scholarly journals Synthetic Studies on Quinoxaline Antibiotics. III. Synthesis of Nortriostin A, a Triostin A Analog LackingN-Methyl Groups on the Cystine and Valine Residues

1984 ◽  
Vol 57 (8) ◽  
pp. 2211-2215 ◽  
Author(s):  
Masaru Shin ◽  
Ken Inouye ◽  
Naoki Higuchi ◽  
Yoshimasa Kyogoku
Keyword(s):  
Methyl Groups ◽  
Triostin A ◽  
Synthetic Studies

scholarly journals Synthetic Studies on Quinoxaline Antibiotics. II. Synthesis of Triostin A

1984 ◽  
Vol 57 (8) ◽  
pp. 2203-2210 ◽  
Author(s):  
Masaru Shin ◽  
Ken Inouye ◽  
Hideo Otsuka
Keyword(s):  
Triostin A ◽  
Synthetic Studies

Synthetic studies in the 1,2-Dithiole series. II. Routes to 4-Methylamino-1,2-dithiole-3-thione

1965 ◽  
Vol 18 (1) ◽  
pp. 61 ◽  
Author(s):  
RFC Brown ◽  
ID Rae ◽  
S Sternhell
Keyword(s):  
Long Range ◽  
Methyl Iodide ◽  
Spin Coupling ◽  
Methyl Groups ◽  
Strong Base ◽  
Ultraviolet Spectra ◽  
Synthetic Studies ◽  
Spin Spin Coupling

4-Amino-1,2-dithiol-3-one has been converted via methylation of its N-tosyl derivative into the 4-methylamino-3-thione (Vb). Methylation of 4-benzamido-1,2- dithiole-3-thione with methyl iodide and a strong base gives 4-bis(methylthio)-methylene-2-phenyl-2-oxazoline-5-thione (VII). The N.M.R. and ultraviolet spectra of the oxazoline thione (VII) and of the corresponding oxazolinone (VIII) and thiazolinone (IX) are discussed in terms of their probable non-planarity. Some examples of long-range spin-spin coupling between protons of non-equivalent methyl groups in isopropylidene structures are reported.

Synthetic studies toward inducamide C

2021 ◽  
Author(s):  
Ardalan A. Nabi ◽  
Lydia M. Scott ◽  
Daniel P. Furkert ◽  
Jonathan Sperry
Keyword(s):  
Natural Product ◽  
Structural Revision ◽  
Synthetic Studies

The rare benzoxazepine ring in the alkaloid inducamide C is unstable and prone to rearrangement, indicating that structural revision of the natural product may be necessary.

Reduction of carbon impurities in aluminium nitride from time-resolved chemical vapour deposition using trimethylaluminum

2020 ◽  
Author(s):  
Polla Rouf ◽  
Pitsiri Sukkaew ◽  
Lars Ojamäe ◽  
Henrik Pedersen
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Aluminium Nitride ◽  
Methyl Groups ◽  
Time Resolved ◽  
Thermally Induced ◽  
Light Emitting ◽  
Carbon Impurities ◽  
Wide Range

<p>Aluminium nitride (AlN) is a semiconductor with a wide range of applications from light emitting diodes to high frequency transistors. Electronic grade AlN is routinely deposited at 1000 °C by chemical vapour deposition (CVD) using trimethylaluminium (TMA) and NH<sub>3</sub> while low temperature CVD routes to high quality AlN are scarce and suffer from high levels of carbon impurities in the film. We report on an ALD-like CVD approach with time-resolved precursor supply where thermally induced desorption of methyl groups from the AlN surface is enhanced by the addition of an extra pulse, H<sub>2</sub>, N<sub>2</sub> or Ar between the TMA and NH<sub>3</sub> pulses. The enhanced desorption allowed deposition of AlN films with carbon content of 1 at. % at 480 °C. Kinetic- and quantum chemical modelling suggest that the extra pulse between TMA and NH<sub>3</sub> prevents re-adsorption of desorbing methyl groups terminating the AlN surface after the TMA pulse. </p>

Detection of Chemical Exchange in Methyl Groups of Macromolecules

2019 ◽  
Author(s):  
Michelle Gill ◽  
Andrew Hsu ◽  
Arthur G. Palmer, III
Keyword(s):  
Relaxation Rate ◽  
Chemical Exchange ◽  
Double Quantum ◽  
Methyl Groups ◽  
Multiple Quantum ◽  
Relaxation Data ◽  
E Coli ◽  
Methyl Trosy ◽  
Dynamics Simulations ◽  
Exchange Broadening

<div> <div> <div> <p>The zero- and double-quantum methyl TROSY Hahn-echo and the methyl <sup>1</sup>H-<sup>1</sup>H dipole- dipole cross-correlation nuclear magnetic resonance experiments enable estimation of multiple quantum chemical exchange broadening in methyl groups in proteins. The two relaxation rate constants are established to be linearly dependent using molecular dynamics simulations and empirical analysis of experimental data. This relationship allows chemical exchange broadening to be recognized as an increase in the Hahn-echo relaxation rate constant. The approach is illustrated by analyzing relaxation data collected at three temperatures for <i>E. coli </i>ribonuclease HI and by analyzing relaxation data collected for different cofactor and substrate complexes of <i>E. coli </i>AlkB. </p> </div> </div> </div>

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