Synthesis of isobornylphenols containing heterocyclic and benzylic fragments

The alkaloids salsolidine, salsoline and (R)-N-benzyl-l-phenylethylamine were added to 7-methyl-2-isobornylphenol using an aminomethylation reaction. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 367–368, July–August, 2008.     

Synthesis of chlorins with a distal vinyl group

A series of chlorins containing a vinyl group on the periphery of the chlorin ring that was attached by linkers of various length, potential monomers for synthesis of polymers containing chlorin via copolymerization, was synthesized from methylpheophorbide a. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 163–166, March–April, 2007.     

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.     

Nystatin—dextran conjugates: Synthesis and characterization

The coupling of nystatin (Nys), a water-insoluble antifungal agent, to dextran via an imine or amine bond was systematically investigated. Dextran was first oxidized to dialdehyde dextran using potassium periodate, purified from the oxidizing agent, and reacted with Nys to form the Schiff base. The Schiff base was reduced to the amine using borohydride. All reactions took place in water. The purification of the oxidized dextran from the oxidizing agent was essential to prevent oxidative degradation of Nys at the coupling step. The effects on the coupling yield of the following factors: dextran molecular weight, degree of oxidation (aldehyde content), Nys to dextran ratio, temperature, and reaction pH were studied. A 95% coupling yield was obtained at the optimized coupling conditions: pH 8.9 ± 0.1, 50% degree of oxidation, and initial ratio of Nys to dialdehyde dextran 1:2.5. In all experiments, dextran was decreased in molecular weight during the oxidation step. Both imine and amine forms of Nys-dextran conjugates were soluble in water and exhibited improved stability in aqueous solutions as compared to the unbound drug. The conjugates showed comparable minimum inhibitory concentration (MIC) values against Candida albicans and Cryptococcus neoformans. The conjugates were about 25 times less toxic than free Nys after a single injection in mice. © 1996 John Wiley & Sons, Inc.     

双喹啉-多胺缀合物的合成及生物活性测定

为了获得具有高活性的神经元保护药物,以1,3-丙二胺、1,4-丁二胺、1,6-己二胺等为原料,合成了4个新的双喹啉-多胺缀合物;利用核磁共振谱、质谱和元素分析确认了目标化合物的结构,同时评价了它们对神经元细胞的保护作用.结果表明,4个目标化合物对神经元细胞的保护作用均较差,说明多胺链并不能增强喹啉对神经元细胞的保护作用.     

Natural chlorins as a promising platform for creating targeted theranostics in oncology

1. Download : Download high-res image (178KB)
2. Download : Download full-size image

     

Clarithromycin-adenine and related conjugates

Macrolide-nucleoside and macrolide-nucleobase conjugates (chimeras) have been synthesised by linking erythromycin A oxime derivatives and clarithromycin C11,C12-oxazolidinone derivatives with 3′-amino-3′-deoxythymidine or adenine through different spacers; clarithromycin-adenine conjugate 16a is the most active species against Micrococcus luteus.     

Synthesis of thiols from isobornylphenols

4-(3-Sulfanylpropyl)-2-isobornyl-6-methylphenol and 4-(sulfanylmethyl)-2,6-diisobornylphenol were synthesized from the corresponding 4-(bromoalkyl)phenols according to known procedures. Isobornylphenol with a trimethylene linker was converted into thiol by alkaline hydrolysis of thiouronium salt. The methylene-bridged analog was obtained by reduction of S-benzyl thioacetate with LiAlH₄.     

Synthesis of 7- and 10-spermine conjugates of paclitaxel and 10-deacetyl-paclitaxel as potential prodrugs

Efficient syntheses of two taxol analogs bearing the linear polyamine spermine at 7- and 10-positions of paclitaxel and 10-deacetyl-paclitaxel have been developed. These polyamine-taxol-conjugates were isolated as water soluble difluoride salts. The aim of the present work was to introduce a chemical modification into taxol skeleton in order to increase drug selectivity toward tumor cells. The cytotoxic activity of these conjugates was evaluated in MCF7 and MCF7-R cell lines. The observed low cytotoxicity suggests that these conjugates could act as potential prodrugs.     

