- Directing spatial disposition of ferrocene around homoadenine tetrads
-
We report synthesis and crystallographic studies of a ferrocenyl conjugate of adenine, where the hydrogen bonding interactions promote and stabilize nucleobase homotetrad formation. The Royal Society of Chemistry.
- Kumar, Jitendra,Purohit, Chandra Shekhar,Verma, Sandeep
-
-
Read Online
- The dielectric properties of low temperature thermally cross-linked polystyrene and poly(methyl methacrylate) thin films
-
Two azide functionalized polymers were synthesized by free radical copolymerization. Each new polymer was effectively cross-linked with a small molecule cross-linker by a thermally activated reaction at 100 °C. This cross-linking method was compatible with plastic substrates for flexible electronic applications. The new method did not use any catalyst and initiator, and did not produce any by-product which could stay in the dielectric layer. The cross-linked thin-films showed good solvent resistance and smooth surfaces. The dielectric characteristics of the cross-linked polymer films were evaluated via quantitative capacitance and leakage current measurements in a metal-insulator-metal (MIM) test structure. The cross-linked thin-films showed significantly reduced leakage current density compared with uncross-linked thin-films in MIM testing devices. This journal is
- Li, Shengxia,Zhang, Qing
-
-
Read Online
- Controlled generation of singlet oxygen by porphyrin-appended gold nanoparticles
-
Porphyrin-appended gold nanoparticles with different chain lengths were synthesized to examine the control over photosensitization. The efficiencies evaluated by singletoxygen generation were adjusted by the average number of porphyrins on one gold nanoparticle and the particle size regardless of the linker chain length between porphyrin site and gold core.
- Shinohara, Akira,Shinmori, Hideyuki
-
-
Read Online
- Dithiocarbamic acid esters as anticancer agent. Part 1: 4-Substituted-piperazine-1-carbodithioic acid 3-cyano-3,3-diphenyl-propyl esters
-
A variety of 4-N atom substituted derivatives were synthesized and evaluated for their in vitro anticancer activities using 4-methylpiperazine-1-carbodithioic acid 3-cyano-3,3-diphenyl-propyl ester 4 as lead compound. Among them, compound 6a without any substituent on 4-N atom (R1 = H) was found to be the most active anticancer agent with IC50 = 5.3 μM against HL-60 and IC50 = 11.5 μM against Bel-7402, respectively. Increase in the polarity and/or introduction of suitable acyl groups at the 4-N atom of the lead compound 4 are favorable for the improvement of activity.
- Hou, Xueling,Ge, Zemei,Wang, Tingmin,Guo, Wei,Cui, Jingrong,Cheng, Tieming,Lai, Chingshan,Li, Runtao
-
-
Read Online
- Lead derivatization of ethyl 6-bromo-2-((dimethylamino)methyl)-5-hydroxy-1-phenyl-1H-indole-3-carboxylate and 5-bromo-2-(thiophene-2-carboxamido) benzoic acid as FabG inhibitors targeting ESKAPE pathogens
-
Our previous studies on FabG have identified two compounds 5-bromo-2-(thiophene-2-carboxamido) benzoic acid (A) and ethyl 6-bromo-2-((dimethylamino)methyl)-5-hydroxy-1-phenyl-1H-indole-3-carboxylate(B) as best hits with allosteric mode of inhibition. FabG is an integral part of bacterial fatty acid biosynthetic system FAS II shown to be an essential gene in most ESKAPE Pathogens. The current work is focussed on lead expansion of these two hit molecules which ended up with forty-three analogues (twenty-nine analogues from lead compound A and fourteen compounds from lead compound B). The enzyme inhibition studies revealed that compound 15 (effective against EcFabG, AbFabG, StFabG, MtFabG1) and 19 (inhibiting EcFabG and StFabG) had potency of broad-spectrum inhibition on FabG panel.
