Platinum(II) Complexes with 1,10‐Phenanthroline and Hydrophilic Alkoxyacetate Ligands as Potential Antitumor Agents

Four platinum complexes, formulated as [Pt(phen)(OCOCH₂OR)₂] (phen=1,10‐phenanthroline, R=Me, Et, ⁱPr, or ^tBu), have been synthesized and well characterized by elemental analysis, IR, ¹H‐NMR, ¹³C‐NMR and ESI‐MS spectroscopy. Replacing chloride groups of the precursor Pt(phen)Cl₂ with alkoxyacetate anions greatly improved the aqueous solubility and cytotoxicity of the resulting platinum complexes. The in vitro cytotoxicity study revealed that complexes 1 – 3 were active in vitro towards four human tumor cell lines, especially complex 1 which exhibited prominent in vitro cytotoxic activity against HCT‐116 cell lines comparable to cisplatin and oxaliplatin. Flow cytometry assay indicated that representative complexes 1 and 2 exerted cytotoxicity on HCT‐116 cell lines through inducing cell apoptosis and blocking cell cycle progression in the S or G2/M phases. The interaction of representative complexes with pET28a plasmid DNA was tested by agarose gel electrophoresis, which demonstrated that complexes 1 and 2 were capable of distorting plasmid DNA mainly by covalent binding and degradation effect.     

1,2,3‐Triazole Tagged 3H‐Pyrano[2,3‐d]pyrimidine‐6‐carboxylate Derivatives: Synthesis,in Vitro Cytotoxicity,Molecular Docking and DNA Interaction Studies

A series of novel ethyl 2,7‐dimethyl‐4‐oxo‐3‐[(1‐phenyl‐1H‐1,2,3‐triazol‐4‐yl)methyl]‐4,5‐dihydro‐3H‐pyrano[2,3‐d]pyrimidine‐6‐carboxylate derivatives 7a – 7m were efficiently synthesized employing click chemistry approach and evaluated for in vitro cytotoxic activity against four tumor cell lines: A549 (human lung adenocarcinoma cell line), HepG2 (human hematoma), MCF‐7 (human breast adenocarcinoma), and SKOV3 (human ovarian carcinoma cell line). Among the compounds tested, the compounds 7a , 7b , 7f , 7l , and 7m have shown potential and selective activity against human lung adenocarcinoma cell line (A549) with IC₅₀ ranging from 0.69 to 6.74 μm . Molecular docking studies revealed that the compounds 7a , 7b , 7f , 7l , and 7m are potent inhibitors of human DNA topoisomerase‐II and also showed compliance with stranded parameters of drug likeness. The calculated binding constants, k_b, from UV/VIS absorptional binding studies of 7a and 7l with CT‐DNA were 10.77 × 10⁴, 6.48 × 10⁴, respectively. Viscosity measurements revealed that the binding could be surface binding mainly due to groove binding. DNA cleavage study showed that 7a and 7l have the potential to cleave pBR322 plasmid DNA without any external agents.     

Synthesis and Antiproliferative Activities of Novel Substituted 5‐Anilino‐α‐Glucofuranose Derivatives

In order to find novel antitumor candidate agents with high efficiency and low toxicity, 14 novel substituted 5‐anilino‐α‐glucofuranose derivatives have been designed, synthesized and evaluated for antiproliferative activities in vitro. Their structures were characterized by NMR (¹H and ¹³C) and HR‐MS, and configuration (R/S) at C(5) was identified by two‐dimensional ¹H,¹H‐NOESY‐NMR spectrum. Their antiproliferative activities against human tumor cells were investigated by MTT assay. The results demonstrated that most of the synthesized compounds had antiproliferative effects comparable to the reference drugs gefitinib and lapatinib. In particular, (5R)‐5‐O‐(3‐chloro‐4‐{[5‐(4‐fluorophenyl)thiophen‐2‐yl]methyl}anilino)‐5‐deoxy‐1,2‐O‐(1‐methylethylidene)‐α‐glucofuranose ( 9da ) showed the most potent antiproliferative effects against SW480, A431 and A549 cells, with IC₅₀ values of 8.57, 5.15 and 15.24 μm , respectively. This work suggested 5‐anilino‐α‐glucofuranose as an antitumor core structure that may open a new way to develop more potent anti‐cancer agents.     

