New membranotropic cationic chlorins derived from pheophytin a: synthesis and evaluation of photodynamic activity

A series of new chlorins bearing the phytyl moiety and different number of cationic groups were synthesized based on pheophytin a. A comparative evaluation of dark cytotoxicity and photodynamic activity of the synthesized compounds was performed using mature mammalian erythrocytes. Both dark and photoinduced hemolytic activities of the synthesized compounds grow with increasing the number of the cationic group in the molecule.

     

Design,synthesis and evaluation of the antioxidant and neuroprotective properties of alkyl- and terpenylphenolchlorin conjugates

The new amide conjugates were synthesized from methyl pheophorbide a and its carboxyl derivatives by reactions with aminomethyl derivatives of 2,4-dimethylphenol, 2-isocamphyl-4- methylphenol, 2-bornyl-4-methylphenol, and 2-isobornyl-4-methylphenol. The antioxidant activity of some conjugates was established by investigation of their ability to inhibit the accumulation of secondary products of lipid peroxidation in a brain of laboratory mice in vitro. The neuroprotective properties of porphyrin and terpenylphenol conjugates have been studied on the model of H₂O₂-induced oxidative stress in SH-SY5Y cells (neuroblastoma).

     

Nickel complexes of chlorophyll derivatives

Nickel complexes of certain phorbine and amide derivatives of chlorophyll a were synthesized. Most of the chlorophyll a derivatives studied form nickel complexes when boiled in toluene with an equimolar amount of nickel acetylacetonate in high yield. The yields of the nickel complexes of the chlorophyll derivatives are determined by the stability of the starting ligand under the reaction conditions.     

Syntheses of Chalcone‐Type Chlorophyll Derivatives Possessing a Bacteriochlorin,Chlorin or Porphyrin π‐System and Their Optical Properties

C3‐(Trans‐2‐arylethenyl)carbonylated chlorophyll derivatives possessing a bacteriochlorin or chlorin π‐system were synthesized by cross‐aldol (Claisen–Schmidt) condensation of methyl pyrobacteriopheophorbide‐a or 3‐acetyl‐3‐devinyl‐pyropheophorbide‐a bearing the C3‐acetyl group with p‐(un)substituted benzaldehydes under basic conditions. The corresponding porphyrin‐type chlorophyll derivatives were prepared by the oxidation (17,18‐didehydrogenation) of the chlorin‐type. Their Qy absorption and fluorescence emission maxima in dichloromethane correlated well with Hammett substituent constants of the p‐substituents. Several electron‐withdrawing p‐substituents suppressed the emission due to photoinduced electron transfer quenching in a molecule. The substitution sensitivities for their maxima and fluorescence quantum yields decreased in the order of bacteriochlorin‐, chlorin‐ and porphyrin‐type derivatives.     

Synthesis and Antitumor Evaluation of Some Newly Synthesized Pyrazolopyrimidine and Pyrazolotriazolopyrimidine Derivatives

A series of novel pyrazolo[3,4-d]pyrimidine 2b, 3, 5b, pyrazolotetrazolopyrimidine 4, and pyrazolotriazolopyrimidine derivatives 6a,b–10a,b have been synthesized and characterized by elemental analysis and spectroscopic data. Furthermore, the cytotoxicity and in vivo antitumor evaluation of some prepared compounds have been assessed, and derivatives 1a and 6b revealed promising activity in comparison to that of Cisplatin.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

New boron-containing 2′-deoxyadenosines

Conjugates of polyhedral boron hydrides with deoxyadenosine were synthesized by the opening of cyclic oxonium derivatives of closo-dodecaborate and cobalt bis(1,2-dicarbollide) with 2′-deoxyadenosine derivatives containing a nucleophilic group in the substituent at C(8). Biological studies of the derivatives obtained for cytotoxicity revealed that the derivatives based on closo-dodecaborate did not exhibit cytotoxicity. The conjugates obtained can be used in further biological trials as potential agents for boron neutron capture therapy of cancer.     

Macromolecular antioxidants based on polysaccharides and 2,6-diisobornyl-4-methylphenol derivatives

New macromolecular antioxidants that were conjugates of dextran or hydroxyethylated starch with functionalized derivatives synthesized from 2,6-diisobornyl-4-methylphenol were prepared. Their antiradical activity compared with derivatives of 2,6-di-tert-butyl-4-methylphenol was studied in a model reaction with 2,2-diphenyl-1-picrylhydrazyl. The studied conjugates exhibited greater activity than sterically hindered phenols not bonded to a polymer chain. The synthesized isobornyl derivatives were more active than previously studied tert-butyl analogs.     

