Stannous Chloride → 1,3-Dihydro-2,1-benzisothiazole 2,2-dioxide

HRID 1776172Notes

Reaction equation

HRID 1776172 reaction equation
[N+:1]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=1[CH2:10][S:11](Cl)(=[O:13])=[O:12])([O-])=O.[Sn](Cl)Cl.C(=O)(O)[O-].[Na+]>C(OCC)(=O)C>[NH:1]1[C:4]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=2[CH2:10][S:11]1(=[O:13])=[O:12]

Participants

5

Reactant 3

HCID 24479Stannous ChlorideHCID 516892Sodium BicarbonateHCID 4305447(2-nitrophenyl)methanesulfonyl Chloride

Product 1

HCID 155360091,3-Dihydro-2,1-benzisothiazole 2,2-dioxide

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
70 °C

Procedure

The title compound was prepared using the method described in WO 98/32438 A1. To a solution of 2-nitro-alpha-toluenesulfonyl chloride (5.1 g, 21.6 mmol) in anhydrous ethyl acetate (250 mL) was added tin (II) chloride (19.3 g, 86 mmol). The reaction was stirred overnight at 70° C., then poured onto ice and neutralized with saturated aqueous sodium bicarbonate. The solution was filtered through Celite, extracted with ethyl acetate, and the organic layer concentrated. To the crude residue was added anhydrous methylene chloride (200 mL) and triethylamine (5 mL). The solution was stirred overnight at room temperature and concentrated under reduced pressure. The product was obtained by silica gel column chromatography (30-100% ethyl acetate in hexanes) followed by recrystallization from methylene chloride/hexanes to give a white solid. (0.24 g, 6.5%). 1H NMR (CDCl3, 300 MHz) δ 7.30-7.22 (m, 2H), 7.07-7.02 (t, 1H, J=7.4 Hz), 6.89-6.86 (dd, 1H, J=0.6, 8.1 Hz), 6.66 (br s, 1H), 4.39 (s, 1H).

Workup

  1. filtrationThe solution was filtered through Celite
  2. extractionextracted with ethyl acetate
  3. concentrationthe organic layer concentrated
  4. additionTo the crude residue was added anhydrous methylene chloride (200 mL) and triethylamine (5 mL)
  5. stirringThe solution was stirred overnight at room temperature
  6. concentrationconcentrated under reduced pressure
  7. customThe product was obtained by silica gel column chromatography (30-100% ethyl acetate in hexanes)
  8. customfollowed by recrystallization from methylene chloride/hexanes
  9. customto give a white solid

Sources & evidence

ORD record
ord-cfae681bc0484decb046ba705b29e26e
Source dataset
uspto-grants-2016_02
Patent number
US09265772B2

Reaction notes

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