Bis‐ and Tetrakis(carboxylato)platinum(IV) Complexes with Mixed Axial Ligands – Synthesis,Characterization, and Cytotoxicity

A series of twelve novel diamminetetrakis(carboxylato)platinum(IV) and 18 novel bis(carboxylato)dichlorido(ethane‐1,2‐diamine)platinum(IV) complexes with mixed axial carboxylato ligands was synthesized and characterized by multinuclear ¹H‐, ¹³C‐, ¹⁵N‐, and ¹⁹⁵Pt‐NMR spectroscopy. Their cytotoxic potential was evaluated (by MTT assay) against three human cancer cell lines derived from ovarian teratocarcinoma (CH1/PA‐1), lung (A549), and colon carcinoma (SW480). In the cisplatin‐sensitive CH1/PA‐1 cancer cell line, diamminetetrakis(carboxylato)platinum(IV) complexes showed IC₅₀ values in the low micromolar range, whereas, for the most lipophilic compounds of the bis(carboxylato)dichlorido(ethane‐1,2‐diamine)platinum(IV) series, IC₅₀ values in the nanomolar range were found.     

Antiviral Activity of Benzimidazole Derivatives. I. Antiviral Activity of 1‐Substituted‐2‐[(Benzotriazol‐1/2‐yl)methyl]benzimidazoles

Forty‐three 2‐[(benzotriazol‐1/2‐yl)methyl]benzimidazoles, bearing either linear (dialkylamino)alkyl‐ or bulkier (quinolizidin‐1‐yl)alkyl moieties at position 1, were evaluated in cell‐based assays for cytotoxicity and antiviral activity against viruses representative of two of the three genera of the Flaviviridae family, i.e. Flaviviruses (Yellow Fever Virus (YFV)) and Pestiviruses (Bovine Viral Diarrhoea Virus (BVDV)), as Hepaciviruses can hardly be used in routine cell‐based assays. Compounds were also tested against representatives of other virus families. Among ssRNA⁺ viruses were a retrovirus (Human Immunodeficiency Virus type 1 (HIV‐1)), two picornaviruses (Coxsackie Virus type B2 (CVB2), and Poliovirus type‐1, Sabin strain (Sb‐1)); among ssRNA^? viruses were a Paramyxoviridae (Respiratory Syncytial Virus (RSV)) and a Rhabdoviridae (Vesicular Stomatitis Virus (VSV)) representative. Among double‐stranded RNA (dsRNA) viruses was a Reoviridae representative (Reo‐1). Two representatives of DNA virus families were also included: Herpes Simplex type 1, (HSV‐1; Herpesviridae) and Vaccinia Virus (VV; Poxviridae). Most compounds exhibited potent activity against RSV, with EC₅₀ values as low as 20 nM . Moreover, some compounds, in particular when bearing a (quinolizidin‐1‐yl)alkyl residue, were also moderately active against BVDV, YFV, and CVB2.     

Synthesis of Novel Chiral Sulfonamide‐Bearing 1,2,4‐Triazole‐3‐thione Analogs Derived from D‐ and L‐Phenylalanine Esters as Potential Anti‐Influenza Agents