Effects of metal and the phytyl chain on chlorophyll derivatives: physicochemical evaluation for photodynamic inactivation of microorganisms

Chlorophyll compounds and their derivatives containing metal or phytyl chain can be used as photosensitizer in photodynamic inactivation of microorganisms (PDI). So, the physicochemical properties and antimicrobial effect of chlorophyll derivatives were investigated: Mg‐chlorophyll (Mg‐Chl), Zn‐chlorophyll (Zn‐Chl), Zn‐chlorophyllide (Zn‐Chlde), Cu‐chlorophyll (Cu‐Chl), pheophytin (Pheo) and pheophorbide (Pheid). The photobleaching experiments showed photostability according to Cu‐Chl > Pheo ∼ Pheid ≫ Zn‐Chl ∼ Zn‐Chlde > Mg‐Chl. This order was discussed in terms of metal and the phytyl chain presences. Pheid and Zn‐Chl in aqueous Tween 80 solution exhibited highest singlet oxygen yield compared with the other derivatives. Chlorophyll derivatives (CD) with phytyl chain was limited by the self‐aggregation phenomenon at high concentrations, even in micellar systems (Tween 80 and P‐123). The antimicrobial effect of CD derivatives was investigated against Staphylococcus aureus, Escherichia coli, Candida albicans and Artemia salina. Pheid showed the best results against all organisms tested, Zn‐Chlde was an excellent bactericide in the dark and Cu‐Chl had no PDI effect. No correlation with CD uptake by microorganisms and darkness cytotoxicity was found. The physicochemical properties allied to bioassays results indicate that Mg‐Chl, Pheo, Zn‐Chl and Pheid are good candidates for PDI.     

Synthesis of isoniazid-1,2,3-triazole conjugates: Antitubercular,antimicrobial evaluation and molecular docking study

In the present study, a series of new isoniazid-1,2,3-triazole conjugates ( 5a-k ) was synthesized via click chemistry approach. The newly synthesized compounds were assessed for their in vitro antitubercular and antimicrobial activities. The compound 5g has displayed potent antitubercular activity against Mycobacterium tuberculosis H37Rv (Mtb) with MIC value 1.56 μg/mL. The active compounds were screened for their cytotoxicity profile by MTT assay against RAW 264.7 cell line. The four compounds have shown good in vitro antimicrobial activities against both antibacterial and antifungal pathogens. A molecular docking study was accomplished to identify the probable mode of action of synthesized derivatives. These compounds have shown excellent binding affinity toward Enoyl-acp reductase (INHA) and DNA gyrase.     

Synthesis and Characterization of Nitrogen and Sulfur Containing 1,4-Naphthoquinones

Abstract

New N,S-disubstituted naphthoquinones were synthesized by reactions of S- and N-nucleophiles with 2,3-dichloro-1,4-naphthoquinone. 2-(Hexadecylthio)-3-(phenylamino)-naphthalene-1,4-dione 5a was synthesized by reaction of 2-chloro-3-(phenylamino)-naphthalene-1,4-dione 3a with hexadecanethiol 4a. The structures of the new synthesized naphthoquinone derivatives were determined by micro analyses and spectroscopic methods (FT-IR, ¹H NMR, ¹³C NMR, MS, and UV/Vis.). Photo- and electrochemical properties of selected compounds were investigated by using fluorescence spectroscopy and the cyclovoltammetry method.     

A Convenient Synthesis of 1-Amino-4-methyl-4H-3-thia-4,5a,10-triazacyclopenta[a]fluoren-5-ones and Some New 2,3-Dihydro-1,3,4-thiadiazoles

1-amino-4-methyl-4H-3-thia-4,5a,10-triazacyclopenta-[a]fluoren-5-one and 6-methyl-6H-,9H-thia-4b,6,9,11,12-pentaazaindeno[1,2-a]-fluorene-5,8-dione derivatives were prepared from 2-methyl-1-oxo-3-thioxo-2,4,9b-trihydropyrimidino[1,6-a] benzimidazole-4-carbonitrile. Also, 2,3-dihydro-1,3,4-thidazoles were synthesized via a reaction of hydrazonoyl chlorides with 3-(methylamino)-2-substituted 3-thioxopropanenitrile. Structures of newly synthesized compounds were elucidated on the basis of elemental analyses, spectral data, and alternative methods synthesis whenever possible.     

Enhancement of Light Absorption Ability of Synthetic Chlorophyll Derivatives by Conjugation with a Difluoroboron Diketonate Group

The enhancement of the light absorption ability of synthetic chlorophyll derivatives is demonstrated. Chlorophyll derivatives directly conjugated with a difluoroboron 1,3‐diketonate group at the C3 position were synthesized from methyl pyropheophorbide‐d through Barbier acylmethylation of the C3‐formyl moiety, oxidation of the C3‐carbinol, and difluoroboron complexation of the diketonate. Electronic absorption spectra in a diluted solution showed that the synthetic conjugates gave an absorption band at λ=400–500 nm, with a Qy band shifted to a longer wavelength of λ≈700 nm. DFT calculations demonstrated that the absorption bands and redshifts were ascribable to the coupling of the LUMO of chlorin with that of the difluoroboron diketonate moiety. The introduction of a pyrenyl group at the C3³‐position of the conjugate afforded an additional charge‐transfer band over λ=500 nm, producing a pigment that bridged the green gap in standard chlorophylls.     

