Results 141 to 150 of about 51,192 (201)

ChemInform Abstract: RING TRANSFORMATIONS OF 4H‐PYRANS. PYRIDINES FROM 2‐AMINO‐4H‐PYRANS

Chemischer Informationsdienst, 1981
AbstractAus den 2‐Amino‐4H‐pyranen (I) erhält man mit Nitrosylschwefelsäure und Essigsäure die entsprechend substituierten Pyridone (II).
C. SEOANE, J. L. SOTO, P. ZAMORANO, M. QUINTEIRO   +3 more
openaire   +1 more source

Structure of 2,4,4,6-tetraphenyl-4H-pyran

Acta Crystallographica Section C Crystal Structure Communications, 1990
C 29 H 22 O cristallise dans P2 1 /c avec a=12,128, b=12,372, c=14,599A, β=105,57°, Z=4 ; affinement jusqu'a R=0,039. Le cycle 4H-pyrane est rigoureusement plan avec les cycles phenyl substitues sur les atomes C(sp 2 ) de C2 et C6. Le cycle presente une conformation bateau legerement tordue avec les angles bateau de 4,3 et 7,7° sur C(sp 2 ) et O ...
J. Vojtěchovský, J. Hašek
openaire   +1 more source

Cyclopropanation of areno-condensed 4H-pyrans with dihalocarbenes

Chemistry of Heterocyclic Compounds, 2020
The addition of dihalocarbenes to 1H-benzo[f]chromenes and 4H-chromenes gave a number of dihalotetrahydro(benzo)cyclopropa[b]-chromenes containing donor and acceptor substituents at different positions. It was found that in the case of 1,3-disubstituted 1H-benzo[f]-chromenes, the reaction proceeds diastereoselectively with the formation of trans ...
Irina А. Semenova, Vitaly А. Osyanin, Maxim R. Demidov, Dmitry V. Osipov, Yuri N. Klimochkin   +4 more
openaire   +1 more source

Michael reaction of methylenemalonaldehydes: Synthetic approach to 4H-pyran-5-carboxaldehydes and 2-amino-4H-pyran-5-carboxaldehydes

Collection of Czechoslovak Chemical Communications, 1987
Base-catalyzed addition of β-dicarbonyl compounds to methylenemalonaldehydes led to tetracarbonyl compounds II which were dehydrated in an acid medium to 4H-pyran-5-carboxaldehydes III. In the addition of compounds containing a nitrile group, the primarily formed addition products were immediately cyclized to give directly 2-amino-4H-pyran-5 ...
Dalimil Dvořák, David Šaman, Jana Hodačová, Vladimír Král, Zdeněk Arnold   +4 more
openaire   +1 more source

2,4,6-Triphenyl-4H-pyran-3,5-dicarboxaldehyde

Acta Crystallographica Section C Crystal Structure Communications, 1996
The structure of 2,4,6-triphenyl-4H-pyran-3,5-dicarboxaldehyde, C25H18O3, a potential fungicide, has a pyran ring in a flattened boat conformation, but with C4 and O3 displaced from the basal plane by 0.299 and 0.159 A, respectively. The aldehyde groups display an ap orientation with respect to the double bonds of that plane.
S. Selladurai, R. Murugesan, K. Subramanian, Y. S. Chen, S. N. Rao, E. M. Holt   +5 more
openaire   +1 more source

Synthesis and properties of 3-formyl-4H-pyrans

Chemistry of Heterocyclic Compounds, 1990
The Vilsmeier formylation of 4H-pyrans afforded 3-formyl-4H-pyrans. These were converted to 3-formylpyrylium salts, from which pyridine or pyridine salts with an aldehyde group at C(3) were obtained. The reaction between 3-formyl-4-allyl-4H-pyran and methyltrifluoromethanesulfonate proceeded via a Koop rearrangement.
K. F. Suzdalev, A. V. Koblik
openaire   +1 more source

4-Phenyl-4H-pyrans as IKCa channel blockers

Bioorganic & Medicinal Chemistry Letters, 2003
AbstractFor Abstract see ChemInform Abstract in Full Text.
Klaus, Urbahns, Ervin, Horváth, Johannes Peter, Stasch, Frank, Mauler   +3 more
openaire   +2 more sources

4H-Pyran-4-one derivatives:

2009
A series of 3-hydroxy-6-methyl-2-((4-substitutedpiperazin-1-yl)methyl)-4H-pyran-4-on e structured compounds were synthesized by reacting 5-hydroxy-2-methyl-4H-pyran-4-one with suitable piperazine derivatives using Mannich reaction conditions. Antibacterial activities of the compounds for E. coli, S. paratyphi, S. flexneri, E.
Us, Demet, Gurdal, Ece, Berk, Barkin, Oktem, Sinem, Kocagoz, Tanil, Caglayan, Berrak, Kurnaz, Isil Aksan, Erol, Dilek Demir   +7 more
openaire   +1 more source

Efficient and Convenient Method for the Synthesis of Poly Functionalised 4H‐Pyrans

Synthetic Communications, 2004
AbstractFor Abstract see ChemInform Abstract in Full Text.
B. P. V. Lingaiah, G. Venkat Reddy, T. Yakaiah, B. Narsaiah, S. N. Reddy, R. Yadla, P. Shanthan Rao   +6 more
openaire   +1 more source

ChemInform Abstract: METALATION OF DIHYDRO‐4H‐PYRANS DERIVATIVES. PREPARATION OF 2‐ALKYL‐3‐CHLORO‐5,6‐DIHYDRO‐4H‐PYRANS

Chemischer Informationsdienst, 1977
AbstractDas Dihydropyran (Ia) oder sein 3‐Chlorderivat (Ib) werden lithiiert und die entstandenen Verbindungen (II) mit Alkyljodiden zu den Titelverbindungen (III) umgesetzt.
O. RIOBE, A. LEBOUC, J. DELAUNAY
openaire   +1 more source