Structure and thermochromism of spiropyrans. Triplet mechanism of the thermal cleavage/closure of the pyran ring

1998 ◽  
Vol 39 (5) ◽  
pp. 642-650 ◽  
Author(s):  
K. K. Kalninsh
Keyword(s):  
Pyran Ring ◽  
Triplet Mechanism ◽  
Thermal Cleavage

Structure-activity relationships in the acronycine and benzo[b]acronycine series: Role of the pyran ring

Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
Q Do ◽  
H Doan Thi Mai ◽  
T Gaslonde ◽  
B Pfeiffer ◽  
S Léonce ◽  
...  
Keyword(s):  
Pyran Ring ◽  
Structure Activity Relationships ◽  
Structure Activity

Recent advances in Minisci-type reactions and applications in organic synthesis

2020 ◽  
Vol 24 ◽  
Author(s):  
Wengui Wang ◽  
Shoufeng Wang
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Organic Synthesis ◽  
Radical Reactivity ◽  
Atom Loss ◽  
Radical Generation ◽  
In Situ Generation ◽  
Thermal Cleavage ◽  
Synthetic Chemist

Abstract:: Minisci-type reactions have become widely known as reactions that involve the addition of carbon-centered radicals to basic heteroarenes followed by formal hydrogen atom loss. While the originally developed protocols for radical generation remain in active use today, in recent years by a new array of radical generation strategies allow use of a wider variety of radical precursors that often operate under milder and more benign conditions. New transformations based on free radical reactivity are now available to a synthetic chemist looking to utilize a Minisci-type reaction. Radical-generation methods based on photoredox catalysis and electrochemistry, which utilize thermal cleavage or the in situ generation of reactive radical precursors, have become popular approaches. Our review will cover the remarkably literature that has appeared on this topic in recent 5 years, from 2015-01 to 2020-01, in an attempt to provide guidance to the synthetic chemist, on both the challenges that have been overcome and applications in organic synthesis.

2,4-Diphenyl-2-(trimethylsilyloxy)-3-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran-5-one

2006 ◽  
Vol 62 (4) ◽  
pp. o1397-o1398
Author(s):  
Yun Liu ◽  
Yong-Miao Shen ◽  
Zhe Li ◽  
Jian-Hua Xu
Keyword(s):  
Title Compound ◽  
Chair Conformation ◽  
Ring System ◽  
Pyran Ring ◽  
Compound C ◽  
Coumarin Ring

In the title compound, C27H26O4Si, the coumarin ring system is essentially planar and the pyran ring adopts a half-chair conformation.

Methoxydifluoromethyl Isocyanate by Thermal Cleavage of a Diazetidine

1960 ◽  
Vol 82 (4) ◽  
pp. 852-853 ◽  
Author(s):  
J. C. Kauer ◽  
A. K. Schneider
Keyword(s):  
Thermal Cleavage

Recent Advances in the Synthesis of Polyfluorenes as Organic Semiconductors

2004 ◽  
Vol 814 ◽  
Author(s):  
David J. Brennan ◽  
Yu Chen ◽  
Shaoguang Feng ◽  
James P. Godschalx ◽  
Gary E. Spilman ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Semiconductor Film ◽  
Melting Temperatures ◽  
Alternating Copolymers ◽  
Polymeric Semiconductor ◽  
Recent Advances ◽  
Thermal Cleavage ◽  
Switching Characteristics ◽  
Initial Results ◽  
Bottom Gate

AbstractNew poly(fluorene-thiophene) alternating copolymers are described in which either the dioctylfluorene or bithiophene units in poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) are replaced by other fluorene or thiophene-based groups, respectively. Improvements in solubility are realized when the bithiophene unit of F8T2 is replaced by dihexylterthiophene or dihexylpentathiophene units. Melting temperatures are also lowered by 50 – 100°C in these polymers when compared to F8T2. Replacement of the bithiophene unit of F8T2 with a dihexylpentathiophene unit also results in a significant improvement in hysteresis (< 2 V vs. 3.5 – 5 V for F8T2). Initial results are also reported on the thermal cleavage of the C8 side groups of F8T2, which yields an insoluble polymeric semiconductor film that continues to exhibit transistor switching characteristics as part of a bottom gate device.

scholarly journals 4-(4-Methoxyphenyl)-5,7-dimethylchroman-2-one

IUCrData ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Jaqueline Evangelista Queiroz ◽  
Giuliana Muniz Vila Verde ◽  
Mariette Miguens Pereira ◽  
Manuela Ramos Silva ◽  
Gilberto L. B. Aquino
Keyword(s):  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Boat Conformation ◽  
Pyran Ring ◽  
Axis Direction ◽  
Π Interactions ◽  
Microwave Assisted ◽  
Compound C ◽  
The Mean

In the title compound, C18H18O3, a dihydrocoumarin synthesizedviaa microwave-assisted hydroarylation reaction, the 4-methoxyphenyl ring is inclined to the mean plane of the coumarin moiety by 78.21 (9)°. The pyran ring has a screw-boat conformation and its mean plane is inclined to the fused benzene ring by 13.88 (11)°. In the crystal, molecules are linkedviaC—H...O hydrogen bonds, forming ribbons along theb-axis direction. The ribbons are linkedviaC—H...π interactions, forming slabs parallel to theabplane.

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