- A convenient strategy for the total synthesis of pisiferic acid type diterpenes
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A practical method for the total synthesis of pisiferic acid type diterpenoids is described. This involves Robinson annulation of the keto ester for the key intermediate.
- Zhu, Hui,Tu, Pengfei
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- Facile access to a series of large polycondensed pyridazines and their utility for the supramolecular synthesis of coordination polymers
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Domino cyclization of ketoenols and hydrazine leads to a series of polycondensed pyridazines, which reveal potential as rigid N-donor multidentate ligands for supramolecular synthesis of open coordination polymers.
- Domasevitch, Konstantin V.,Solntsev, Pavlo V.,Krautscheid, Harald,Zhylenko, Iryna S.,Rusanov, Eduard B.,Chernega, Alexander N.
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Read Online
- Reduced Phenalenyl in Catalytic Dehalogenative Deuteration and Hydrodehalogenation of Aryl Halides
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Dehalogenative deuteration reactions are generally performed through metal-mediated processes. This report demonstrates a mild protocol for hydrodehalogenation and dehalogenative deuteration of aryl/heteroaryl halides (39 examples) using a reduced odd alternant hydrocarbon phenalenyl under transition metal-free conditions and has been employed successfully for the incorporation of deuterium in various biologically active compounds. The combined approach of experimental and theoretical studies revealed a single electron transfer-based mechanism.
- Singh, Bhagat,Ahmed, Jasimuddin,Biswas, Amit,Paira, Rupankar,Mandal, Swadhin K.
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p. 7242 - 7255
(2021/05/29)
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- Enantiopure Chiral Concave 1,10-Phenanthrolines
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Chiral information has been introduced into concave 1,10-phenanthrolines of different ring sizes by using a 2,7-disubstituted naphthalene bridgehead, which causes axial chirality. A tetraphenolic 2-(dihydroxynaphthyl)-9-(dihydroxyphenyl)-1,10-phenanthroline was synthesized as a key intermediate. Two strategies were followed to obtain the bimacrocyclic chiral concave 1,10-phenanthrolines: quadruple Williamson ether synthesis or alkenylation of the OH groups and subsequent ring-closing metathesis followed by hydrogenation. The overall yields of bimacrocyles 19 were 10 to 17 % starting from the respective Suzuki coupling of the substituted arenes 11 and 13 to 2,9-dichloro-1,10-phenanthroline (5). Racemic mixtures of the three concave 1,10-phenanthrolines 19 were separated by using chiral high-performance liquid chromatography (HPLC) techniques, and their absolute stereochemistry was assigned by comparison of simulated and experimental circular dichroism (CD) spectra. The enantiopure concave 1,10-phenanthrolines were used as ligands in a copper-catalysed cyclopropanation, and their selectivity was determined by chiral gas chromatography (GC).
- Reck, Lisa M.,Haberhauer, Gebhard,Lüning, Ulrich
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p. 1119 - 1131
(2016/03/05)
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- 1:1 and 2:1 cocrystallizations of alkoxy-substituted naphthalene derivatives with octafluoronaphthalene through arene-perfluoroarene interactions
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Naphthalene derivatives with laterally orientated short side chains readily form cocrystals with octafluoronaphthalene in which the position and the length of the lateral chain can control the 1:1 and 2:1 cocrystallization stoichiometries and overlapped a
- Hori, Akiko,Takeda, Haruhi,Premkumar, J. Richard,Sastry, G. Narahari
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p. 193 - 197
(2015/03/05)
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- Synthesis and biological evaluation of 1-benzylidene-3,4-dihydronaphthalen- 2-one as a new class of microtubule-targeting agents
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A series of 1-benzylidene-3,4-dihydronaphthalen-2-one derivatives were designed and synthesized, and their biological activities in vitro and in vivo were evaluated. The results showed a number of the title compounds exhibiting potent nanomolar activity in several human cancer cell lines. Of these, compound 22b showed the strongest inhibitory activity against human CEM, MDA-MBA-435, and K562 cells (IC50 = 1 nM), displayed in vitro inhibition of tubulin polymerization (IC50 = 3.93 μM), and significantly induced cell cycle arrest in G2/M phase. In addition, compound 22b could inhibit the tumor growth in colon nude mouse xenograft tumor model significantly and seemed safer than CA-4 when achieving a similar tumor suppression. This study provided a new molecular scaffold for the further development of antitumor agents that target tubulin.
