[Simultaneous determination of four N-lauryl amino acid surfactants in facial cleansers by high performance liquid chromatography-ultraviolet detection].

Significant developments have recently been achieved in the field of N-lauryl amino acid (NLAA) surfactants derived from renewable resources. Compared with conventional surfactants, NLAAs exhibit remarkable surfactant properties, exceptional biodegradability, good biocompatibility, and high safety profiles. These attributes have led to the widespread use of NLAAs in personal-care products. The detection methods employed for NLAAs include two-phase titration (TT), spectrophotometric analysis (SA), and high performance liquid chromatography (HPLC). However, because both TT and SA measure the total concentration of anionic active matter, identifying and quantifying individual compounds in a sample containing multiple anionic surfactants is impossible. The presence of cationic surfactants in the sample also introduces interferences, which lead to significant errors. Compared with TT and SA, HPLC offers direct and rapid testing procedures. However, compounds with no or weak UV-visible light absorption exhibit low sensitivity when detected by UV, necessitating the use of detectors such as differential refractive index detectors (RIDs), evaporative light scattering detectors (ELSDs), or charged aerosol detectors (CADs). Most HPLC users consider UV light as the fundamental configuration of the instrument, and other detectors are less commonly employed. Therefore, establishing a new HPLC method suitable for the UV detection of NLAAs is of practical significance. In this study, a novel HPLC-UV method was developed for the simultaneous detection of N-lauryl glutamine (LG), N-lauryl glycine (LC), N-lauryl alanine (LA), and N-lauryl sarcosine (LS) by optimizing the mobile-phase composition and selecting an appropriate chromatographic column and detection wavelength. The samples were mixed with acetonitrile-0.10% H3PO4 aqueous solution (60∶40, v/v) and sonicated for 10 min, then stayed at room temperature for 5 min. Subsequently, the mixture was filtered through a 0.22 µm filter membrane and separated on an Agilent Eclipse Plus C18 column (150 mm×4.6 mm, 5 µm). The mobile phase used for separation consisted of acetonitrile-0.10% H3PO4 aqueous solution at a flow rate of 1.0 mL/min. The detection wavelength was set at 205 nm, and the injection volume was 10 µL. The results demonstrated that the four NLAAs exhibited good linearity in the range of 2.0-800.0 mg/L, with correlation coefficients (r)≥0.9995. The limits of detection (LODs) ranged from 0.17 to 0.49 mg/L, and limits of quantification (LOQs) ranged from 0.57 to 1.63 mg/L. The relative standard deviations (RSDs) for precision, repeatability, and stability over 24 h were all below 2.0%. Using this method, the NLAA contents of five facial-cleanser products were determined. The results demonstrated that all five samples contained one or more NLAAs, and the total NLAA contents ranged from 64.58 to 97.01 mg/g. The five spiked-sample recoveries of the NLAAs at four different spiked levels (0.60, 4.50, 15.00, 24.00 mg/g) ranged from 94.3% to 107.4%, indicating satisfactory accuracy. However, the actual NLAA composition and label for one facial-cleanser product were not consistent with our test results. This finding demonstrates the necessity of strengthening market monitoring through testing. The proposed method has the advantages of simple pretreatment, rapid testing, good precision, high accuracy, and appropriate stability. Thus, it is suitable for the determination of NLAA contents in facial cleansers and provides an effective technical reference for the raw-material purity assessment, synthetic yield detection, and product quality control of this type of surfactant.

Iridium-Catalyzed Intramolecular Asymmetric Allylic Etherification of Pyrimidinemethanols: Enantioselective Construction of Multifunctionalized Pyrimidine-Fused Oxazepines.

An iridium-catalyzed intramolecular asymmetric allylic etherification of pyrimidinemethanols is described. In the presence of chiral-bridged biphenyl phosphoramidite ligand L3 and triethylborane, this process provided a class of novel pyrimidine-fused oxazepanes in up to 99% yield with 99.5% enantiomeric excess. The work addresses the challenge of insufficient nucleophilicity of aliphatic alcohols for allyl substitution and indicates the vital value of chiral-bridged biphenyl phosphoramidites. Various multifunctionalized transformations of the products further demonstrate the robust synthetic utility of this methodology.

Design, synthesis and pharmacological evaluation of ß-carboline derivatives as potential antitumor agent via targeting autophagy.