- Varakala, Saiprasad Dasugari,Reshma, Rudraraju Srilakshmi,Schnell, Robert,Dharmarajan, Sriram
-
-
- Targeted Delivery of mRNA with One-Component Ionizable Amphiphilic Janus Dendrimers
-
Targeted and efficient delivery of nucleic acids with viral and synthetic vectors is the key step of genetic nanomedicine. The four-component lipid nanoparticle synthetic delivery systems consisting of ionizable lipids, phospholipids, cholesterol, and a PEG-conjugated lipid, assembled by microfluidic or T-tube technology, have been extraordinarily successful for delivery of mRNA to provide Covid-19 vaccines. Recently, we reported a one-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimer (IAJD) synthetic delivery system for mRNA relying on amphiphilic Janus dendrimers and glycodendrimers developed in our laboratory. Amphiphilic Janus dendrimers consist of functional hydrophilic dendrons conjugated to hydrophobic dendrons. Co-assembly of IAJDs with mRNA into dendrimersome nanoparticles (DNPs) occurs by simple injection in acetate buffer, rather than by microfluidic devices, and provides a very efficient system for delivery of mRNA to lung. Here we report the replacement of most of the hydrophilic fragment of the dendron from IAJDs, maintaining only its ionizable amine, while changing its interconnecting group to the hydrophobic dendron from amide to ester. The resulting IAJDs demonstrated that protonated ionizable amines play dual roles of hydrophilic fragment and binding ligand for mRNA, changing delivery from lung to spleen and/or liver. Replacing the interconnecting ester with the amide switched the delivery back to lung. Delivery predominantly to liver is favored by pairs of odd and even alkyl groups in the hydrophobic dendron. This simple structural change transformed the targeted delivery of mRNA mediated with IAJDs, from lung to liver and spleen, and expands the utility of DNPs from therapeutics to vaccines.
- Zhang, Dapeng,Atochina-Vasserman, Elena N.,Maurya, Devendra S.,Liu, Matthew,Xiao, Qi,Lu, Juncheng,Lauri, George,Ona, Nathan,Reagan, Erin K.,Ni, Houping,Weissman, Drew,Percec, Virgil
-
supporting information
p. 17975 - 17982
(2021/11/10)
-
- LIPIDS FOR LIPID NANOPARTICLE DELIVERY OF ACTIVE AGENTS
-
Compounds are provided having the following structure: (I) or a pharmaceutically acceptable salt, tautomer, or stereoisomer thereof, wherein R1, R2, R3, R4, R5, L1, L2, L3, G1, G2, and G3 are as defined herein. Use of the compounds as a component of lipid nanoparticle formulations for delivery of a therapeutic agent, compositions comprising the compounds and methods for their use and preparation are also provided.
- -
-
Page/Page column 66; 79
(2020/07/25)
-
- Approach to a Substituted Heptamethine Cyanine Chain by the Ring Opening of Zincke Salts
-
Cyanine dyes play an indispensable and central role in modern fluorescence-based biological techniques. Despite their importance and widespread use, the current synthesis methods of heptamethine chain modification are restricted to coupling reactions and nucleophilic substitution at the meso position in the chain. Herein, we report the direct transformation of Zincke salts to cyanine dyes under mild conditions, accompanied by the incorporation of a substituted pyridine residue into the heptamethine scaffold. This work represents the first general approach that allows the introduction of diverse substituents and different substitution patterns at the C3′-C5′ positions of the chain. High yields, functional tolerance, versatility toward the condensation partners, and scalability make this method a powerful tool for accessing a new generation of cyanine derivatives.
- ?tacková, Lenka,?tacko, Peter,Klán, Petr
-
supporting information
p. 7155 - 7162
(2019/05/10)
-
- An Azo Coupling Strategy for Protein 3-Nitrotyrosine Derivatization
-
Herein, a strategy for the selective derivatization of 3-nitrotyrosine-containing proteins using the classic azo coupling reaction as the key step is described. This novel approach featured multiple advantages and was successfully applied to detect picomole levels of protein tyrosine nitration in biological samples.
