نتایج جستجو برای: pyran

تعداد نتایج: 1454  

2013
Jae Kyun Lee Sun-Joon Min Yong Seo Cho Joo Hwan Cha Sung Ok Won

In the title compound, C25H27FO3, each of the cyclo-hexenone rings adopts a half-chair conformation, whereas the six-membered pyran ring adopts a flattened boat conformation, with the O and methine C atoms deviating by 0.0769 (15) and 0.196 (2) Å, respectively, from the plane of the other four atoms (r.m.s. deviation = 0.004 Å). The C=C double bond adopts an E conformation. The dihedral angle b...

Journal: :The Journal of organic chemistry 2006
Uttam K Tambar Taichi Kano John F Zepernick Brian M Stoltz

The natural product saudin was found to induce hypoglycemia in mice and, therefore, could be an appealing lead structure for the development of new agents to treat diabetes. A diastereoselective tandem Stille-oxa-electrocyclization reaction has been developed which provides access to the core structure of saudin in a rapid and convergent manner. This new reaction has been extended to the conver...

2013
P. Sharmila G. Jagadeesan Rajesh Raju Raghunathan Raghavachary S. Aravindhan

In the title compound, C30H29BrN2O5, the β-lactam ring is essentially planar, with the O atom displaced from this plane by 0.856 (9) Å, and forming dihedral angles of 24.35 (13) and 89.42 (14)° with the planes of the benzene substituent groups on this ring. The tetra-hydro-pyran ring adopts an envelope conformation with the C atom bearing the β-lactam ring as the flap. In the crystal, weak C-H⋯...

2012
K. Mahesh Kumar Dalbir Kour Kamini Kapoor N. M. Mahabaleshwaraiah O. Kotresh Vivek K. Gupta Rajni Kant

In the title compound, C(16)H(16)ClNO(2)S(2), the piperidine ring is in a chair conformation. In the coumarin ring system, the dihedral angle between the benzene and pyran rings is 3.5 (1)°. In the crystal, a weak C-H⋯O hydrogen bond links mol-ecules into chains along [001]. In addition, π-π stacking inter-actions are present involving the benzene and pyran rings, with a centroid-to-centroid di...

2015
Yoshinobu Ishikawa

In the title compound, C11H8O3, the fused-ring system is almost planar (r.m.s. deviation = 0.020 Å), with the largest deviation from the least-squares plane [0.0462 (17) Å] being for a pyran C atom. The dihedral angle between the plane of the fused-ring system and acetyl plane is 5.149 (16)°. In the crystal, the fused rings are linked by aromatic π-π stacking inter-actions [centroid-centroid di...

Journal: :Molecules 2007
Xuehui Liu Yuxin Cui

The structure of a representative pyrazolo[3,4]pyran derivative was determined by 1D and 2D NMR techniques. Complete 1H and 13C chemical shifts for this compound are reported. Careful analysis of the HMBC (Heteronuclear Multi-Bond Correlation) spectrum helped to elucidate the configuration of the derivative around C7 and C8. The results showed that the characteristic double-strong and double-we...

2017
A K Bauri S Foro A F M M Rahman

In the title compound, tetra-hydro-seselin, C14H16O3, a pyran-ocoumarin [systematic name: 8,8-dimethyl-3,4,9,10-tetra-hydro-2H,8H-pyrano[2,3-f]chromen-2-one] obtained from the hydrogenation of seselin in the presence of Pd/C in MeOH at room temperature, the dihedral angle between the central benzene ring and the best planes of the outer fused ring systems are 6.20 (7) and 10.02 (8)°. In the cry...

Journal: :Molecules 2013
Harold D Cooper Dennis L Wright

Phelligridin G is an unusual natural product that contains an embedded spiro-fused furanone core. We have investigated two furan-based synthetic approaches towards the spirocyclic core structure of this natural product from readily available 2-phenylfurans. Although initial studies involving an oxidative cyclization were unsuccessful, we were ultimately able to access this key system through ...

Journal: :Dyes and Pigments 2021

Abstract A series of new azo disperse dyes was synthesized by coupling 4-hydroxy-6-methyl-2H-pyran-2-one (triacetic acid lactone, TAL) or its hydrogenated derivative 4-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one (dihydro triacetic DHTAL) with diazonium salts derived from aniline, 4-bromoaniline, 4-nitroaniline, 4-methoxyaniline, 2,4-dimethoxyaniline and 2,5-dimethoxyaniline. Spectroscopic data ...

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