4-Methylmorpholine → HCID 69531264, compound

Participants

Reaction Conditions

Reaction Steps

1.8 g (5 mmol) of ethoxycarbonyl-L-tyrosine cyclohexyl-ammonium salt (Example 3, Step A2) are dissolved in 20 ml of ethyl acetate and 6 ml of 1 M KHSO4. The phases are separated, the ethyl acetate phase is washed neutral with water, dried over anhydrous sodium sulfate and evaporated at a pressure of 2.0-2.5 kPa. The residue is dissolved in 5 ml of dimethylformamide, chilled to −15° C. and under constant stirring 0.55 ml (5 mmol) of N-methyl-morpholine and 0.66 ml of isobutyl chlorofomnnate are added. After 10 min. the following solution chilled to −15° C. is added: 1.5 g (5 mmol) of methyl L-isoleucyl-L-alaninate oxalate (Example 3, Step A4) and 1.4 ml (10 mmol) of triethylamine in 5 ml of dimethylformamide. The reaction mixture is stirred under cooling for 30 min, then at room temperature for further 30 min, then it is filtered and evaporated at a pressure of 2.0-2.5 kPa. The residue is dissolved in 30 ml of ethyl acetate, washed with 2×10 ml of 1 M KHSO4 and 2×10 ml of water, and evaporated at 2.0-2.5 kPa. The residue is crystallyzed with diethyl ether, filtered, washed with diethyl ether and dried in a vacuum desiccator.

Provenance & Evidence