- Liu, Jia,Zheng, Can-Hui,Ren, Xiao-Hui,Zhou, Feng,Li, Wei,Zhu, Ju,Lv, Jia-Guo,Zhou, You-Jun
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scheme or table
p. 5720 - 5733
(2012/07/30)
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- Synthesis and antifungal activities of novel 2-aminotetralin derivatives
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Novel 2-aminotetralin derivatives were synthesized as antifungal agents. The 2-aminotetralin scaffold was chemically designed to mimic the tetrahydroisoquinoline ring of the lead molecule described before. Their antifungal activities were evaluated in vitro by measuring the minimal inhibitory concentrations (MICs). Compounds 10a, 12a, 12c, 13b, and 13d are more potent than fluconazole against seven testing human fungal pathogens. Compound 10b exhibits much higher antifungal activities against all of the four fluconazole-resistant clinic Candida albicans strains than the control drugs including amphotericin B, terbinafine, ketoconazole, and itraconazole. The mode of action of some compounds to the potential receptor lanosterol 14α-demethylase (CYP51) was investigated by molecular docking. The studies presented here provide a new structural type for the development of novel antifungal compounds. Furthermore, 10b was evaluated in vivo by a rat vaginal candidiasis model, and it was found that 10b significantly decreases the number of fungal colony counts.
- Yao, Bin,Ji, Haitao,Cao, Yongbin,Zhou, Youjun,Zhu, Jü,Lü, Jiaguo,Li, Yaowu,Chen, Jun,Zheng, Canhui,Jiang, Yuanying,Liang, Rongmei,Tang, Hui
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p. 5293 - 5300
(2008/03/18)
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- Tuning the size of macrocyclic cavities in trianglimine macrocycles
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The synthesis of aromatic dicarboxaldehydes is described along with their reactivity in the [3 + 3] cyclocondensation reaction with (1R,2A)- diaminocyclohexane to give trianglimine macrocycles. In particular, the scope and limitation of the reaction with regard to complete control of the cavity size of the macrocycles is discussed producing a total of 11 macrocycles with different cavity sizes ranging from 9 to 23 A. The Royal Society of Chemistry 2005.
- Kuhnert, Nikolai,Burzlaff, Nicolai,Patel, Chirag,Lopez-Periago, Ana
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p. 1911 - 1921
(2007/10/03)
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- Photolytic, thermal, addition, and cycloaddition reactions of 2-diazo-5,6- and -3,8-disubstituted acenaphthenones
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Preparation and varied thermal and photolytic reactions of 2-diazo-5,6-(disubstituted)acenaphthenones (11a-d) and 2-diazo-3,8- dimethoxyacenaphthenone (12) are reported. Alcohols react thermally and photolytically with 11a-c with losses of N2 to yield 2-alkoxynaphthenones (24a,b and 47a,b) and acenaphthenones (25 and 48a,b). Aniline and diphenylamine are converted by 11a-c at 180°C to acenaph[1,2-6]indoles (29a,b and 53a,b). Thermolyses of 11a-c at ～450°C (0.15 mmHg) yield reduction products 25 and 48a,b, respectively. Wolff rearrangements to 1,8-naphthyleneketenes (15a-d) and/or their derivatives are not observed in the above experiments. Oxygen converts 11a-c thermally to acenaphthenequinones (19a-c) and/or 1,8-naphthalic anhydrides. Insertion, addition, substitution, and/or isomerization reactions occur upon irradiation of 2-diazoacenaphthenones in cyclohexane, benzene, and tetrahydrofuran. Photolysis of 11d in benzene in the presence of O2 yields the insertion-oxidation product 2-hydroxy-5,6-dinitro-2-phenylacenaphthenone (60). Photolyses of 11a-c in nitriles result in N2 evolution and dipolar cycloaddition to give acenaph[1,2-d]oxazoles (41 and 61a,b). Acetylenes undergo thermal and photolytic cycloaddition/1,5-sigmatropic rearrangement reactions with 11a-d with N2 retention to give pyrazolo[5,1-a]quinolin-7-ones (69f-j). 2-Diazoacenaphthenones 1a and 11a react thermally and photolytically with electronegatively-substituted olefins with N2 expulsion to yield (E)- and (Z)-2-oxospiro[acenaphthylene-1(2H),1′cyclopropanes] 73a-c and 74a-c, respectively. The mechanisms of the reactions of la, 11a-d, and 12 reported are discussed.
