ORCID Profile
0000-0002-2094-0820
Current Organisations
The University of Auckland
,
Nankai University
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Publisher: Elsevier BV
Date: 12-2023
Publisher: Wiley
Date: 30-03-2010
Abstract: A homologous set of 9,9-dialkyl-4,5-diazafluorene compounds were prepared by alkylation of 4,5-diazafluorene with the appropriate alkyl bromide and under basic conditions. The structures of these simple organic compounds were confirmed by spectroscopic techniques (FTIR, NMR, and FABMS). Their biological effects toward a panel of human carcinoma cells, including Hep3B hepatocellular carcinoma, MDAMB-231 breast carcinoma, and SKHep-1 hepatoma cells, were investigated a structure-activity correlation was established with respect to the length of the alkyl chain and the fluorene ring structure. The relationship between the mean potency [log(1/IC(50))] and alkyl chain length was systematically studied. The results show that compounds with butyl, hexyl, and octyl chains exhibit good growth inhibitory effects toward these three human carcinoma cell lines, and the 9,9-dihexyl-4,5-diazafluorene further exhibits antitumor activity in athymic nude mice Hep3B xenograft models. For the structurally related dialkylfluorenes that lack the diaza functionality, in vitro cytotoxicity was not observed at clinically relevant concentrations.
Publisher: American Chemical Society (ACS)
Date: 04-11-2021
Publisher: Wiley
Date: 19-09-2022
DOI: 10.1002/AOC.6882
Abstract: Reactions of Ru 3 (CO) 12 with 6‐methyl‐2‐pyridinyl‐ethanol ligands 6‐CH 3 ‐2‐PyCH 2 CR 1 R 2 OH [R 1 H, R 2 2‐CH 3 OC 6 H 4 ( L1H ) R 1 H, R 2 2‐CF 3 C 6 H 4 ( L2H ) R 1 R 2 CH 3 ( L3H ) and R 1 H, R 2 2,6‐(CH 3 O) 2 C 6 H 3 ( L4H )] in refluxing THF afforded the corresponding trinuclear ruthenium clusters (6‐CH 3 ‐2‐PyCH 2 CR 1 R 2 O)( μ 2 ‐H)Ru 3 (CO) 9 [R 1 H, R 2 2‐CH 3 OC 6 H 4 ( 1 ) R 1 H, R 2 2‐CF 3 C 6 H 4 ( 2 ) R 1 R 2 CH 3 ( 3 ) and R 1 H, R 2 2,6‐(CH 3 O) 2 C 6 H 3 ( 4 )], respectively. All the four new clusters were well characterized by elemental analysis, IR, 1 H, and 13 C nuclear magnetic resonance. Furthermore, their crystal structures were determined by single‐crystal X‐ray diffraction analysis. The ruthenium clusters were proved to be efficient catalysts for the oxidation of saturated CH bonds with tert ‐butyl hydroperoxide (TBHP) as the oxidant in CH 3 CN/H 2 O (1:4) at room temperature.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0DT01142H
Abstract: New ligands H(2)L2-H(2)L6 comprise the cyclen macrocycle which is N,N'-dialkylated at the 1,7-nitrogen atoms by three- and four-carbon alkyl chains bearing terminal sulfonic (C(3) H(2)L2), phosphonic (C(3) H(2)L3, C(4) H(2)L4) or carboxylic acid (C(3) H(2)L5, C(4) H(2)L6) groups, and HL7 is N-monoalkylated by a four-carbon sulfonic acid group. The ligands were prepared by alkylation of a bridged bisaminal intermediate. The syntheses of cobalt(III) complexes containing a tetradentate cyclen, N,N'-1,7-Me(2)cyclen, cyclam or L2-L7 ligand together with the bidentate 8-quinolinato (8QO(-)) ligand, of interest as it is a model for a more potent cytotoxic analogue, were investigated. Coordination of ligands (L) cyclen, N,N'-1,7-Me(2)cyclen or cyclam to cobalt(III) was achieved using Na(3)[Co(NO(6))] to form [Co(L)(NO(2))(2)](+). HOTf (trifluoromethansulfonic acid) was used to prepare the triflato complexes [Co(L)(OTf)(2)](+), followed by substitution of the labile triflato ligands to yield [Co(L)(8QO)](ClO(4))(2) isolated as the perchlorate salts. One further ex le containing cyclam and the 5-hydroxymethyl-8-quinolinato ligand was also prepared by this method. Complexes containing the pendant arm ligands L2-L6 were prepared from the cobalt precursor trans-[Co(py)(4)Cl(2)](+). Reaction of this complex with H(2)L2·4HCl and 8QOH produced [Co(L2)(8QO)] in one step and contains two deprotonated sulfonato pendant arms. The reaction of H(2)L3·4HBr with [Co(py)(4)Cl(2)](+) gave [Co(L3)]Cl in which L3 acts as a hexadenate ligand with the three-carbon phosphonato side chains coordinated to cobalt. H(2)L5·4HCl bearing three-carbon carboxylic acid pendant arms gave a similar result. The four-carbon ligands were coordinated to cobalt by reaction of [Co(py)(4)Cl(2)](+) with H(2)L4·4HBr or H(2)L6·4HCl to give [Co(HL4)Cl(2)] or [Co(H(2)L6)Cl(2)]Cl, which in turn with 8QOH gave the 8QO(-) complexes [Co(L4)(8QO)] bearing anionic phosphate pendant arms or [Co(H(2)L6)(8QO)]Cl(2) containing neutral carboxylic acid side chains. The reaction of Na(3)[Co(CO(3))(3)] with the mono-N-alkylated ligand HL7·4HCl and then HOTf gave [Co(L7)(CO(3))] and then in turn [Co(L7)(OTf)(2)]. The carbonato complex [Co(L7)(CO(3))] with [8QO](2)[SO(4)] produced [Co(L7)(CO(3))]. All complexes containing L7 bear an anionic sulfonato group on the side chain. The synthesis and characterisation of the six new ligands based on N-alkylated cylen ligand and the cobalt complexes outlined above are described, along with cyclic voltammograms of the 8QO(-) complexes and the molecular structures determined by X-ray crystallography of [Co(cyclen)(H(2)O)(2)](OTf)(3) (formed by aquation of the triflato complex), [Co(cyclen)(8QO)](ClO(4))(2), Co(L2)(8QO)·2H(2)O, Co(L4)(8QO)·6H(2)O and [Co(H(2)L6)Cl(2)]Cl·H(2)O. These demonstrate the coordination of the cyclen ligand in the folded anti-O,syn-N configuration with the N-alkylated nitrogens occupying apical positions.
