Contrasting Diastereoselectivity between Cyclic Nitrones and Azomethine Ylides. Stereocontrolled Pathways to cis-anti-anti-cis-Oxazatetraquinanes from a Bicyclic Nitrone

Reddy, D. Narasimha; Reddy, G. S.; Beatriz, Adilson; Corey, E. J.

doi:10.1021/acs.orglett.1c01787

Cited by 6 publications

(2 citation statements)

References 7 publications

(9 reference statements)

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“…By creating molecular ordering in the trans isomer as a result of the reversible trans-cis isomerization brought on by ultraviolet radiation, the LC's mesophase structure is stabilized, whereas the phase structure is disrupted by disordering the cis isomer. The cis isomer will therefore have a lower clearing point than the trans one [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Laterally Chloro-Substituted Schiff Base Ester Liquid Crystals: Mesomorphic and Optical Properties

et al. 2023

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A new class of Schiff base/ester compounds: ICln, 4-((2′-chlorophenylimino)methyl)phenyl-4″-alkoxy benzoates, were synthesized and their mesophase characteristics and thermal behavior were evaluated. Differential scanning calorimetry (DSC) was used to study mesophase transitions, and polarized optical microscopy was carried out to identify the phases (POM). The results show that all compounds are monomorphic, and enantiotropic nematic (N) phases were seen at all side chains. It was found that lateral Cl atoms in the terminal benzene ring influence both conformation and mesomorphic properties. Comparisons between the present investigated lateral Cl derivatives and their laterally neat, as well as their isomeric, compounds have been briefly discussed. Results revealed that the insertion of lateral Cl substituent in the molecular structure impacts the type and stability of the formed mesophases. The exchanges of the ester-connecting moiety improve their thermal nematic stability than their previously prepared structurally isomeric derivatives. These compounds exhibit a broad absorption in the UV-Visible region, including a peak in UV region and a tail around 550 nm, and there were observed to be absorption tail increases and energy band gap decreases with the increase of the alkoxy side chain length. The photoluminescence (PL) intensity was noted to be quenched for the bulky alkoxy group ascribed to non-radiative recombination through the defect states. Moreover, time resolved fluorescence decay spectra reveal that both the radiative and non-radiative recombination lifetime increases with the increase of alkoxy side chain length.

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Section: Introductionmentioning

confidence: 99%

Preparation of Laterally Chloro-Substituted Schiff Base Ester Liquid Crystals: Mesomorphic and Optical Properties

et al. 2023

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“…C) Reddy et al reported the preparation of nitrones by oxidation of bicyclic amines with urea hydrogen peroxide (UHP) at room temperature in methanol in the presence of catalytic sodium tungstate dihydrate 7. Epoxy cycloadducts were prepared in yields of 54-66% by the sequential selective oxidation and intramolecular 1,3-dipolar cycloaddition of methyl 2-(allylaryl)glycinates with an excess of aqueous hydrogen peroxide in the presence of catalytic amounts of sodium tungstate dihydrate 8.…”

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confidence: 99%