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- Volume 16, Issue 8, 2019
Letters in Organic Chemistry - Volume 16, Issue 8, 2019
Volume 16, Issue 8, 2019
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Synthesis of Carbohydrate Derived Non-ionic Gemini Surfactants and Study of Their Micellar and Reverse Micellar Behavior - A Review
Authors: Nirmal Singh and Lalit SharmaGemini surfactants (gemini) are a distinct class of amphiphiles having more than one hydrophobic tail and hydrophilic head group connected via a spacer. These surfactants usually have better surface active properties than corresponding conventional surfactant of equal chain length. Depending upon the nature of charge on head group, these geminis may be cationic or anionic. If there is no charge on head group, the geminis are termed as non-ionic. Carbohydrate derived gemini surfactants carry sugar moiety linked with each of the conventional surfactants, which are further connected by spacer. The sugar moiety was found to enhance the aggregation tendencies. Moreover, due to the presence of sugar moiety, these surfactants are non-toxic and biodegradable. Due to chiral nature of sugar moiety, these surfactants can be used for chiral recognition of some chiral drugs in order to improve their aqueous solubility. Non-ionic surfactants are more important than ionic surfactants as in the latter case, due to repulsion among the same charged head group, aggregation does not take place readily. However, in case of non-ionic surfactants, the head group carries no charge, so there is no repulsion, thus micelle forms easily and at low concentration. The only repulsive forces among head groups are due to hydration shell formed by solvent molecules.
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A Facile and Convenient Synthesis of Boc-Protected 5-Carboxyspermine
Authors: Jong-Soo Choi, Jae-Won Park, Bieong-Kil Kim, Kyung-Oh Doh and Young-Bae SeuGene therapy is a powerful technology for treating incurable and hereditary disease in humans. In the recent years, a lot of studies have been done on the development of DNA carriers. Nonviral vectors, like liposomes, polymers, and micelles, has become common vehicles due to their safety. The key compound of DOGS, DOSPA and DOSPER is the 5-carboxyspermine which formed the poly amine head-group and carries four positive charges. In general, multivalent head-group shows more transfection efficiency than monovalent analogues. In this paper, the efficient and simple synthesis of Boc-protected 5-carboxyspermine is described. Boc-protected polyamines were synthesized from (S)- 2,5-diaminopentanoic acid monohydrochloride (L-ornithine) monohydrochloride through both cyanoethylation and direct catalytic reduction of nitriles with the combination of nickel (II) chloride, sodium borohydride and di-tert-butyl decarbonate (BOC2O) in a one-pot two-reaction.
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Novel Pyrazolyl Benzoxazole Conjugates: Design, Synthesis, Molecular Docking Studies and in vitro Anticancer Activities
More LessNowadays, hybrid drugs have gained a significant role in the treatment of different health problems. Most of the hybrid molecules with different heterocyclic moieties were proved to be potent anti-tumor agents in cancer chemotherapy. Hence, the present study is aimed at the evaluation of in vitro anticancer activity of novel hybrid molecules (pyrazolyl benzoxazole conjugates) and to investigate their anticancer activity by molecular docking studies. Designed, synthesized and characterized the novel pyrazolyl benzoxazole conjugates. Anticancer activity of these compounds was determined by SRB assay. Then molecular docking studies were carried out against proto-oncogene tyrosine-protein kinase (ATP-Src, PDB: 2BDF), a putative target for cancer. All the synthesized compound derivatives were evaluated against MCF-7, KB, Hop62 and A549 cancer cell lines. Compounds 9b and 9c exhibited excellent anticancer activities with GI50 values of <0.1 μM against MCF-7 and A549 cell lines. Compound 9e exhibited good antitumor activity on MCF-7 and A-549 with GI50 values of 0.12 μM and 0.19 μM respectively. Compound 9g showed better anticancer activity on A-549 cancer cell line with GI50 of 0.34 μM. The two-hybrid molecules 9b and 9c are found to be comparably potent with the standard drug doxorubicin and may act as drug lead compounds in medicinal chemistry aspect. The present docking investigation proved that having benzoxazole of compound 9c at the position of benzofuran of reference compound (N-acetyl pyrazoline derivative) might be valid for contributing to anti-cancer activity.
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Tribromoisocyanuric Acid as a Green Cohalogenating Reagent: An Efficient Transformation of Alkynes into α,α-Dibromoketones and Vicinal Dibromoalkenes
Authors: Lívia T.C. Crespo, Mô nica R. Senra, Pierre M. Esteves and Marcio C.S. de MattosThe co-halogenation reaction of alkynes with tri-bromoisocyanuric acid in acetic acid, followed by aqueous work-up produced α,α-di-bromoketones (44-84%), while the reaction in aqueous acetonitrile in the presence of KBr produced vicinal di-bromoalkenes (66-86%). The usefulness of the methodology was demonstrated employing green metrics for the comparison of TBCA with analogous N-halo reagents in co-halogenation reactions of alkynes.
