2-Thienyl analogues of ephedrine and ψ-ephedrine

Barker, J. M.; Byron, D. J.; Huddleston, P. R.

doi:10.1039/j39690002183

Cited by 22 publications

(23 citation statements)

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“…FcNMe 2 + + and its UV/Vis spectrum have already been described in as hort note dating from 1965. [17] Plots of the molecule structures are displayed in Figure 1, and crystal data and details to the structure solutiona nd refinementc an be retrievedf rom Tables S1 and S2, Supporting Information. Ta ble S3 (Supporting Information) summarizest he most important bond lengths and angles.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

Electrochemical, Spectroelectrochemical, Mößbauer, and EPR Spectroscopic Studies on Ferrocenyl‐Substituted Tritylium Dyes

Oßwald

Casper

Anders

et al. 2018

Chemistry A European J

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Four monoferrocenyl tritylium derivatives with donor-substituted (OMe, NMe ) aryl rings are reported, along with their spectroscopic and electrochemical properties. All the complexes show a one-electron reduction and a quasi-reversible ferrocene oxidation at a very positive potential. Small quadrupole splittings, ΔE , in Mößbauer spectra agree with highly electron-deficient ferrocenes. Comparison of the experimental half-wave potentials for ferrocene oxidation, E (Fc/Fc ), with those estimated from established correlations of E (Fc/Fc ) with ΔE indicates that the E values of the anisyl-substituted congeners FcOMe and FcMeOMe are affected by Coulombic repulsion between the positive charges at the Fe ion and the neighboring methylium site. Electronic spectra are recorded and interpreted with the aid of quantum chemical calculations. UV/Vis spectroelectrochemical measurements as well as chemical reduction provide insight into the redox-induced color changes upon ferrocene oxidation or upon reduction to the neutral trityl radicals. The neutral radicals reversibly form EPR-silent dimers. This process is studied by temperature-dependent EPR spectroscopy, and thermodynamic data for their dimerization are determined. Experimental and quantum chemical data suggest that the dimers assume classical hexaarylethane structures as opposed to normal or "offset" Jacobson-Nauta-type structures.

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Section: Synthesis and Characterizationmentioning

confidence: 99%

Electrochemical, Spectroelectrochemical, Mößbauer, and EPR Spectroscopic Studies on Ferrocenyl‐Substituted Tritylium Dyes

Oßwald

Casper

Anders

et al. 2018

Chemistry A European J

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“…Electronically asymmetrical derivatives of the Julolidine (IV) and Kairoline (V; R=Me) of triarylmethane dyes show hypsochromic shifts of the absorption bands relative to those of the methoxy analogues of Malachite Green and Brilliant Green, in accordance with enhanced conjugation through the kairolyl and juloidyl groups [17,18] leading progressively to less electronically symmetrical system. Replacement of the terminal methyl group in the kairoline analogues by a cyanoethyl group (V; R=C 2 H 4 CN) leads to bathochromic shifts due to the electron-withdrawing effect of the CN group which decreases the ability of the terminal nitrogen atom to conjugate with the aromatic system (Table 7).…”

Section: Resultsmentioning

confidence: 98%

Synthesis and electronic absorption spectra of some novel methoxy half-analogs of Malachite Green and Brilliant Green

Saadatjou

Hallas

2008

Fibers Polym

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In this work, various series of triarylmethane dyes containing one or more terminal methoxy substituent together with a variable tertiary amino group have been synthesized. The effects of electron-donating and electron-withdrawing groups have been systematically examined and electron absorption spectra of dyes determined. The absorption bands of the methoxy half-analogues of Malachite Green and Brilliant Green show pronounced hypsochromic shifts together with reduction in intensity owing to the inherent electronic asymmetry of the system. The corresponding dye bases are incompletely ionized in acid solution. Julolidine and Kairoline analogues of these dyes produce further hypsochromic shifts of both visible absorption bands in accordance with enhanced conjugation of the terminally bridged substituents. Crowding substituents at the central carbon atom in the series of methoxy half-analogues produce hypsochromic shifts of the absorption bands owing to the inherent electronic asymmetry; bond order alteration throughout the system ensures that crowding effects are minimized by rotation about essential single bonds.

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“…An attempt to obtain the same compound by the mixed anhydride reaction failed. The compound can be prepared using acetic anhydride (12). Reaction of 7 with Ac-Glu-OH gave a 70% recovery of Ac-Glu-OH.…”

Section: Resultsmentioning

confidence: 99%

“…It is known that when N-protected aspartic acid (9) (the same holds for glutamic acid) is coupled without protection at the p-COOH-group, the product is a mixture of a-carboxy (12) and P-carboxy (13)-substituted isomers (Scheme 2; see later) (1). Two products emerge because as soon as one of the carboxy groups is activated (10d and e), it is attacked by the other one, giving internal anhydride 11, which is the species that undergoes aminolysis (see ref.…”

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confidence: 99%

2,4‐Dimethyl‐5(4H)‐oxazolone as reagent for activation and coupling of N‐substituted aspartic acid

Benoiton

Chen

1994

International Journal of Peptide and Protein Research

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Reaction of the title oxazolone with N‐benzyloxycarbonyl‐L‐aspartic acid in dichloromethane followed by addition of phenylalanine methyl ester. HCI and N‐methylmorpholine gave a 90% yield of a mixture of α‐and β‐isomers of Z‐aspartylphenylalanine methyl esters in a 7:3 ratio. Reaction of the oxazolone with N‐acetyl‐L‐aspartic acid anhydride gave a 75 % yield of crystalline N‐acetyl‐L‐aspartic acid anhydride. tert‐Butoxycarbonylaspartic and Z‐glutamic acids also underwent activation to give the anhydrides.

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2-Thienyl analogues of ephedrine and ψ-ephedrine

Cited by 22 publications

References 0 publications

Electrochemical, Spectroelectrochemical, Mößbauer, and EPR Spectroscopic Studies on Ferrocenyl‐Substituted Tritylium Dyes

Electrochemical, Spectroelectrochemical, Mößbauer, and EPR Spectroscopic Studies on Ferrocenyl‐Substituted Tritylium Dyes

Synthesis and electronic absorption spectra of some novel methoxy half-analogs of Malachite Green and Brilliant Green

2,4‐Dimethyl‐5(4H)‐oxazolone as reagent for activation and coupling of N‐substituted aspartic acid

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