No abstract

No abstract

Kilogram-scale synthesis of a bioactive pentapeptide in solution by "3+2" fragment coupling strategy has been successively accomplished in the development of OGP (10-14), a minimal OGP-derived sequence that retains the full proliferative activity of the osteogenic growth peptide. The synthetic scheme, coupling conditions and scaling up of the process are systematically studied, the epimerization of the tripeptide fragment and pentapeptide are also evaluated. .65 (t, J = 7.6 Hz, 3H), 7.40 (t, J = 7.4 Hz, 3H), 7. 34 -7.27 (m, 3H), 7.25 (d, J = 4.1 Hz, 3H), 7.17 (d, J = 8.5 Hz, 2H), 4.56 (s, 1H), 4.19 (d, J = 11.2 Hz, 1H), 4.16 -4.06 (m, 3H), 3.89 -3.76 (m, 3H), 3.05 (dd, J = 13.9, 4.2 Hz, 1H), 2.95 (d, J = 9.8 Hz, 1H), 2.79 -2.68 (m, 2H), 1.41 -0.85 (m, 9H). Fmoc-Tyr(tBu)-Gly-Phe-OSu (3)To a stirred solution of Fmoc-Tyr(tBu)-Gly-Phe-OH (2.76 kg, 4.16mol) and HOSu (0.67 kg, 5.83mol, 1.4eq) in dry THF (25 L), a solution of DCC (1.21 kg, 5.83mol, 1.4eq) in dry THF (5 L) was added slowly under ice-cooling within 3h, then the solution was stirred overnight at ambient temperature.After cooling for 1 h, the resulting precipitate was filtered and filtrate was used further reaction without purification. TLC: a 2 , R f =0.3. Boc-Gly-OH (4)The mixture of glycine (1 kg, 13.32mol) and NaHCO 3 (1.12 kg, 13.32mmol) in H 2 O (15 L) was added slowly to the solution of Boc 2 O (3.06 L, 13.32mol) in THF (10 L) and stirred at ambient temperature for 5h. When TLC indicated the absence of starting material, the residue was evaporated and distributed by H 2 O (20 L), EtOAc (7 L) and light petroleum (7 L). The organic layer was removed and the aqueous phase adjusted to pH 2-3 with 10% citric acid solution. After extracted with EtOAc (3×10 L), the aqueous layer was separated and the combined organic extracts were washed with saline (2×10 L), dried with magnesium sulfate and evaporated to give a white crystal (1.98 kg, 84.85%). m.p.85.7～86.5°C, Boc-Gly-Gly-OH (5)Boc-Gly-OH (1.98 kg, 11.3mol) and HONp (1.73 kg, 12.43mol, 1.1eq) or HOSu (1.43 kg, 12.43mol, 1.1eq) were dissolved in dry 1,4-dioxane (25 L), a solution of DCC (2.8 kg, 13.56mol, 1.2eq) in dry 1,4-dioxane (10 L) was added and the mixture stirred for 8-10h. After cooling for 2h, the precipitate was removed, the filtrate was used directly for next reaction without purification, TLC: a 1 , R f =0.4, 0.3.The mixture of glycine (0.94 kg, 12.43mol, 1.1eq) and NaHCO 3 (1.05 kg, 12.43mol, 1.1eq) in H 2 O (10 L) was slowly added to the solution of Boc-Gly-ONp (get by above step) in 1,4-dioxane (25 L). The solution was stirred at about 25°C for 7 h, then evaporated under reduced pressure. The residue was acidified to a pH 2-3 with 10% citric acid and extracted with EtOAc (3×20 L). The organic phase was successively washed with saline (20 L), dried, and evaporated to give Boc-Gly-Gly-OH (2.37 kg, 90.3%) as a white schistose crystals. m.p.123.5～125.5°C, TLC: a 3 , R f =0.2, HPLC: e, 6.53min, purity 93.5%, Calc. for C 7 H 13 NO 4 : C, 46.55; H, 6.94; N, 12.06. Found: C, 45.40; H, 6.02; N, 14.13...

As a result of the varying degrees of light scattering on surface, nanopapers prepared by filtration and casting present different optical properties.

The effects of lignophenols and pulp fibers as reinforcing elements in biocomposites were studied with poly-(3-hydroxybutyrate) (PHB) biopolymers and polystyrene (PS) matrix materials. Lignophenols and (NH2(CH2)3Si(OC2H5)3) were compared as plasticizing or compatibilizing additives in tests of composite properties. PHB and PP were blended with pulp fiber cellulose and lignophenol by torque rheometer, and the test specimens were processed via injection moulding. Various testing methods, including tensile and impact tests, SEM, XRD, TGA, and ART-FTIR were used to investigate the properties of the composites. PHB and PP-cellulose fiber composites with strong mechanical properties could be created by using a torque rheometer as a mixer at 190 ºC with very short mixing times. The (NH2(CH2)3Si(OC2H5)3) was found to improve the mechanical features of the PP, but not very obviously for both tensile and impact strengths of PHB. However, the lignophenols positively affected the PHB-pulp fiber composites. In summary, a novel method has been demonstrated for creating biodegradable composites with pulp fibers in the absence of a coupling agent, and lignophenols may be applicable as an additive in the cases described in this study.