Oxazole/Thiazole and Triazole Hybrids Based on α-Amino Acids

Valdomir, Guillermo; Padrón, Juan I.; Padrón, José M.; Martı́n, Victor S.; Davyt, Danilo

doi:10.1055/s-0033-1339139

“…Thus, the synthesis was done in two steps involving (i) the Ramirez olefination of aldehyde to give 1,1′-dibromoalkenes 10a–c in good yields and (ii) Corey–Fuchs reaction (Scheme ). , For this latest way, the reaction performed with DBU only led to very low yields (<10%) . Finally, the classical Corey–Fuchs reaction carried out with n -BuLi as the base at −78 °C gave the desired terminal alkynes 5a–c with an excellent yield (Scheme ).…”

Section: Resultsmentioning

confidence: 98%

“…HRMS were recorded on a microTOFQ (Bruker) ESI/QqTOF spectrometer. The compounds 3b , 3c , 4 , 5b, and 10b used in the first pathway were synthesized according to the methods reported in refs , and , respectively. According to the second pathway, compounds 12 , 13, and 14 were obtained by following ref and derivative 6 according to ref .…”

Section: Methodsmentioning

confidence: 99%

Synthesis and Photoswitching Properties of Bioinspired Dissymmetric γ-Pyrone, an Analogue of Cyclocurcumin

Pecourneau

¹

,

Losantos

²

,

Monari

³

et al. 2021

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Cyclocurcumin (CC), a turmeric curcuminoid with potential therapeutic properties, is also a natural photoswitch that may undergo E/Z photoisomerization under UV light. To be further exploited in relevant biological applications, photoactivation under near-infrared (NIR) irradiation is required. Such requirement can be met through opportune chemical modifications, by favoring two-photon absorption (TPA) probability. Herein, a general and efficient synthesis of a biomimetic 2,6disubstituted-γ-pyrone analogue of CC is described, motivated by the fact that molecular modeling previews an order of magnitude increase of its NIR TPA compared to CC. Three retrosynthetic pathways have been identified (i) via an aryl-oxazole intermediate or via aryl-diynone through (ii) a bottom-up or (iii) a top-down approach. While avoiding the passage through unstable synthons or low-yield intermediate reactions, only the latest approach could conveniently afford the 2,6-disubstituted-γ-pyrone analogue of CC, in ten steps and with an overall yield of 18%. The photophysical properties of our biomimetic analogue have also been characterized showing an improved photoisomerization yield over the parent natural compound. The potentially improved nonlinear optical properties, as well as enhanced stability, may be correlated to the enforcement of the planarity of the pyrone moiety leading to a quadrupolar D−π−A−π−D system.

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“…Thus, the synthesis was done in two-steps involving i) a Ramirez olefination of aldehyde to give 1,1'-dibromoalkenes 10a-c in good yields then ii) Corey-Fuchs reaction (Scheme 3). 18,19 For this latest way, the reaction performed with DBU only led to very low yields (< 10%). 20 Finally, the classical Corey-Fuchs reaction carried out with n-BuLi as base at -78°C gave the desired terminal alkynes 5a-c with an excellent yield (Scheme 3).…”

Section: Methodsmentioning

confidence: 99%

Synthesis and photoswitching properties of bioinspired dissymmetric gamma-pyrone, analogue of cyclocurcumin

Pecourneau¹,

Losantos²,

Monari

³

et al. 2021

Preprint

View full text Add to dashboard Cite

Cyclocurcumin, a turmeric curcuminoid with potential therapeutic properties, is also a natural photoswitch that may undergo E/Z photoisomerization under UV light. In order to be further exploited in relevant biological applications, photoactivation under near infrared (NIR) irradiation is required. Such requirement can be met through opportune chemical modifications,and most notably by favoring two-photon absorption (TPA) probability. Herein, a general and efficient synthesis of a biomimetic 2,6-g-pyrone analogue of cyclocurcumin is described, motivated by the fact that molecular modeling previews an order of magnitude increase of the NIR TPA cross-section for the latter compared to the natural counterpart. Three retrosynthetic pathways have been identified (i) via an aryl-oxazole intermediate or via an aryl-diynone through (ii) a bottom-up or (iii) a top-down approach. While avoiding the passage through unstable synthons or low yield intermediate reactions, only the latest approach could conveniently afford the 2,6-g-pyrone analogue of cyclocurcumin, in ten steps and with an overall yield of 18%. The photophysical properties of our biomimetic analogue have also been characterized showing an improved photo-isomerization yield over the parent natural compound. The potentially improved non-linear optical properties, as well an enhanced stability, may be correlated to the enforcement of the planarity of the pyrone moiety leading to a quadrupolar D-p-A-p-D system.<br>

show abstract

“…14 . 18,19 For this latest way, the reaction performed with DBU only led to very low yields (< 10%). 20 Finally, the classical Corey-Fuchs reaction carried out with n-BuLi as base at -78°C gave the desired terminal alkynes 5a-c with an excellent yield (Scheme 3).…”

Section: Synthesis Of 26-g-pyrone Analogue Of Cyclocurcuminmentioning

confidence: 99%

Synthesis and Photoswitching Properties of Bioinspired Dissymmetric 2,6-Gamma-Pyrone, Analogue of Cyclocurcumin

Pecourneau¹,

Losantos²,

Monari³

et al. 2021

Preprint

View full text Add to dashboard Cite

Cyclocurcumin, a turmeric curcuminoid with potential therapeutic properties, is also a natural photoswitch that may undergo E/Z photoisomerization under UV light. In order to be further exploited in relevant biological applications, photoactivation under near infrared (NIR) irradiation is required. Such requirement can be met through opportune chemical modifications,and most notably by favoring two-photon absorption (TPA) probability. Herein, a general and efficient synthesis of a biomimetic 2,6-g-pyrone analogue of cyclocurcumin is described, motivated by the fact that molecular modeling previews an order of magnitude increase of the NIR TPA cross-section for the latter compared to the natural counterpart. Three retrosynthetic pathways have been identified (i) via an aryl-oxazole intermediate or via an aryl-diynone through (ii) a bottom-up or (iii) a top-down approach. While avoiding the passage through unstable synthons or low yield intermediate reactions, only the latest approach could conveniently afford the 2,6-g-pyrone analogue of cyclocurcumin, in ten steps and with an overall yield of 18%. The photophysical properties of our biomimetic analogue have also been characterized showing an improved photo-isomerization yield over the parent natural compound. The potentially improved non-linear optical properties, as well an enhanced stability, may be correlated to the enforcement of the planarity of the pyrone moiety leading to a quadrupolar D-p-A-p-D system.<br>

show abstract

Oxazole/Thiazole and Triazole Hybrids Based on α-Amino Acids

Cited by 15 publications

References 9 publications

Synthesis and Photoswitching Properties of Bioinspired Dissymmetric γ-Pyrone, an Analogue of Cyclocurcumin

Synthesis and Photoswitching Properties of Bioinspired Dissymmetric γ-Pyrone, an Analogue of Cyclocurcumin

Synthesis and photoswitching properties of bioinspired dissymmetric gamma-pyrone, analogue of cyclocurcumin

Synthesis and Photoswitching Properties of Bioinspired Dissymmetric 2,6-Gamma-Pyrone, Analogue of Cyclocurcumin

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