Application of the Morita-Baylis-Hillman reaction in the synthesis of 3-[(N-cycloalkylbenzamido)methyl]-2-quinolones as potential HIV-1 integrase inhibitors.

A practicable six-step synthetic pathway has been developed to access a library of novel 3-[(N-cycloalkylbenzamido)methyl]-2-quinolones using Morita-Baylis-Hillman methodology. These compounds and their 3-[(N-cycloalkylamino)methyl]-2-quinolone precursors have been screened as potential HIV-1 integrase (IN) inhibitors. A concomitant survey of their activity against HIV-1 protease and reverse-transcriptase reveals selective inhibition of HIV-1 IN.

Heteroditopic P,N ligands in gold(I) complexes: synthesis, structure and cytotoxicity.

New heteroditopic, bi- and multidentate imino- and aminophosphine ligands were synthesised and complexed to [AuCl(THT)] (THT=tetrahydrothiophene). X-ray crystallography confirmed Schiff base formation in three products, the successful reduction of the imino-group to the sp(3)-hybridised amine in several instances, and confirmed the formation of mono-gold(I) imino- and aminophosphine complexes for four Au-complexes. Cytotoxicity studies in cancerous and non-cancerous cell lines showed a marked increase in cytotoxicity upon ligand complexation to gold(I). These findings were supported by results from the 60-cell line fingerprint screen of the Developmental Therapeutics Programme of the National Institutes of Health for two promising compounds. The cytotoxicity of some of these ligands and gold(I)complexes is due to the induction of apoptosis. The ligands and gold(I)complexes demonstrated selective toxicity towards specific cell lines, with Jurkat T cells being more sensitive to the cytotoxic effects of these compounds, while the non-cancerous human cell line KMST6 proved more resistant when compared to the cancerous cell lines. Results from the NIH DTP 60 cell-line fingerprint screen support the observed enhancement of cytotoxicity upon gold(I) complexation. One gold(I)complex induced high levels of apoptosis at concentrations of 50 µM in all the cell lines screened in this study, while some of the other compounds selectively induced apoptosis in the cell lines. These results point towards the potential for selective toxicity to cancerous cells through the induction of apoptosis.

Novel furocoumarins as potential HIV-1 integrase inhibitors.

A series of seven novel, rationally designed N-substituted 3-{3,5-dimethylfuro[3,2-g]coumarin-6-yl}propanamides have been prepared as potential HIV-1 integrase (IN) inhibitors via a five-step pathway commencing with resorcinol and diethyl 2-acetylglutarate, and the HIV-1 IN inhibition potential of these compounds has been examined relative to raltegravir, a known HIV-1 IN inhibitor.

Gold-phosphine binding to de novo designed coiled coil peptides.

The coordination of the therapeutically interesting [AuCl(PEt(3))] to the de novo designed peptide, TRIL23C, under aqueous conditions, is reported here. TRIL23C represents an ideal model to investigate the binding of [AuCl(PEt(3))] to small proteins in an effort to develop novel gold(I) phosphine peptide adducts capable of mimicking biological recognition and targeting. This is due to the small size of TRIL23C (30 amino acids), yet stable secondary and tertiary fold, symmetric nature and the availability of only one thiol binding site. [AuCl(PEt(3))] was found to react readily with the Cys side chain in a 1:1 ratio as confirmed by UV-visible, (31)P NMR and mass spectrometry. Circular dichroism confirmed that the coiled coil structure was retained on coordination of the {Au(PEt(3))}(+) unit. Redesign of the exterior of TRIL23C based on a biologically relevant recognition sequence found in GCN4, did not alter the coordination chemistry of [AuCl(PEt(3))]. To the best of our knowledge, this represents the first report on the coordination of gold(I) phosphine compounds to de novo designed peptides, and could lead to the generation of novel gold(I) phosphine peptide therapeutics in the future.

Modification of HIV-1 reverse transcriptase and integrase activity by gold(III) complexes in direct biochemical assays.

