With zinc(II) chloride; hydroxylamine-O-sulfonic acid In water at 80℃; for 10h;
Secondary Amides from Ketones; General Procedure
General procedure: To a stirring solution of ZnCl2 (0.05 mmol, 10 mol%) in H2O (2 mL) at r.t. in an open round-bottom flask, ketone 1 (0.5 mmol, 1.0 equiv) wasadded, followed by HOSA (1.5 equiv). The reaction mixture was stirred at the indicated temperature and for the duration indicated in Scheme 2. After completion, the reaction mixture was diluted with EtOAc (15 mL) and washed with sat. aq Na2CO3 (3 × 5 mL). The organic layer was washed with brine (5 mL) and dried over anhydrous Na2SO4.The crude product obtained after removal of all volatiles in vacuo was washed with n-hexane to remove some minor nonpolar impurities.
With cesiumhydroxide monohydrate; copper(II) bis(trifluoromethanesulfonate); hydroxylamine-O-sulfonic acid In dichloromethane; 2,2,2-trifluoroethanol at 70℃; for 20h;
Amides from Ketones
General procedure: To a stirred solution of Cu(OTf)2 (0.05 mmol, 10 mol%) in TFE/CH2Cl2 (1:4, 2-3 mL) were added ketone (0.5 mmol, 1.0 equiv), HOSA (2.0 equiv), and CsOH·H2O (2.0 equiv) at rt. The reaction mixture was maintained at the temperature and for the time indicated in Scheme 2. After completion, the mixture was diluted with CH2Cl2 (10 mL) and washed with sat. aq Na2CO3 (3 × 5 mL). The combined organic layers were washed with brine (5 mL) and dried (anhyd Na2SO4). The crude product obtained after removal of all volatiles in vacuo was purified by SiO2 (100-200 mesh) chromatography using EtOAc/hexane as eluent.
With mesitylenesulfonylhydroxylamine In acetonitrile at 20℃; for 16h;
General procedure for the preparation of amides from ketones
General procedure: To a round bottom flask, equipped with a magnetic stirring bar, was added ketone 1 (0.5 mmol, 1.0 equiv.) and acetonitrile (2 mL) at room temperature. To this stirred solution, freshly prepared O-(Mesitylsulfonyl)hydroxylamine 2 (2.0 equiv.) was added. The reaction mixture was stirred for the specified duration and temperature. The progress of the reaction was monitored by TLC. After completion, the reaction mixture was diluted with ethyl acetate (10 mL) and washed with a saturated aqueous NaHCO3 solution (3 x 5 mL). The combined organic layer was washed with brine solution and dried over anhydrous Na2SO4. Solvent was removed under reduced pressure to get the crude product. The reaction that required elevated temperature was stirred first at room temperature for 2 hours after addition of MSH and then heated at 70 °C for the specified time.