- Blair, Patricia A.,Chang, Sou-Jen,Shechter, Harold
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p. 7123 - 7133
(2007/10/03)
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- Cyclopropylcarbinyl-type ring openings. Reconciling the chemistry of neutral radicals and radical anions
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Cyclopropylcarbinyl → homoallyl and related rearrangements of radical ions (a) are frequently used as mechanistic "probes" to detect the occurrence of single electron transfer in chemical and biochemical processes, (b) provide the basis for mechanism-base
- Stevenson, J. Paige,Jackson, Woodward F.,Tanko
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p. 4271 - 4281
(2007/10/03)
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- Substituted heterocyclic compounds, method for preparing and compositions containing same
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The invention relates to compounds of formula (I): wherein: R1, R2and R3are as defined in the description, X is as defined in the description, Y represents an oxygen atom, a sulphur atom, a C(H)qgroup, SO or SO2, n is equal to from 0 to 5, A represents a NR5R6group, and medicinal products containing the same which are useful in treating or in preventing melatoninergic disorders.
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- TRICYCLIC AMIDES
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The invention relates to a compound selected from these of formula (I) : STR1 in which R 7, R 8, Y, n and A are as defined in the description, and medicinal product containing the same useful for treating a disorder of the melatoninergic system.
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- An artificial receptor for dimethyl aspartate
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[trans-5,15-Bis(2,7-dihydroxy-1-naphthyl)-2,3,7,8,12,13,17,18-octaethy lporphyrinato]zinc(II) (1), a trifunctionalized porphyrin host, was prepared as a receptor for amino acid derivatives, particularly those having a hydrogen-bonding site in the side chain. The free energy changes for the binding of Leu-OMe, Asp-OMe, and Glu-OMe to 1 were -5.8 kcal/mol, -6.6 kcal/mol, and -5.9 kcal/mol, showing a selectivity for Asp-OMe. 1H NMR titration experiments indicated that three simulteneous attractive interactions, one coordination interaction, and two hydrogen-bonding interactions, are operating in the host-guest complex. The preference for Asp-OMe over Glu-OMe was found to originate from the favorable enthalpy term for Asp-OMe. The free energy change, the enthalpy change, and the entropy change were determined and split into contributions arising from coordination interaction and from hydrogen-bonding interactions by use of reference hosts. Comparison of enthalpy and entropy changes suggests that the host-guest complex becomes more ordered as the number of recognition pairs increases.
- Mizutani, Tadashi,Murakami, Takeshi,Kurahashi, Takuya,Ogoshi, Hisanobu
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p. 539 - 548
(2007/10/03)
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- Regioselective Monomethylation of Unsymmetrical Naphthalenediols with Methanolic HCl
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Treatment of naphthalene-1,3-diol and naphthalene-1,7-diol with methanol containing dry hydrogen chloride at room temperature gives exclusively 3-methoxy-1-naphthol and 7-methoxy-1-naphthol, respectively.Of the other two unsymmetrical naphthalenediols, the 1,2-isomer was unreactive and the 1,6-isomer gave a mixture of regioisomers under the same conditions.Two symmetrical diols (the 1,5- and 2,7-isomers) examined by the same procedure gave the monomethyl ethers in 60-70percent yields.
- Bell, Kevin H.,McCaffery, Leslie F.
