Diisopropylamine → (RS)-3-(2-hydroxy-4-methyl-pent-3-enyl)-benzo[d]isothiazol-6-ol

HRID 342199Notes

Reaction equation

[CH3:1][C:2]1[C:6]2[CH:7]=[CH:8][C:9]([OH:11])=[CH:10][C:5]=2[S:4][N:3]=1.[Li+].CC([N-]C(C)C)C.C(NC(C)C)(C)C.C([Li])CCC.[CH3:32][C:33]([CH3:37])=[CH:34][CH:35]=[O:36].C(=O)([O-])O.[Na+]>C1COCC1.CCOCC.C(O)(=O)C>[OH:36][CH:35]([CH:34]=[C:33]([CH3:37])[CH3:32])[CH2:1][C:2]1[C:6]2[CH:7]=[CH:8][C:9]([OH:11])=[CH:10][C:5]=2[S:4][N:3]=1

Participants

Conditions

Temperature: -78 °C

Procedure

1.5 g of 3-methyl-benzo[d]isothiazol-6-ol in 26 ml of THF are added to a LDA solution previously prepared from 3.9 ml of diisopropylamine and 16.0 ml of n-butyllithium (1.6M in hexane) in 23 ml of THF and the mixture is stirred at -78° C. 2.5 ml of 3-methyl-2-butenal in 40 ml of THF are added. The reaction mixture is thawed overnight and neutralized with 3.9 ml of acetic acid in 20 ml of ether. The mixture is added to sodium hydrogen carbonate solution, the inorganic phase is extracted with ethyl acetate and the organic phases are washed with sodium chloride solution and dried. The crude product is purified by chromatography (silica gel, ethyl acetate:hexane 1:1). 1.5 g of (RS)-3-(2-hydroxy-4-methyl-pent-3-enyl)-benzo[d]isothiazol-6-ol are obtained.

Workup

extractionthe inorganic phase is extracted with ethyl acetate
washthe organic phases are washed with sodium chloride solution
customdried
customThe crude product is purified by chromatography (silica gel, ethyl acetate:hexane 1:1)

Sources & evidence

ORD record: ord-4c99b9643117459f8cdb4bef669e8787
Source dataset: uspto-grants-1999_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05856503

Reaction notes

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