Conjugates of natural chlorins and isobornylphenols with a different length of the spacer between the chlorin and terpenephenolic fragments: synthesis and antioxidant activity

Russian Chemical Bulletin - Conjugates containing chlorine and isobornylphenolic fragments, which are connected by spacers of different lengths, were synthesized from methyl pheophorbide a. The...     

Synthesis and properties of vinyl monomer/enzyme conjugates

Monomer conjugation of an enzyme followed by copolymerization with free monomer is a useful method of enzyme immobilization. L-asparaginase was conjugated with N-succinimidyl acrylate. Analysis of the conjugated enzyme via isoelectric focusing showed that a molar ratio of 9.5 free monomers per enzyme was needed during the conjunction for each vinyl group bound. Only 3% of the enzyme activity was lost per vinyl group added, and conjugation of an average of four monomers per enzyme thermally destabilized the enzyme only at temperatures above 50‡C. Activity of the enzyme at physiological temperatures was relatively unaffected.     

Synthesis and antiradical activity of hybrid antioxidants based on isobornylphenols

Alkylation of isobornylphenols with allylbenzene in the presence of homogeneous and heterogeneous catalysts of different nature has been studied. The maximum yield of phenols containing isobornyl and 1-phenylpropyl moieties has been achieved in the presence of catalyst FIBAN K-1 at 100°С and catalyst concentration of 10%. The inhibiting action of isobornylphenol derivatives has been studied in the model reaction of ethylbenzene oxidation. Hybrid antioxidants on the basis of isobornylphenols were found to actively interact with peroxide radicals and, therefore, they can be considered as promising additives for conservation of quality and increase in service life of different organic compounds and materials.     

Synthesis of terpenophenols via direct alkylation of phenols by terpenes

Literature data on the alkylation of phenolic compounds by mono-, sesqui-, and diterpenes in the presence of various catalysts are reviewed.Novosibirsk Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, Novosibirsk, fax (3832) 34 47 52, e-mail: shreed@nioch.nsc.ru. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 198–207, May–June, 2000.     

Synthesis of peptidomimetic-spirostane hybrids via Ugi reaction: a versatile approach for the formation of peptide-steroid conjugates

A general approach towards the preparation of peptide-steroid conjugates has been addressed. Utilizing the Ugi reaction, five peptidomimetic-steroid hybrids were achieved in good to excellent yields from carboxy- and amino-spirostanes and mono-protected α-amino acids. Diverse synthetic routes, specially focused on the formation of secosteroids, were implemented to introduce Ugi-type functionalities at different positions of the steroidal nucleus. This versatile approach is suitable for the formation of stable conjugates of steroids with other biologically relevant molecules.     

Synthesis of PEG–iridium conjugates and their use as hydrogenation catalysts in a water/substrate two-phase medium

New syntheses of PEG-(OCH₂C₅H₄N)₂ and PEG-(OC₆H₄PPh₂)₂ (PEG: poly(ethylene glycol)) conjugates are reported. An iridium hydrogenation catalyst 1, is shown to catalyze hydrogenation in a water/substrate two-phase system. Attachment of 1 to PEG to make 2 and 3 succeeds in making the complex water-soluble and allows it to retain some of its catalytic ability, but leads to micelle formation that inhibits the separation of organic and aqueous phases.     

Polymer conjugates for focal and targeted delivery of drugs

Polymer therapeutics is a very promising and rapidly growing area of nanomedicine, which has significantly improved the therapeutic potential of low‐molecular‐weight drugs and proteins for cancer treatment. Conjugation of toxic drugs to high‐molecular‐weight carriers can lead to reduction in systemic toxicity, longer retention time in the body, improved biodistribution and therapeutic efficacy, and site‐specific passive accumulation thanks to the leaky tumor vasculature. Furthermore, a targeting moiety can be coupled to the polymer–drug conjugate in order to actively and selectively deliver it to the desired tissue and cellular target. This review presents a summary of currently developed polymer therapeutics with detailed focus on their components and supramolecular structure. The use of polymeric nanocarriers for cancer angiogenesis‐targeted delivery is illustrated by specific examples. Copyright © 2013 John Wiley & Sons, Ltd.