Publisher: Elsevier BV
Date: 08-2011
DOI: 10.1016/J.BMC.2011.06.076
Abstract: A series of cobalt complexes of the potent DNA minor groove alkylator 1-(chloromethyl)-3-(5,6,7-trimethoxyindol-2-ylcarbonyl)-2,3-dihydro-1H-pyrrolo[3,2-f]quinolin-5-ol (seco-6-azaCBI-TMI) were prepared from a series of N-substituted cyclen ligands. The final N-substituted complexes carried formal overall charges ranging from +2 to -2 and showed limited improvements in solubility. They showed similar stabilities to that of the complex with the unsubstituted cyclen ligand, and large but variable attenuation of the cytotoxicity of the free alkylator (2-30-fold), compared to 150-fold for the unsubstituted ligand. However, they had oxic/hypoxic ratios (2-22-fold) comparable to that of the unsubstituted cyclen complex (5).
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0DT00045K
Abstract: An efficient method for direct oxygenation of primary arylamines to nitriles and amides with switchable selectivity was developed using N,O-bidentate Ru 3 clusters as catalysts.
Publisher: American Chemical Society (ACS)
Date: 17-06-2013
DOI: 10.1021/IC4006967
Abstract: A series of cobalt(III) complexes of the potent DNA minor groove alkylator (1-(chloromethyl)-5-hydroxy-1H-pyrrolo[3,2-f]quinolin-3(2H)-yl)(5,6,7-trimethoxy-1H-indol-2-yl)methanone (3 seco-CPyI-TMI), with cyclam or cyclen auxiliary ligands (L3 and L5) containing a cross-bridging ethylene (CH2CH2) group or the N,N'-dimethyl derivatives of these (L4 and L6), was prepared. Two 8-quinolinato (2) model complexes of these, [Co(L3)(2)](ClO4)2 and [Co(L6)(2)](ClO4)2, and the aquated derivative [Co(L6)(H2O)2](OTf)3 were characterized by X-ray crystallography. Electrochemistry of the 8-quinolinato model complexes showed that the Co(III)/(II) reduction potential was lowered relative to the unsubstituted cyclen ligand. Evaluation of the cytotoxicity of the racemic seco-CPyI cobalt complexes in vitro showed considerable attenuation of their cytotoxicity relative to the free alkylator and marked hypoxic selectivity, especially [Co(L3)(3)](2+) (9), which was 81-212-fold more potent under hypoxia than 20% oxygen in a panel of 10 human tumor cell lines. However, 9 did not elicit significant killing of hypoxic cells in HT29 tumor xenografts, suggesting possible pharmacological limitations in vivo.
Publisher: Wiley
Date: 16-06-2021
DOI: 10.1002/AOC.6336
Abstract: Treatment of Ru 3 (CO) 12 with one equivalent of 2‐indolyl‐6‐pyridinyl‐alcohol ligands 2‐(C 8 H 6 N)‐6‐(CR 1 R 2 OH)C 5 H 3 N (R 1 = R 2 = Me ( L1H ) R 1 = R 2 = C 2 H 5 ( L2H ) R 1 , R 2 = −(CH 2 ) 4 ‐ ( L3H ) & R 1 , R 2 = −(CH 2 ) 5 ‐ ( L4H )) in refluxing THF afforded the corresponding trinuclear ruthenium clusters L(μ 2 ‐H)Ru 3 (CO) 9 ( 1a – 1d ), respectively. All the novel Ru complexes were well characterized by NMR, elemental analyses and IR spectra. Structures of complexes 1a , 1c , and 1d were further determined by X‐ray crystallographic studies. Complexes 1a – 1d were applied to catalytic Oppenauer‐type oxidation of secondary alcohols with acetone as oxidant, and complex 1a was found to be the most efficient catalyst.
Publisher: American Chemical Society (ACS)
Date: 26-09-2022
Abstract: We present a convenient and efficient protocol to synthesize quinolines and quinazolines in one pot under mild conditions. A variety of substituted quinolines were synthesized in good to excellent yields (up to 97% yield) from the dehydrogenative cyclizations of 2-aminoaryl alcohols and ketones catalyzed by readily available Co(OAc)
No related grants have been discovered for Guo-Liang Lu.