- Liu, Yuxin,Zhou, Pengcheng,Da, Honghong,Jia, Huiyi,Bai, Feifei,Hu, Guodong,Zhang, Baoxin,Fang, Jianguo
-
supporting information
p. 11228 - 11232
(2019/08/07)
-
- Asymmetric Syntheses of Amaryllidaceae Alkaloids (-)-Crinane and (+)-4a-Dehydroxycrinamabine
-
A palladium-catalyzed asymmetric allyl-allyl cross-coupling reaction to construct the chiral quaternary carbon center of crinane alkaloids has been developed. On the basis of an efficient approach, the enantioselective synthesis of (-)-crinane (1) is presented, and the first asymmetric total synthesis of (+)-4a-dehydroxycrinamabine (2) was achieved by subsequent oxidation, 1,4-conjugate addition, RCM reaction, reductive amination, and Pictet-Spengler reaction. The method provided an alternative strategy for the syntheses of crinane alkaloids and other Amaryllidaceae natural products.
- Gao, Ya-Ru,Wang, Da-Yu,Wang, Yong-Qiang
-
supporting information
p. 3516 - 3519
(2017/07/17)
-
- Design, synthesis and in vitro evaluation of amidoximes as histone deacetylase inhibitors for cancer therapy
-
Amindoximes are geometric isomers of N-hydroxyamidines which are bioisosteres of hydroxamates. Since amindoxime group is capable of chelating transition metal ions including zinc ion, amindoximes should possess histone deacetylases (HDACs) inhibitory activity. In this work, we designed and synthesized a series of amindoximes, examined their inhibitory activities against HDACs, and investigated their cytotoxicity to human cancer cells. Preliminary results demonstrated that amindoximes possessed submicromolar HDACs inhibitory activity, with noteworthy enhancement compared with hydroxamates. Furthermore, the amindoximes arrested HCT116 and A549 cells in G2/M phase and showed good efficacy in inducing cells death. We provided a proof-of-concept that amindoximes could be used as HDACs inhibitors and hold great promise as epigenetic drugs.
- Jiao, Peifu,Jin, Peng,Li, Chencan,Cui, Lechao,Dong, Lihua,Pan, Bin,Song, Wentong,Ma, Liang,Dong, Jinlong,Song, Lei,Jin, Xinjie,Li, Faming,Wan, Maosheng,Lv, Zhitao,Geng, Qiaohong
-
supporting information
p. 4679 - 4683
(2016/09/13)
-
- Design, synthesis and biological evaluation of saccharin-based N-hydroxybenzamides as histone deacetylases (HDACs) inhibitors
-
We report the development of a novel series of saccharin-based N-hydroxybenzamides as histone deacetylases inhibitors. Among them, 6j exhibited potent HDACs inhibitory activity against Hela nuclear extract. Further biological evaluation found 6i showed similar antiproliferative activities in vitro compared with the approved SAHA.
- Fu, Huansheng,Han, Leiqiang,Hou, Xuben,Dun, Yanyan,Wang, Lei,Gong, Xiaowei,Fang, Hao
-
supporting information
p. 5774 - 5781
(2015/11/11)
-
- Allylsilane-interrupted homo-Nazarov cyclization and synthesis of bicyclo[3.2.1]octan-8-ones
-
The combination of homo-Nazarov cyclization of 2-(tert- butyldiphenylsilylmethyl)cyclopropyl vinyl ketone leading to oxyallyl cation and its subsequent [3+2] capture by allylsilane has been demonstrated as an useful strategy for the construction of functionalized bicyclo[3.2.1]octan-8-ones. The [3+2] capture proceeds exclusively in the exo mode to make the overall reaction diastereoselective. The less substituted end of the oxyallyl cation was found to react nearly two times faster than the more substituted end.
- Yadav, Veejendra K.,Naganaboina, Vijaya K.,Hulikal, Vijaykumar
-
supporting information
p. 2015 - 2018
(2014/04/03)
-
- Consequences of linker length alteration of the α7 nicotinic acetylcholine receptor (nAChR) agonist, SEN12333
-
A series of ligands based on SEN12333, containing either contracted or elongated alkyl chains, were synthesized and evaluated in molecular docking studies against a homology model of the α7 nicotinic acetylcholine receptor (nAChR) subtype. The predicted binding of all ligands was highly similar, with the exception of the analog containing a 5 methylene unit spacer. However, in vitro competition binding assays revealed that the ligands possessed dissimilar binding affinities, with a Ki range of more than an order of magnitude (Ki = 0.50 to >10 μM), and only SEN12333 itself exhibited functional activity at the α7 nAChR.
