:13]2[CH:18]=[CH:17][CH:16]=[C:15]([O:19][CH3:20])[CH:14]=2)[CH:10]=1)=[O:5])C.[Li+].[OH-]>O1CCOCC1>[CH2:21]([N:7]1[CH:8]=[C:9]([C:11]#[C:12][C:13]2[CH:18]=[CH:17][CH:16]=[C:15]([O:19][CH3:20])[CH:14]=2)[CH:10]=[C:6]1[C:4]([OH:5])=[O:3])[CH3:22]Participants
Procedure
To a solution of 1-ethyl-4-(3-methoxy-phenylethynyl)-1H-pyrrole-2-carboxylic acid ethyl ester (3.5 g, 11.76 mmol) in dioxane (70 mL) was added LiOH (2M, 35 mL). The reaction mixture was stirred at room temperature for 3 days, and then concentrated in vacuo. The residue was dissolved in H2O (30 ml) and extracted with ether. Under cooling the aqueous was acidified with HCl (3N) and extracted with EtOAc. The organic extracts were dried over MgSO4. Evaporation and recrystallzation from ether and hexane gave the 1-ethyl-4-(3-methoxy-phenylethynyl)-1H-pyrrole-2-carboxylic acid intermediate as light yellow solid (2.55 g, 79% yield), mp 129° C., 1H NMR (400 MHZ, CDCl3) δ 1.26 (t, 3H), 3.73 (s, 3H), 4.26-4.28 (q, 2H), 6.96-6.97 (m, 2H), 6.99-7.0 (m, 2H), 7.23-7.24 (m, 1H), 7.46 (s, 1H), 12.46 (bs, 1H), MS m/e (M−H)− 268.1.
Workup
- concentrationconcentrated in vacuo
- dissolutionThe residue was dissolved in H2O (30 ml)
- extractionextracted with ether
- temperatureUnder cooling the
- extractionextracted with EtOAc
- dry with materialThe organic extracts were dried over MgSO4
- customEvaporation and recrystallzation from ether and hexane
Sources & evidence
- ORD record
- ord-6ce21cd52fee46d0b6214f107634aeee
- Source dataset
- uspto-grants-2010_04
- Patent number
- US07705030B2
Reaction notes
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