964 resultados para 4-dihydroxy-6-methyl benzoate
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In the molecular structure of the title compound, C21H25NO4, the dihydropyridine ring adopts a flattened boat conformation while the cyclohexenone ring is in an envelope conformation. In the crystal structure, molecules are linked into a two-dimensional network parallel to (10 (1) over bar) by N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds. The network is generated by R-4(4)(30) and R-4(4)(34) graph-set motifs.
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The title compound, C24H24N2O3S, exhibits antifungal and antibacterial properties. The compound crystallizes with two molecules in the asymmetric unit, with one molecule exhibiting 'orientational disorder' in the crystal structure with respect to the cyclohexene ring. The o-toluidine groups in both molecules are noncoplanar with the respective cyclohexene-fused thiophene ring. In both molecules, there is an intramolecular N-H...N hydrogen bond forming a pseudo-six-membered ring which locks the molecular conformation and eliminates conformational flexibility. The crystal structure is stabilized by O-H...O hydrogen bonds; both molecules in the asymmetric unit form independent chains, each such chain consisting of alternating 'ordered' and 'disordered' molecules in the crystal lattice.
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Benzothiazoles are multitarget agents with broad spectrum of biological activity. Among the antitumor agents discovered in recent years, the identification of various 2-(4-aminophenyl) benzothiazoles as potent and selective antitumor drugs against different cancer cell lines has stimulated remarkable interest. Some of the benzothiazoles are known to induce cell cycle arrest, activation of caspases and interaction with DNA molecule. Based on these interesting properties of benzothiazoles and to obtain new biologically active agents, a series of novel 4,5,6,7-tetrahydrobenzo[d]thiazole derivatives 5(a-i) were synthesized and evaluated for their efficacy as antileukemic agents in human leukemia cells (K562 and Reh). The chemical structures of the synthesized compounds were confirmed by H-1 NMR, LCMS and IR analysis. The cytotoxicity of these compounds were determined using trypan blue exclusion, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Results showed that, these compounds mediate a significant cytotoxic response to cancer cell lines tested. We found that the compounds having electron withdrawing groups at different positions of the phenyl ring of the thiourea moiety displayed significant cytotoxic effect with IC50 value less than 60 mu M. To rationalize the role of electron withdrawing group in the induction of cytotoxicity, we have chosen molecule 5g (IC50 similar to 15 mu M) which is having chloro substitution at ortho and para positions. Flow cytometric analysis of annexin V-FITC/ propidium iodide (PI) double staining and DNA fragmentation suggest that 5g can induce apoptosis.
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Heterocyclic urea derivatives play an important role as anticancer agents because of their good inhibitory activity against receptor tyrosine kinases (RTKs), raf kinases, protein tyrosine kinases (PTKs), and NADH oxidase, which play critical roles in many aspects of tumorigenesis. Benzothiazole moiety constitutes an important scaffold of drugs, possessing several pharmacological functions, mainly the anticancer activity. Based on these interesting properties of benzothiazoles and urea moiety to obtain new biologically active agents, we synthesized a series of novel 1-((S)-2-amino-4,5,6.7-tetrahydrobenzo[d]thiazol-6-yl)-3-(substituted phenyl)urea derivatives and evaluated for their efficacy as antileukemic agents against two human leukemic cell lines (K562 and Reh). These compounds showed good and moderate cytotoxic effect to cancer cell lines tested. Compounds with electron-withdrawing chloro and fluoro substituents on phenyl ring showed good activity and compounds with electron-donating methoxy group showed moderate activity. Compound with electron-withdrawing dichloro substitution on phenyl ring of aryl urea showed good activity. Further, lactate dehydrogenase (LDH) assay, flow cytometric analysis of annexin V-FITC/propidium iodide (PI) double staining and DNA fragmentation studies showed that compound with dichloro substitution on phenyl ring of aryl urea can induce apoptosis.
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In the title compound, C26H23FN2, the dihedral angle between the 4-fluorophenyl ring and the adjacent phenyl ring is 62.3 (1)degrees. The crystal structure is stabilized by C-H center dot center dot center dot pi interactions.
