2382-08-3Relevant articles and documents
Photoinduced cycloadditions of N-methyl-1,8-naphthalenedicarboximides with alkynes
Liu, Qing-Jian,Shen, Yong-Miao,An, Hui-Ying,Grampp, Günter,Landgraf, Stephan,Xu, Jian-Hua
, p. 1131 - 1138 (2006)
Photoinduced cycloadditions of N-methyl-1,8-naphthalenedicarboximide 1 with phenylacetylenes 2a-2c, cyclopropylacetylene 2d, diphenylacetylenes 2e-2f and 1-phenylpropyne 2g were investigated. In the case of phenylacetylenes 2a, 2b and cyclopropylacetylene 2c, photoreaction with 1 takes place at the naphthalene C(1)C(2) bond to give the cyclobutene products. For 4-methoxyphenylacetylene 1c, the cyclobutene 3c is obtained together with the 4-benzo[a]thebenidinone 4c derived from a primary oxetene product formed by [2+2] addition of the imide carbonyl with the alkyne. Similar to 2c, photocycloaddition of 1 with 2e and 2f gave the cyclobutenes 7e, 7f, 8f and the 4-benzo[a]thebenidinone products 9e, 9f and 10f, respectively, derived from the corresponding oxetenes. Photoreaction of 1 with 2g gave cyclobutene 7g and benzo[a]thebenidinone 9g. Sensitization experiment and internal heavy atom effect study showed that these reactions proceed from the ππ* singlet excited state of 1. Estimation of the free energy change for electron transfer between 11* and the alkynes and the calculation of charge and spin density distribution in the anion radical of 1 and the cation radical of the alkynes suggested that the cyclobutene products are formed by direct [2+2] cycloaddition of 11* with the alkyne, while the formation of the oxetene products is the result of electron transfer interaction between 11* and the alkyne. The regioselectivity in the oxetene formation is accounted for by charge and spin density distribution in the anion radical of 1 and the cation radical of the alkyne.
Mechanistic studies of the azomethine ylide-forming photoreactions of N- (silylmethyl)phthalimides and N-phthaloylglycine
Takahashi, Yasutake,Miyashi, Tsutomu,Yoon, Ung Chan,Oh, Sun Wha,Mancheno, Maria,Su, Zhuoyi,Falvey, Daniel F.,Mariano, Patrick S.
, p. 3926 - 3932 (1999)
In earlier studies we have shown that irradiation of MeCN solutions of N-[(trimethylsilyl)methyl]phthalimide and N-phthaloylglycine in the presence of electron-deficient olefins (e.g., methyl acrylate) results in the production of cycloadducts. In addition, irradiation of these substances in aqueous MeCN leads to formation of N-methylphthalimide. Laser flash photolysis and fluorescence spectroscopy have now been employed to investigate the mechanistic details of these novel excited-state processes. The results of this effort show that azomethine ylides are the key reactive intermediates in these processes. In addition, the investigations provide information about the dynamics of several ylide decay pathways and the nature of the excited states responsible for the ylide-forming silyl-migration (singlet and triplet) and decarboxylation (triplet) reactions. Pulsed irradiations of MeCN solutions of N-[(trimethylsilyl)methyl]phthalimide (1) and N-phthaloylglycine (2) give rise to transients whose absorption and decay properties are consistent with their assignment as azomethine ylides. Kinetic analysis of the decay of the ylides in the presence of dipolarophiles, methyl acrylate and acrylonitrile, provides the rates of the dipolar cycloaddition reactions. Reactions of methyl acrylate with the ylides produced by pulsed irradiation of N-[(trimethylsilyl)methyl]phthalimide (1) and N- phthaloylglycine (2) occur with respective bimolecular rate constants of 8.9 x 106 and 2.7 x 107 M-1 s-1. Methanol promotes the decay of the N- [(trimethylsilyl)methyl]phthalimide-derived ylide by a process which is second order in MeOH and has a kinetic OD-isotope effect of 4.3. In contrast, quenching of this ylide by acetic acid is first order in AcOH. The results suggest that the mechanism for MeOH-promoted decay involves initial and reversible formation of a silylate complex via nucleophilic addition of MeOH to the ylide. This is then followed by rate-limiting proton transfer from MeOH to the carbanionic center in the silylate complex either in concert with or preceding desilylation. The mechanism for AcOH-induced ylide decay has these steps reversed; i.e., rate-limiting proton transfer precedes AcOH- induced desilylation. Also, MeOH catalyzes the decay of the ylide derived by irradiation of N-phthaloylglycine by a process which is first order in MeOH and has a kinetic OD-isotope effect of 1.5. Finally, the observations (1) of complete loss of fluorescence of the 1,8- and 2,3-naphthalimide chromophores upon changing the N-substituent from methyl to (trimethylsilyl)methyl and (2) that ylide formation from 1 can be xanthone triplet sensitized suggest that the ylide-forming, silyl-transfer reactions of the (silylmethyl)phthalimides can occur in both the singlet and triplet excited-state manifolds.