- Beinat, Corinne,Banister, Samuel D.,Van Prehn, Saundra,Doddareddy, Munikumar Reddy,Hibbs, David,Sako, Michael,Chebib, Mary,Tran, Thao,Al-Muhtasib, Nour,Xiao, Yingxian,Kassiou, Michael
-
supporting information; experimental part
p. 2380 - 2384
(2012/05/05)
-
- Pyrrolidinobenzoic acid inhibitors of influenza virus neuraminidase: The hydrophobic side chain influences type A subtype selectivity
-
Neuraminidase (NA) plays a critical role in the life cycle of influenza virus and is a target for new therapeutic agents. A series of influenza neuraminidase inhibitors with the pyrrolidinobenzoic acid scaffold containing lipophilic side chains at the C3 position have been synthesized and evaluated for influenza neuraminidase inhibitory activity. The size and geometry of the C3 side chains have been modified in order to investigate structure-activity relationships. The results indicated that size and geometry of the C3-side chain are important for selectivity of inhibition against N1 versus N2 NA, important type A influenza variants that infect man, including the highly lethal avian influenza.
- Li, Yanwu,Silamkoti, Arundutt,Kolavi, Gundurao,Mou, Liyuan,Gulati, Shelly,Air, Gillian M.,Brouillette, Wayne J.
-
experimental part
p. 4582 - 4589
(2012/09/05)
-
- Mono-, bis- and tetrahydroxy phthalocyanines as building blocks for monomolecular layer assemblies
-
We have developed three basic phthalocyanine structures, containing one, two, or four hydroxy groups, which are simple to synthesize and purify, as well as can be characterized well by NMR and MS. These building blocks can easily be further modified to have anchor groups, which make the molecules suitable for attachment to solid substrates. We have used thioacetate and pentafluorophenyl ester moieties, giving target phthalocyanines the ability to self-assemble on gold, metal oxides, and glass. Bonding densities calculated from the absorbances of the layers suggest mean molecular area to be in the range of 13 nm 2, which can be partially controlled by side substituents and the number of linkers.
- Sariola, Essi,Kotiaho, Anne,Tkachenko, Nikolai V.,Lemmetyinen, Helge,Efimov, Alexander
-
experimental part
p. 397 - 411
(2010/11/17)
-
- Dramatic influence of the orientation of linker between hydrophilic and hydrophobic lipid moiety in liposomal gene delivery
-
A number of prior studies have demonstrated that the DNA-binding and gene transfection efficacies of cationic amphiphiles crucially depend on their various structural parameters including hydrophobic chain lengths, headgroup functionalities, and the nature of the linker-functionality used in tethering the polar headgroup and hydrophobic tails. However, to date addressing the issue of linker orientation remains unexplored in liposomal gene delivery. Toward probing the influence of linker orientation in cationic lipid mediated gene delivery, we have designed and synthesized two structurally isomeric remarkably similar cationic amphiphiles 1 and 2 bearing the same hydrophobic tails and the same polar headgroups connected by the same ester linker group. The only structural difference between the cationic amphiphiles 1 and 2 is the orientation of their linker ester functionality. While lipid 1 showed high gene transfer efficacies in multiple cultured animal cells, lipid 2 was essentially transfection incompetent. Findings in both transmission electron microscopic and dynamic laser light scattering studies revealed no significant size difference between the lipoplexes of lipids 1 and 2. Findings in confocal microscopic and fluorescence resonance energy transfer (FRET) experiments, taken together, support the notion that the remarkably higher gene transfer efficacies of lipid 1 compared to those of lipid 2 presumably originate from higher biomembrane fusogenicity of lipid 1 liposomes. Differential scanning calorimetry (DSC) and fluorescence anisotropy studies revealed a significantly higher gel-to-liquid crystalline temperature for the lipid 2 liposomes than that for lipid 1 liposomes. Findings in the dye entrapment experiment were also consistent with the higher rigidity of lipid 2/cholesterol (1:1 mole ratio) liposomes. Thus, the higher biomembrane fusibility of lipid 1 liposomes than that of lipid 2 liposomes presumably originates from the more rigid nature of lipid 2 cationic liposomes. Taken together, the present findings demonstrate for the first time that even as minor a structural variation as linker orientation reversal in cationic amphiphiles can profoundly influence DNA-binding characteristics, membrane rigidity, membrane fusibility, cellular uptake, and consequently gene delivery efficacies of cationic liposomes.