A series of novel ß-carboline derivatives was designed, synthesized and evaluated as potential anticancer agents. Among them, compound 6g showed the most potent antiproliferative activity against the 786-0, HT-29 and 22RV1 cell lines with IC50 values of 2.71, 2.02, and 3.86 µM, respectively. The antitumor efficiency of compound 6gin vivo was also evaluated, and the results revealed that compound 6g significantly suppressed tumor development and reduced tumor weight in a mouse colorectal cancer homograft model. Further investigation on mechanisms of action demonstrated that compound 6g inhibited HCT116 cell growth by stimulating the ATG5/ATG7-dependent autophagic pathway. These molecules might be served as candidates for further development of colorectal cancer therapy agent.

Design, synthesis and mechanism of action of novel 1,9-disubstituted ß-carboline derivatives as antitumor agents.

A range of novel 1,9-disubstituted ß-carboline derivatives was designed, synthesized and evaluated as potential anticancer agents. The preliminary study suggested that compounds 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h tested in this study exerted potent antiproliferative effects on ten selected human tumor cell lines, with compound 6e being the most effective antiproliferative agent against the BGC-823, A375 and HT-29 cell lines, with IC50 values of 23.9, 9.3, and 3.6 µM, respectively. In addition, the antitumor capability of compound 6e was also evaluated in vivo, which demonstrated that compound 6e distinctly inhibited colorectal tumor growth in syngeneic BALB/c mice. Further research into the fundamental mechanism revealed that compound 6e inhibited colorectal cancer growth through the ATG5 (autophagy-related-5)/ATG7 (autophagy-related-7)-dependent autophagy pathway. This research can contribute to further clinical application of ß-carboline derivatives as new antitumor drugs.

Synthesis of novel 4,7-disubstituted quinoline derivatives as autophagy inducing agents via targeting stabilization of ATG5.

A series of new 4,7-disubstituted quinoline derivatives was designed, synthesized and evaluated for their antiproliferative activity. The results demonstrated that compounds 10c, 10g, 10i, 10j and 10k displayed potent antiproliferative activity with IC50 value of lower than 5.0 µM against human tumor cell lines, and N-(3-nitrophenyl)-7-((3,4,5-trimethoxybenzyl)oxy)quinoline - 4-amine 10k was found to be the most potent antiproliferative agent against HCT-116, HepG2, BCG-823, A549 and A2780 cell lines with IC50 values of 0.35, 1.98, 0.60, 0.39 and 0.67 µM, respectively. The antitumor efficacy of the representative compound 10k in mice was also evaluated, and the results showed that compound 10k effectively inhibited tumor growth and decreased tumor weight in animal models. Further investigation on mechanism of action indicated that compound 10k could inhibit colorectal cancer growth through inducing autophagy via excessively targeting stabilization of ATG5. Therefore, these quinoline derivatives are a new class of molecules that have the potential to be developed as new antitumor drugs.

Bivalent ß-Carbolines Inhibit Colorectal Cancer Growth through Inducing Autophagy.

In this study, a series of alkyl diamine linked bivalent ß-carbolines was synthesized and evaluated as antitumor agent. The results demonstrated that most compounds displayed good antiproliferative activities with IC50 value lower than 10 µM against a panel of human tumor cell lines, and compound 8 was found to be the most potent antiproliferative agent with IC50 value of 1.39, 1.96, 1.42, 1.49, 1.32, 1.96 and 1.63 µM against human breast cancer cell line (MCF-7), human adenocarcinoma cell line (769-P), human malighant melanoma cell line (A375), human ovarian cancer cell line (SK-OV-3), human colon carcinoma cell line (HCT-116), human gastric cancer cell line (BGC-823) and human esophageal squamous carcinoma cell line (Eca-109), respectively. Further investigations on mechanism of action of this class of compound demonstrated that the representative compound 8 inhibited colorectal cancer growth through inducing autophagy.

Pd-catalyzed asymmetric Suzuki-Miyaura coupling reactions for the synthesis of chiral biaryl compounds with a large steric substituent at the 2-position.

