Photoisomerization of trans‐2‐[4′‐(Dimethylamino)styryl]benzothiazole

Mishra, Ashwini Kumar; Thangamani, Arumugam; Chatterjee, Soumya; Chipem, Francis A. S.; Krishnamoorthy, G.

doi:10.1111/j.1751-1097.2012.01227.x

Cited by 19 publications

(16 citation statements)

References 35 publications

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“…As a result, yield of 1 markedly improved to 56%. Isolated yield of 1 (14%) was significantly lower than NMR yield, because product 1 was unstable, as was also reported for PBB3 18) and its derivatives. 19) To explore the reaction mechanism, we next investigated Knoevenagel condensation using other benzothiazole analogs under the optimized conditions (Table 1).…”

Section: Resultssupporting

confidence: 60%

Knoevenagel Condensation between 2-Methyl-thiazolo[4,5-b]pyrazines and Aldehydes

2022

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Knoevenagel condensation, an olefin-forming reaction from active methyl/methylene-containing compounds and aldehydes, is a fundamental and useful synthetic method. Benzothiazoles are, however, out of the scope of Knoevenagel condensation. Here, we report that Knoevenagel condensation between aldehydes and 2-methyl-thiazolo[4,5-b]pyrazines (MeTPy), a fused ring structure comprising pyrazine and thiazole, proceeded smoothly, despite minor structural differences from benzothiazoles. This finding will be useful for short synthesis of MeTPy-containing functional molecules, such as a tau probe analog 1.

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Section: Resultssupporting

confidence: 60%

Knoevenagel Condensation between 2-Methyl-thiazolo[4,5-b]pyrazines and Aldehydes

2022

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“…The blue shift and hypochromic effect are caused by the formation of the cis isomer. 50 The present study showed that in all the solvents, upon irradiation, the trans isomer is converted to the cis isomer. The presence of isosbestic points suggest a one-to-one conversion between the trans and cis isomers.…”

Section: Fluorescence Quantum Yield and Isomerizationmentioning

confidence: 93%

Photoinduced intramolecular charge transfer in trans-2-[4′-(N, N-dimethylamino)styryl]imidazo[4,5- b]pyridine: effect of introducing a C=C double bond

Mishra

Sahu

Tripathi

et al. 2014

Photochem Photobiol Sci

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The spectral characteristics of trans-2-[4'-(N,N-dimethylamino)styryl]imidazo[4,5-b]pyridine (t-DMASIP-b) have been investigated using absorption and fluorescence techniques, and compared with 2-(4'-N,N-dimethylamino)imidazo[4,5-b]pyridine (DMAPIP-b). The study reveals that introduction of a C[double bond, length as m-dash]C double bond strongly perturbs the photophysics of the system. Unlike DMAPIP-b, t-DMASIP-b emits a single emission in aprotic and protic solvents. The emission occurs from the locally excited state in nonpolar solvents and from a planar intramolecular charge transfer (PICT) state in polar solvents. Multiple linear regression analysis suggests that among the different solvent parameters, the dipolar interaction contributes more to the stabilization of the system in both the ground and excited states. Theoretical calculations suggest that, unlike in DMAPIP-b, proton coupled twisted intramolecular charge transfer (TICT) emission does not occur in t-DMASIP-b. The higher quantum yield obtained in the viscous solvent glycerol is attributed to the restriction of the twisting of the olefinic bond. The photoirradiation of t-DMASIP-b shows that isomerization takes place in all solvents, including viscous glycerol. The theoretically simulated potential energy surface shows that isomerization occurs via a phantom state, which is a nonradiative process. The rise in temperature favors the photoisomerization, thus, the fluorescence quantum yield decreases. The prototropic study indicates that, unlike in DMAPIP-b, the protonation takes place at different places to form the monocations.

