Lithium Hydroxide → (1aS,5aR)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalene-4-carboxylic acid
Reaction equation
C([O:3][C:4]([C:6]1[S:13][C:12]([CH3:14])=[C:11]2[C:7]=1[CH2:8][C@H:9]1[C:15]([CH3:17])([CH3:16])[C@H:10]12)=[O:5])C.[Li+].[OH-]>C(O)C.O>[CH3:16][C:15]1([CH3:17])[C@@H:9]2[CH2:8][C:7]3[C:11]([C@H:10]12)=[C:12]([CH3:14])[S:13][C:6]=3[C:4]([OH:5])=[O:3]Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 70 °C
Procedure
To a solution of crude (1aS,5aR)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalene-4-carboxylic acid ethyl ester (10.3 g, 41.2 mmol) in ethanol (200 mL) a solution of 2N aq. LiOH (300 mL) is added. The resulting mixture is stirred at 70° C. for 1 h, cooled to rt and diluted with water (250 mL). The aq. solution is extracted three times with DCM (125 mL) before it is acidified to pH 3 by adding citric acid. The acidified solution is extracted twice with DCM (2×250 mL). These second extracts are combined, dried over Na2SO4, filtered and evaporated to leave (1aS,5aR)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalene-4-carboxylic acid (7.0 g) as a yellow solid. LC-MS: tR=0.95 min, [M+1]+=223.00. 1H NMR (CDCl3): δ3.04-2.92 (m, 1H), 2.83 (d, J=19.3 Hz, 1H), 2.39 (s, 3H), 1.91-1.87 (m, 2H), 1.13 (s, 3H), 0.73 (s, 3H).
Workup
- temperaturecooled to rt
- extractionThe aq. solution is extracted three times with DCM (125 mL) before it
- additionby adding citric acid
- extractionThe acidified solution is extracted twice with DCM (2×250 mL)
- dry with materialdried over Na2SO4
- filtrationfiltered
- customevaporated
Sources & evidence
- ORD record
- ord-91d40d4808574e80b30f5e4b55ff0792
- Source dataset
- uspto-grants-2009_10
- Patent number
- US07605269B2
Reaction notes
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