Dynamics of Isolated 1,8-Naphthalimide and N-Methyl-1,8-naphthalimide: An Experimental and Computational Study
Gerbich, Thiemo,Schmitt, Hans-Christian,Fischer, Ingo,Mitri?, Roland,Petersen, Jens
, p. 2089 - 2095 (2016)
In this work we investigate the excited-state structure and dynamics of the two molecules 1,8-naphthalimide (NI) and N-methyl-1,8-naphthalimide (Me-NI) in the gas phase by picosecond time- and frequency-resolved multiphoton ionization spectroscopy. The energies of several electronically excited singlet and triplet states and the S1 vibrational wavenumbers were calculated. Nonadiabatic dynamics simulations support the analysis of the radiationless deactivation processes. The origin of the S1 ← S0 (ππ?) transition was found at 30 082 cm-1 for NI and at 29 920 cm-1 for Me-NI. Furthermore, a couple of low-lying vibrational bands were resolved in the spectra of both molecules. In the time-resolved scans a biexponential decay was apparent for both Me-NI and NI. The fast time constant is in the range of 10-20 ps, whereas the second one is in the nanosecond range. In accordance with the dynamics simulations, intersystem crossing to the fourth triplet state S1 (ππ?) → T4 (nπ?) is the main deactivation process for Me-NI due to a large spin-orbit coupling between these states. Only for significant vibrational excitation internal conversion via a conical intersection becomes a relevant deactivation pathway. (Figure Presented).
Target Enzyme-Activated Two-Photon Fluorescent Probes: A Case Study of CYP3A4 Using a Two-Dimensional Design Strategy
Ning, Jing,Wang, Wei,Ge, Guangbo,Chu, Peng,Long, Feida,Yang, Yongliang,Peng, Yulin,Feng, Lei,Ma, Xiaochi,James, Tony D.
, p. 9959 - 9963 (2019)
The rapid development of fluorescent probes for monitoring target enzymes is still a great challenge owing to the lack of efficient ways to optimize a specific fluorophore. Herein, a practical two-dimensional strategy was designed for the development of an isoform-specific probe for CYP3A4, a key cytochrome P450 isoform responsible for the oxidation of most clinical drugs. In first dimension of the design strategy, a potential two-photon fluorescent substrate (NN) for CYP3A4 was effectively selected using ensemble-based virtual screening. In the second dimension, various substituent groups were introduced into NN to optimize the isoform-selectivity and reactivity. Finally, with ideal selectivity and sensitivity, NEN was successfully applied to the real-time detection of CYP3A4 in living cells and zebrafish. These findings suggested that our strategy is practical for developing an isoform-specific probe for a target enzyme.
Isoindolinone Synthesis: Selective Dioxane-Mediated Aerobic Oxidation of Isoindolines
Thapa, Pawan,Corral, Esai,Sardar, Sinjinee,Pierce, Brad S.,Foss, Frank W.
, p. 1025 - 1034 (2019/01/24)
N-Alkyl and N-aryl-isoindolinones were prepared by a dioxane-mediated oxidation of isoindoline precursors. The transformation exhibits unique chemoselectivity for isoindonlines. A chiral tertiary (3°)-benzylic position was not racemized during oxidation, and methyl indoprofen was prepared by late stage oxidation. Mechanistic studies suggest a selective H atom transfer, which avoids many known oxidation (by-)products of isoindolinones.