- Rajesh, Mukthavaram,Sen, Joyeeta,Srujan, Marepally,Mukherjee, Koushik,Sreedhar, Bojja,Chaudhuri, Arabinda
-
p. 11408 - 11420
(2008/03/27)
-
- Preparation of 2,3-dihydroselenolo[2,3-b]pyridines and related compounds by free-radical means
-
Photolysis of the thiohydroximate ester derivative 21 of 2-carboethoxy-2-(2-(benzylseleno)pyridin-3-yl)tridecylcarboxylic acid (20) affords 2-dodecyl-2-carboethoxy-2,3-dihydroselenolo[2,3-b]pyridine (22) in 89% yield in a process presumably involving intramolecular homolytic substitution by a tertiary alkyl radical at selenium with loss of a benzyl radical. Alternatively, rearrangement of O-(ω-haloalkyl)esters 34 of 2-carboethoxy-N-hydroxypyridine-2-selone affords azonianaphthalenium halides 37 in 79% yield. The Royal Society of Chemistry 2006.
- Fenner, Tahli,White, Jonathan M.,Schiesser, Carl H.
-
p. 466 - 474
(2008/01/27)
-
- Ruthenium porphyrin catalyzed tandem sulfonium/ammonium ylide formation and [2,3]-sigmatropic rearrangement. A concise synthesis of (±)-platynecine
-
meso-Tetrakis(p-tolyl)porphyrinatoruthenium(II) carbonyl, [Ru II(TTP)(CO)], can effect intermolecular sulfonium and ammonium ylide formation by catalytic decomposition of diazo compounds such as ethyl diazoacetate (EDA) in the presence of allyl sulfides and amines. Exclusive formation of [2,3]-sigmatropic rearrangement products (70-80% yields) was observed without [1,2]-rearrangement products being detected. The Ru-catalyzed reaction of EDA with disubstituted allyl sulfides such as crotyl sulfide produced an equimolar mixture of anti- and syn-2-(ethylthio)-3-methyl-4- pentenoic acid ethyl ester. The analogous "EDA + N,N- dimethylcrotylamine" reaction afforded a mixture of anti- and syn-2-(N,N-dimethylamino)-3-methyl-4-pentenoic acid ethyl esters with a diastereoselectivity of 3:1. The observed catalytic activity of [Ru II(TTP)(CO)] for the ylide [2,3]-sigmatropic rearrangement is comparable to the reported examples involving [Rh2(CH 3CO2)4] and [Cu(acac)2] as catalyst. Similarly, cyclic sulfonium and ammonium ylides can be produced by intramolecular reaction of a diazo group tethered to allyl sulfides and amines under the [RuII-(TTP)(CO)]-catalyzed reaction conditions. The subsequent [2,3]-sigmatropic rearrangement of the cyclic ylides furnished 2-allyl-substituted sulfur and nitrogen heterocycles in good yields (>90%). By employing [RuII(TTP)(CO)] as catalyst, the cyclic ammonium ylide [2,3]-sigmatropic rearrangement reaction was successfully applied for the total synthesis of (±)-platynecine starting from cis-2-butenediol.
- Zhou, Cong-Ying,Yu, Wing-Yiu,Chan, Philip Wai Hong,Che, Chi-Ming
-
p. 7072 - 7082
(2007/10/03)
-
- Unsymmetrical DNA cross-linking agents: Combination of the CBI and PBD pharmacophores
-
A set of 10 compounds, each combining the seco-1,2,9,9a-tetrahydrocyclopropa[c]benz[e]indol-4-one (seco-CBI) and pyrrolo [2,1-c] [1,4] benzodiazepine (PBD) pharmacophores, was designed and prepared. These compounds were anticipated to cross-link between N3 of adenine and N2 of guanine in the minor groove of DNA. The compounds, which differ in the chain length separating the two alkylation subunits, and the configuration of the CBI portion, showed great variation in cellular toxicity (over 4 orders of magnitude in a cell line panel) with the most potent example exhibiting IC50S in the pM range. Cytotoxicity correlated with the ability of the compounds to cross-link naked DNA. Cross-linking was also observed in living cells, at much lower concentrations than for a related symmetrical PBD dimer. A thermal cleavage assay was used to assess sequence selectivity, demonstrating that the CBI portion controlled the alkylation sites, while the PBD substituent increased the overall efficiency of alkylation. Several compounds were tested for in vivo activity using a tumor growth delay assay against WiDr human colon carcinoma xenografts, with one compound (the most cytotoxic and most efficient cross-linker) showing a statistically significant increase in survival time following a single iv dose.