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p. 731 - 737
(2007/10/02)
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- 2-Amido-8-methoxytetralins: A Series of Nonindolic Melatonin-like Agents
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A series of unsubstituted and methoxy-substituted 2-amidotetralins (4a-q) was prepared and evaluated for their ability to complete for 2-iodomelatonin binding to chicken retinal membranes and for their potency to inhibit the calcium-dependent release of dopamine from rabbit retina.The lead compound, 2-acetamido-8-methoxytetralin (4j), showed a moderate affinity (Ki = 46 nM) and potency (IC50 = 1.4 nM) at the melatonin receptor.The structural requirements necessary for optimal agonistic activity at the melatonin receptor are as follows.First, the amido group, which should have a small, nonbranched alkyl group, is essential for affinity, and second, the methoxy substituent at the 8-position of the 2-amidotetralin ring is essential for optimal agonistic activity at the melatonin receptor.We concluded that this series of unsubstituted and methoxy-substituted 2-amidotetralins constitutes a class of nonindolic melatonin-like agents that can be used as pharmacological tools to further characterize melatonin receptors and to elucidate the mode of action of melatonin.
- Copinga, Swier,Tepper, Pieter G.,Grol, Cor J.,Horn, Alan S.,Dubocovich, Margarita L.
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p. 2891 - 2898
(2007/10/02)
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- Propellahexaene by Triple Shapiro Degradation. Structural and Electronic Properties of This Maximally Unsaturated Hydrocarbon and Consequences of O-Methylation of Its Propellatrienetrione Precursors
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The trienetriones 6 and 7 were prepared and transformed into their tris(phenylsulfonyl)hydrazones to arrive at the title hydrocarbon (5).These derivatives were subjected in turn to triple Shapiro degradation.The D3 symmetric nature of the resulting hexaene was suggested by its NMR spectra and corroborated by X-ray crystallographic analysis.When this molecule is viewed down its central C-C bond, its dramatic propeller-like shape is made evident.Thermochemical experiments established 5 to be a rather stable substance.Photoelectron spectroscopic studies involving 5and its less unsaturated analogues 24 and 25 are also detailed.By this means, the electronic structure of 5 was shown to be such that there are no ?-MO's amid its high-lying ? MO's.MNDO calculations for 5 predict the central bond to be 1.61 Angstroem (experimental value = 1.57 Angstroem).Also described are experiments detailing the fate of both 7 and its C3v symmetric isomer 6 on attempted 3-fold O-methylation.In the first instance, the major product happens to be 3,6,9-trimethoxyphenanthrene (42).Skeletal rearrangement is not encountered with 6.Rather, the major product is dimethoxy enone 39, which is accompanied by lesser amounts of 2,7-dimethoxynaphthalene (40).On further processing of 39, fragmentation to 40 occurs to a major extent, although it has proven possible to acquire limited amounts of the trimethoxy hexaene 41.The interesting divergence in chemical response exhibited by 6 and 7 has no parallel.Finally, the relative rates and stereochemical course (where relevant) of the Diels-Alder reaction of N-methyltriazolinedione (MTAD) with 5, 24, and 25 are reported.The reactivity order is 5 > 24 > 25, the hexaene being consumed instantaneously on mixing at room temperature.The facial selectivity exhibited by 24 during its initial capture by MTAD is best rationalized in terms of steric control.Like considerations apply to the pathways followed by 44, 45 and 5 in their reactions with the same dienophile.Consequently, orbital symmetry considerations do not appear to play a major role in these processes.
- Paquette, Leo A.,Liang, Shaowo,Waykole, Liladhar,DeLucca, George,Jendralla, Heiner,et al.
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p. 1598 - 1611
(2007/10/02)
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- Manganese(III)-Mediated Formylation of Aromatic Compounds in the Presence of Malonic Acid
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The reaction of naphthlenes with malonic acid in the presence of manganese(III) acetate gives naphthalenecarbaldehydes and naphthalenecarboxylic acids.Similar reactions of anthracene, pyrene, and methoxybenzenes also yield formylated and carboxylated products.It was found that the formyl group introduced to the aromatic ring was not derived from carboxymethyl radical generated directly by the thermolysis of manganese(III) acetate, but from a dicarboxymethyl radical formed by the interaction of malonic acid and manganese(III) acetate.In addition, it was also found that the dicarboxymethyl radicals attacked the position of the highest electron density on the aromatic ring and that this formylation was effective when the ionization potential of the aromatic copound was lower than 7.8 eV.
