Lithium Hydroxide → (1aS,5aR)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalene-4-carboxylic acid

HRID 1924807Notes

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-]>CCO.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

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 EtOH (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 give (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): δ 3.04-2.92 (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-8f27f003fc28447ab42daa4782b23e30
Source dataset: uspto-grants-2012_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08178562B2

Reaction notes

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