Fan Xiao-dong

Synthesis and characterization of inexpensive 3-Nε-benzyloxycarbonyl-L-lysyl-morpholine-2,5-dione

In this paper, we call 3-Nɛ-benzyloxycarbonyl-L-lysyl-morpholine-2,5-dione “Compound A”. The starting material used abroad is expensive and the yield is low (16%–28%); furthermore, to our best knowledge, no characterization of Compound A is available in the open literature. We now use low-cost L-lysine as starting material, succeed in raising the yield of Compound A to about 66%, and characterize it. In the synthesis of Compound A, the reactive processes used by us included the protection of amino group of lysine, acetylation, and intramolecular cyclizative condensation reaction. Benzoxycarbonyl chloride was selected as amino group protection agent, and the yield was elevated by replacing sodium bicarbonate with triethyl amide as the acid’s neutralizer. The resulting material or Compound A was cyclizative; its structure and properties were characterized by infrared (IR), Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR) and elemental analysis. The results of characterization show that: (1) Compound A has a chiral carbon next to the carbonyl group, so the formation of the ring structure is not sterospecific; (2) the melting point is about 254.5°C. The homopolymer and copolymers of Compound A with lactide or caprolactone have reaction-active groups and excellent biocompatibility and biodegradability; so they can be used in tissue engineering and as controlled-drug-release carriers.