Novel enantiopure 1,2,4‐trizole‐3‐thiones containing a benzensulfonamide moiety were synthesized via multistep reaction sequence starting with D‐phenylalanine methyl ester and L‐phenylalanine ethyl ester as a source of chirality. The chemical structures of all compounds were characterized by elemental analysis, UV, IR, ¹H NMR, ¹³C NMR, 2D NMR (HETCOR), and mass spectral data. All compounds were tested in vitro antiviral activity against a broad variety of DNA and RNA viruses and in vitro cytostatic activity against murine leukemia (L1210), human T‐lymphocyte (CEM) and human cervix carcinoma (HeLa) cell lines. Although enantiopure 1,2,4‐triazole‐3‐thione analogs in (R) configuration emerged as promising anti‐influenza A H1N1 subtype in Madin Darby canine kidney cell cultures (MDCK), their enantiomers exhibited no activity. Especially compounds 18a , 21a , 22a , 23a , and 24a (EC₅₀: 6.5, 6.1, 2.4, 1.6, 1.7 μM, respectively) had excellent activity against influenza A H1N1 subtype compared to the reference drug ribavirin (EC₅₀: 8.0 μM). Several compounds have been found to inhibit proliferation of L1210, CEM and HeLa cell cultures with IC₅₀ in the 12–53 μM range. Compound 5a and 27a in (R) configuration were the most active compounds (IC₅₀: 12–22 μM for 5a and IC₅₀: 19–23 μM for 27a ). Chirality 28:495–513, 2016. © 2016 Wiley Periodicals, Inc.     

Synthesis of 6‐[4‐(4‐Propoxyphenyl)piperazin‐1‐yl]‐9H‐purine Derivatives as Antimycobacterial and Antifungal Agents: In Vitro Evaluation and In Silico Study

A series of novel alkyl substituted purines were synthesized. 6‐[4‐(4‐Propoxyphenyl)piperazin‐1‐yl]‐9H‐purine was used as the key starting material, which was synthesized via a multistep protocol and finally subjected for N‐alkylation with various alkyl halides with an aim to get prospective antimicrobial agents. The structures of the novel compounds were established by substantiating them through spectral techniques like ¹H‐NMR, ¹³C‐NMR, FT‐IR and EI‐MS. They were explored for antitubercular activity against Mycobacterium tuberculosis H37RV. Furthermore, they were checked for their antimicrobial activity concerning bacterial and fungal strains. The title compounds exhibited considerable antimicrobial activity without any significant toxicity. In silico studies depicted their good binding profile against Mycobacterium tuberculosis enoyl reductase (InhA; PDB ID: 4TZK) and Candida albicans dihydrofolate reductase (PDB ID: 1AI9). The title compounds obeyed Lipinski's parameters and have exhibited good drug‐like properties.     

2,5‐Diketopiperazines from the Marine‐Derived Fungus Aspergillus fumigatus YK‐7

Five new diketopiperazines, prenylcyclotryprostatin B ( 1 ), 20‐hydroxycyclotryprostatin B ( 2 ), 9‐hydroxyfumitremorgin C ( 3 ), 6‐hydroxytryprostatin B ( 4 ), and spirogliotoxin ( 5 ), were isolated from the marine‐derived fungus Aspergillus fumigatus YK‐7, along with nine known compounds, 6 – 14 . Their structures were elucidated by spectroscopic methods, and their antiproliferative effects on human leukemic monocyte lymphoma U937 and human prostate cancer PC‐3 cell lines were assessed in vitro. Compounds 10, 12 , and 13 exhibited significant cell growth‐inhibitory activities against U937 cell line, with the IC₅₀ values of 1.8, 0.2, and 0.5 μM , respectively.     

Synthesis,Cytotoxicity and Antimicrobial Evaluation of New Coumarin‐Tagged β‐Lactam Triazole Hybrid

A series of coumarin‐tagged β‐lactam triazole hybrids ( 10a – 10o ) were synthesized and tested for their cytotoxic activity against MDA‐MB‐231 (triple negative breast cancer), MCF‐7 (estrogen receptor positive breast cancer (ER+)) and A549 (human lung carcinoma) cancer cell lines including one normal cell line, HEK‐293 (human embryonic kidney). Two compounds 10b and 10d exhibited substantial cytotoxic effect against MCF‐7 cancer cell lines with IC₅₀ values of 53.55 and 58.62 μm , respectively. More importantly, compounds 10b and 10d were non‐cytotoxic against HEK‐293 cell lines. Structure–activity relationship (SAR) studies suggested that the nitro and chloro group at the C‐3 position of phenyl ring are favorable for anticancer activity, particularly against MCF‐7 cell lines. Furthermore, antimicrobial evaluation of these compounds revealed modest inhibition of examined pathogenic strains with compounds 10c and 10i being the most promising antimicrobial agents against Pseudomonas aeruginosa and Candida albicans, respectively.     

