4-Methylmorpholine → 4-(4-Hydroxy-benzenesulfonyl)-2,2-dimethyl-thiomorpholine-3-carboxylic acid methyl ester

Participants

Reaction Steps

To a solution of 0.5 g (2.6 mmol) of 4-hydroxybenzenesulfonyl chloride (J. Org. Chem. 1973, 38, 1047) in 5 mL of chloroform at room temperature was added 0.706 mL (2.86 mmol) of N,O-bis(trimethylsilyl)acetamide. The reaction mixture was stirred for 1 h and added a solution of 0.41 g (2.16 mmol) of methyl (3S)-2,2-dimethyl-3-thiomorpholinecarboxylate in 1 mL of chloroform in one portion, followed by 0.48 mL (4.37 mmol) of N-methylmorpholine. The resulting mixture was stirred for 18 h and 10 mL of methanol was added and the resulting mixture was heated to reflux for 1 h. The reaction was diluted with ethyl acetate, washed with water, 5% HCl and brine, dried over MgSO4 filtered and concentrated in vacuo. The residue was triturated with ether:hexanes (1:2) to provide 0.62 g (83%) of 4-(4-hydroxy-benzenesulfonyl)-2,2-dimethyl-thiomorpholine-3- carboxylic acid methyl ester as a pale yellow solid. Electrospray Mass Spec: 344.4 (M−H)−

Provenance & Evidence