Gold(I) and gold(III) complexes have been previously investigated for potential biomedical applications including as anti-HIV agents. The oxidising nature of some gold(III) complexes yields well-documented cellular toxicity in cell-based assays but the effect in direct biochemical assays has not been fully investigated. In this study, gold(III) complexes were evaluated in HIV-1 reverse transcriptase and HIV-1 integrase biochemical assays. The gold(III) tetrachlorides KAuCl(4) and HAuCl(4) yielded sub-micromolar IC(50)'s of 0.947 and 0.983µM in the direct HIV-1 RT assay, respectively, while IC(50)'s ranging from 0.461 to 8.796µM were obtained for seven selected gold(III) complexes. The gold(III) tetrachlorides were also effective inhibitors of integrase enzymatic activity with >80% inhibition obtained at a single dose evaluation of 10µM. RT inhibition was decreased in the presence of a reducing agent (10mM DTT) and against the M184V HIV-1 RT mutant, while none of the gold(III) complexes were effective inhibitors in cell-based antiviral assays (SI values <5.95). Taken together, the findings of this study demonstrate that gold(III) complexes modify HIV-1 enzyme activity in direct biochemical assays, most likely through protein oxidation.

{µ-1,2-Bis[bis(4-meth-oxy-phen-yl)phosphan-yl]-1,2-dimethyl-hydrazine-κP:P'}bis-[chloridogold(I)] tetra-hydro-furan disolvate.

The title compound, [Au(2)Cl(2)(C(30)H(34)N(2)O(4)P(2))]·2C(4)H(8)O, is formed from a bidentate phosphine ligand complexed to two almost linearly coordinated gold(I) atoms [P-Au-Cl = 175.68 (3) Å]. The nuclei are 3.122 (2) Šapart. The mol-ecule exhibits a twofold rotation axis.

{µ-1,2-Bis[bis-(4-meth-oxy-phen-yl)phosphan-yl]-1,2-diethyl-hydrazine-κP:P'}bis-[chloridogold(I)] tetra-hydro-furan disolvate.

The title compound, [Au(2)Cl(2)(C(32)H(38)N(2)O(4)P(2))]·2C(4)H(8)O, is formed from a bidentate phosphine ligand complexed to two linear gold(I) nuclei [P-Au-Cl = 175.98 (3)°]. The nuclei are 3.1414 (2) Šapart. The mol-ecule exhibits a twofold symmetry axis. Stacks of the compound are formed through inter-molecular C-H⋯Cl inter-actions, while the tetra-hydro-furan (THF) solvate is further attached to the stacks through weak C-H⋯O hydrogen bonding from the THF O atom to two separate H atoms on the complex.

[µ-1,2-Bis(diphenyl-phosphan-yl)-1,2-diethyl-hydrazine-κP:P']bis-[chlorido-gold(I)] tetra-hydro-furan disolvate.

The title compound, [Au(2)Cl(2)(C(28)H(30)N(2)P(2))]·2C(4)H(8)O, was synthesized from a bidentate phosphine ligand complexed to two linear gold(I) chloride moieties. The Au(I) atom is in an almost linear coordination with a P-Au-Cl angle of 179.22 (4)°. The complex molecules reside on a twofold rotation axis.

Poly[[µ(2)-1,2-bis-(diphenyl-phosphan-yl)-1,2-diethylhydrazine]-µ(4)-nitrato-µ(2)-nitrato-silver(I)].

The title compound, [Ag(2)(NO(3))(2)(C(28)H(30)N(2)P(2))](n), crystallizes in polymeric α-helices. Three O atoms from three different nitrate ions in equatorial positions and two Ag atoms at axial positions set up a trigonal bipyramid. These units are linked by the phosphine ligands into endless helical chains that run along the c axis. The crystal used for the data collection was a racemic twin.

[µ-1,2-Bis(diphenyl-phosphan-yl)-1,2-dimethyl-hydrazine-κP:P']bis-[chlorido-gold(I)].

The title compound, [Au(2)Cl(2)(C(26)H(26)N(2)P(2))], is formed from a bidentate phosphine ligand complexed to two linearly coordinated gold(I) atoms. The gold(I) atoms are 3.4873 (7) Šapart. The mol-ecule exhibits a crystallographic twofold rotation axis.