Synthesis and investigation of the conversion reactions of pyrimidine‐thiones with nucleophilic reagent and evaluation of their acetylcholinesterase,carbonic anhydrase inhibition,and antioxidant activities

The conversion reactions of pyrimidine‐thiones with nucleophilic reagent were studied during this scientific research. For this purpose, new compounds were synthesized by the interaction between 1,2‐epoxy propane, 1,2‐epoxy butane, and 4‐chlor‐1‐butanol and pyrimidine‐thiones. These pyrimidine‐thiones derivatives ( A–K ) showed good inhibitory action against acetylcholinesterase (AChE), and human carbonic anhydrase (hCA) isoforms I and II. AChE inhibition was in the range of 93.1 ± 33.7–467.5 ± 126.9 nM. The hCA I and II were effectively inhibited by these compounds, with K_i values in the range of 4.3 ± 1.1–9.1 ± 2.7 nM for hCA I and 4.2 ± 1.1–14.1 ± 4.4 nM for hCA II. On the other hand, acetazolamide clinically used as CA inhibitor showed K_i value of 13.9 ± 5.1 nM against hCA I and 18.1 ± 8.5 nM against hCA II. The antioxidant activity of the pyrimidine‐thiones derivatives ( A–K ) was investigated by using different in vitro antioxidant assays, including Cu²⁺ and Fe³⁺ reducing, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH^?) radical scavenging, and Fe²⁺ chelating activities.     

Novel Nucleolipids of Pyrimidine β‐D‐Ribonucleosides: Combinatorial Synthesis,Spectroscopic Characterization,and Cytostatic/Cytotoxic Activities

Four series of nucleolipids with either uridine, 5‐methyluridine, 5‐fluorouridine, and 6‐azauridine as β‐D ‐ribonucleoside component have been prepared in a combinatorial (not parallel!) manner (see Formulae). All compounds have been characterized by elemental analyses, ESI mass spectrometry as well as by ¹H‐, and ¹³C‐NMR, and UV spectroscopy. A selection of eight nucleolipids with different lipophilizing moieties, based on earlier findings, as well as of 5‐fluorouridine as control were first tested on their cytotoxic effect towards PMA‐differentiated human THP‐1 macrophages. Those compounds which did not exhibit a significant inhibitory effect on the survival of the macrophages were next tested on their cytostatic/cytotoxic effect towards the human astrocytoma/oligodendroglioma GOS‐3 cells as well as against the rat malignant neuroectodermal BT4Ca cell line. Additionally, induction of apoptosis of the cell lines was evaluated. It turned out that particularly a combined lipophilization of the nucleosides by an 2′,3′‐O‐ethyl levulinate residue plus a farnesyl moiety at N(3) of the pyrimidine moiety of the corresponding nucleolipids leads to an active compound with the highest probability.     

One‐Pot Synthesis of New (1,3‐Thiazolo[5,4‐b]pyridin‐2‐yl)benzenediols and Their Antiproliferative Activities against Human Cancer Cell Lines

A one‐pot synthesis of new 4‐(1,3‐thiazolo[5,4‐b]pyridin‐2‐yl)benzene‐1,3‐diols has been described. The compounds were prepared by the reaction of sulfinylbis[(2,4‐dihydroxyphenyl)methanethione] derivatives, with various substituents in the aryl rings, with 2‐chloropyridin‐3‐amines. Their structures were deduced from IR and, ¹H‐ and ¹³C‐NMR spectroscopic, mass spectrometric, and elemental analyses. The antiproliferative properties of some of the products against human cancer cell lines were comparable to those of cisplatin. Structure? activity analysis showed that the presence of hydrophobic substituents in both heterocyclic fused and phenyl rings of the compounds improves their biological effects. Further, an additional OH group in the resorcinol moiety reduced the antiproliferative activity.     

