Publications (25) View all
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Article: Partially Hydrogenated 7‐Oxa[5]helicenes and [5]Helicenes: Synthesis, Structures, and Dynamics
Annalen der Chemie und Pharmacie 04/2011; 2011(16):2940 - 2947. · 3.10 Impact Factor -
Article: Partially Hydrogenated 7‐Oxa [5] helicenes and [5] Helicenes: Synthesis, Structures, and Dynamics
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ABSTRACT: An efficient and convenient synthesis of partially hydrogenated functionalized [5]helicenes and oxa[5]helicenes, such as (1,2,5,6-tetrahydro-3-oxa-dibenzo[c,g]phenanthren-4-ylidene)acetonitriles 6 and (5,6-dihydro-3-oxa-dibenzo[c,g]phenanthren-4-ylidene)acetonitriles 8, has been developed through base-catalyzed ring transformation of 5,6-dihydro-4-amin-1-yl-2-oxo-2H-benzo[h]chromene-3-carbonitriles 4 by 2-tetralones 5. The molecular structures of the partially hydrogenated oxahelicenes were examined by spectroscopic methods and by X-ray crystallographic analysis. In order to calculate the inversion barrier of the helimeric enantiomers P-6e and M-6e and of P-8a and M-8a, the molecular geometries of both, the ground states and the transition states were optimized by the density functional theory (DFT) using B3LYP/6-311G*. Based on these structures, RI-SCS-MP2/TZVP single-point energies (ORCA) were calculated to permit a prediction for the rotational barrier. The accuracy of the calculated value for 6e was confirmed by DNMR experiments with line-shape analysis. Our ring-transformation protocol provides an easy access to functionalized helicenes and heterohelicenes with the flexibility of substituent variations and opens new perspectives for further exploration.European Journal of Organic Chemistry 01/2011; · 3.33 Impact Factor -
Article: Vapor-phase processable novel nonplanar donor-acceptor quateraryls for blue OLEDs(#).
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ABSTRACT: A novel series of thermally stable blue light emitting quateraryls with a piperidine donor and a nitrile acceptor was prepared from a ketene- S, S-acetal under mild conditions without using an organometal catalyst. The performance of a blue quateraryl 6e was investigated by fabricating a multilayer OLED with a configuration of ITO/PEDOT:PSS (40 nm)/quateraryl (60 nm)/BCP (6 nm)/Alq(3) (20 nm)/LiF (0.5 nm)/Al (200 nm), which exhibited blue emission with a low turn on voltage of 4 V at a brightness of 0.22 cd/m(2).Organic Letters 07/2008; 10(12):2553-6. · 5.86 Impact Factor -
Article: Synthesis of 3-phenyl-4-phenylvinyl benzopyranones and the corresponding 2,2-dimethyl-benzopyrans with structural similarity to estradiol, as estrogen receptor ligands.
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ABSTRACT: 7-Methoxy-3-phenyl-4-phenylvinyl benzopyran-2-ones and the corresponding 2,2-dimethyl-benzopyrans, substituted with different alkylamino residues were synthesized. Except compound 13e, all compounds showed high level of estrogen agonistic activity (>81 %) whereas, compounds 13 b-e and 15a showed significant estrogen antagonistic activity (>20 %). X-Ray analysis of a 7-methoxy-3-phenyl-4-phenylvinyl benzopyran-2-one derivative 13d showed its structural resemblance to endogenous estrogen, 17beta-estradiol. Estrogenic and antiestrogenic activities of these derivatives demonstrate their estrogen receptor (ER) binding ability. The lack of hydroxyl groups at appropriate positions resulted in poor Relative Binding Affinity (RBA).Medicinal Chemistry 10/2007; 3(5):446-54. · 1.50 Impact Factor -
Article: Amide derivatives of 2,3-diarylacrylophenone as estrogen receptor binding ligands.
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ABSTRACT: Substituted amidoalkyl derivatives of 2,3-diarylacrylophenones carrying the amide chain on the 3-aryl residue have been prepared by reacting corresponding phenolic 2,3-diarylacrylophenones with haloalkyl carboxylic acid esters, their hydrolysis and subsequent treatment with different alkyl amines. Compounds thus prepared were evaluated for their relative binding affinity (RBA) towards estrogen receptors (ER), estrogen agonistic and antagonistic activities. Out of eleven amide derivatives thus prepared, compounds 7, 13, 15-19, 23, 24 showed significant estrogen antagonistic activity. Interestingly the phenolic compound 7 and the acid ester 18 also exhibited estrogen inhibiting property. Majority of the dimethoxy derivatives (R = OCH(3)) showed significantly high estrogenic activity. In order to throw light on their SAR, In silico docking of the acrylophenone derivatives in the ligand binding site of the ERalpha and their comparison with pure steroidal estrogen antagonist ICI-164,384 and the non-steroidal antiestrogen raloxifene, was carried out. Crystal structure of compound 6 revealed relative trans-geometry of the 2(B) and 3(C) phenyl rings.Medicinal Chemistry 06/2007; 3(3):241-53. · 1.50 Impact Factor