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Recently we have reported the effect of (S)-6-aryl urea/thiourea substituted-2-amino-4,5,6,7-tetrahydrobenzod]thiazole derivatives as potent anti-leukemic agents. To elucidate further the Structure Activity Relationship (SAR) studies on the anti-leukemic activity of (S)-2,6-diamino-4,5,6,7 tetrahydrobenzod]thiazole moiety, a series of 2-arlycarboxamide substituted-(S)-6-amino-4,5,6,7-tetrahydrobenzod]thiazole were designed, synthesized and evaluated for their anti-leukemic activity by trypan blue exclusion, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) assays and cell cycle analysis. Results suggest that the position, number and bulkiness of the substituent on the phenyl ring of aryl carboxamide moiety at 2nd position of 6-amino-4,5,6,7-tetrhydrobenzod]thiazole play a key role in inhibiting the proliferation of leukemia cells. Compounds with ortho substitution showed poor activity and with meta and para substitution showed good activity. (C) 2010 Elsevier Masson SAS. All rights reserved.
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The details of the first total synthesis of a natural thapsane lg containing three contiguous quaternary carbon atoms, starting from cyclogeraniol (9) '5 described. The Claisen rearrangement of 9 with methoxypropene in the presence of a catalytic amount of propionic acid produced ketone 10. Rhodium acetate-catalyzed intramolecular cyclopropanation of a-diazo-&keto ester 12, obtained from 10 via 8-keto ester 8, furnished cyclopropyl keto ester 7. Lithium in liquid ammonia reductive cleavage of cyclopropyl compound 7 gave a 1:l mixture of hydrindanone 6 and keto1 13. Wittig methylenation of 6 furnished ester 21. Epoxidation of 21, followed by BF3-OEt2-catalyzed rearrangement of epoxide 23 afforded hemiacetal 25. Treatment of hemiacetal 25 with triethylsilane in trifluoroacetic acid furnished lactone 22, a degradation product of various thapsanes. Finally, DIBAH reduction of lactone 22 generated the thapsane
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Isolation and structure elucidation of kiritiquinone, a new benzoquinone 2 5 dihydroxy-6-methyl 3 (hemeos 16-enyl)-1 4 benzoquinone from the frutis of Masca indica (Roxb) A DC is described
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In the title compound, C17H18N2O2S, the 1,3-diazinane-2-thione ring system is not coplanar with the benzene ring and methoxyphenyl ring system, the dihedral angle between the planes being 65.58 (13) and 89.18 (10)degrees, respectively. The crystal structure is characterized by intermolecular O-H...S, N-H...S, N-H...O and C-H...S hydrogen bonding.
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DDHQ/TCC esters 3a–f, 7a–g were prepared either by oxidation of spiroketones 1 with DDQ/Image -chloranil or by condensation of acid chloride with DDHQ/TCC. NaBH4 reduction of unsaturated DDHQ 3a–b and TCC 7a–c esters gave the corresponding allylic alcohols in good yield without any observable 1,4-addition products. Reduction of saturated esters 3e, 7d, gave the corresponding alcohols. Alkyl esters 5 and 6, methyl benzoate and phenyl benzoate remained unaffected under these reduction conditions. In the reduction of compound 7e containing both alkyl and TCC esters, TCC ester is selectively reduced. Reduction of TCC mono esters 7f–g gave the lactones. The observed facile reduction has been rationalised.
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A new series of luminescent 4-(2-(4-alkoxyphenyl)-6-methoxypyridin-4-yl) benzonitriles containing three ring systems, viz. methoxy pyridine, benzonitrile and alkoxy benzene with variable alkoxy chain length, with bent-core structures were synthesized as potential mesogens and characterized by spectral techniques. Their liquid crystalline behavior was investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and variable temperature powder X-ray diffraction (PXRD) measurements. The study reveals that compounds with shorter chain lengths i.e. m = 4] exclusively exhibit the nematic phase while compounds with longer chain lengths i.e. m = 6-14 (only even)] show predominantly the orthorhombic columnar phase. Single crystal X-ray analysis of 4-(2-(4-butyloxy/octyloxyphenyl)-6-methoxypyridin-4-yl) benzonitriles reveals that they possess slightly non-planar unsymmetrical bent structures and their molecular packing consists of nonconventional H-bond interactions; it also explains the observed liquid crystalline phase. An optical study indicates that the title compounds are good blue emitting materials showing absorption and emission bands in the range 335-345 nm and 415-460 nm, respectively. An electrochemical study of 4-(2-(4-octyloxyphenyl)-6-methoxypyridin-4-yl) benzonitrile shows a band gap of 1.89 eV with HOMO and LUMO energy levels of -5.06 and -3.17 eV, respectively. Also, density functional theory (DFT) calculations confirm its optimized geometry, electronic absorption and frontier molecular orbital distributions.