Tris(triphenylphosphinegold)oxonium salts

The oxonium salts (Ph₃PAu)₃O⁺X^- where X^-  BF₄^-, CF₃COO^-, MnO₄^- have been prepared. These salts are formed from coordinatively unsaturated Ph₃PAu⁺ cations in alkaline or acid media. An X-ray study of (Ph₃PAu)₃O⁺BF₄^- indicates that the oxonium ions are dimeric in the crystalline form. The fragment (Ph₃PAu)₃O has a pyramidal structure: the oxygen atom is outside the Au₃ plane.     

3-(Thiazolidin-3-yl)rhodanines. A novel class of rhodanine derivatives

α-Bromoacetylaminorhodanines 1 were reacted with NH₄SCN yielding 3-(thiazolidin-3-yl)rhodanines 4 , a novel type of rhodanine derivatives bearing a uncommon N-N ring-connection.     

The Structure of Tris(3',5'-dimethylpyrazol-1-yl)-s-triazine and Its Use as a Ligand in Coordination Chemistry

The crystal and molecular structure of the title compound (Me₂-TPzT) has been determined by X-ray analysis. The observed molecular conformation presents the nitrogen atoms of three pyrazole rings in the same relative positions. The molecules are joined through intermolecular contacts forming chains that are arranged in a distorted hexagonal symmetry. Two complexes containing this ligand have been prepared: [{Pd(en)}₃(Me₂-TPzT)](PF₆)₆ and [{Ag(PPh₃)}3(Me₂-TPzT)](ClO₄)₃, which, due to their insolubility, have been characterized only by microanalysis, IR, ¹H NMR and, in the latter case, by mass spectrometry.     

Tridentate bipyrazole compounds with a side-arm as a new class of antitumor agents

Eight tridentate bipyrazole derivatives with different side arms have been prepared in one step and with good yields. The products were screened for their cytotoxic activity against three tumor cell lines—human breast cancer cell line MDA-MB231, human prostate cancer cell line PC3, and human colorectal cell line LoVo, by use of colorimetric MTT assay. Structure–activity relationships reflected the effect of substituted drugs. Among this series, two compounds had remarkable in-vitro antiproliferative activity against the LoVo cell line with IC50 values ranging from 2.6 to 2.7 μg ml^?1. All the compounds had suitable drug-like characteristics according to Lipinski’s rule.     

3-(2,5-Dioxopyrrolidin-1-yl), 3-(2,6-dioxopiperidin-1-yl), and 3-(1,3-dioxoisoindolin-2-yl)rhodanines. a novel type of rhodanine derivatives

3-Aminorhodanine 2 was reacted with cyclic anhydrides yielding 3-(2,5-dioxopyrrolidin-1-yl), 3-(2,6-dioxopiperidin-1-yl), and 3-(1,3-dioxoisoindolin-2-yl)rhodanine 6-8 , which in turn were condensated in 5 position with several aldehydes yielding the new rhodanine derivatives 9-11 .     

Synthesis of 3'-beta-carbamoylmethylcytidine (CAMC) and its derivatives as potential antitumor agents

3'-beta-Carbamoylmethylcytidine (CAMC) and its derivatives were synthesized using an intramolecular Reformatsky-type reaction promoted by SmI2 as the key step. In vitro tumor cell growth inhibitory activity was evaluated and CAMC was found to exhibit potent cytotoxicity against various human tumor cell lines. From a structure-activity relationship study it was postulated that the cytotoxic mechanism of action of CAMC did not require phosphorylation at the 5'-hydroxyl group. This study provides a novel strategy for the development of a new type of antitumor nucleoside.     

Synthesis of (1-substituted piperidin-4-yl)-1H-benzimidazoles and (1-substituted piperidin-4-yl)-3,4-dihydroquinazolines as possible antihypertensive agents

Structural modifications of 4-piperidylbenzimidazolinones (I) by replacing the benzimidazolinone group with other heterocycles (2-cyanoamino, 2-ethoxy, and 2-methylbenzimidazole and 2-cyanoamino-3,4-dihydroquinazoline) has been made and a number of new piperidines (II) were synthesized as potential antihypertensive agents.     

Synthesis of 3-substituted 7-(3,3-dimethyl-1-triazeno)-10-methylphenothiazines as potential antitumor agents

A series of 3-substituted (chloro, bromo, fluoro or methyl) 7-(3,3-dimethyl-1-triazeno)-10-methylphenothiazines were synthesized as potential antitumor agents. Treatment of p-substituted anilines with ammonium thiocyanate in the presence of bromine gave 6-substituted 2-aminobenzthiazoles which, after methylation with methyl iodide were hydrolyzed in 50% potassium hydroxide to give 5-substituted 2-methylaminothiophenols in moderate yield. Condensation of methylaminothiophenols with 3,4-dichloronitrobenzene in ethanol under an atomsphere of nitrogen gave adducts which were cyclized in dimethylformamide under the catalysis of copper and cuprous iodide to give 3-substituted 7-nitro-10-methylphenothiazines. The nitro group was reduced to the amino function with stannous chloride. Diazotization of the amines followed by coupling with dimethylamine gave the corresponding triazenes.     

