Synthesis and characterization of a selenium-containing substrate of .alpha.-chymotrypsin. Selenium-77 nuclear magnetic resonance observation of an acyl-.alpha.-chymotrypsin intermediate

Biochemistry ◽  
1986 ◽  
Vol 25 (19) ◽  
pp. 5625-5632 ◽  
Author(s):  
Gregory P. Mullen ◽  
R. Bruce Dunlap ◽  
Jerome D. Odom
1987 ◽  
Vol 65 (9) ◽  
pp. 2305-2311 ◽  
Author(s):  
Raj K. Chadha ◽  
John E. Drake ◽  
Neil T. McManus ◽  
Anil Mislankar

Complexes of the general formula [HgX2(Me3MCH2SeMe)]2, where M = Si, Ge; X = Cl, Br, I, have been prepared and characterized by 1H nuclear magnetic resonance and Raman spectroscopy. Crystal structures of [HgX2(Me3SiCH2SeMe)]2, where X = Cl, Br, and I (1, 2, and 3 respectively), show that they have centrosymmetric dinuclear structures. The crystals of 1 and 2 are monoclinic, while those of 3 are triclinic. For 1: P21/c, a = 14.235(11), b = 6.551(6), c = 14.211(9) Å, β = 117.33(5)°, Z = 2, and R = 0.0560. For 2: P21/c, a = 14.329(6), b = 6.695(2), c = 14.819(4) Å, β = 118.47(2)°, Z = 2, and R = 0.0540. For 3: [Formula: see text], a = 7.651(2), b = 8.387(2), c = 12.321(4) Å, α = 90.07(2), β = 91.80(2), γ = 116.02(2)°, Z = 1, and R = 0.0565. All three complexes show the expected pseudotetrahedral geometry about mercury. The stereochemical differences arise in the arrangement of the bulky trimethylsilylmethyl groups, which in the HgI2 adduct are rotated away from the centre of the molecule but which in the HgCl2 and HgBr2 adducts are turned towards the centre. These are the first dinuclear structures reported of HgBr2 and HgI2 adducts since it was demonstrated 46 years ago by Evans etal. that [HgBr2(AsBu3)]2 was present in [HgBr2(AsBu3)2•HgBr2].


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Madhuresh Kumar Sethi ◽  
Vijendra Singh Rawat ◽  
Jayaprakash Thirunavukarasu ◽  
Rajakrishna Yerramalla ◽  
Anish Kumar

Twenty-six possible as well as observed impurities during the preparation of Tolvaptan have been identified, prepared, and characterized by HPLC (high performance liquid chromatography), NMR (nuclear magnetic resonance), and mass spectra. Control of these impurities, formed during various stages of Tolvaptan preparation, has been mentioned in this paper.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5272
Author(s):  
Rong Zhong ◽  
Hui Hu ◽  
Yanfang Zhou

A trifunctional photoinitiator based on commercial photoinitiators 2-hydroxy-2-methylpropiophenone (Irgacure1173) and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure2959) was synthesized by an esterization reaction. Its structure was characterized by UV-Vis spectrometry, Infrared Transformed Fourier, Proton Nuclear Magnetic Resonance Spectra, 13 Carbon Nuclear Magnetic Resonance Spectra, Mass Spectrometry, and Thermogravimetry. In addition, its photoinitiating activity was investigated. The results showed that the novel photoinitiator had good photoinitiating activity and thermal stability compared to commercial photoinitiators. The migration of the residual photoinitiator in the cured film was lower than that of 1173 and 2959.


2010 ◽  
Vol 7 (1) ◽  
pp. 49-54
Author(s):  
K. M. Khalifa ◽  
A. M. Hamil ◽  
A. Gasem ◽  
A. Abdulsalam

The present work deals with synthesis and characterization of the ligand 2-[(4-aminophnyl)imino]-1,2-diphenyl-1-ethanone and their complexes with Ni(II) and Cu(II) ions. The synthesized ligand and its complexes have been characterized by elemental analysis, infrared, electronic, nuclear magnetic resonance and mass spectra. The metal ligand ratio was found to be 1:1. Square planer geometry for both complexes was suggested.


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