- Tercel, Moana,Stribbling, Stephen M.,Sheppard, Hilary,Siim, Bronwyn G.,Wu, Kent,Pullen, Susan M.,Botting, K. Jane,Wilson, William R.,Denny, William A.
-
p. 2132 - 2151
(2007/10/03)
-
- Rearrangement of ammonium ylides produced by intramolecular reaction of catalytically generated metal carbenoids. Part 1. Synthesis of cyclic amines
-
Cyclic amines have been prepared in good yield by [2,3]-rearrangement of ammonium ylides produced by intramolecular reaction of copper carbenoids tethered to allylic amines. Copper(II) acetylacetonate is the optimum catalyst for carbenoid/ylide generation from the diazo ketone precursor, and reactions must be performed at elevated temperatures in order to obtain reasonable reaction rates and high yields. The reaction has been used to prepare five- to eight-membered cyclic amines. In cases where the substrate possesses a substituent on the tether connecting the diazo group to the allylic amine, tandem ylide formation and rearrangement delivers a high yield of the expected 2,5-dialkylpyrrolidinone or 2,6-dialkylpiperidinone, but low levels of diastereocontrol are obtained. Two new methods have been developed for the synthesis of diazo ketones containing a nucleophilic allylic amine substituent. The first method involves conjugate addition of allylic amines to unsaturated diazo ketones and is high yielding but of limited scope. The alternative general sequence involving nitrogen protection, α-diazo ketone formation, deprotection and allylation can be used to prepare the substrates required for intramolecular tandem ylide formation and rearrangement.
- Clark,Hodgson,Goldsmith,Street
-
p. 3312 - 3324
(2007/10/03)
-
- A new type of carboxypeptidase A inhibitors designed using an imidazole as a zinc coordinating ligand
-
2-(4-Imidazoyl)hydrocinnamic acid (1) and its congeners (2-4) having different length of alkyl chain spacers between the imidazole ring and the α-carbon to the carboxylate of 1 have been designed, synthesized and evaluated as inhibitors for carboxypeptidase A to show that they are competitive inhibitors for the enzyme. Inhibitor 1 was most potent having the K(i) value of 0.8 μM. The present study demonstrates that imidazole ring is an effective zinc coordinating ligand that can be useful for the design of inhibitors for zinc proteases.
- Lee, Kyung Joo,Joo, Keum Chan,Kim, Eun-Jung,Lee, Mijoon,Kim, Dong H.
-
p. 1989 - 1998
(2007/10/03)
-
- Synthesis and biological activity of 3-aryloxy-3-phenylpropanamines
-
Some new 3-aryloxy-3-phenylpropanmaines (6-12) have been synthesized.Their strucrures have been elucidated by mass, IR and 1H-NMR spectra and by elemental analysis.These compounds and thirteen other compounds (13-25) (synthesized earlier) have been tested for antidepressant, anorexigeniv and hypotensive activities.SAR is discussed in this note.
- Sharma, V. L.,Bhandari, Kalpana,Singh, C. M.,Dua, P. R.
