Two-Step, One-Pot Synthesis of Visible-Light-Responsive 6-Azopurines

Kolarski, Dušan; Szymański, Wiktor; Feringa, Ben L.

doi:10.1021/acs.orglett.7b02361

Cited by 33 publications

(25 citation statements)

References 40 publications

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“…The respective arylamines 13a – c were converted into their corresponding hydrazines 14a – c via diazonium-salt formation using sodium nitrite and subsequent reduction using tin(II) chloride [70]. The following nucleophilic substitution at a chloro-substituted purine ( 15a , b ) or thienopyrimidine ( 15c ), respectively, and subsequent oxidation of the hydrazine moiety afforded the corresponding azobenzene derivatives 16a – d [71].…”

Section: Resultsmentioning

confidence: 99%

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Azologization of serotonin 5-HT₃ receptor antagonists

Rustler¹,

Maleeva²,

Bregestovski³

et al. 2019

Beilstein J. Org. Chem.

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The serotonin 5-hydroxytryptamine 3 receptor (5-HT3R) plays a unique role within the seven classes of the serotonin receptor family, as it represents the only ionotropic receptor, while the other six members are G protein-coupled receptors (GPCRs). The 5-HT3 receptor is related to chemo-/radiotherapy provoked emesis and dysfunction leads to neurodevelopmental disorders and psychopathologies. Since the development of the first serotonin receptor antagonist in the early 1990s, the range of highly selective and potent drugs expanded based on various chemical structures. Nevertheless, on-off-targeting of a pharmacophore’s activity with high spatiotemporal resolution as provided by photopharmacology remains an unsolved challenge bearing additionally the opportunity for detailed receptor examination. In the presented work, we summarize the synthesis, photochromic properties and in vitro characterization of azobenzene-based photochromic derivatives of published 5-HT3R antagonists. Despite reported proof of principle of direct azologization, only one of the investigated derivatives showed antagonistic activity lacking isomer specificity.

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Section: Resultsmentioning

confidence: 99%

“…General procedure for the synthesis of purine- and thienopyrimidine-substituted arylazobenzenes and depiction of the corresponding structures [70–71]. …”

Section: Resultsmentioning

confidence: 99%

Azologization of serotonin 5-HT₃ receptor antagonists

Rustler¹,

Maleeva²,

Bregestovski³

et al. 2019

Beilstein J. Org. Chem.

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“…31,[35][36][37] Phenylazothiophenes could also display T-shaped Z-isomers, accompanied with low Z→E photoisomerization yields in general, while their t1/2 (20 °C) were at the timescale of hours or less. 32,33 Azo switches bearing a benzoheterocycle such as quinoline, 27 indole, 38 indazole, 39 and purine 40 were also reported. Their extended π system led to red-shifted π-π* absorption and generally accelerated back relaxation with t1/2 from nanoseconds to days.…”

Section: Introductionmentioning

confidence: 99%

Azobispyrazole Family as Photoswitches Combining (Near-)Quantitative Bidirectional Isomerization and Widely Tunable Thermal Half-Lives from Hours to Years

He¹,

Shangguan²,

Zhang

et al. 2021

Preprint

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Azobenzenes <a>are classical </a>molecular photoswitches that have received widespread application. In recent endeavors of molecular design, replacing one or both phenyl rings by heteroaromatic ones is emerging as a strategy to expand the molecular diversity and to access improved photoswitch properties. However, the currently available heteroaryl azo switches generally show limitations on E ⇆ Z photoisomerization yields and/or Z-isomer stability. Here we report a family of azobispyrazoles as new photoswitches, which combine (near-)quantitative bidirectional photoconversions and widely tunable Z-isomer thermal half-lives (t1/2) from hours to years. A visible-light-activated photoswitch is also obtained. Systematic experimental and theoretical investigations reveal the different geometric and electronic structures of azobispyrazoles from those of phenylazopyrazoles, overcoming the conflict existing in the latter between effective photoconversion and Z-isomer stability. Our work shows the great potential of azobispyrazoles in developing photoresponsive systems and can inspire the rational design of new photoswitches making use of bis-heteroaryl azo architecture.

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“…Meanwhile, structurally related heterocyclic analogues of azobenzenes have been ignored for a long time. In recent years, this gap was partially filled with a representative synthesis of several photoswitchable azo derivatives with excellent photophysical properties incorporating pyridine, [13] pyrazole, [14] imidazole, [15] indazole [16] or some other nitrogen heterocyclic subunits [14b,17] linked to an azo moiety. However, 1,2,5‐oxadiazole‐based photoswitchable azo compounds have not been studied so far.…”

Section: Introductionmentioning

confidence: 99%

Novel Arylazo‐1,2,5‐oxadiazole Photoswitches: Synthesis, Photoisomerization and Nitric Oxide Releasing Properties

et al. 2020

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A series of novel molecular photoswitches incorporating an aryldiazenyl moiety linked to a 1,2,5-oxadiazole (furazan) or 1,2,5-oxadiazole 2-oxide (furoxan) subunit was synthesized by a simple and step-economic chemical route. Upon visible light irradiation, (E)-arylazo-1,2,5-oxadiazoles underwent photoisomerization to the corresponding (Z)-isomers which are stable under ambient conditions. Structural factors affecting the photoswitching ability were also revealed. Synthesized photoswitches exhibited good performance due to the absence of fatigue or decomposition over at least ten cycles under air in a temperature range of 20-60°C. NO donor properties of the synthesized arylazofuroxans were also evaluated in vitro and it was found that (Z)-arylazofuroxans released significantly larger amounts of NO than the corresponding (E)-isomers, which suggests strong potential of these molecular photoswitches in photopharmacology and other biomedical applications.

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Two-Step, One-Pot Synthesis of Visible-Light-Responsive 6-Azopurines

Cited by 33 publications

References 40 publications

Azologization of serotonin 5-HT₃ receptor antagonists

Azologization of serotonin 5-HT₃ receptor antagonists

Azobispyrazole Family as Photoswitches Combining (Near-)Quantitative Bidirectional Isomerization and Widely Tunable Thermal Half-Lives from Hours to Years

Novel Arylazo‐1,2,5‐oxadiazole Photoswitches: Synthesis, Photoisomerization and Nitric Oxide Releasing Properties

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Two-Step, One-Pot Synthesis of Visible-Light-Responsive 6-Azopurines

Cited by 33 publications

References 40 publications

Azologization of serotonin 5-HT3 receptor antagonists

Azologization of serotonin 5-HT3 receptor antagonists

Azobispyrazole Family as Photoswitches Combining (Near-)Quantitative Bidirectional Isomerization and Widely Tunable Thermal Half-Lives from Hours to Years

Novel Arylazo‐1,2,5‐oxadiazole Photoswitches: Synthesis, Photoisomerization and Nitric Oxide Releasing Properties

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Azologization of serotonin 5-HT₃ receptor antagonists

Azologization of serotonin 5-HT₃ receptor antagonists