Réaction #2345871

Équation de réaction

diethyl (S)-2-(2,3-dihydro-6-nitro-3-oxo-1,2-benzisothiazol-2-yl)glutarate

→

diethyl (S)-2-(6-amino-2,3-dihydro-3-oxo-1,2-benzisothiazol-2-yl)glutarate

Rendement 93.6%

Solvants

acetic acid

Conditions de réaction

Traitement

1. 1
   workup.STIRRINGThe reaction mixture was stirred 30 minutes
2. 2
   workup.ADDITIONafter the last addition
3. 3
   Filtrationfiltered
4. 4
   Concentrationconcentrated in vacuo
5. 5
   Autrethe residue absorbed onto silica gel (20 g) from a methylene chloride solution
6. 6
   AutrePurification by chromatography on silica gel (150 g)
7. 7
   Lavageeluting with ethyl acetate:hexane (1:1→2:1)

Mode opératoire

A solution of diethyl (S)-2-(2,3-dihydro-6-nitro-3-oxo-1,2-benzisothiazol-2-yl)glutarate (4.0 g, 10 mmol) and suspended iron (1.0 g, 18 mmol) in acetic acid (100 ml) was stirred under nitrogen for 1 hour at 55° C. Additional iron (3×0.25 g, 13 mmol) was added at intervals of 1, 1.25, and 1.75 hours. The reaction mixture was stirred 30 minutes after the last addition, filtered, concentrated in vacuo, and the residue absorbed onto silica gel (20 g) from a methylene chloride solution. Purification by chromatography on silica gel (150 g) eluting with ethyl acetate:hexane (1:1→2:1) gave diethyl (S)-2-(6-amino-2,3-dihydro-3-oxo-1,2-benzisothiazol-2-yl)glutarate (3.3 g) as an oil. 1H NMR (DMSO-d6, 300 MHz) δ: 1.15 (t, J=7 Hz, 3H, ester CH3), 1.17 (t, J=7 Hz, 3H, ester CH3), 1.95-2.38 (m, 4H, glu CH2CH2), 4.02 (q, J=7 Hz, 2H, ester CH2), 4.13 (q, J=7 Hz, 2H, ester CH2), 5.08-5.15 (m, 1H, glu CH), 6.09 (br s, 2H, NH2), 6.62 (dd, J=9,2 Hz, 1H, Ar), 6.84 (d, J=2 Hz, 1H, Ar), 7.50 (d, J=9 Hz, 1H, Ar). Mass spectrum (CI-CH4): 353 (M+1, 100%). Anal. Calculated for C16H20N2O5S: C, 54.53; H, 5.72; N, 7.95; S, 9.10. Found: C, 54.34; H, 5.73; N, 7.87; S, 9.00.

Source