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Synthesis of (R)-2-benzylmorpholine employing catalytic stereospecific rearrangement of L-Phenylalaninol
Authors: Mandapati B. Reddy and Ramasamy AnandhanAn efficient synthesis of (R)-2-benzylmorpholine has been accomplished starting from L-phenylalaninol by employing stereospecific rearrangement of β-amino alcohol using catalytic amount of (CF3CO)2O as a key step.
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A Green and Efficient Synthesis of Substituted 2-(4-(2-Oxo-2H-chromen-3-yl)thiazol-2-yl)-3-phenylacrylonitriles Under Environmentally Benign Conditions
Authors: Kotthireddy Kavitha, Devulapally Srikrishna, Pramod K. Dubey and Pasula AparnaAn efficient and convenient method for the condensation of various aldehydes with 2-(4-(2- oxo-2H-chromen-3-yl)thiazol-2-yl)acetonitrile has been demonstrated via triphenylphosphinecatalyzed Knoevenagel condensation in good to excellent yields. The effect of solvent on this reaction was studied. In addition, a tandem method for the synthesis of 2-(4-(2-oxo-2H-chromen-3-yl)thiazol-2- yl)acetonitrile has been outlined using tetrabutylammonium tribromide as an efficient, green and ecofriendly reagent. Subsequently, the latter was reacted with various aromatic aldehydes in the presence of PEG-600 as reaction media to afford the title compounds. These reactions have widened the scope and applicability of the use of tetrabutylammonium tribromide, triphenylphosphine in organic synthesis. All these synthesized compounds were characterized by IR, 1H-NMR, Mass and 13C-NMR spectral data.
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Chemical Constituents and Cytotoxicity of Euphorbia vajravelui
More LessEuphorbia species are important in traditional medicines as well as in horticulture. Though 82 Euphorbia species are reported from India, most of the species are yet to be explored for the phytochemicals or bioactivities. The present study reports the phytochemical and cytotoxicity studies of the Western Ghats endemic plant Euphorbia vajravelui. Compounds were isolated from the extracts of E. vajravelui using column chromatography and were characterized through various spectroscopic techniques. The structures were further confirmed through single crystal XRD. The major pentacyclic triterpene 3β-friedelinol was estimated using a validated HPTLC method. Cytotoxicity of the extracts was tested against human cervical cancer cell line HeLa and normal cardiac myoblasts cell line H9C2 using MTT assay. The pentacyclic triterpenoids taraxeryl acetate, epi-friedelinyl acetate, 3β-friedelinol, taraxerol, 3α-friedelinol and friedelane-2β,3α-diyl diacetate and the phenolic compound 3,4,3'-tri-Omethyl ellagic acid 4'-rutinoside were isolated and characterized from E. vajravelui. Single crystal XRD data of epi-friedelinyl acetate, taraxerol and 3α-friedelinol were also reported. The major compound 3β-friedelinol was found to contain 0.33 ± 0.03%, estimated through a validated HPTLC method. The extracts were non-toxic towards normal cell line H9C2 (cardiac myoblasts) and showed negligible cytotoxic effects towards cervical cancer cell line HeLa upto100 μg/mL concentration. The major compounds isolated from E. vajravelui were triterpenoids and single crystal XRD data unambiguously confirmed the structures. The latex extract was non toxic towards normal cell line H9C2 and cancer cell line HeLa and the result was relevant especially in the context of the eco-toxicological concerns around Euphorbia species. This is the first report of the phytochemical and cytotoxicity studies of the Western Ghats endemic species E. vajravelui.
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Mechanistic and Kinetic Study of Atmospheric Oxidation of Chlordane Initiated by OH Radicals
Authors: Zhezheng Ding, Yayi Yi, Fei Xu, Qingzhu Zhang, Xiaoli Xu and Wenxing WangChlordane, one of the extremely hazardous Persistent Organic Pollutants (POPs), was widely used as pesticides all over the world and its residues have been detected at high concentrations in many areas. As a species of Semi-Volatile Organic Compounds (SVOCs), chlordane exists mainly in the atmosphere where it can be migrated and transformed. Due to the carcinogenic and mutagenic properties, understanding its atmospheric fate is of great significance. In the present work, the oxidation mechanism of chlordane initiated by OH radicals under the atmospheric conditions was investigated by using Density Functional Theory (DFT). The geometrical structures were optimized at the M06- 2X/6-311+g(d,p) level and single-point energies were calculated at the M06-2X/6-311+g(3df,2p) level. The relevant rate constants of the key elementary reactions were calculated by using Rice-Ramsperger- Kassel-Marcus (RRKM) theory at 298 K and 1 atm. All of the energetically favorable pathways were discussed in detail, and theoretical results showed that the oxidation products are dichlorochlordene, hydroxychlrodane, cycloketone and dichloracyl. Combined with available experimental observation, this study can, therefore, help to clarify the atmospheric fate of chlordane.
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Synthesis of (E)-vinyl Isobutyronitriles via Fe(III)-catalyzed Decarboxylative Cross-coupling of Cinnamic Acids and AIBN under Additive-free Conditions
Authors: Xuemei Xu, Zaigang Luo, Yuyu Fang and Peng LiuA facile, efficient, additive-free and eco-friendly protocol for the synthesis of (E)-vinyl isobutyronitriles via Fe(III)-catalyzed decarboxylative cross-coupling of cinnamic acids and AIBN (azodiisobutyronitrile) has been developed. The presented methodology offers several advantages such as easy accessibility and stability of substrates, inexpensive catalyst and simple post-treatment procedure.
