4222-20-2Relevant academic research and scientific papers
One-pot synthesis of photochromic naphthopyrans in the solid state
Tanaka, Koichi,Aoki, Hiroko,Hosomi, Hiroyuki,Ohba, Shigeru
, p. 2133 - 2134 (2000)
matrix presented p-TsOH-catalyzed condensation reactions of 1,1-diaryl-2-propyn-1-ol (1) and 2-naphthol (2) in the solid state gave 3,3-diaryl-3H-naphtho[2,1-b]pyran (6) via Claisen rearrangement. Similar reactions of 1 with 2,6-(7) and 2,7-dihydroxynaphthalenes (8) afforded naphthodipyrane derivatives 9 and 10, respectively. Bis-naphthopyran derivatives 12 were also obtained by the reaction of 1,1,6,6-tetraaryl-2,5-hexadiyn-1,6-diol (11) and 2-naphthol (2) in the solid state.
Photochromism of diarylnaphthopyrans
Van Gemert,Bergomi,Knowles
, p. 67 - 73 (1994)
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.
Photophysics and kinetics of naphthopyran derivatives, part 3: A general procedure to uniquely identify the kinetic and spectroscopic parameters of ABC(2k,2φ) systems and application to naphthopyran reactions
Maafi,Brown
, p. 421 - 430 (2006)
A new procedure has been developed with the aim of determining the kinetic and spectroscopic parameters of any photochemical systems of the generic ABC(2k,1φ) and ABC(2k,2φ) types. General expressions of the colorability and the equilibrium concentration ratio of two (of the three involved) species at a photostationary state or a state of thermal equilibrium have been derived. The procedure has been successfully applied to achieve unique identifiability for the seven sequences of the ABC(2k,1φ and 2φ) type that may represent naphthopyran dynamics. It is demonstrated that the reactivity of this particular compound is certainly described by a higher kinetic level than those (three or four reaction steps) considered in the present study.
Pd-Catalyzed Formal [3 + 3] Heteroannulation of Allylic gem-Diacetates: Synthesis of Chromene-Based Natural Products and Exploration of Photochromic Properties
Kumar, Prashant,Kumar, Pravesh,Ramasastry, S. S. V.,Venkataramani, Sugumar
, p. 963 - 970 (2022/01/19)
Palladium-catalyzed allylic alkylation reactions of allylic gem-diacetates are rarely explored. This work unveils an unusual chemical reactivity pattern of allylic gem-diacetates and establishes them as new prototypes to synthesize complex benzo[f]chromene systems. Under the reaction conditions, the diacetates behave as 1,3-dicationic equivalents and undergo a [3 + 3] heteroannulation with 2-naphthols (and meta-substituted phenols) to produce novel polycyclic chromenes possessing spiro-, tri-, and tetrasubstituted carbon centers. The versatility of the method is demonstrated in the synthesis of several chromene-based bioactive natural products. Further, interesting photochromic properties of the new classes of benzo[f]chromenes are also discovered.
Spectral manifestation of protonation of photochromic naphthopyrans
Barachevsky, Valery А.,Gorelik, Alexander М.,Kobeleva, Оlga I.,Valova, Тatyana М.,Venidiktova, Оlga V.
, (2020/09/22)
The formation of proton complexes of the photoinduced colored open form of naphthopyrans in solutions was first discovered and investigated by spectral-kinetic method. The complexes exhibit a new absorption band in the visible region, which is bathochromically shifted relative to the absorption band of the photoinduced colored open form. With an increase in the concentration of perchloric or hydrochloric acid, this long-wavelength absorption band appears immediately after the addition of acids to solutions of photochromic compounds. The protonation efficiency depends on the strength of the acids.
