Scalable Syntheses of N^α‐Benzyloxycarbonyl‐L‐ornithine and of N^α‐(9‐Fluorenylmethoxy)carbonyl‐L‐ornithine.

Abstract

Amino acids Amino acids U 0400Scalable Syntheses of N α -Benzyloxycarbonyl-L-ornithine and of N α -(9-Fluorenylmethoxy)carbonyl-L-ornithine. -(MASIUKIEWICZ, E.; WIEJAK, S.; RZESZOTARSKA*, B.; Org. Prep. Proced. Int. 34 (2002) 5, 521-527; Inst. Chem., Pedagog. Univ. Opole, PL-45-052 Opole, Pol.; Eng.) -F. Santoso 02-165

Optimized syntheses of Fmoc azido amino acids for the preparation of azidopeptides

“…For the synthesis of azido acids 41 and 42 , derivatives of l ‐ornithine and l ‐lysine, we applied the strategy of orthogonal functional group protection (Scheme ). Synthesis started from commercially available l ‐ornithine·HCl 33 or l ‐lysine·HCl 34 , and the reaction with copper acetate monohydrate under basic conditions afforded [Orn(Boc)] 2 Cu 35 or [Lys(Boc)] 2 Cu 36 , respectively, which were isolated by a perfect filtering off of their insoluble copper complexes.…”

“…Protected acid 37 was prepared by the reaction of 35 (10.2 g; 19.4 mmol) and 8-quinolinol (7.3 g; 50.4 mmol), using the method described previously [56][57][58][59]…”

“…The strategy of orthogonal functional group protection [56][57][58][59] of L-ornithine and L-lysine is usually used for the synthesis of their azido derivatives.…”

Molecular and crystal structure of Nα-(9-fluorenyl)-methoxycarbonyl-L-ornithine hydrochloride diethyl ether solvate

“…NC~-Fmoc-L-Om HC1 [25] was dissolved in methanol, diethyl ether was added, and this solution was left for slow crystallisation. Colourless crystals have m.p.…”

Stereochemistry of Sagittamide A: Prediction and Confirmation.

“…1 To a solution of the known galactose derivative 1) (5 g, 11.1 mmol) in absolute EtOH (125 mL) was added NaBH 4 (840 mg, 22.2 mmol) in small portions. After addition was complete, the reaction mixture was stirred at rt for 5 h. Following this period, the solvent was removed under reduced pressure and the residue was dissolved in EtOAc (50 mL), which was then treated carefully with a saturated NH 4 Cl aqueous solution (25 mL). The resultant biphasic mixture was stirred vigorously at rt for 1 h. The organic layer was separated and the aqueous layer was extracted with EtOAc (6×25 mL).…”