Pd-catalyzed asymmetric Suzuki-Miyaura couplings of 3-methyl-2-bromophenylamides, 3-methyl-2-bromo-1-nitrobenzene and 1-naphthaleneboronic acids have been successfully developed and the corresponding axially chiral biaryl compounds were obtained in very high yields (up to 99%) with good enantioselectivities (up to 88% ee) under mild conditions. The chiral-bridged biphenyl monophosphine ligands developed by our group exhibit significant superiority to the naphthyl counterpart MOP in both reactivity and enantioselectivity control. The large steric hindrance from π-conjugated ortho-substituents of the bromobenzene substrates and the Pd···O interaction between carbonyl and palladium seem essential to achieve high enantioselectivity.

Design, synthesis and biological evaluation of new quinoline derivatives as potential antitumor agents.

A series of new quinoline derivatives was designed, synthesized and evaluated for their antiproliferative activity. The results demonstrated that compounds 11p, 11s, 11v, 11x and 11y exhibited potent antiproliferative activity with IC50 value of lower than 10 µM against seven human tumor cell lines, and N-(3-methoxyphenyl)-7- (3-phenylpropoxy)quinolin-4-amine 11x was found to be the most potent antiproliferative agent against HCT-116, RKO, A2780 and Hela cell lines with an IC50 value of 2.56, 3.67, 3.46 and 2.71 µM, respectively. The antitumor efficacy of the representative compound 11x in mice was also evaluated, and the results showed that compound 11x effectively inhibited tumor growth and decreased tumor weight in animal models. Further investigation on mechanism of action indicated that compound 11x could inhibit colorectal cancer growth through ATG5-depenent autophagy pathway. Therefore, these quinoline derivatives are a new class of molecules that have the potential to be developed as new antitumor drugs.

Enantioselective synthesis of chiral heterocyclic biaryls via asymmetric Suzuki-Miyaura cross-coupling of 3-bromopyridine derivatives.

A series of chiral heterocyclic biaryls with a pyridyl moiety were prepared in moderate to good yields with up to 92% ee via asymmetric Suzuki-Miyaura coupling. The chiral-bridged biphenyl monophosphine ligand L1 was found to be much more effective in the reaction enantioselection than its counterpart binaphthyl monophosphine ligands.

Design, synthesis, structure-activity relationships and mechanism of action of new quinoline derivatives as potential antitumor agents.

A series of new quinoline derivatives was designed, synthesized and evaluated as potential antitumor agents. The results indicated that most compounds exhibited potent antiproliferative activity, and 7-(4-fluorobenzyloxy)N-(2-(dimethylamino)- ethyl)quinolin-4-amine 10g was found to be the most potent antiproliferative agent against human tumor cell lines with an IC50 value of less than 1.0 µM. Preliminary structure-activity relationships analysis suggested that (1) the large and bulky alkoxy substituent in position-7 might be a beneficial pharmacophoric group for antiproliferative activity; (2) the amino side chain substituents in position-4 facilitated the antiproliferative activity of this class of compounds; and (3) the length of the alkylamino side chain moiety affected the antiproliferative potency, with two CH2 units being the most favorable. Further investigation of the mechanism of action of this class of compounds demonstrated that the representative compound 10g triggered p53/Bax-dependent colorectal cancer cell apoptosis by activating p53 transcriptional activity. Moreover, the results showed that compound 10g effectively inhibited tumor growth in a colorectal cancer xenograft model in nude mice. Thus, these quinoline derivatives might serve as candidates for the development of new antitumor drugs.

Synthesis and structure-activity relationships of asymmetric dimeric ß-carboline derivatives as potential antitumor agents.

A series of newly asymmetric dimeric ß-carbolines with a spacer of 4-6 methylene units between the indole nitrogen and the harmine oxygen were synthesized. Structures of all the novel synthesized compounds were confirmed by their spectral and analytical studies. All of the synthesized compounds were screened for their in vitro cytotoxic activity against nine cancer cell lines. The results revealed that compounds 7c, 7o and 7s exhibited the highest cytotoxic activities with IC50 values of less than 20 µM against the tumor cell lines tested. Acute toxicities and antitumor efficacies of the selected compounds in mice were also evaluated, and compound 7o exhibited potent antitumor activities with the tumor inhibition rate of over 40%. The wound healing assay displayed a specific impairment in the motility of the HT-29 cells, which suggested the anti-metastatic potential of compound 7o. Moreover, compound 7o had obvious angiogenesis inhibitory effects in the chicken chorioallantoic membrane (CAM) assay. Preliminary structure-activity relationship (SAR) analysis indicated that: (1) 3-phenylpropyl substituent at the N9-position of the indole ring was the most suitable group giving rise to potent cytotoxic agents; (2) the spacer length affected the antitumor potencies, and four methylene units were more favorable.