Organometallic 3-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines as potential anticancer agents

Six organometallic complexes of the general formula [M(II)Cl(η(6)-p-cymene)(L)]Cl, where M = Ru (11a, 12a, 13a) or Os (11b, 12b, 13b) and L = 3-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines (L1-L3) have been synthesized. The latter are known as potential cyclin-dependent kinase (Cdk) inhibitors. All compounds have been comprehensively characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, UV-vis spectroscopy, ESI mass spectrometry, and X-ray crystallography (11b and 12b). The multistep synthesis of 3-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines (L1-L3), which was reported by other researchers, has been modified by us essentially (e.g., the synthesis of 5-bromo-1H-pyrazolo[3,4-b]pyridine-3-carboxylic acid (3) via 5-bromo-3-methyl-1H-pyrazolo[3,4-b]pyridine (2); the synthesis of 1-methoxymethyl-2,3-diaminobenzene (5) by avoiding the use of unstable 2,3-diaminobenzyl alcohol; and the activation of 1H-pyrazolo[3,4-b]pyridine-3-carboxylic acids (1, 3) through the use of an inexpensive coupling reagent, N,N'-carbonyldiimidazole (CDI)). Stabilization of the 7b tautomer of methoxymethyl-substituted L3 by coordination to a metal(II) center, as well as the NMR spectroscopic characterization of two tautomers 7b-L3 and 4b'-L3 in a metal-free state are described. Structure-activity relationships with regard to cytotoxicity and cell cycle effects in human cancer cells, as well as Cdk inhibitory activity, are also reported.     

Green synthesis of 1,3,4-oxadiazole derivatives based on N-arylidene-2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide as potential antitumor agents

Design of a new series of 1,3,4-oxadiazole derivatives was achieved in good yield via treatment of N-arylidene-2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide with cerium (IV) ammonium nitrate as a catalyst. They can be formulated also using one-pot reaction of 2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide, aromatic aldehyde and cerium (IV) ammonium nitrate in dichloromethane. The structural formulas of all synthesized products were elucidated based on their elemental and spectral analyses. In addition, MTT assay was used to evaluate antitumor activity of the synthesized molecules and some of them showed potent activity in comparison with Doxorubicin as a standard drug.     

Efficient microwave-assisted synthesis of 1-(1H-indol-1-yl)-2-phenyl-3-(1H-1,2,4-triazol-1-yl)propan-2-ols as antifungal agents

New conazole antifungals, in the series of triazole alcohols 23a-d and 24a-e incorporating an indole moiety substituted at 5-position by halogens, a cyano or 4-methoxyphenyl group, have been synthesized by ring opening of corresponding oxiranes 15 and 16. These dihalogeno intermediates and their congeneers could be prepared in high yields by Corey-Chaykovsky reaction under microwave irradiation.     

Synthesis and in-vitro antitumor activity of 1-[3-(indol-1-yl)prop-1-yn-1-yl]phthalazines and related compounds

A series of novel 3-(indol-1-yl)prop-1-yn-1-yl-substituted phthalazines and related azines was prepared via a concise pathway by palladium-catalyzed cross-coupling of appropriate halo-azines and N-propargylindoles. Some of the compounds exhibited significant antitumor activity in an in-vitro assay.     

The uses of 3-α-bromoacetylcoumarin in a novel syntheses of 3-(coumarin-3-yl) pyridazine and 3-(coumarin-3-yl) ketoximothiophene derivatives

Novel syntheses of bromohydrazones and ketoximes could be realized by reactions of 3-α-bromoacetylcoumarin with a variety of reagents. Such compounds reacted readily with nucleophiles to give unique heterocyclic systems. © 1996 John Wiley & Sons, Inc.     

Tris(2-hydroxyethyl)ammonium salts: 2,8,9-Trihydroprotatranes

New method of synthesis of tris(2-hydroxyethyl)ammonium salts, 2,8,9-trihydroprotatranes X-[HN(CH₂CH₂OH)₃]⁺, based on the reaction of tris(2-hydroxyethyl)amine (triethanolamine) with ammonium salts NH₄X (X = F, Cl, Br, I, NO₃, ClO₄) was developed. ¹H, ¹³C, ¹⁵N NMR and IR spectra of these protatranes were investigated, as well as those of their analogs with X = RCH₂COO (R = H; 2-MeC₆H₄O; 2-Me-4ClC₆H₃O; 2-MeC₆H₄S; 4-ClC₆H₄S; 4-ClC₆H₄SO₂; 3-IndS; 3-(PhCH₂-IndS) prepared from the corresponding acids RCH₂COOH and triethanolamine. The parameters of IR and NMR spectra of the studied protatranes were governed by the nature of substituent X, which also determined the character of the intra and intermolecular hydrogen bonds NH⋯O and OH⋯O in the protatrane framework.