Results 51 to 60 of about 20,891 (238)

PRENYLATED XANTHONES FROM Rheedia acuminata (reprinted from Acta Amazônica, 23(2/3):181-185) [PDF]

Acta Amazonica, 1994
Pyranojacareubin; 1,5-dihydroxy-6',6'-dimethyl-2H-pyran(2,,3':6,7) -6",6"-dime-thyl-2H,4H-pyran(2",3":2,3)xanthone and a new xanthone l,6-dihydroxy-5-methoxy-6',6'-dime-thyl-2H-pyran(2',3':3,2)-7-(3,3-dimethylprop-2-enyl)xanthone were isolated from the ...
Maria das G. B. ZOGHBI, Patrícia D. de D. B. LIMA, Maria do P. Socorro C. da CUNHA, Angelo da C. PINTO   +3 more
doaj   +1 more source

Retro‐Hetero‐Michael Addition Strategies in Organic Synthesis

European Journal of Organic Chemistry, EarlyView.
In this review, synthetic approaches to carbo‐ and heterocyclic compounds, including natural products, published in the last 15 years (2011–2025) which have either relied upon or included a retro‐hetero‐Michael addition step at any stage are discussed.
Dina Scarpi, Ernesto G. Occhiato
wiley   +1 more source

Novel Tunable CuX₂-Mediated Cyclization Reaction of Cyclopropylideneacetic Acids and Esters for the Facile Synthesis of 4-Halomethyl-2(5H)-furanones and 4-Halo-5,6-dihydro-2H-pyran-2-ones [PDF]

, 2016
A mixture of cyclopropylideneacetic acids (or esters) and CuBr2 (or CuI/I2) in aqueous acetonitrile afforded 4-substituted 2(5H)-furanones or 3,4-substituted 5,6-dihydro-2H-pyran-2-ones in moderate to good yields.
Xian Huang (820390), Hongwei Zhou (93199)   +1 more
core   +1 more source

Asymmetric Synthesis of Tertiary α‐Aryl Stereocentres in Tetrahydro‐4H‐pyran‐4‐ones Using Pd‐Catalyzed Decarboxylative Asymmetric Protonation

European Journal of Organic Chemistry, EarlyView.
The Pd‐catalyzed decarboxylative asymmetric protonation (DAP) has been developed for sterically hindered tetrahydro‐4H‐pyran‐4‐one derived α‐aryl‐β‐keto esters. A substrate scope of nine examples of DAP showed that substrates containing a di‐ortho methoxy substitution pattern on the aryl ring gave rise to the highest enantioselectivities of up to 85 ...
Fionn McNeill, Joffrey Scriven, Fritz Bahns, Anugam V. Krishna, Julia Bruno‐Colmenarez, Patrick J. Guiry   +5 more
wiley   +1 more source

Novel reactions of arsonium ylides and substituted 2H-pyran-5-carboxylates, a new preparation for functionalised vinylcyclopropanecarboxylates and dihydrofurans [PDF]

, 1996
Substituted alkyl 2-pyran-5-carboxylates have been condensed with arsonium ylides to form substituted vinylcyclopropanecarboxylates and in a number of cases also ...
Moorhoff, CM (15481859)
core  

Uses of 3-(2-Bromoacetyl)-2H-chromen-2-one in the Synthesis of Heterocyclic Compounds Incorporating Coumarin: Synthesis, Characterization and Cytotoxicity

Molecules, 2015
In this work, 3-bromoacetylcoumarin was used as the key starting material for the synthesis of pyran, pyridine, thiophene, thiazole and pyrazole derivatives through its reaction with different reagents.
Rafat M. Mohareb, Nadia Y. MegallyAbdo
doaj   +1 more source

Organic photonic synaptic transistors for bionic vision: From spectral engineering to flexible intelligent perception

FlexMat, EarlyView.
Different wavelength photonic synapses are used for biomimetic visual applications. Abstract Bionic intelligent visual perception systems have significant application prospects in fields such as autonomous driving and robotics, medical imaging and auxiliary diagnosis, security and monitoring.
Longlong Jiang, Shan Wu, Silu Feng, Heyi Huang, Wangyu Wu, Hong Han, Yao Ni   +6 more
wiley   +1 more source

Synthesis, Anti-Inflammatory, and Molecular Docking Studies of New Heterocyclic Derivatives Comprising Pyrazole, Pyridine, and/or Pyran Moieties

Pharmaceuticals
Introduction: Inhibiting cyclooxygenase-2 (COX-2) is a potential strategy in inflammation therapy. Thus, developing COX-2 inhibitors plays a pivotal role in efficient inflammation treatment.
Mohamed A. M. Abdel Reheim, Hend S. Abdel Rady, Omnia A. Mohamed, Abdelfattah Hassan, Ibrahim S. Abdel Hafiz, Hala M. Reffat, Fahmy Gad Elsaid, Mamdouh Eldesoqui, Dalal Sulaiman Alshaya, Abdelnaser A. Badawy, Eman Fayad, Aboubakr H. Abdelmonsef   +11 more
doaj   +1 more source

Allyl 6-amino-4-(4-chlorophenyl)-5-cyano-2-methyl-4H-pyran-3-carboxylate

IUCrData, 2019
In the title compound, C17H15ClN2O3, the 4H-pyran ring exhibits a shallow-boat conformation and the chlorobenzene ring occupies an axial position. The O-allyl side chain is disordered over two orientations in a 0.585 (14):0.415 (14) ratio. In the crystal,
G. Anantha Krishnan, T. Mohandas, C. Udhaya Kumar, M. Velayutham Pillai, P. Sakthivel   +4 more
doaj   +1 more source

Impact of climate‐induced compositional shifts of ethanol and acidity on aroma release and perception in red wine: a case study on γ‐nonalactone and massoia lactone

Journal of the Science of Food and Agriculture, EarlyView.
Abstract BACKGROUND Climate change‐driven warming is increasing wine ethanol, promoting an atypical convergence between pH and titratable acidity (TA), and favouring the accumulation of specific wine volatiles: γ‐nonalactone (γ‐C9) and massoia lactone (MLac).
Roberto Salvatore Di Fede, Elisabetta Pittari, Luigi Moio, Paola Piombino   +3 more
wiley   +1 more source