-
p. 1000 - 1003
(2007/10/03)
-
- Syntheses and Physical Properties of Ferrocene Derivatives (II) Liquid Crystallinity and Multiple Melting Behavior of Ferrocene Derivatives
-
Nine kinds of monosubstituted ferrocene derivatives, ω-alkyl 4-ferrocenylbenzoate, were prepared.The derivatives containing 4, 6, 10 and 11 carbon atoms in the flexible alkyl chain of the compounds showed liquid crystallinity, and multiple melting behavior was observed in the compounds containing 4, 6 and 11 carbon atoms.An appearance of the liquid crystallinity showed a carbon number dependence on the flexible alkyl chain. - Keywords: ferrocene, liquid crystal, multiple melting behavior, phase transition, transition metal complex
- Hanasaki, Tomonori,Ueda, Mitsunori,Nakamura, Naotake
-
p. 329 - 336
(2007/10/02)
-
- Steroids
-
Steroids of the formula STR1 wherein R1 to R4, X and n have the significance given in the description, which lower the intestinal resorption of cholesterol and plasma cholesterol and a process of making same from corresponding steroids having an alcohol residue of the formula --O--X--OH in the 3-position.
- -
-
-
- The Effect of Carbonyl Containing Terminal Chains on Mesomorphic Properties in 4,4'-Disubstituted Phenylbenzoates and Phenylthiobenzoates. 4. Phenylbenzoates Containing A (CH2)nCO2R' Group (n = 0-2) on the Phenolic End
-
The effect of a (CH2)nCO2R' group on the mesomorphic properties of the esters where X = alkyl or alkoxy, Y = (CH2)nCO2R'(R' = C7 and C9) and n = 0-2 has been studied by synthesizing these esters and determining their mesomorphic properties by hot-stage polarizing microscopy.The starting phenols were prepared by esterification of 4-hydroxybenzoic, phenylacetic or phenylpropionic acids.Both the benzyl and methoxycarbonyl protecting groups were tried with the latter giving higher yields when n = 0 because of better solubility of the protected acid.No mesophases were observed in the esters when n = 1, nematic and smectic A phases occurred when n = 2 and smectic A and C phases when n = 0.A few 1,4-cyclohexane diesters were also prepared using these phenols.The mesomorphic properties of these esters followed the same trend observed in the phenylbenzoates escept no C phases were observed.Comparisons of the transition temperatures for these esters with those for Y = R' showed that both small increases or decreases were observed for Y = CO2R'.However, the addition of a spacer methylene group (n = 1 and 2) always gave lower temperatures with the amount of lowering being much greater for n = 2 than n = 1.A comparison of transition temperatures for Y = CO2R', OCOR', COR' and OR' indicated that these temperatures were higher when Y = COR' as expected from dipole moment considerations but were lower when Y = CO2R' than when Y = OCOR', the opposite expected from these considerations.This trend was also observed in the cyclohexane diesters.Transition temperatures were always higher for the esters when Y has an oxygen atom adjacent to the benzene ring.Therefore, esters with Y = O(CH2)nCO2R', n = 1 and 2 were also synthesized.The phenols were prepared by alkylation of 4-benzyloxyphenol with the bromo esters followed by hydrogenolysis.However, these esters showed no mesophases except the cyclohexane diester with n = 2.
- Neubert, M. E.,Leung, K.,Jirousek, M. R.,Ezenylimba, M. C.,Sabol-Keast, S.,et al.
-
-
- The Synthesis of Indolizidine and Quinolizidine Ring Systems by Free Radical Cyclization of 4-Aza-6-methoxycarbonyl-5-hexenyl Radicals
-
The formation of bicyclic amines by the intramolecular cyclization of 4-aza-6-methoxycarbonyl-5-hexenyl radicals is described.The direct attachment of a nitrogen atom to the double bond changes the electronic nature of the alkene such that the cyclization is less efficient than the all carbon analogue or the other aza-substituted 5-hexenyl cyclizations.The reaction has been used in a short, convenient synthesis of a variety of indolizidines from methyl nicotinate.In addition, the cyclization was used as the key step in a short synthesis of (+/-)-epilupinine from methyl nicotinate.
- Beckwith, Athelstan L. J.,Westwood, Steven W.
-
p. 5269 - 5282
(2007/10/02)
-
- 2-Aminomethyl- and 2-(2-aminoethyl)-substituted 4,5-diphenyloxazoles
-
2-Aminomethyl- and 2-(2-aminoethyl)-substituted 4,5-diphenyloxazoles of the general formula STR1 and salts thereof with non-toxic organic or inorganic acids having antiphlogistic, analgesic, anti-aggregant and local anaesthetic properties with low toxicity are provided, as well as processes for preparing them.
- -
-
-