- Nishino, Hiroshi,Tsunoda, Katsunori,Kurosawa, Kazu
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p. 545 - 550
(2007/10/02)
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- Enzymes in organic synthesis. 37. Preparation and characterization of potential decalindione substrates of horse liver alcohol dehydrogenase
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The preparations of ten decalindiones for investigation as substrates of horse liver alcohol dehydrogenase are reported.The structure characterizations include clarifications of some ambiguities in the decalin literature.
- Jones, J. Bryan,Dodds, David R.
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p. 2397 - 2404
(2007/10/02)
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- ACYLATION OF 2,7-DIMETHOXYNAPHTHALENE
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During the acylation of 2,7-dimethoxynaphthalene with acetyl chloride in the presence of boron trifluoride etherate 1-acetyl-2,7-dimethoxynaphthalene is formed.In polyphosphoric acid the main product is its 3-isomer, whereas in nitrobenzene and dichloroethane in the presence of aluminium chloride a mixture of both compounds is formed.Further acetylation of these ketones leads to 1,8- and 1,6-diacetyl-2,7-dimethoxynaphthalene respectively.The results are explained by the instability of 1-acetyl-2,7-dimethoxynaphthalene in the presence of strong protic acids.
- Gorelik, A. M.,Reznichenko, A. V.,Andronova, N. A.,Luk'yanets E. A.
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p. 183 - 189
(2007/10/02)
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- Reactions with Thioethoxide Ion in N,N-Dimethylformamide. III. Regioselective Demethylation of 4-(2',7'-Dimethoxy-1'-naphthyl)-2-methylbutan-2-ol
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Reaction of 2,7-dimethoxy-1-methylnaphthalene with sodium thioethoxide in N,N-dimethylformamide leads to a mixture of approximately equal parts of the isomeric O-monomethyl ethers of 1-methylnaphthalene-2,7-diol, but under the same conditions 4-(2',7'-dimethoxy-1'-naphthyl)-2-methylbutan-2-ol undergoes regioselective demethylation of the more hindered 2'-methoxyl group.
- Cannon, Jack R.,Feutrill, Geoffrey I.,Wong, Laurence C. H.
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p. 2575 - 2580
(2007/10/02)
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- HALOGENATION REGIOSELECTIVE EN SERIE AROMATIQUE-II CHLORATION DES NAPHTOLS ET LEURS ETHERS A L'AIDE DE REACTIFS METTANT EN JEU DES INTERACTIONS DU TYPE DONNEUR-ACCEPTEUR
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The regispecific chlorination of naphtols by hexachlorocyclohexadienones as selective chlorinating reagents is described.The selectivity attained is better than that which we have obtained with phenol derivatives and confirms the importance of the donor-acceptor interaction between the reagent and the naphthol during the chlorination.
- Guy, Alain,Lemaire, Marc,Guette, Jean-Paul
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p. 2347 - 2354
(2007/10/02)
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- The kinetics of proton and deuteron transfer from 4-nitrophenylnitromethane and 1-(4-nitrophenyl)-1-nitroethane to 2,7-dimethoxy-1,8-bis(dimethylamino)naphthalene in acetonitrile solvent
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4-Nitrophenylnitromethane reacts with 2,7-dimethoxy-1,8-bis(dimethylamino)naphthalene in acetonitrile in a bimolecular proton transfer, which shows a primary deuterium isotope effect, kH/kD = 12.2 at 25 deg C.The large isotope effect on the enthalpy of activation. (ΔHD(*) - ΔHH(*) = 4.6 +/- 0.3 kcal mol-1 is consistent with a significant contribution of proton tunnelling to the reaction rate of the protium substrate.The analogous reaction of 1-(4-nitrophenyl)-1-nitroethane with the same base in acetonitrile gives contrasting kinetics and reaction parameters.The reaction is first order, showing no dependence on base concentration.While the isotope effect kH/kD = 9.3 at 25 deg C, the enthalpy of activation difference (ΔHD(*) - ΔHH(*) is only 0.5 +/- 0.1 kcal mol-1.It is concluded that the 1-(4-nitrophenyl)-1-nitroethane undergoes a slow dissociation, with a very small dissociation constant, followed by a fast association with the base to yield the carbanion ion-pair.
- Leffek, Kenneth T.,Pruszynski, Przemyslaw
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p. 3034 - 3038
(2007/10/02)
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