Citric Acid → HCID 178495743, compound

Participants

Reaction Steps

2.50 g (6.24 mmol) of the dicyclohexylammonium salt of N-Boc-(S)—O-methyl-serine are dissolved in 20 ml 5% citric acid, the aqueous phase is extracted 2× with 20 ml of ethyl acetate, the combined organic phases are dried over sodium sulphate and freed from solvent i. vac. The residue is dissolved together with 1.23 g (6.55 mmol) 4-bromo-1,2-phenylenediamine in 30 ml THF and 1.42 ml (14.0 mmol) triethylamine and 4.97 ml (7.80 mmol) of a 50% solution of PPA in ethyl acetate are added with stirring in the ice bath. After 5 minutes stirring in the ice bath the mixture is heated to ambient temperature and stirred for 23 hours at ambient temperature. The reaction mixture is poured into 100 ml of water and the aqueous phase is extracted with ethyl acetate. The combined organic phases are extracted with sat. sodium carbonate solution and water, dried over sodium sulphate and evaporated down i. vac.

Provenance & Evidence