Reaction equation
[Cl:1][C:2]1[C:3]([OH:12])=[CH:4][C:5]2[CH:9]=[CH:8][S:7][C:6]=2[C:10]=1[Cl:11].C([Li])CCC.C(Cl)(Cl)(Cl)Cl.C(=O)=O.[CH:26](=[O:28])[CH3:27].Cl>O1CCCC1>[Cl:1][C:2]1[C:3]([OH:12])=[CH:4][C:5]2[CH:9]=[C:8]([CH:26]([CH3:27])[OH:28])[S:7][C:6]=2[C:10]=1[Cl:11]Participants
Reactant 5
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 25 g of 6,7-dichloro-5-hydroxybenzo[b]thiophene in 145 ml of dried tetrahydrofuran at -25° to -30° is added 110 ml of 2.5M n-butyllithium maintaining a temperature below -21°. After the addition, the carbon tetrachloride-dry ice bath is replaced with an ice-water bath and the mixture is stirred at 0°-5° for 4 hrs. A solution of 7.5 ml of freshly distilled acetaldehyde in 10 ml tetrahydrofuran is added dropwise. And additional 2 ml of acetaldehyde is added and the solution is stirred for 1 hr. The solution is poured onto 500 ml of a cold 5% hydrochloric acid solution and the mixture is extracted with ethyl ether. The ether extracts are washed, dried over anhydrous magnesium sulfate, filtered and solvent is removed to give a solid. Recrystallization from ethyl acetate and hexane gives 20 g of 6,7-dichloro-5-hydroxy-α-methylbenzo[b]thiophene-2-methanol, mp 173°-174°.
Workup
- additionAfter the addition
- stirringthe solution is stirred for 1 hr
- extractionthe mixture is extracted with ethyl ether
- washThe ether extracts are washed
- dry with materialdried over anhydrous magnesium sulfate
- filtrationfiltered
- customsolvent is removed
- customto give a solid
- customRecrystallization from ethyl acetate and hexane
Sources & evidence
- ORD record
- ord-be3fe63115264d5db3c89544b72c8512
- Source dataset
- uspto-grants-1985_07
- Patent number
- US04528399
Linked notes
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