- Photophysical properties of dibenzotropylium cation incorporated within acidic ZSM-5 zeolite
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Dibenzotropylium ion (DT+) has been generated as an indefinitely persistent species within the channels of ZSM-5 in its H+-form. Diffuse reflectance laser flash photolysis has allowed detection of a transient (two bands: 300 nm, sharp and ~440 nm broad) decaying in the μs time-scale that has been assigned to the corresponding triplet excited state. The tight fit of DT+ within the straight channels (5.2×5.7A?2) of ZSM-5 and the presence of coadsorbed water explain why the DT+ triplet excited state is not quenched by oxygen but interacts with triethylamine, which is highly water-soluble. In the latter case, formation of a new transient compatible with DT· (λmax=270 and 350 nm) through electron transfer from the amine to DT+ triplet is observed.
- Luz Cano, María,Chrétien, Michelle N.,García, Hermenegildo,Scaiano
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Read Online
- Steric structure–activity relationship of cyproheptadine derivatives as inhibitors of histone methyltransferase Set7/9
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Set7/9 is a histone lysine methyltransferase, but it is also thought to be involved in a wide variety of pathophysiological functions. We previously identified cyproheptadine, which has a characteristic butterfly-like molecular conformation with bent tricyclic dibenzosuberene and chair-form N-methylpiperidine moieties, as a Set7/9 inhibitor. In this work, we synthesized several derivatives in order to examine the steric structure–inhibitory activity relationship. We found that even a small change of molecular shape due to reduction or replacement of the 10,11-olefinic bond of the tricyclic ring generally resulted in a drastic decrease of the inhibitory activity. Our results should be useful not only for development of more potent and selective inhibitors, but also for the construction of novel inhibitor scaffolds.
- Fujiwara, Takashi,Ohira, Kasumi,Urushibara, Ko,Ito, Akihiro,Yoshida, Minoru,Kanai, Misae,Tanatani, Aya,Kagechika, Hiroyuki,Hirano, Tomoya
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Read Online
- An efficient, large-scale synthesis of cytenamide
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Dibenzosuberenone (5H-dibenzo[a,d]cyclohepten-5-one) was reduced to the corresponding alcohol by sodium borohydride/MeOH and converted to the corresponding 5-chloro compound by thionyl chloride/benzene, treatment of which with CuCN/toluene gave the corresponding nitrile. Hydrolysis by ethanolic KOH yielded the corresponding amide, cytenamide (5H-dibenzo[a,d]cycloheptene-5-carboxamide).
- Bedford, Colin T.
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p. 153 - 155
(2018/04/20)
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- Phosphine-alkene ligands as mechanistic probes in the pauson-khand reaction
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An alkyne tetracarbonyl dicobalt complex with a chelated phosphine-alkene ligand, in which the phosphorus atom and the alkene from the ligand are attached to the same cobalt atom has been prepared, isolated, and characterized by X-ray crystallography. The
- Ferrer, Catalina,Benet-Buchholz, Jordi,Riera, Antoni,Verdaguer, Xavier
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supporting information; experimental part
p. 8340 - 8346
(2010/09/08)
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- Mapping the active site in a chemzyme: Diversity in the N-substituent in the catalytic asymmetric aziridination of imines
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(Chemical Equation Presented) The active site of the aziridination catalyst derived from either the VANOL or VAPOL ligand and B(OPh)3 is larger than expected and can accommodate not only significant substitution on the diarylmethyl unit of the imine but also that alkyl (but not perfluorylalkyl) substituents on the aryl groups lead to enhanced rates and enantioselection. The screen of diarylmethyl N-substituents on the imine revealed that the 3,5-di-tert-butyldianisylmethyl group (BUDAM) gave exceptionally high asymmetric inductions for imines of aryl aldehydes.
- Zhang, Yu,Lu, Zhenjie,Desai, Aman,Wulff, William D.
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supporting information; experimental part
p. 5429 - 5432
(2009/06/20)
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- Polycyclic phosphiranes: Synthesis of C-substituted BABAR-Phos compounds
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BABAR-Phos is a very stable polycyclic phosphirane which is easily synthesized in few steps from dibenzosuberenone. BABAR-Phos is remarkably stable and is not oxygenated with O2 nor does it react with sulfur in boiling toluene. BABAR-Phos can be used as a ligand in homogenous catalysis. Substituents at the carbon of the PC2 heterocycle can be introduced and asymmetric BABAR-Phos were prepared. The coordination chemistry of rhodium complexes containing these as ligands was investigated.
- Laeng, Florian B.,Gruetzmacher, Hansjoerg
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p. 187 - 190
(2007/10/03)
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- Protease inhibitors: Synthesis of bacterial collagenase and matrix metalloproteinase inhibitors incorporating arylsulfonylureido and 5-dibenzo-suberenyl/suberyl moieties
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Novel matrix metalloproteinase (MMP)/bacterial collagenase inhibitors are reported, considering the sulfonylated amino acid hydroxamates as lead molecules. A series of compounds was prepared by reaction of arylsulfonyl isocyanates with N-(5H-dibenzo[a,d]cyclohepten-5-yl)- and N-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-yl) methyl glycocolate, respectively, followed by the conversion of the COOMe to the carboxylate/hydroxamate moieties. The corresponding derivatives with methylene and ethylene spacers between the polycyclic moiety and the amino acid functionality were also obtained by related synthetic strategies. These new compounds were assayed as inhibitors of MMP-1, MMP-2, MMP-8 and MMP-9, and of the collagenase isolated from Clostridium histolyticum (ChC). Some of the new derivatives reported here proved to be powerful inhibitors of the four MMPs mentioned above and of ChC, with activities in the low nanomolar range for some of the target enzymes, depending on the substitution pattern at the sulfonylureido moiety and on the length of the spacer through which the dibenzosuberenyl/suberyl group is connected with the rest of the molecule. Several of these inhibitors also showed selectivity for the deep pocket enzymes (MMP-2, MMP-8 and MMP-9) over the shallow pocket ones MMP-1 and ChC.
