Sodium Hydroxide → HCID 66790816, compound

Participants

Reaction Steps

57 mL (or approximately 26 mmol) of the aqueous solution of phosphoric acid mono-{6-amino-2-[(4-amino-benzenesulfonyl)-isobutyl-amino]-hexyl}ester (XIX) was neutralized with 40 mL of 1N sodium hydroxide. The pH of the solution (pH˜4-5) was then adjusted to pH=8 by adding 150 mL solution of saturated of sodium bicarbonate. To this well stirred solution was added a freshly prepared solution, in 130 mL of acetone, of methoxycarbonylamino-3,3-diphenyl-propionic acid 2,5-dioxo-pyrrolidin-1-yl ester (13.34 g, 34 mmol) prepared according to Anderson et al J. Am. Chem. Soc. 1964, 1839. The resulting clear solution was stirred for 12 h. The reaction mixture was concentrated and the remaining aqueous phase extracted twice with ethyl acetate. The aqueous phase was then acidified with 1N hydrochloric acid and the resulting suspension extracted with ethyl acetate. The organic phase was washed with water then dried over sodium sulfate, filtered and concentrated on a rotary evaporator. The solid residue was again suspended in ethyl acetate and acidified with HCl (g). The resulting beige precipitate was collected by filtration to give 12.5 g (66%) of the title product. Purity was determined by LC_MS and is greater than 97%.

Provenance & Evidence