Synthesis, structure-activity relationships and preliminary mechanism of action of novel water-soluble 4-quinolone-3-carboxamides as antiproliferative agents.

A series of novel water-soluble 4-quinolone-3-carboxamides was prepared and evaluated as antiproliferative agents. Preliminary results indicated that most compounds tested in this study showed potent antiproliferative potencies against human tumor cell lines, and compound 8k was found to be the most potent antiproliferative agents with IC50 value of lower than 10 µM against nine human tumor cell lines. These results suggested that (1) the alkylamino side chain substituent was the advisable pharmacophoric group for the enhanced antiproliferative activities; (2) the length of the alkylamino side chain moiety also affected their antiproliferative potencies, and three methylene units were more favorable; (3) introducing arylated alkyl substituent into N1-position of quinolone facilitated antiproliferative activities of this class of compounds. Further investigations on mechanism of action of this class of compound demonstrated that the representative compound 8k could trigger p53/Bax-independent colorectal cancer cell apoptosis via inducing ROS accumulation.

Synthesis and biological evaluation of novel alkyl diamine linked bivalent ß-carbolines as angiogenesis inhibitors.

We have synthesized and evaluated a series of novel alkyl diamine linked bivalent ß-carbolines as potent angiogenesis inhibitors. The results demonstrated that most bivalent ß-carbolines exhibited significant antiproliferative effects against human umbilical vein cell lines EA.HY926. Compound 4m was found to be the most potent antiproliferative agent with IC50 value of 2.16 µM against EA.HY926 cell lines. Mechanism investigations revealed that compound 4m could significantly inhibit EA.HY926 cells migration and tube formation in a dose-dependent manner. Moreover, compound 4m also showed obvious angiogenesis inhibitory effects in CAM assay, and the antiangiogenetic potency was more potent than the reference drug Endostar. The bivalent ß-carbolines might be served as candidates for the development of vascular targeting antitumor drugs.

Design, synthesis and biological evaluation of novel alkyl diamine linked bivalent ß-carbolines as angiogenesis inhibitors.

A series of novel alkyl diamine linked bivalent ß-carbolines was synthesized and evaluated for antiproliferative activity, inhibition of cell migration and tube formation, and anti-angiogenic activity in vivo. The results showed that most bivalent ß-carbolines displayed significant antiproliferative effect against human umbilical vein cell lines EA.HY926. Compound 2s was found to be the most potent antiproliferative agent with IC50 value of 1.06µM against EA.HY926 cell lines. Further investigations on mechanisms of action revealed that compound 2s significantly inhibited EA.HY926 cells migration and tube formation in a dose-dependent manner. Moreover compound 2s exhibited significant angiogenesis inhibitory effects in CAM assay, and the antiangiogenetic potency was comparable with the reference drug Endostar (30µM).

Synthesis and mechanisms of action of novel harmine derivatives as potential antitumor agents.

A series of novel harmine derivatives bearing a benzylindine substituent in position-1 of ß-carboline ring were synthesized and evaluated as antitumor agents. The N2-benzylated ß-carboline derivatives 3a-g represented the most interesting anticancer activities and compound 3c was found to be the most active agent to diverse cancer cell lines such as gastric carcinoma, melanoma and colorectal cancer. Notably, compound 3c showed low toxicity to normal cells. The treatment significantly induced cell apoptosis. Mechanistically, PI3K/AKT signaling pathway mediated compound 3c-induced apoptosis. Compound 3c inhibited phosphorylation of AKT and promoted the production of reactive oxygen species (ROS). The ROS scavenger, LNAC and GSH, could disturb the effect of compound 3c induced apoptosis and PI3K activity inhibitor LY294002 synergistically enhanced compound 3c efficacy. Moreover, the results from nude mice xenograft model showed that compound 3c treatment effectively inhibited tumor growth and decreased tumor weight. Collectively, our results demonstrated that compound 3c exerts apoptotic effect in cancer cells via suppression of phosphorylated AKT and evocation of ROS generation, which suggested that compound 3c might be served as a promising therapeutic agent for cancer treatment.

