Efficient Oxidative Conversion of Aldehydes to 2‐Substituted Oxazolines and Oxazines Using (Diacetoxyiodo)benzene.

Karade, Nandkishor N.; Tiwari, Girdharilal B.; Gampawar, Sumit V.

doi:10.1002/chin.200748113

Cited by 3 publications

(3 citation statements)

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“…This methodology could broaden the field of in situ drug synthesis for varying applications including but not limited to cancer therapeutics. [68][69][70][71][72] Furthermore, CDNI-Pro could be used for applications that involve other roles for proline beyond aldol catalysis. 73,74 Future work aims to expand the irradiation wavelengths to enable catalyst activation with visible to near IR regions for a more functionally versatile caged catalyst.…”

Section: Discussionmentioning

confidence: 99%

Caged Proline in Photoinitiated Organocatalysis

et al. 2019

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Organocatalysis is an emerging field in which small metal-free organic structures catalyze a diversity of reactions with remarkable stereoselectivity. The ability to selectively switch on such pathways upon demand has proven to be a valuable tool in biological systems. Light as a trigger provides the ultimate spatial and temporal control of activation. However, there have been limited examples of photo triggered catalytic systems. Herein, we describe the synthesis and application of a caged proline system that can initiate organocatalysis upon irradiation. The caged proline was generated using the highly efficient 4-carboxy-5,7-dinitroindolinyl (CDNI) photocleavable protecting group in a 4-step synthesis. Advantages of this system include water solubility, biocompatibility, high quantum yield for catalyst release, and responsiveness to two-photon excitation. We showed the light triggered catalysis of a crossed aldol, a Mannich, and a self-aldol condensation reaction. We also demonstrated light initiated catalysis leading to the formation of a biocide in situ, which resulted in the growth inhibition of E. coli, with as little as 3 minutes of irradiation. This technique can be broadly applied to other systems by which the formation of active forms of drugs can be catalytically assembled remotely via two-photon irradiation.

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Section: Discussionmentioning

confidence: 99%

Caged Proline in Photoinitiated Organocatalysis

et al. 2019

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“…Due to the immense applications, these pharmaceutically important scaffolds attract the interest of synthetic organic chemists and tremendous research efforts from the past years are focused on the development of efficient routes for the preparation of 2oxazoline derivatives. In this direction, multiple synthetic strategies which involve different substrates like imidate hydrochlorides [14], orthoesters [15], aldehydes [16][17][18][19], carboxylic acids [20][21][22][23][24], or their derivatives like ester [25][26][27][28], nitriles [29][30][31][32][33], and thioamides [34] have been developed to prepare the oxazolines. Despite the potential applications of these reported procedures, they suffer from several limitations, such as hazardous reaction conditions, expensive catalysts, longer reaction times, tedious work-up procedures, and a deficit of general applicability.…”

Section: Introductionmentioning

confidence: 99%

Ultrasound-Accelerated, Concise, and Highly Efficient Synthesis of 2-Oxazoline Derivatives Using Heterogenous Calcium Ferrite Nanoparticles and Their DFT Studies

Bendi

Atri

Rao³

et al. 2021

Journal of Chemistry

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A rapid and operationally simple approach for synthesising biologically relevant 2-oxazoline derivatives has been developed through highly efficient ultrasound-promoted coupling reactions of thioamides and amino alcohols using calcium ferrite nanoparticles as heterogeneous catalysts. The major advantage of using ultrasound irradiation lies in the drastic reduction of reaction time as compared with conventional stirring. Furthermore, quantum chemical investigations for the synthesised 2-oxazoline derivatives have been carried out at the DFT/B3LYP/6-311 + G (d, p) level of theory to predict the optimized geometry. The molecular properties such as bond lengths, bond orders, Milliken charges, frontier molecular orbitals, global reactivity descriptors, molecular electrostatic potential map, and thermodynamic parameters of all the compounds have also been reported at the same level of theory.

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“…Preliminary work commenced with substrate 4 . 14 A dual catalysis approach was considered according to which the chiral acid would deliver the desired iminium ion pair and excitation would occur by energy transfer from a sensitizer. 2,3-Dimethylbutadiene was employed as the olefin component in the reaction.…”

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confidence: 99%

Enantioselective [2 + 2] Photocycloaddition via Iminium Ions: Catalysis by a Sensitizing Chiral Brønsted Acid

et al. 2021

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N , O -Acetals derived from α,β-unsaturated β-aryl substituted aldehydes and (1-aminocyclohexyl)methanol were found to undergo a catalytic enantioselective [2 + 2] photocycloaddition to a variety of olefins (19 examples, 54–96% yield, 84–98% ee ). The reaction was performed by visible light irradiation (λ = 459 nm). A chiral phosphoric acid (10 mol %) with an ( R )-1,1′-bi-2-naphthol (binol) backbone served as the catalyst. The acid displays two thioxanthone groups attached to position 3 and 3′ of the binol core via a meta -substituted phenyl linker. NMR studies confirmed the formation of an iminium ion which is attached to the acid counterion in a hydrogen-bond assisted ion pair. The catalytic activity of the acid rests on the presence of the thioxanthone moieties which enable a facile triplet energy transfer and an efficient enantioface differentiation.

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Efficient Oxidative Conversion of Aldehydes to 2‐Substituted Oxazolines and Oxazines Using (Diacetoxyiodo)benzene.

Cited by 3 publications

References 1 publication

Caged Proline in Photoinitiated Organocatalysis

Caged Proline in Photoinitiated Organocatalysis

Ultrasound-Accelerated, Concise, and Highly Efficient Synthesis of 2-Oxazoline Derivatives Using Heterogenous Calcium Ferrite Nanoparticles and Their DFT Studies

Enantioselective [2 + 2] Photocycloaddition via Iminium Ions: Catalysis by a Sensitizing Chiral Brønsted Acid

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