4-Methylmorpholine → Boc-Tyr-(D)Ala-Gly-Phe methioninol

Participants

Reaction Steps

4.1 g of Boc-Tyr-(D)Ala-Gly-OH and 1.1 ml of N-methyl-morpholine are dissolved in 50 ml of absolute tetrahydrofuran and 1.0 ml of chloroformic acid ethyl ester added dropwise at -15°. After 5 minutes, a solution of 4.0 g of H-Phe-methioninol trifluoroacetate and 1.2 ml of N-methylmorpholine in 50 ml of DMF is added. After 1 hour's stirring at 0°, the reaction mixture is evaporated and the residue taken up in acetic acid. The solution is repeatedly washed with 10% phosphoric acid and 1 N sodium bicarbonate. After evaporation of the acetic esters, the residue is crystallised from methanol/ether. M.P. 158°.

Provenance & Evidence