Antiproliferative Evaluation of Some 2‐[2‐(2‐Phenylethenyl)‐cyclopent‐3‐en‐1‐yl]‐1,3‐benzothiazoles: DFT and Molecular Docking Study

The 2‐[2‐(2‐phenylethenyl)cyclopent‐3‐en‐1‐yl]‐1,3‐benzothiazoles were synthesized from the reactions of 7‐benzylidenebicyclo[3.2.0]hept‐2‐en‐6‐ones with 2‐aminobenzenethiol. The antiproliferative activities of 2‐[2‐(2‐phenylethenyl)cyclopent‐3‐en‐1‐yl]‐1,3‐benzothiazoles were determined against C6 (rat brain tumor) and HeLa (human cervical carcinoma cells) cell lines using BrdU cell proliferation ELISA assay. Cisplatin and 5‐fluorouracil (5‐FU) were used as standards. The most active compound was 2‐{(1S,2S)‐2‐[(E)‐2‐(4‐methylphenyl)ethenyl]cyclopent‐3‐en‐1‐yl}‐1,3‐benzothiazole against C6 cell lines with IC₅₀=5.89 μm value (cisplatin, IC₅₀=14.46 μm and 5‐FU, IC₅₀=76.74 μm ). Furthermore, the most active compound was 2‐{(1S,2S)‐2‐[(E)‐2‐(2‐methoxyphenyl)ethenyl]cyclopent‐3‐en‐1‐yl}‐1,3‐benzothiazole against HeLa cell lines with IC₅₀=3.98 μm (cisplatin, IC₅₀=37.95 μm and 5‐FU, IC₅₀=46.32 μm ). Additionally, computational studies of related molecules were performed by using B3LYP/6‐31G+(d,p) level in the gas phase. Experimental IR and NMR data were compared with the calculated results and were found to be compatible with each other. Molecular electrostatic potential (MEP) maps of the most active 2‐{(1S,2S)‐2‐[(E)‐2‐(2‐methoxyphenyl)ethenyl]cyclopent‐3‐en‐1‐yl}‐1,3‐benzothiazole against HeLa and the most active 2‐{(1S,2S)‐2‐[(E)‐2‐(4‐methylphenyl)ethenyl]cyclopent‐3‐en‐1‐yl}‐1,3‐benzothiazole against C6 were investigated, aiming to determine the region that the molecule is biologically active. Biological activities of mentioned molecules were investigated with molecular docking analyses. The appropriate target protein (PDB codes: 1 M17 for the HeLa cells and 1JQH for the C6 cells) was used for 2‐{(1S,2S)‐2‐[(E)‐2‐(2‐methoxyphenyl)ethenyl]cyclopent‐3‐en‐1‐yl}‐1,3‐benzothiazole and 2‐{(1S,2S)‐2‐[(E)‐2‐(4‐methylphenyl)ethenyl]cyclopent‐3‐en‐1‐yl}‐1,3‐benzothiazole molecules exhibiting the highest biological activity against HeLa and C6 cells in the docking studies. As a result, it was determined that these molecules are the best candidates for the anticancer drug.     

Room temperature and highly enantioselective additions of alkyltitanium reagents to aldehydes catalyzed by a titanium catalyst of (R)‐h8‐binol

