Chinpiao Chen

Covalent linkage of nanodiamond-paclitaxel for drug delivery and cancer therapy

A nanoparticle-conjugated cancer drug provides a novel strategy for cancer therapy. In this study, we manipulated nanodiamond (ND), a carbon nanomaterial, to covalently link paclitaxel for cancer drug delivery and therapy. Paclitaxel was bound to the surface of 3-5 nm sized ND through a succession of chemical modifications. The ND-paclitaxel conjugation was measured by atomic force microscope and nuclear magnetic resonance spectroscopy, and confirmed with infrared spectroscopy by the detection of deuterated paclitaxel. Treatment with 0.1-50 microg ml(-1) ND-paclitaxel for 48 h significantly reduced the cell viability in the A549 human lung carcinoma cells. ND-paclitaxel induced both mitotic arrest and apoptosis in A549 cells. However, ND alone or denatured ND-paclitaxel (after treatment with strong alkaline solution, 1 M NaOH) did not induce the damage effects on A549 cells. ND-paclitaxel was taken into lung cancer cells in a concentration-dependent manner using flow cytometer analysis. The ND-paclitaxel particles were located in the microtubules and cytoplasm of A549 cells observed by confocal microscopy. Furthermore, ND-paclitaxel markedly blocked the tumor growth and formation of lung cancer cells in xenograft SCID mice. Together, we provide a functional covalent conjugation of ND-paclitaxel, which can be delivered into lung carcinoma cells and preserves the anticancer activities on the induction of mitotic blockage, apoptosis and anti-tumorigenesis.

Organic functionalization of ultradispersed nanodiamond: synthesis and applications

This work describes the chemical modification of ultradispersed nanodiamond results in the enrichment of the surface hydroxyl groups as by FT-IR, TGA, RGA-MS and XRD measurements. These hydroxyl groups can be conveniently functionalized with long chain alcohols (oxyhexanol) for easy manipulation of different functional groups. The surface loading of the oxyhexanol groups were found to be 0.13 mmol/g of nanodiamond. The functionalities on the surface of the modified nanodiamond afford a new solid phase for the synthesis of peptides to facilitate the covalent attachment of drug molecules. The conjugation of chiral ligands with a nanodiamond yields a new enantioselective heterogeneous catalyst that exhibits moderate to good enantioselectivity in the asymmetric aldol reaction.

Preparation of acyl fluorides with hydrogen fluoride-pyridine and 1,3-dicyclohexylcarbodiimide

This work presents an efficient procedure for preparing acyl fluorides by simply reacting carboxylic acid with hydrogen fluoride-pyridine and 1,3-dicyclohexylcarbodiimide (DCC) in dichloromethane. The acyl fluorides were converted in situ to the corresponding benzyl carboxylic esters by adding benzyl alcohol and triethylamine to the reaction mixture.

Synthesis and anticancer evaluation of vitamin K3 analogues

Abstract Novel vitamin K 3 analogues were synthesized and evaluated for their anticancer activity. Compound 6 , 9 , 10 , 11 , 14 , and ( ± ) 15 demonstrated a strong inhibitory activity against the tumor cells of A-549, Hep G2, MCF7, MES-SA, MES-SA/Dx5, MKN45, SW-480, and TW-039. Compound ( ± ) 15 displayed potent tumor cell cytotoxicity, and compound 14 selectively affected MCF7, even though it did not influence normal cells Detroit551 and WI-38. Compound ( ± ) 15 inhibited MES-SA and MES-SA/Dx5, and this specific result shows that compound ( ± ) 15 may become a good anticancer drug candidate.

Total Synthesis of (+)-Antroquinonol and (+)-Antroquinonol D

The first total synthesis of (+)-antroquinonol and (+)-antroquinonol D, two structurally unique quinonols with a sesquiterpene side chain, is described. The route features an iridium-catalyzed olefin isomerization-Claisen rearrangement reaction (ICR), lactonization, and Grubbs olefin metathesis. The requisite α,β-unsaturation was achieved via the selenylation/oxidation protocol and elimination of β-methoxy group to provide two natural products from a common intermediate.

An expedient synthesis of honokiol and its analogues as potential neuropreventive agents.

An efficient synthesis of honokiol with Suzuki-Miyaura cross coupling obtained an overall yield of 45%. The proposed approach successfully synthesized several structurally similar alkyl, alkenyl and alkynyl analogues, seven of which showed potential neuropreventive activity against MPP(+)-induced and CHP/TBHP oxidative stress induced neuroblastoma cell death.

The size of interstellar nanodiamonds revealed by infrared spectra of CH on synthetic diamond nanocrystal surfaces

Infrared spectra of CH stretches have been investigated on the surfaces of synthetic diamond crystallites (5, 100, and 700 nm in diameter) to provide insights into the mid-infrared emission bands of stardusts in interstellar media. While the spectrum of 5-nm diamonds fails to display the distinct 2835 cm−1 (or 3.53 μm) band, a remarkably good match of the absorption bands of larger diamond grains with the emission observed for the stars Elias 1 and HD 97048 is obtained. Suggested by this study, the nanodiamonds that can display such characteristic emission bands at 3.53 μm in these two interstellar systems have a size significantly larger than 5 nm.

Manganese(II) chloride catalyzed highly efficient one-pot synthesis of propargylamines and fused triazoles via three-component coupling reaction under solvent-free condition

A one-pot green and highly efficient method for the synthesis of propargylamines and diastereoselective synthesis of fused triazoles via three-component coupling in the presence of manganese(II) chloride as a catalyst and a catalyst-free 1,3-dipolar cycloaddition reaction, respectively, without using a co-catalyst or activator is reported. This methodology is efficient, eco-friendly, operationally simple and effective for reactions involving aromatic, aliphatic, and heterocyclic aldehydes, and provides an easy access to propargylamines in excellent yields, fused triazoles in good yield and excellent diastereoselectivities.

Facile carbohydrate-based stereocontrolled divergent synthesis of (+)-pericosines A and B

An isomer-divergent synthesis of naturally occurring pericosines A and B is described starting from a known D-ribose derived ene-diol in 35% and 41% overall yields respectively of which the latter is the best synthetic method reported for pericosine B. The key features of this synthesis include the stereoselective NHK vinylation of the terminal aldehyde to the versatile diolefinic chiral intermediate and elegant conversions of the same to the corresponding final products via RCM (Ring Closing Metathesis).

Facile and efficient aromatization of 1,4-dihydropyridines with M(NO3)2·XH2O, TNCB, TBAP and HMTAI and preparation of deuterium labeled dehydronifedipine from nifedipine-d3

The easy and efficient aromatization of various 1,4-dihydropyridines was investigated using various metal nitrates, trinitratocerium(IV) bromate (TNCB), and tetrabutyl ammonium periodate (TBAP) as oxidant in acetic acid at 100 degrees C, as well as hexamethylenetetramine-iodine (HMTAI) reflux in methanol. The efficient conversion of nifedipine-d(3) to dehydronifedipine-d(3) as an internal standard can be used in the measurement of nifedipine concentration in a body.