Facile access to 2,2-diaryl 2: H -chromenes through a palladium-catalyzed cascade reaction of ortho -vinyl bromobenzenes with N -tosylhydrazones
Huang, Xueliang,Yu, Yinghua,Zhang, Heng
supporting information, p. 5115 - 5119 (2020/07/23)
A palladium-catalyzed cascade reaction of ortho-vinyl bromobenzenes with N-tosylhydrazones has been developed, which provides a facile approach to 2,2-disubstituted 2H-chromenes. The migration of palladium from the aryl to vinyl position is crucial, as the in situ produced vinyl palladium intermediate could further react with diazo compounds to generate the reactive species for the sequential annulation. This journal is
Access to Electron-Deficient 2,2-Disubstituted Chromanes: A Highly Regioselective One-Pot Synthesis via an Inverse-Electron-Demand [4 + 2] Cycloaddition of ortho-Quinone Methides
Tanaka, Kenta,Kishimoto, Mami,Asada, Yosuke,Tanaka, Yuta,Hoshino, Yujiro,Honda, Kiyoshi
, p. 13858 - 13870 (2019/11/03)
We report the one-pot synthesis of 2,2-disubstituted chromanes with electron-withdrawing substituents. This reaction provides a simple yet efficient route to a wide range of electron-deficient chromanes in high yield and excellent regioselectivity. The reaction of salicylaldehyde with 1,1-disubstituted ethylenes smoothly furnishes these electron-deficient chromanes, which can be further transformed into functionalized chromanes or chromene. For example, BW683C was effectively synthesized from 5-chlorosalicylaldehyde with 4-chlorostyrene in two steps in excellent yield. The present reaction thus provides versatile access to functionalized electron-deficient chromanes and chromenes and therefore constitutes a promising tool for the synthesis of biologically and photochemically active molecules.
Temperature-controlled divergent synthesis of 4-alkoxy- or 4-alkenyl-chromanes via inverse electron-demand cycloaddition with in situ generated ortho-quinone methides
Tanaka, Kenta,Kishimoto, Mami,Hoshino, Yujiro,Honda, Kiyoshi
supporting information, p. 1841 - 1845 (2018/04/11)
The temperature-controlled divergent synthesis of 4-alkoxy- or 4-alkenyl-chromanes via inverse electron-demand cycloaddition with in situ generated ortho-quinone methides under identical reaction conditions except for thermal condition has been developed. At room temperature, the reaction generated 4-methoxychromanes, whereas the reaction performed at room temperature to 100 °C gave 4-alkenylchromanes. Trifluoromethanesulfonic acid was efficiently suitable in the reaction to give the 4-substituted chromanes. This divergent synthetic strategy exhibits a new method giving carbon–carbon or carbon–oxygen bond by controlling the reaction temperature.
A Simple and Versatile Strategy for Rapid Color Fading and Intense Coloration of Photochromic Naphthopyran Families
Inagaki, Yuki,Kobayashi, Yoichi,Mutoh, Katsuya,Abe, Jiro
, p. 13429 - 13441 (2017/10/05)
Benzo-annulated chromenes, i.e., naphthopyrans, are well-known photochromic molecules that undergo photochemical ring-opening reactions to form two colored open-ring isomers, the transoid-cis and transoid-trans forms, upon light irradiation. Though the transoid-cis form returns thermally to the uncolored closed form, the fading rate of the transoid-trans form is extremely slow because of its higher thermal stability. This slow fading behavior of the transoid-trans form is responsible for the persistence of residual color for several minutes to hours, and prevents the application of such molecules to fast photoswitching materials. We have found a new simple and versatile strategy to substantially reduce the amount of the undesirable long-lived colored transoid-trans form by introducing an alkoxy group at the 1-position of azino-fused chromenes, i.e., 8H-pyranoquinazolines. The alkoxy group effectively reduces the formation of the transoid-trans form due to C-H···O intramolecular hydrogen bonding in the transoid-cis form. Moreover, the introduction of a condensed aromatic ring at the 3-position was found to be effective to increase the photosensitivity of the ring-opening reaction. This strategy can also be applied for naphthopyran derivatives and is useful for the development of fast photoresponsive photochromic lenses and fast photoswitching applications such as dynamic holographic materials and molecular actuators.
Experimental and theoretical investigations of cyanide detection using a photochromic naphthopyran
Sahoo, Priyaranjan,Prakash, Kunal,Kumar, Satish
, p. 183 - 192 (2017/01/10)
Photochromic naphthopyran derivatives were synthesised for anion recognition applications. The crystal structure, experimental and theoretical investigation of photochromic and anion sensing properties of a simple naphthopyran derivative were investigated. The naphthopyran derivative displayed good fatigue resistance and selective sensing response towards cyanide ions. The mechanism of complex formation was suggested based on NMR studies. Theoretical calculations were performed to understand the experimental results. An excellent correlation between the theoretical and experimental data was observed.