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“…To this purpose, we here explored styrylbenzothiazoles (SBTs) as alternative photoswitchable scaffolds, and evaluated them for chemical biology use by creating SBT-based MT-inhibiting photopharmaceuticals whose applications we demonstrate especially in live cell studies with in situ photoswitching. We expected that, as compared to azobenzenes, the central C=C double bond of styrylbenzothiazoles 31,32 would endow them with increased robustness towards GSH reduction and higher thermal stability of the Z state, while avoiding photoresponse to wavelengths above 460 nm (due to the absence of an n-π* band) 33 ; yet that, compared to stilbenes, the benzothiazole would redshift the π-π* band enough to be photoswitched with visible light 34 while also blocking photochemical degradation. 35 Accordingly, we synthesise a rationally designed series of SBTubs (SBT-based tubulin-inhibitors) and evaluate them as biochemically robust, GFP-orthogonal, photoswitchable analogues of CA4.…”

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confidence: 99%

Photoswitchable microtubule inhibitors enabling robust, GFP-orthogonal optical control over the tubulin cytoskeleton

Gao

Kraus

Wranik

et al. 2019

Preprint

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Here we present GFP-orthogonal optically controlled reagents for reliable and repetitive in cellulo modulation of microtubule dynamics and its dependent processes. Optically controlled reagents ("photopharmaceuticals") have developed into powerful tools for high-spatiotemporal-precision control of endogenous biology, with numerous applications in neuroscience, embryology, and cytoskeleton research. However, the restricted chemical domain of photopharmaceutical scaffolds has constrained their properties and range of applications. Styrylbenzothiazoles are an as-yet unexplored scaffold for photopharmaceuticals, which we now rationally design to feature potent photocontrol, switching microtubule cytoskeleton function off and on according to illumination conditions. We show more broadly that this scaffold is exceptionally chemically and biochemically robust as well as substituent-tolerant, and offers particular advantages for intracellular biology through a range of desirable photopharmaceutical and drug-like properties not accessible to the current classes of photoswitches. We expect that these reagents will find powerful applications enabling robust, high precision, optically controlled cell biological experimentation in cytoskeleton research and beyond. Introduction:Molecular photoswitches have been used to install optical control over a broad range of phenomena, with applications from material sciences 1,2 through to reversible photocontrol of ligand binding affinities 3 and manipulation of diverse cellular processes in chemical biology 4,5 . For studies of temporally-regulated and spatially anisotropic biological systems, particularly those that simultaneously support several cellular functions, photoswitchable inhibitors conceptually enable a range of powerful studies not accessible with other tool systems. [6][7][8] A prime example of such spatiotemporally regulated, multifunctional systems is the microtubule (MT) cytoskeleton. This complex cellular network plays central roles in nearly all directed mechanical processes, such as intracellular transport and cell motility; its crucial function in cell proliferation has also made it a central anticancer drug target. 9-11 Yet, whereas cytoskeleton research typically aims to study a subset of MT-dependent processes that are spatially and/or temporally localised, nearly all MT inhibitors reported as tool compounds for biological research are drugs that are active wherever they are distributed, including at sites and at times where drug activity is not desired. 12 This restricts the scope of applications and utility of these inhibitors for selective research into the various, highly dynamic, anisotropic processes dependent on MTs. 13 The structure of the colchicine site MT inhibitor combretastatin A-4 (CA4; Fig 1a) 14 has recently inspired photoswitchable solutions to the problem of achieving spatiotemporal control over MT inhibition. CA4 is a stilbene whose Z-isomer (cis) binds tubulin, acts as a low nanomolar cytotoxin in cellulo, and reached Phase III trials as an ...

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Photoisomerization of trans‐2‐[4′‐(Dimethylamino)styryl]benzothiazole

Cited by 19 publications

References 35 publications

Knoevenagel Condensation between 2-Methyl-thiazolo[4,5-<i>b</i>]pyrazines and Aldehydes

Knoevenagel Condensation between 2-Methyl-thiazolo[4,5-<i>b</i>]pyrazines and Aldehydes

Photoinduced intramolecular charge transfer in trans-2-[4′-(N, N-dimethylamino)styryl]imidazo[4,5- b]pyridine: effect of introducing a C=C double bond

Photoswitchable microtubule inhibitors enabling robust, GFP-orthogonal optical control over the tubulin cytoskeleton

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