Determination of binding modes and binding constants for the complexes of 6H-pyrido[4,3-b]carbazole derivatives with DNA.

The binding modes and binding constants for the complexes of forty types of pyridocarbazole derivatives 1-40 with double stranded DNAs (dsDNAs) were reported. The binding modes were determined by a combination of a deflection spectroscopy and orientation of the corresponding molecule in the DNA-based film with chain alignment. All of the compounds exhibited the intercalation-binding mode. Its binding constants Ka for the complexes, determined by quartz crystal microbalance (QCM), varied from 1.7×105 to 4.5×107M-1 according to the substituents on the pyridocarbazole framework and the sequences of dsDNA. The binding constants Ka of pyridocarbazole derivatives possessing the 2-(ω-amino)alkyl group and 5-(ω-amino)alkylcarbamyl group were larger than those of the corresponding ω-ureido derivatives. These ω-amino compounds exhibited strong GC base-pair preference in complexation. The Ka values decreased with the increasing NaCl concentration. It was clarified by a molecular modeling that the framework of the 2-tethered ω-amino derivative was completely overlapped with the stacking GC base-pairs leading to the formation of the stable intercalative-complex, and that the framework of the 5-tethered ureido derivative was half overlapped leading to the formation of the unstable complex. Furthermore, there were good linear relationships between lnKa and the relative stabilities Srel of the complexes. Contrary to our expectation, there was no linear relationship between lnKa and IC50 against Sarcoma-180, NIH3T3, and HeLa S-3 cell lines.

Oxidative Coupling of Terminal Alkynes with Aldehydes Leading to Alkynyl Ketones by Using Indium(III) Bromide.

An indium(III)-promoted direct acylation of terminal alkynes using aldehydes leading to ynones was developed. In contrast to the previous addition reactions of alkynes to aldehydes, which provide propargylic alcohols, the oxidative coupling proceeded exclusively to afford alkynyl ketones. The products were likely generated through an Oppenauer oxidation of the indium propargylic alkoxide species by excess amounts of aldehydes.

Gallium-catalyzed reductive chlorination of carboxylic acids with copper(II) chloride.

Described herein is the direct chlorination of carboxylic acids using copper(II) chloride via a gallium(III)-catalyzed reduction in the presence of a hydrosiloxane. During this reductive chlorination, the counteranions of CuCl2 functioned as a chloride source.

Synthesis and in vitro antitumor activity of novel 2-alkyl-5-methoxycarbonyl-11-methyl-6H-pyrido[4,3-b]carbazol-2-ium and 2-alkylellipticin-2-ium chloride derivatives.

Twenty-one types of novel ellipticine derivatives and pyridocarbazoles (5-methoxycarbonyl-11-methyl-6H-pyrido[4,3-b]carbazoles) with a nitrosourea moiety, linked by an oxydiethylene unit at the 2 position, were synthesized, and their cytotoxicity against HeLa S-3 cells was evaluated. Some of these new compounds exhibited potent antitumor activity by comparison with that of ellipticine.

Indium(III)-catalyzed reductive bromination and iodination of carboxylic acids to alkyl bromides and iodides: scope, mechanism, and one-pot transformation to alkyl halides and amine derivatives.

Highly effective indium(III)-catalyzed reductive bromination or iodination of a variety of carboxylic acids with 1,1,3,3-tetramethyldisiloxane (TMDS) and a source of bromine or iodine is described. This functional group interconversion has high tolerance for several functional groups, such as halogens, a hydroxy group, a nitro group, an olefin part, and a sulfide moiety. This indium catalytic system is also applicable to the reductive iodination of aldehyded, acyl chlorides, and esters. Furthermore, this reducing system can be applied to the one-pot synthesis of alkyl halides and amine derivatives via the addition of nucleophiles. Insight into the reaction mechanism was gained via the time course of (1)H and (13)C NMR monitoring experiments and the corresponding stepwise reactions.

Copper-catalyzed three- five- or seven-component coupling reactions: the selective synthesis of cyanomethylamines, N,N-bis(cyanomethyl)amines and N,N'-bis(cyanomethyl)methylenediamines based on a Strecker-type synthesis.

We have demonstrated that a cooperative catalytic system comprised of CuCl and Cu(OTf)(2) could be used to effectively catalyse the three-, five- and seven-component coupling reactions of aliphatic or aromatic amines, formaldehyde, and trimethylsilyl cyanide (TMSCN), and selectively produce in good yields the corresponding cyanomethylamines, N,N-bis(cyanomethyl)amines and N,N'-bis(cyanomethyl)methylenediamines.

Indium-catalyzed reductive bromination of carboxylic acids leading to alkyl bromides.

The combination of 1,1,3,3-tetramethyldisiloxane (TMDS) and trimethylbromosilane (Me(3)SiBr) with a catalytic amount of indium bromide (InBr(3)) undertook direct bromination of carboxylic acids, which produced the corresponding alkyl bromides in good to excellent yields. The reducing system was tolerant to several functional groups.

Single-step thioetherification by indium-catalyzed reductive coupling of carboxylic acids with thiols.