Convenient Synthesis of Novel Nitrogen Bridgehead Heterocycles Utilizing 3‐Mercapto‐6H‐[1,2,4,5]oxatriazino[3,2‐a]isoindol‐6‐one as a New Synthon

Considering oxatriazino[a]isoindole as a wealthy structure for developing molecules of impressive therapeutic potentials, some new oxatriazino[3,2‐a]isoindoles analogs were synthesized. Thus, 3‐mercapto‐6H‐[1,2,4,5]oxatriazino[3,2‐a]isoindol‐6‐one ( 5 ), was prepared as one‐pot three‐components product and subjected to a series of manipulations including cycloaddition reactions to annulate a series of pharmacophoric motif conjugates. The structures of the newly synthesized compounds were elucidated based on their correct elemental and spectroscopic data.     

Synthesis and anti-tumor activity evaluation of novel podophyllotoxin derivatives

In order to investigate the effects on the cytotoxicity of indole-3-oxalylamino podophyllotoxin analogs, seven novel podophyllotoxin derivatives were synthesized.The compounds were tested against Hela, K562 or K562/A02 cancer cells in vitro,four of which showed significant cytotoxicity.Among them 9a,9b and 9c were superior to the positive control VP-16.     

Synthesis of cobalt bis(dicarbollide) conjugates with natural chlorins by the Sonogashira reaction

Novel boron-containing conjugates based on the alkynylated cobalt bis(dicarbollide) anion and chlorin e ₆ and purpurinimide p-iodophenyl derivatives were synthesized by the Sonogashira reaction. These conjugates can accumulate in the cancer cell cytoplasm and can be considered as potential candidates for using in boron neutron capture therapy of tumors.     

Synthesis and Antiviral Evaluation of Some 5‐N‐Arylaminomethyl‐2‐glycosylsulphanyl‐1,3,4‐oxadiazoles and Their Analogs against Hepatitis A and Herpes Simplex Viruses

N‐Arylaminomethyl‐3H‐1,3,4‐oxadiazole‐2‐thiones 2a,b were prepared from the corresponding N‐arylglycinoylhydrazides. A number of their thioglycoside derivatives 4–7a–c and S‐functionalized analogs 8–11a,b were synthesized by the reaction with different acetobromosugars and acyclic hydroxyalkylating agents. The antiviral activity of a number of the synthesized compounds against herpes simplex virus type 1 (HSV‐1) and hepatitis A virus (HAV) was evaluated. Compounds 5a and 5b showed promising results against HAV.     

Design and synthesis of novel water-soluble amino acid derivatives of chlorin p6 ethers as photosensitizer

Eight new water-soluble amino acid derivatives of chlorin p₆ ethers 6a-h were designed and synthesized using purpurin-18 (2) as key intermediate. All target compounds exhibited better phototoxicity than talaporfin and the most phototoxic compound 6d showed IC₅₀ values of 0.20 μmol/L against A549 cell and 0.41 μmol/L against B16-F10 cell, which represented 31- and 24-fold increase of PDT antitumor efficacy compared to talaporfin.     

Synthesis of 3,3′‐Di(2‐Pyridyl)‐1,1′‐Bi‐2‐Naphthol Derivatives

Abstract

A new kind of (S)‐3,3′‐dipyridyl BINOLs (3a–d) with C ₂‐symmetry were synthesized in 79–84% yields by Suzuki coupling of the diboronic acid dipinacol ester (S)‐1 containing a (S)‐binaphthyl group with bromopyridine derivatives (2a–d) followed by hydrolysis.     

Synthesis of tetracyclic thienotriazolopyridines based on hydrazine derivatives of fused pyridinethiones

A method for the synthesis of hydrazine derivatives of fused pyridinethiones based on alicyclic and heterocyclic ketones has been developed. Successive heterocyclization of these hydrazine derivatives was carried out in order to obtain new derivatives of tricyclic triazolo[4,3-a]pyridines, tetracyclic thieno[3,2-e][1,2,4]triazolo[4,3-a]pyridines, as well as a new heterocyclic system of thieno[2,3-c][1,2,4]triazolo[3,4-a]-2,7-naphthyridine.

     

Design,synthesis, and toward a side-ring optimization of tricyclic thieno[2,3-d]pyrimidin-4(3H)-ones and their effect on melanin synthesis in murine B16 cells

Abstract

Herein, we report the synthesis of 48 novel 3-sulfonylamides containing a tricyclic thieno[2,3-d]pyrimidin-4(3H)-one moiety, and their influence on melanin synthesis in murine B16 cells. All target sulfonylamides were synthesized through key intermediate 3-nitro-thieno[2,3-d]pyrimidin-4(3H)-ones using three types of ipso-nitration reactions. In this case, we converted the pyrido[1,2-a]- fragment of the thieno[2,3-d]pyrimidine moiety to pyrrolo[1,2-a]- and azepino[1,2-a]- side-rings in order to evaluate the bioactivities of the synthesized derivatives for a structure activity-relationships point of view. The obtained results suggest that some of the selected compounds revealed a promising influence on melanin synthesis in murine B16 cells and may serve as lead compounds for further drug discovery and development.