mgso 4 and concentrated to give the clean product as a colorless oil 70 mg in 82 yield compound 64 compound 62 30 mg was dissolved in 4 n hcl in dioxane 2 0 ml the reaction mixture was stirred for 1 5 hours the dioxane was then removed in vacuo the residue was dissolved in pyridine 1 0 ml then cooled to 0 u00b0 c in an ice bath toluenesulfonylchloride 63 mg was added in portions after the addition the reaction mixture was stirred at room temperature for 12 tours the pyridine was then removed in vacuo the residue was taken up in methylene chloride dithyl ether 1 1 v v 100 ml the mixture was washed with dilute brine 3 u00d7 20 ml dried over mgso 4 and concentrated to give a liquid residue the crude product was purified by column chromatography with ethyl acetate hexane 4 6 v v as eluent to give the clean product as a colorless oil 25 g in 74 yield analogous reactions will append a carboxyamido group cyclic imino carboxylic acids cyclic imino carboxylic acids are a class of u03b2 amino acid residues wherein the amino functionality itself is part of a ring structure these u03b2 amino acids can also be used as residues in the present invention general experimental procedure a peptide.