Sulfurous Acid → HCID 23675696, compound

HRID 1378935Notes

Reaction equation

[Cl:1][C:2]1[C:3]2[C:7]([CH:8]=[CH:9][CH:10]=1)=[N:6][N:5]([CH3:11])[CH:4]=2.C([Li:16])CCC.[S:17](=O)([OH:19])[OH:18]>C(OCC)C>[Cl:1][C:2]1[C:3]2[C:7]([CH:8]=[CH:9][CH:10]=1)=[N:6][N:5]([CH3:11])[C:4]=2[S:17]([O-:19])=[O:18].[Li+:16]

Participants

Conditions

Temperature: -30 °C

Procedure

A solution containing 16 g (0.1 mol) of 4-chloro-2-methyl-2H-indazole in 300 ml of ethyl ether, was cooled to -30° C., and 85.4 g (0.2 mol) of n-butyl lithium (15% hexane solution) was dropwise added thereto. The mixture was stirred for one hour at the same temperature. Then, an excess amount of sulfurous acid gas was blown thereinto at a temperature of not higher than -20° C. for 3 hours. After completion of the reaction, the mixture was returned to room temperature and diluted with ethyl ether, and the product was subjected to filtration. Crystals were dried to obtain crude lithium 4-chloro-2-methyl-2H-indazole-3-sulfinate. This product was used for the subsequent reaction without purification.

Workup

waitat a temperature of not higher than -20° C. for 3 hours
customAfter completion of the reaction
customwas returned to room temperature
filtrationthe product was subjected to filtration
customCrystals were dried

Sources & evidence

ORD record: ord-99b3e4c3adbb4f988bae7c1bd2c23ce4
Source dataset: uspto-grants-1997_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05670452

Reaction notes

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