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Design, Synthesis and Anticancer Evaluation of Carbazole Fused Aminopyrimidine Derivatives
Authors: Zanjam Spandana, Reddymasu Sreenivasulu and Mandava V. Basaveswara RaoCarbazole is an important type of tricyclic nitrogen containing compound and isolated first from coal tar in 1872 by Graebe and Glazer. Carbazole alkaloids have received considerable attention since their discovery in the 1960’s and their derivatives are well known for their pharmacological activities. Many recent studies have reported that carbazole derivatives exhibit a variety of biological activities. Toxicity of test compound in cells was determined by MTT assay based on mitochondrial reduction of yellow MTT tetrazolium dye to a highly blue colored formazan product. Among the ten synthesized compounds, 12c, 12d, 12e, 12f, 12g and 12i were showed good activity. In which 12c, 12d and 12e showed moderate activity on MCF-7 cancer cell line. Compounds 12f, 12g and 12i showed more potent activity than control. Compounds 12f, 12g and 12i showed more potent activity than control adriamycin. In future, we will plan further mechanistic studies on most potent active compounds 12f, 12g and 12i.
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Synthesis, X-ray, DFT Studies and Antimicrobial Properties of New Quinolinylphosphonates
Authors: Mona Arsanious, Shaban Darwish, El-Sayed Shalaby and Dina El-GhwasThe phosphorus atom in hexamethyl phosphorus triamide 5 attacks the carbonyl function in 2-chloroquinoline-3-carbaldehyde 4a to give the bis-quinolinyl ethanone product 6. On the other hand, quinoline ring-attack proceeds by the same phosphorus reagent upon reaction with 2-chloroquinoline- 3-aldoxime 4b yielding phosphonate 7. Meanwhile, the reaction of the tris-aminophosphine reagent 5 with 2-chloroquinoline- 3-(p-chlorophenyl)imine 4c affords the respective α-aminophosphonate 8. Moreover, the attack by phosphine 5 on 2-chloroquinoline-3-imines 4d and 4e produces the respective cyclic azophosphole derivatives 9a and 9b. [(2-chloroquinolin-3-yl)methylidene]propane dinitrile 4f reacts with phosphine 5 to yield [(2-chloroquinolinen-3-yl) 2,2-dicyanoethyl]tetramethylphosphonic diamide 10. Structural elucidations for the new products were based on compatible analytical and spectroscopic data. Moreover, the structures assigned for compounds 7 and 9a were unambiguously confirmed by X-ray crystallographic measurements. Biological evaluations indicated that compounds 4a,c exhibit antibacterial potency against Gram-positive bacteria and 4a,c and 9a show activity against Candida albicans strain.
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Visible Light Assisted Hantzsch Reaction: Synthesis of Polycyclic Dihydropyridines
Authors: Ankusab N. Nadaf and Kalegowda ShivashankarThe polycyclic dihydropyridine nucleus represents the heterocyclic system of invaluable core motifs with wide applications in chemical, biological and physical properties. Although this kind of compounds have been extensively synthesized by other groups, the synthesis of these compounds under CFL light intensity were not explored. The synthesis of polycyclic dihydropyridine derivatives were achieved through the reaction of 4-hydroxycoumarin, aromatic aldehydes and ammonium acetate under CFL light irradiation conditions. A series of polycyclic dihydropyridine derivatives were prepared under CFL light irradiation conditions with high yield, short reaction time, ambient condition and without the use of catalyst. The results displayed an efficient method for the synthesis of polycyclic dihydropyridine derivatives. Clean profile, short reaction time, low cost and use of CFL light intensity instead of catalyst making it a genuinely green protocol.
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Phosphomolybdic Acid (PMA)-catalyzed One-pot Synthesis of 2,3-Dihydroquinazolines
Authors: Chuanhuan Chen, A. Xuejiao, Xia Li, Guoli Huang and Bo LiuWe have developed a new method for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones in good to excellent yields via phosphomolybdic acid (PMA)-catalyzed cyclocondensation of 2- aminobenzamides with aldehydes or ketones in N,N-dimethylformamide (DMF) at room temperature. The present method proves to be efficient in terms of short reaction time, high yield, simple workup and easy purification.
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Volumes & issues
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Volume 21 (2024)
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Volume 20 (2023)
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Volume 19 (2022)
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Volume 18 (2021)
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Volume 17 (2020)
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Volume 16 (2019)
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Volume 15 (2018)
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Volume 14 (2017)
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Volume 13 (2016)
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Volume 12 (2015)
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Volume 11 (2014)
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Volume 10 (2013)
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Volume 9 (2012)
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Volume 8 (2011)
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Volume 7 (2010)
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Volume 6 (2009)
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Volume 5 (2008)
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Volume 4 (2007)
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Volume 3 (2006)
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Volume 2 (2005)
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Volume 1 (2004)