Direct thioetherification from a variety of aromatic carboxylic acids and thiols using a reducing system combined with InBr(3) and 1,1,3,3-teramethyldisiloxane (TMDS) in a one-pot procedure is demonstrated. It was also found that a system combined with InI(3) and TMDS underwent thioetherification of aliphatic carboxylic acids with thiols.

Structure-activity relationship in the antitumor activity of 6-, 8- or 6,8-substituted 3-benzylamino-ß-carboline derivatives.

We synthesized 47 kinds of 3-amino- or 3-benzylamino-ß-carboline derivatives with a substituent on the 6-, 8-, or 6,8-carbon atoms and evaluated their antitumor activities for Hela S-3 and Sarcoma 180 cell lines using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Consequently, we succeeded to develop 3-benzylamino-8-methylamino-ß-carboline (17a) and 8-methylamino-3-(3-phenoxybenzyl)amino-ß-carboline (17c) with antitumor activity with IC(50) values of 0.046, 0.032 µM, respectively, against HeLa S-3 cell line, which are higher than that of previously reported 3-(3-phenoxybenzyl)amino-ß-carboline (10e) of 0.074 µM. Furthermore, effects of Cl group at 6-carbon atom on the type of cell death was evaluated using 3-benzylamino-6-chloro-ß-carboline (10b), 3-benzylamino-ß-carboline (10d), N-(3-benzylamino)-6-chloro-9H-ß-carbolin-8-yl)benzamide (14g), and N-(3-benzylamino-9H-ß-carbolin-8-yl)benzamide (17b) to show no effect. Hoechst 33342 staining and DNA fragmentation assay suggested that these compounds induced cell death by apoptosis. In addition, using flow cytometry analysis, we established that the cell death pathway was through the arrest of the cell cycle in the G(2)/M phase.

Copper-catalyzed [5+1] annulation of 2-ethynylanilines with an N,O-acetal leading to construction of quinoline derivatives.

A novel copper-catalyzed [5 + 1] annulation of 2-ethynylanilines with an N,O-acetal, which functioned as a C1 part, leading to the preparation of quinoline derivatives with an ester substituent on the 2-position is described. A combination of CuBr(2) and trifluoroacetic acid (TFA) promoting [5 + 1] annulation of the 2-ethynylaniline with ethyl glyoxylate is also demonstrated.

Augmented autocrine bone morphogenic protein (BMP) 7 signaling increases the metastatic potential of mouse breast cancer cells.

As malignant breast cancers progress, they acquire the ability to spread to other regions of the body, including bone and lung, but the molecular mechanism underlying the increase in metastatic potential is not fully understood. Here we studied murine 4T1E/M3 highly bone marrow metastatic breast cancer cells, which we established previously. These cells show upregulated expression of bone morphogenetic protein (BMP) 7 and BMP receptors, as well as augmented phosphorylation of Smad1/5/8. Both anchorage-independent cell growth measured in colony forming assays and cell migration measured in wound healing assays were suppressed in 4T1E/M3 cells following treatment with a neutralizing anti-BMP7 antibody or knockdown of BMP7 gene expression. In addition, metastasis of 4T1E/M3 cells to the spine and lung and intracellular levels of phosphorylated Smad1/5/8 were suppressed by knocking down BMP7. Conversely, overexpression of BMP7 in the weakly metastatic parental 4T1E cells augmented their anchorage-independent growth, migration and metastasis to spine and lung. Taken together, our results strongly suggest that augmented autocrine BMP7 signaling leads to increases in the anchorage-independent cell growth, migration and metastatic potential in our bone marrow metastatic breast cancer model.

3-(3-Phenoxybenzyl)amino-ß-carboline: a novel antitumor drug targeting α-tubulin.

3-(3-Phenoxybenzyl)amino-ß-carboline 2h showed extremely-high activity; the IC(50) value was 0.074 µM. To verify 2h-induced cell death types, we observed the chromatin condensation, the DNA fragmentation and activated caspase-3 using Hoechst 33342, agarose electrophoresis and western blot, and suggesting 2h-induced cell death type was apoptosis. Flow cytometry showed that 2h-treated cell was induced SubG1 cell population after G2/M cell cycle arrest. In addition, using affinity chromatography and peptide mass fingerprinting, we found that interacting protein with this compound was α-tubulin protein.

Synthesis of tri- or tetrasubstituted pyrimidine derivatives through the [5+1] annulation of enamidines with either N,N-dimethylformamide dialkyl acetals or orthoesters and their application in a ring transformation of pyrimidines to pyrido[2,3-d]pyrimidin-5-one derivatives.

The [5+1] annulation of enamidines, which were prepared from functionalized silanes, organolithium compounds and two nitriles, with N,N-dimethylformamide dialkyl acetals as the C1 unit is described, leading to the synthesis of tri- and tetrasubstituted pyrimidine derivatives under catalyst- and solvent-free reaction conditions. Furthermore, the [5+1] annulation of enamidines by using orthoesters as the C1 unit is described, in which catalytic amounts of ZnBr(2) catalyze the annulation to produce polysubstituted pyrimidines under toluene or xylene reflux conditions. Moreover, the combination of a reductive ring-opening reaction with [Mo(CO)(6)] and a subsequent intramolecular cyclization with tBuOK effectively causes a skeletal transformation from the pyrimidines containing an isoxazolyl and an ethoxy substituent to form pyrido[2,3-d]pyrimidin-5-one frameworks in excellent yield.

