- Dynamic solvent effects on the thermal cyclization of a hexadienone formed from a diphenylnaphthopyran: An example of a system with distinctly separate medium and chemical contributions to the overall reaction coordinate
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Pressure effects on the rate of thermal fading of a colored hexadienone formed from 3,3-diphenyl-3 H-naphtho[2,1-b]pyran were measured at various temperatures in three highly viscous solvents, e.g., 2,4-dicyclohexyl-2-methylpentane, glycerol triacetate, and 2-methylpentane-2,4-diol, as well as in their chemically similar nonviscous counterparts, e.g., methyl acetate, ethanol, and methylcyclohexane. It was demonstrated that the medium and the chemical coordinate had to be treated separately. The experimental data and quantum-mechanical computations agreed with the formation of a cyclic activated complex. The dynamic solvent effects in the systems had to be described by a two-dimensional model that includes separately defined chemical and medium coordinates.
- Goto, Yoshitaka,Takahashi, Toru,Ohga, Yasushi,Asano, Tsutomu,Hildebrand, Michael,Weinberg, Noham
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- A method for synthesizing naphthopyridene photochromic dyes using a microchannel reactor
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The present invention relates to a method of synthesizing photochromic dyes using a microchannel reactor. In the alkynol coupling reaction, after adjusting the temperature of the mobile phase system containing the reaction raw materials to the reaction te
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Paragraph 0031-0033
(2022/01/20)
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- Facile synthesis of 2h-benzo[h]chromenes via an arylamine-catalyzed mannich cyclization cascade reaction
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A simple arylamine-catalyzed Mannich-cyclization cascade reaction was developed for facile synthesis of substituted 2H-benzo[h]chromenes. The notable feature of the process included the efficient generation of ortho-quinone methides (o-QMs) catalyzed by a
- Gao, Feng,Ji, Peng,Meng, Xiang,Wang, Wei,Zeng, Fanxun,Zhang, Yueteng
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- Catalysis by β-Cyclodextrin Hydrate - Synthesis of 2,2-Disubstituted 2H-Chromenes in Aqueous Medium
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A cost-effective, operationally simple and eco-compatible protocol for the one-pot synthesis of photochromic pyrans by the reaction of propargyl alcohols as well as propargyl ethers with differently substituted phenols under ambient atmosphere in aqueous
- Ghatak, Avishek,Khan, Sagar,Bhar, Sanjay
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supporting information
p. 435 - 443
(2016/02/18)
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- Convenient synthesis of naphthopyrans using montmorillonite K-10 as heterogeneous catalyst
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A simple and mild procedure for the synthesis of different naphthopyrans providing high yields in a short reaction time was reported. The reaction of propargylic alcohols with α- or β-naphthol and dihydroxy naphthalenes in the presence of montmorillonite K-10 was studied. This reaction afforded high yields of the corresponding naphthopyrans. In addition, a number of new phenylene and biphenylen-linked bisnaphthopyrans were synthesized providing excellent yields via the one-pot reaction of bis-propargyl alcohols with β-naphthol.
- Hosseinzadeh, Rahman,Mohadjerani, Maryam,Javad Ardestanian, Mohammad,Naimi-Jamal, Mohammad Reza,Lasemi, Zahra
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p. 1081 - 1089
(2014/11/08)
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- A novel method for the synthesis of substituted benzochromenes by ethylenediamine diacetate-catalyzed cyclizations of naphthalenols to α,β-unsaturated aldehydes. Concise synthesis of the natural products lapachenole, dihydrolapachenole, and mollugin
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A new synthetic route for biologically interesting benzochromenes was developed starting from naphthalenols and α,β-unsaturated aldehydes in the presence of ethylenediamine diacetate. This methodology was applied for the total synthesis of the biologicall
- Yong, Rok Lee,Yun, Mi Kim
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p. 2401 - 2413
(2008/03/29)
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- The effect of a sulphur bridge on the photochromic properties of indeno-fused naphthopyrans
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The synthesis of four new 2,2-diphenyl-2H-naphtho[1,2-b]pyrans with a fused indeno group at the f face and a sulphur junction between the 2,2-phenyl groups is described. The photochromic properties in solution of these novel compounds were investigated under continuous irradiation. Compared to known indeno-fused naphthopyrans, these new compounds showed a significant bathochromic shift in the spectra of the open forms, faster ring closure kinetics and an expected decrease in the colourabilities.
- Coelho, Paulo J.,Salvador, Maria A.,Oliveira, M. Manuel,Carvalho, Luis M.
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p. 2593 - 2599
(2007/10/03)
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- Synthesis and Photochromic Behaviour of Naphthopyrans, Pyranoquinolines, Pyranoquinazolines and Pyranoquinoxalines
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New chromenes annulated with different six-membered azaheterocycles were prepared, i.e., the 3H-pyrano[3,2-f]quinolines 9/10 and 14, the 8H-pyrano[2,3-h]isoquinoline 11, the 8H-pyrano[3,2-f]quinazoline 12, the 8H-pyrano[3,2-f]quinoxaline 13, and the 2H-pyrano[2,3-f]isoquinoline 15. The synthesis was achieved using conveniently substituted α,β-unsaturated aldehydes and organotitanium intermediates arising from azaheterocyclic phenols. Their photochromic behaviour (photocolouration yield, UV/VIS spectrum of photomerocyanines, rate constant of thermal bleaching) were studied besides those of corresponding naphthopyrans. The heterocycle effect and the role of substituents in the pyran moiety were investigated quantitatively through the study of the photochromic properties and the solvent effects. Diaryl-substituted azino-fused chromenes, especially isoquinoline derivatives, exhibit increased colourabilities and bathochromically shifted spectra for photomerocyanines which open up new prospects for photochromic applications.
- Pozzo, Jean-Luc,Samat, Andre,Guglielmetti, Robert,Dubest, Roger,Aubard, Jean
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p. 725 - 738
(2007/10/03)
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- Photochromism of diarylnaphthopyrans
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A series of 3,3-diaryl-3H-naphtho[2,1-b]pyrans were prepared and their photochromic properties measured in plastic matrix. The influence of a variety of substituents on color, intensity, and fade were studied.
- Van Gemert,Bergomi,Knowles
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