New strategy for the azido-ascorbic acid reaction: A convenient chemosensor and its imaging in garlic slice tissues
Zhang, Dan,Li, Na,Ma, Yiming,Wang, Ruixue,Wang, Jinyi,Wang, Junru
, p. 6707 - 6712 (2018/05/07)
Ascorbic acid (AA) is a vital nutritional factor in many fruits and plants, and abnormal levels of AA are closely associated with several diseases. Therefore, the development of convenient methods for monitoring AA levels in biological systems is of great importance. In this work, we designed and synthesized three chemosensors for the rapid turn-on detection of AA via a new strategy for the azido-ascorbic acid reaction. The chemosensors were based on a 1,8-naphthalimide moiety with the azide group at different sites (probes 1, 2, and 3). The experimental results demonstrated that probe 2 showed high selectivity toward AA, having an experimental limit of detection of 74 nM. Its reduction was easier than that of probe 3 with a 3-substituted azide group. Moreover, probe 2 was successfully used for imaging of AA in garlic slice tissue for the first time.
Self-assembled aromatic molecules as efficient organic structure directing agents to synthesize the silicoaluminophosphate SAPO-42 with isolated Si species
Martínez-Franco, Raquel,Cantín, ángel,Vidal-Moya, Alejandro,Moliner, Manuel,Corma, Avelino
, p. 2981 - 2989 (2015/05/13)
The use of self-assembled aromatic molecules through π-π interactions has allowed the preparation of the silicoaluminophosphate (SAPO) form of the LTA, SAPO-42, with controlled Si content as isolated Si sites in the framework, and high thermal stability. Different SAPO-42 zeotypes can be synthesized with different acidity, morphology, and crystal size, depending on the selected quinolinium derived aromatic molecule as OSDA and the amount of fluoride content in the synthesis gels.
Copper-catalyzed oxidation of arene-fused cyclic amines to cyclic imides
Yan, Xiaoyu,Fang, Kun,Liu, Hailan,Xi, Chanjuan
supporting information, p. 10650 - 10652 (2013/11/06)
A novel copper-catalyzed oxidation of arene-fused cyclic amines to the corresponding cyclic imides has been developed. The reaction can be used to synthesize 1,3-disubstituted TPD in high yields.
An orthomanganation route to 2-substituted derivatives of N-methyl-1,8-naphthalimide
Nicholson, Brian K.,Crosby, Paul M.,Maunsell, Kieran R.,Wyllie, Megan J.
, p. 49 - 54 (2012/11/13)
N-methyl naphthalimide can be readily cyclomanganated at the 2-position, directed by the adjacent amide O atom. Di-cyclomanganation also occurs readily to attach Mn(CO)4 groups at both 2, 7 positions. An X-ray structure determination of the mono-substituted example confirmed the five-membered metallocyclic ring. Cleavage of the Mn-C bond by HgCl2 or ICl generates 2-substituted HgCl or I derivatives respectively. Reaction of the mono-cyclomanganated N-methyl naphthalimide with phenylacetylene gives an (η5-cyclohexadienyl)Mn(CO)3 complex where the cyclohexadienyl ring has formed by two PhCCH adding in a formal [2 + 2 + 2] process across the C(1)-C(2) bond of the naphthalimide, breaking the aromaticity of the naphthalene ring as shown by a single crystal structure determination.
Effect of addition of trifluoroacetic acid on the photophysical properties and photoreactions of aromatic imides
Matsubayashi, Kazuhiko,Shiratori, Hideo,Kubo, Yasuo
scheme or table, p. 9291 - 9296 (2011/01/12)
The UV and IR spectra of N-methyl-1,8-naphthalimide in benzene showed a two-step consecutive complexation (hydrogen bond formation) with trifluoroacetic acid (TFA). The equilibrium constant K1 for the first complexation in benzene was determined from the UV spectrum to be 48 M-1. The fluorescence intensities of the imide in benzene were found to be remarkably enhanced by the addition of TFA. Furthermore, photochemical cyclobutane formation of the imide with styrene in benzene was enhanced by the addition of TFA. Enhancement of the fluorescence intensity and the photoreaction of the imide by complexation with TFA was explained by a decrease of the efficiency of the intersystem crossing from 1(ππ*) to 3(nπ*), that results from an increase in the energy of the 3(nπ*) level due to the complexation.