3-benzylamino-ß-carboline derivatives induce apoptosis through G2/M arrest in human carcinoma cells HeLa S-3.

ß-carboline derivatives are known as the lead compounds for anti-tumor agents. To examine an optimal structure for anti-tumor activity, we synthesized a variety of ß-carboline derivatives, possessing a variety of substituents on the nitrogen atom of the amino group of 3-amino-ß-carboline, and evaluated their anti-tumor activity for HeLa S-3 cell line. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that an optimal structure for anti-tumor activity was 3-cyclohexylmethylamino (1e) or 3-benzylamino-ß-carboline (1f). An optimal counter anion of 2-methyl-3-benzylamino- ß-carbolinium salts was a triflate anion 2c. In addition, the introduction of a hydroxyl group on the meta-position of the benzyl group of 3-benzylamino-ß-carboline (3e) enhanced its anti-tumor activity. Hoechst 33342 staining and DNA fragmentation assay suggested that 1f, 2c and 3e induced cell death by apoptosis unlike 1e. Flow cytometry analysis showed that 1f, 2c and 3e induced cell apoptosis through arrest of the cell cycle in the G2/M phase.

Hf(OTf)4-catalyzed regioselective n-aminomethylation of indoles and related NH-containing heterocycles.

Under Lewis acidic conditions using Hf(OTf)(4), the aminomethylation of an indole derivative with a typical N,O-acetal preferentially produced kinetically favored N-aminomethylated indole derivatives instead of thermodynamically favored 3-aminomethylated indoles.

Highly selective conversion of nitrobenzenes using a simple reducing system combined with a trivalent indium salt and a hydrosilane.

Controlling the type of indium salt and hydrosilane enables a highly selective reduction of aromatic nitro compounds into three coupling compounds, azoxybenzenes, azobenzenes and diphenylhydrazines, and one reductive compound, anilines.

A single-step synthesis of enynes: Pd-catalyzed arylalkynylation of aryl iodides, internal alkynes, and alkynylsilanes.

An unprecedented single-step synthesis of enyne derivatives through Pd-catalyzed arylalkynylation of aryl iodides, internal alkynes, and alkynylsilanes is described.

Chemokine CCL2/MCP-1 negatively regulates metastasis in a highly bone marrow-metastatic mouse breast cancer model.

Bone is the most frequent site of breast cancer metastasis, and once such metastasis occurs, complete remission is extremely difficult to achieve. In an effort to define the mechanisms underlying metastatic spread of breast cancer to bone, we previously developed and characterized the highly bone metastatic 4T1E/M3 mouse breast cancer cells. We found that following injection into mice, 4T1E/M3 cells exhibited greater bone metastasis and greater in vitro anchorage-independent growth and cell migration than their parental cells (4T1E). We also found that expression of intracellular adhesion molecule-1 (ICAM-1) is crucially involved in these metastatic activities of 4T1E/M3 cells. In the present study, our analysis of gene and protein expression revealed that production of chemokine CCL2 (MCP-1) is dramatically reduced in 4T1E/M3 cells, and that restoration of CCL2 expression in 4T1E/M3 cells diminishes their metastasis to bone and lung. Overexpression of CCL2 in 4T1E/M3 cells significantly reduced not only in vitro anchorage-independent cell growth and cell migration, but also mRNA and cell surface expression of ICAM-1. Conversely, knocking down CCL2 in 4T1E parental cells augmented their metastatic spread to spine and lung. The expression of ICAM-1 was also upregulated in 4T1E-derived CCL2 knockdown cells. Taken together, these results suggest that CCL2 expression may negatively regulate breast cancer metastasis to bone marrow and lung in our model and that expression of ICAM-1 plays a crucial role in that process.

An unprecedented approach to 4,5-disubstituted pyrimidine derivatives by a ZnCl(2)-catalyzed three-component coupling reaction.

We have developed a ZnCl(2)-catalyzed three-component coupling reaction involving a variety of functionalized enamines, triethyl orthoformate, and ammonium acetate, which leads to the production of 4,5-disubstituted pyrimidine derivatives in a single step. The procedure can be successfully applied to the efficient synthesis of mono- and disubstituted pyrimidine derivatives, using methyl ketone derivatives instead of enamines.

Me3SiCl-promoted three-component coupling reaction of a functionalized enamine, an acetal, and an alkyne: an unprecedented approach to the synthesis of tetrasubstituted pyridines via a [3 + 2 + 1] intermolecular cyclization.

We have identified a Me3SiCl-mediated three-component coupling reaction of a functionalized enamine, N,N-dimethylformamide diethyl acetal, and an internal alkyne having an electron-withdrawing group that produces 2,3,4,5-tetrasubstituted pyridine derivatives in good to excellent yields via a single-step reaction.