Highly enantioselective synthesis of 2,3-dihydro-1H-imidazo[2,1-a]isoindol-5(9bH)-ones via catalytic asymmetric intramolecular cascade imidization-nucleophilic addition-lactamization.

Highly enantioselective catalytic asymmetric intramolecular cascade imidization-nucleophilic addition-lactamization of N(1)-alkylethane-1,2-diamine with methyl 2-formylbenzoate catalyzed by a chiral phosphoric acid represents the first efficient method for the preparation of medicinally interesting chiral 2,3-dihydro-1H-imidazo[2,1-a]isoindol-5(9bH)-ones with high yields and excellent enantioselectivities. This strategy has been shown to be quite general toward various methyl 2-formylbenzoates.

Synthesis and photophysical properties of europium(III)-ß-diketonate complexes applied in LEDs.

Six ß-diketonate ligands were used to prepare the corresponding antenna europium(III) ternary complexes using 1,10-phenanthroline as an ancillary ligand. All the complexes exhibited high decomposition temperatures. Photophysical properties such as FT-IR spectra, UV-Vis absorption spectra, excitation and emission spectra, relative luminescent intensity ratios, luminescence decay curves and quantum yields based on the complexes were systematically studied and compared with each other. The energy-transfer mechanism was proposed as a ligand-sensitized luminescence process. Bright red light-emitting diodes (LEDs) were then fabricated by coating the complexes onto 395 nm-emitting InGaN chips. The light emission from the InGaN chips could be completely absorbed in the spectra of LEDs. The Commission International de I'Eclairage (CIE) chromaticity coordinates are close to the National Television Standard Committee (NTSC) standard value for the red color. All these findings indicate that these Eu(III) complexes are promising red phosphors for fabrication of near UV-based white LEDs.

Synthesis and structure--activity relationships of N²-alkylated quaternary ß-carbolines as novel antitumor agents.

A series of novel N(2)-alkylated quaternary ß-carbolines was synthesized by modification of position-1, 2, 7 and 9 of ß-carboline nucleus with various alkyl and arylated alkyl substituents, and their cytotoxic activities in vitro and antitumor potencies in mice were evaluated. Compound 3m was found to be the most potent antitumor agent. SARs analysis revealed that (1) the substituents in position-2 and 9 of ß-carboline nucleus played a vital role in modulation of antitumor activity; (2) the benzyl and 3-phenylpropyl substituents in position-2 and 9 of ß-carboline ring were the optimal substituents giving rise to significant antitumor agent. These compounds might be a novel promising class of antitumor agents with clinical development potential.

Synthesis and structure-activity relationships of harmine derivatives as potential antitumor agents.

Harmine, a naturally occurring ß-carboline alkaloid, showed good antitumor activities together with remarkable neurotoxic effects in animal models. In order to search for novel leading compounds endowed with better antitumor activities and less neurotoxicities, a series of harmine derivatives were designed and synthesized by modification of position-2, 7 and 9 of ß-carboline nucleus, and their cytotoxic activities against human tumor cell lines were investigated. Acute toxicities and antitumor activities of the selected compounds in mice were also evaluated. Structure-activity relationships studies confirmed that (1) the 7-methoxy structural moiety was the pharmacophore responsible for the neurotoxic effects of this class of compounds; (2) the substituents in position-2 and 9 played a vital role in modulation of their antitumor activities.

Design, synthesis and in vitro and in vivo antitumor activities of novel bivalent ß-carbolines.

A series of bivalent ß-carbolines with a spacer of three to ten methylene units between the indole nitrogen was synthesized and evaluated as antitumor agents. The results demonstrated that compounds 18c, 21b, 25a and 31b exhibited strong cytotoxic activities with IC(50) value of lower than 20 µM against four tumor cell lines. Acute toxicities and antitumor efficacies of the selected compounds in mice were also evaluated, compounds 18b, 21b, 26a and 31b exhibited potent antitumor activities with tumor inhibition rate of over 40% in animal models. Preliminary structure-activity relationships analysis indicated that (1) the spacer length affected antitumor potencies, and four to six methylene units were more favorable; (2) the introduction of appropriate substituent into position-1 of ß-carboline facilitated antitumor potencies.