Saccharin → 3,3-diphenyl-2H-1,2-benzothiazole 1,1-dioxide

HRID 127356

Reaction equation

HRID 127356 reaction equation
[S:1]1([C:12]2[C:7](=[CH:8][CH:9]=[CH:10][CH:11]=2)[C:5](=O)[NH:4]1)(=[O:3])=[O:2].[C:13]1([Mg]Br)[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1>O1CCCC1>[C:13]1([C:5]2([C:7]3[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=3)[C:7]3[CH:8]=[CH:9][CH:10]=[CH:11][C:12]=3[S:1](=[O:3])(=[O:2])[NH:4]2)[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1

Participants

4

Procedure

Various procedures have been reported for synthesizing 3-substituted-benz[d]isothiazole-1,1-dioxides and 3,3-disubstituted-2,3-dihydrobenz[d]isothiazole-1,1-dioxides from saccharin (3-oxo-2,3-dihydrobenz[d]isothiazole-1,1-dioxide) and from saccharin pseudo-chloride (3-chlorobenz[d]isothiazole-1,1-dioxide). As reported by A. Mustafa et al, J. Chem. Soc., 1952, p. 1339, the treatment of saccharin pseudo-chloride with excess phenylmagnesium bromide gave the corresponding 3,3-diphenyl-2,3-dihydrobenz[d]isothiazole-1,1-dioxide in almost quantitative yield. Methyl-, ethyl-, n-propyl- and n-butylmagnesium halides were reported by these authors to react analogously. R. A. Abramovitch et al, J. Chem. Soc., Perkin Trans I, 1974 (22), p. 2589, reviewed and reinvestigated the reactions of saccharins with alkyl and aryl Grignard reagents and found that either the 3-alkyl (or 3-aryl)-benz[d]-isothiazole-1,1-dioxide and/or the open-chain tertiary alcohol, o--CH2OH benzenesulfonamide wherein R is alkyl (or aryl) were obtained with one exception. When saccharin was treated with an excess of phenylmagnesium bromide in boiling tetrahydrofuran, 3,3-diphenyl-2,3-dihyrobenz[d]isothiazole-1,1-dioxide was obtained as the minor product together with the open-chain tertiary alcohol.

Workup

  1. customto react analogously
  2. customwere obtained with one exception

Sources & evidence

ORD record
ord-8f5132ffe216448db2af1f601b3bd68a
Source dataset
uspto-grants-1981_03
Patent number
US04255578

Linked notes

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