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

HRID 1447834

Reaction equation

HRID 1447834 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 (3chlorobenz[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-CR2OH 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-dihydrobenz[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-93b571087c6841c4b6ebd684decdde74
Source dataset
uspto-grants-1979_12
Patent number
US04178447

Linked notes

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