Three alkyltitanium reagents of RTi(O‐i‐Pr)₃ (R = Cy ( 1a ), i‐Bu ( 1b ), and n‐Bu ( 1c )) were prepared in good yields. The high‐resolution mass spectroscopy showed that 1b and 1 c in the gas phase are monomeric species. However, the solid state of 1a revealed a dimeric structure. Asymmetric additions of 1a , 1b , 1c to aldehydes catalyzed by a titanium catalyst of (R)‐H₈‐BINOL were studied at room temperature. The reactions produced desired secondary alcohols in good yields with good to excellent enantioselectivities of up to 94% ee. Reactivity and enantioselectivity differences, in terms of steric bulkiness of the R nucleophiles, are herein described. The addition reactions of secondary c‐hexyl to aldehydes were slower than the reactions of primary i‐butyl or n‐butyl nucleophiles. For the primary alkyls, lower enantioselectivities were obtained for products from addition reactions of the linear n‐butyl as compared with the enantioselectivities of products from the addition reactions of the branched i‐butyl group. The same stereochemistry of RTi(O‐i‐Pr)₃ addition reactions as the addition reactions of organozinc, organoaluminum, Grignard, or organolithium reagents directly supports the argument of that titanium‐catalyzed addition reactions of aldehydes involve an addition of an organotitanium nucleophile. Chirality, 2011. © 2011 Wiley‐Liss, Inc.     

N‐[2‐[(3‐Chlorophenyl)amino]‐phenyl]‐3‐(difluoromethyl)‐1‐methyl‐1H‐pyrazole‐4‐carboxamide: Synthesis,Crystal Structure,Molecular Docking and Biological Activities

In continuation of our previous research on the development of novel pyrazole‐4‐carboxamide with potential antifungal activity, compound SCU2028 , namely N‐[2‐[(3‐chlorophenyl)amino]phenyl]‐3‐(difluoromethyl)‐1‐methyl‐1H‐pyrazole‐4‐carboxamide, was synthesized by new method, structurally characterized by IR, HR‐ESI‐MS, ¹H‐ and ¹³C‐NMR spectra and further identified by single‐crystal X‐ray diffraction. In pot tests, compound SCU2028 showed good in vivo antifungal activity against Rhizoctonia solani (R. solani) and IC₅₀ value of it was 7.48 mg L^?1. In field trials, control efficacy of compound SCU2028 at 200 g.a.i. ha^?1 was 42.30 % on the 7^th day after the first spraying and 68.10 % on the 14^th day after the second spraying, only slightly lower than that of thifluzamide (57.20 % and 71.40 %, respectively). Further in vitro inhibitory activity showed inhibitory ability of compound SCU2028 was 45‐fold higher than that of bixafen and molecular docking of compound SCU2028 to SDH predicted its binding orientation in the active site of the target protein SDH. These results suggested that compound SCU2028 was a potential fungicide for control of rice sheath blight.     

Structural Characterization and Biological Evaluation of 18‐Nor‐ent‐labdane Diterpenoids from Grazielia gaudichaudeana

The phytochemical investigation of Grazielia gaudichaudeana aerial parts yielded 15 compounds, including diterpenes, triterpenes, sterols and flavonoids. With exception to ent‐kaurenoic acid diterpenes, the compounds isolated are being described for the first time in this species. Some unusual ¹H‐NMR chemical shifts of 18‐nor‐ent‐labdane ( 7 – 9 ) led us carry out a conformational analysis by theoretical calculations in order to support the experimental data. Moreover, due to the limitation of studies focused on pharmacological potential of Grazielia gaudichaudeana, the present study was carried out to investigate the antioxidant, antiproliferative, antiviral, antileishmanial and antimicrobial activities from the extract, fractions and isolated compounds obtained from this species. Ethyl acetate fraction showed significant activity in the antiproliferative assay, with GI₅₀ range of 3.9 to 27.2 μg mL^?1. Dichloromethane fraction, rich in diterpenoids, inhibited all human tumor cell lines tested, and the nor‐labdane 7 showed potent cytotoxic activity against glioma and ovary cancer cell lines.     

