HCID 18606052, compound → HCID 18606036, compound

Participants

Reaction Steps

A soluion of azapeptide 16S (more mobile diastereomer; (0.335 g; 0.774 mmol) in trifluoroacetic acid (5 ml) was allowed to stand for 3 hours. The reside after evaporation wa combined with sodium hydroxide (1 N; 3 ml) and THF (0.5 ml) and the resulting solution was stirred under nitrogen for 18 hrs. After neutralization with dilute hydrochloric acid, the solution was placed onto a column of DOWEX 50W-X4 ion-exchange resin (5 g). The product wa eluted with 20:1 H2O-pyr and freeze-dried to a white foam (0.215 g; 0.1=616 mmol; 80%). A portion of this material (0.052 g) was purified by chromatography on silica gel (85:30:5:1 CHCl3 -CH3OH-H2O:HOAc), affording pure product (0.031 g). The disodium salt (0.025 g) precipitated from CH2Cl2 ; m.p. 220-225 (dec). TLC (silica gel; 10:5:1:3 EPAW) Rf=0.45. Analysis: Calculated for C17H23N3O 5 . 2Na: C, 51.65; H, 5.82; N, 10.63. Found: C, 51.54; H, 5.79; N, 10.28. MS (for diacid): m/e 403 (monotrimethylsilyl of M+ -H2O). NMR (CDCl3). 1.7-2.3 (6H, m); 2.6-2.8 (2H, m); 3.00 (3H, s); 3.5-3.6 (3H, m); 4.3-4.5 (1H, m); 7.1-7.3 (5H, m); 7.4-8.0 (2H, broad).

Provenance & Evidence