- Ilies, Monica,Banciu, Mircea D.,Scozzafava, Andrea,Ilies, Marc A.,Caproiu, Miron T.,Supuran, Claudiu T.
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p. 2227 - 2239
(2007/10/03)
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- Synthesis of 2,4-diaminopyrido[2,3-d]pyrimidines and 2,4-diamino-quinazolines with bulky dibenz[b,f]azepine and dibenzo[a,d]-cycloheptene substituents at the 6-position as inhibitors of dihydrofolate reductases from Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium
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The synthesis of four previously undescribed 2,4-diaminopyrido[2,3-d]pyrimidines (3,4) and 2,4-diaminoquinazolines (5,6) with a bulky tricyclic aromatic group at the 6-position is described. Condensation of dibenz[b,f]azepine with 2,4-diamino-6-bromomethylpyrido[2,3-d]pyrimidine (8) and 2,4-diamino-6-bromomethylquinazoline (17) in the presence of sodium hydride afforded N-[(2,4-diaminopyrido[2,3-d]-pyrimidin-6-yl)methyl]dibenz[b,f]azepine (3) and N-[(2,4-diaminoquinazolin-6-yl)methyl]dibenz[b,f]-azepine (4), respectively. Condensation of 5-chlorodibenzo[a,d]cycloheptene (19) and 5-chloro-10,11-dihydrodibenzo[a,d]cycloheptene (20) with 2,4,6-triaminoquinazoline (13) afforded 5-[(2,4-diamino-quinazolin-6-yl)amino]-5H-dibenzo[a,d]cycloheptene (5) and the corresponding 10,11-dihydro derivative (6), respectively. The bromides 8 and 17, as hydrobromic acid salts, were obtained from the corresponding nitriles according to a standard three-step sequence consisting of treatment with Raney nickel in formic acid followed by reduction with sodium borohydride and bromination with dry hydrogen bromide in glacial acetic acid. Compounds 3-6 were evaluated in vitro for the ability to inhibit dihydrofolate reductase from Pneumocystis carinii, Toxoplasma gondii, Mycobacterium avium, and rat liven Compounds 3 and 4 were potent inhibitors of all four enzymes, with IC50 values in the 0.03-0.1 μM range, whereas 5 was less potent. However the selectivity of all four compounds for the parasite enzymes relative to the rat enzyme was 100-fold selectivity for the T. gondii and M. avium enzyme and 21-fold selectivity for the P. carinii enzyme.
- Rosowsky,Fu,Queener
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p. 921 - 926
(2007/10/03)
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- Conformational analysis of some 5-substituted 5H-dibenzo[a,d]-cycloheptenes
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Conformations and inversion barriers of 5H-dibenzo[a,d]cycloheptene (1a), 5-amino-5H-dibenzo[a,d]cycloheptene (1b), 5-chloro-5H-dibenzo[a,d]cycloheptene (1e), 5-hydroxy-5H-dibenzo[a,d]cycloheptene (1d), 5-methyl-5H-dibenzo[a,d]cycloheptene (1f), N-benzyl-5H-dibenzo[a,d]cyclohepten-5-imine (2) and N-(5H-dibenzo[a,d]cyclohepten-5-yl)benzylideneamine (1c) have been studied by means of dynamic nuclear magnetic resonance spectroscopy (DNMR) techniques, and comparison of the experimentally derived thermodynamic parameters was made with MM3, PM3 and ab initio calculated results. Attempts to determine the inversion barrier of 3-isopropyl-5H-dibenzo[a,d]cyclohepten-5-one (3) failed.
- Hjelmencrantz, Anders,Friberg, Annika,Berg, Ulf
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p. 1293 - 1300
(2007/10/03)
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- Pharmaceutical compositions of 4-(dibenzo-[a,d]cycloalkenyl)piperazine compounds and methods
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Pharmaceutical compositions comprising 4-(dibenzo[a,d]cycloalkenyl)piperazine compounds and the use of said piperazine compounds for treatment of certain cardiovascular disorders are disclosed.
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- Tricyclic pharmacological agents, intermediates and methods of making
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5-(3-Substituted prop-cis-1-enyl)- and 5-(3-substituted prop-trans-1-enyl)- derivatives of 5H-dibenzo[a,d]cycloheptenes and 10,11-dihydro-5H-dibenzo[a,d]cycloheptenes and methods of making. The process of preparing the 5-(3-substituted prop-cis-1-enyl)- derivatives comprises hydrogenation of the appropriate 5-(3-substituted prop-1-ynyl)- derivatives in the presence of a noble metal catalyst. The 5-(3-substituted prop-trans-1-enyl)- derivatives can be prepared via treatment of the appropriate 5-(3-substituted prop-1-ynyl)- derivative with an alkali metal (e.g. sodium) in the presence of ammonia. Both the 5-(3-amino-cis- and 3-amino-substituted prop-trans-1-enyl)- derivatives exhibit antihistamine activity and are further useful in the treatment of, and/or palliation of, abnormal conditions occurring in mammals, related to the central nervous system. The remaining compounds have utility as intermediates for pharmacologically active compounds.
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