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

HRID 128440

Reaction equation

HRID 128440 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-disubstituted-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 quatitative 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-5796a313534e4c53a638b9d738e8580c
Source dataset
uspto-grants-1981_03
Patent number
US04259498

Linked notes

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