Results 21 to 30 of about 44,043 (291)

Pedicularis L. Genus. Systematics, botany, phytochemistry, chemotaxonomy, ethnopharmacology, and other [PDF]

, 2019
In this review, the relevance of the plant species belonging to the Pedicularis L. genus has been considered from different points of view. Particular emphasis was given to phytochemistry and ethnopharmacology, since several classes of natural compounds ...
Bianco, Armandodoriano, Ciccòla, Alessandro, De Vita, Daniela, Foddai, Sebastiano, Franceschin, Marco, Frezza, Claudio, Guiso, Marcella, Nicoletti, Marcello, Serafini, Ilaria, Serafini, Mauro, Tomassini, Lamberto, Toniolo, Chiara, Venditti, Alessandro, Ventrone, Antonio   +13 more
core   +1 more source

Organocatalysis in Synthesis: L-Proline as an Enantioselective Catalyst in the Synthesis of Pyrans and Thiopyrans

Molecules, 2012
The multicomponent reaction (MCR) of aromatic aldehydes 1 and malononitrile (2) with active methylenes 5a–h in the presence of L-proline produced pyrans and thiopyrans 6a–h stereospecifically and in good yields.
Noura Saad Al-Hokbany, Noha M. Hilmy Elnagdi   +1 more
doaj   +1 more source

SAM-dependent enzyme-catalysed pericyclic reactions in natural product biosynthesis. [PDF]

, 2017
Pericyclic reactions-which proceed in a concerted fashion through a cyclic transition state-are among the most powerful synthetic transformations used to make multiple regioselective and stereoselective carbon-carbon bonds.
Chen, Mengbin, Hai, Yang, Houk, KN, Liu, Fang, Ohashi, Masao, Sato, Michio, Tang, Man-Cheng, Tang, Yi, Watanabe, Kenji, Yang, Zhongyue   +9 more
core   +1 more source

Convergent Total Synthesis of 16β‐Hydroxylpseudobufarenogin

Angewandte Chemie, EarlyView.
We present a novel convergent strategy that integrates Pd/Ag‐promoted Suzuki–Miyaura coupling with Ir‐catalyzed radical‐relay cyclization, enabling the first total synthesis of 16β‐hydroxylpseudobufarenogin. This approach is broadly applicable to the total synthesis of various oxygenated bufadienolides by simply modifying the fragment structures ...
Wataru Shigematsu, Yo Matsumoto, Koichi Hagiwara, Masayuki Inoue   +3 more
wiley   +2 more sources

Crystal structure of 4-(6-chloro-4-oxo-4H-chromen-3-yl)-2-methylamino-3-nitro-4H,5H-pyrano[3,2-c]chromen-5-one chloroform monosolvate

Acta Crystallographica Section E: Crystallographic Communications, 2015
In the title compound, C23H14Cl4N2O7, the pyran ring has an envelope conformation with the methine C atom as the flap. The chromene rings are almost planar (r.m.s.
Rajamani Raja, Subramani Kandhasamy, Paramasivam T. Perumal, A. SubbiahPandi   +3 more
doaj   +1 more source

Strategies Toward Accessing Enantioenriched (Hetero)Benzo‐Fused 5‐ and 6‐ Membered Rings via Intermolecular Carbometalation

Angewandte Chemie, EarlyView.
The use of transition‐metal catalysts and design of chiral ligands have allowed chemists to access highly functionalized benzofused 5‐ and 6‐ membered rings in high yield and enantioselectivity. A common strategy used relies on an intermolecular carbometalation across alkynes and olefins, usually followed by a subsequent intramolecular carbometalation.
Clara Jans, Armaan Grewal, Xavier Abel‐Snape, Mark Lautens   +3 more
wiley   +2 more sources

Crystal structure of ethyl (2S)-9-methoxy-2-methyl-4-oxo-3,4,5,6-tetrahydro-2H- 2,6-methanobenzo[g][1,3,5]oxadiazocine-11-carboxylate

Acta Crystallographica Section E: Crystallographic Communications, 2015
In the title compound, C15H18N2O5, the methoxyphenyl ring makes a dihedral angle of 84.70 (12)° with the mean plane of the tetrahydropyrimidin-2(1H)-one ring.
A. Dhandapani, S. Manivarman, S. Subashchandrabose, B. Gunasekaran   +3 more
doaj   +1 more source

Alcohol‐Directed Carboamination of Conjugated Enynes

Angewandte Chemie, EarlyView.
The first general three‐component intermolecular Pd‐catalyzed carboamination of conjugated enynes enables the coupling of anilines and aryl triflates to produce functionalized allenic amines, utilizing a native alcohol directing group to control regioselectivity.
Helena Solé‐Àvila, Duncan K. Brownsey, Hugo Senelle, Jerome Waser   +3 more
wiley   +2 more sources

Diastereoselective synthesis of 3,4-dihydro-2H-pyran-4-carboxamides through an unusual regiospecific quasi-hydrolysis of a cyano group

Beilstein Journal of Organic Chemistry, 2016
An efficient diastereoselective approach for the synthesis of functionalized 3,4-dihydro-2H-pyran-4-carboxamides with variable frame was developed based on the reaction of available 4-oxoalkane-1,1,2,2-tetracarbonitriles (adducts of TCNE and ketones ...
Mikhail Yu. Ievlev, Oleg V. Ershov, Mikhail Yu. Belikov, Angelina G. Milovidova, Viktor A. Tafeenko, Oleg E. Nasakin   +5 more
doaj   +1 more source

The crystal structures of two new coumarin derivatives: 2-(4-{2-[(2-oxo-2H-chromen-4-yl)oxy]acetyl}piperazin-1-yl)acetamide and N-(2,4-dimethoxybenzyl)-2-[(2-oxo-2H-chromen-4-yl)oxy]acetamide

Acta Crystallographica Section E: Crystallographic Communications, 2019
The title compounds, 2-(4-{2-[(2-oxo-2H-chromen-4-yl)oxy]acetyl}piperazin-1-yl)acetamide, C17H19N3O5, (I), and N-(2,4-dimethoxybenzyl)-2-[(2-oxo-2H-chromen-4-yl)oxy]acetamide, C20H19NO6, (II), are new coumarin derivatives.
S. Syed Abuthahir, M. NizamMohideen, V. Viswanathan, M. Govindhan, K. Subramanian   +4 more
doaj   +1 more source