Biotransformation of (−)‐(R)‐α‐Phellandrene: Antimicrobial Activity of Its Major Metabolite

Terpene derivatives converted by microbial biotransformation constitute an important resource for natural pharmaceutical, fragrance, and aroma substances. In the present study, the monoterpene α‐phellandrene was biotransformed by 16 different strains of microorganisms (bacteria, fungi, and yeasts). The transformation metabolites were initially screened by TLC and GC/MS, and then further characterized by NMR spectroscopic techniques. Among the six metabolites characterized, 6‐hydroxypiperitone, α‐phellandrene epoxide, cis‐p‐menth‐2‐en‐1‐ol, and carvotanacetone, which originated from (?)‐(R)‐α‐phellandrene, are reported for the first time in this study. Additionally, the substrate and the metabolite 5‐p‐menthene‐1,2‐diol were subjected to in vitro antibacterial and anticandidal tests. The metabolite showed moderate‐to‐good inhibitory activities (MICs=0.125 to >4 mg/ml) against various bacteria and especially against Candida species in comparison with its substrate (?)‐(R)‐α‐phellandrene and standard antimicrobial agents.     

Synthesis,Structure, DNA‐Binding Properties,and Cytotoxicity of Ruthenium(II) Polypyridyl Complexes

Many ruthenium(II) complexes show high antitumor activities, and the in vitro antitumor activities are usually related to DNA binding. We designed and synthesized two Ru^II polypyridyl complexes, [Ru(dmp)₂(fpp)]²⁺ (dmp=2,9‐dimethyl‐1,10‐phenanthroline; fpp=2‐[3,4‐(difluoromethylenedioxy)phenyl]imidazo[4,5‐f] [1,10]phenanthroline and [Ru(phen)₂(fpp)]²⁺ (phen=1,10‐phenanthroline). The DNA‐binding properties of these complexes have been investigated by spectroscopic titration, DNA melting experiments, viscosity measurements, and photoactivated cleavage. The mechanism studies of photocleavage revealed that singlet oxygen (¹O₂) and superoxide anion radical (O$\rm{{_{2}^{{^\cdot} -}}}$ ) may play an important role in the photocleavage. The cytotoxicity of complexes 1 and 2 have been evaluated by MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) method; complex 2 shows slightly higher anticancer potency than 1 does against all the cell lines screened.     

Asymmetric epoxidation of cinnamyl alcohol with optically active titanium complexes

A family of titanium(IV) alkoxo compounds [{Ti(O‐i‐Pr)₂(OR)₂}₂] 1–4 prepared by alcohol exchange of Ti(O‐i‐Pr)₄ and a chiral higher‐boiling alcohol [ROH = 1,2:3,4‐di‐O‐isopropylidene‐α‐d ‐galactopyranose, 1,2:5,6‐di‐O‐isopropylidene‐α‐d ‐glucofuranose, (1R,2S,5R)‐(?)‐menthol, (1S‐endo)‐(?)‐borneol, (1S,2R,5S)‐(+)‐menthol, and (+)‐borneol] has been tested to evaluate their catalytic activity and stereoselectivity in the asymmetric epoxidation of cinnamyl alcohol. © 2005 Wiley‐Liss, Inc. Chirality     

Resolution of 1‐n‐Butyl‐3‐Methyl‐3‐Phospholene 1‐Oxide With TADDOL Derivatives and Calcium Salts of O,O'‐Dibenzoyl‐(2R,3R)‐ or O,O'‐di‐p‐Toluoyl‐(2R,3R)‐tartaric Acid

The resolution methods applying (?)‐(4R,5R)‐4,5‐bis(diphenylhydroxymethyl)‐2,2‐dimethyldioxolane (“TADDOL”), (?)‐(2R,3R)‐α,α,α',α'‐tetraphenyl‐1,4‐dioxaspiro[4.5]decan‐2,3‐dimethanol (“spiro‐TADDOL”), as well as the acidic and neutral Ca²⁺ salts of (?)‐O,O'‐dibenzoyl‐ and (?)‐O,O'‐di‐p‐toluoyl‐(2R,3R)‐tartaric acid were extended for the preparation of 1‐n‐butyl‐3‐methyl‐3‐phospholene 1‐oxide in optically active form. In one case, the intermediate diastereomeric complex could be identified by single‐crystal X‐ray analysis. The absolute P‐configuration of the enantiomers of the phospholene oxide was also determined by comparing the experimentally obtained and calculated CD spectra. Chirality 26:174–182, 2014. © 2014 Wiley Periodicals, Inc.