Synthesis of the cis and trans isomers of 4-Chloro-L-proline, 4-Bromo-L-proline, and 4-Amino-L-proline

1967 ◽  
Vol 20 (7) ◽  
pp. 1493 ◽  
Author(s):  
RH Andreatta ◽  
V Nair ◽  
AV Robertson ◽  
WRJ Simpson
Keyword(s):  
Methyl Ester ◽  
Sodium Borohydride ◽  
Protecting Groups ◽  
Hydroxyl Group ◽  
Side Reactions ◽  
Trans Isomers ◽  
Azide Ion ◽  
Cis And Trans Isomers ◽  
Proline Derivatives ◽  
Cis And Trans

cis- and trans-4-Chloro- and 4-bromo-L-prolines have been synthesized stereospecifically, the key step being SN2 displacement of a free or substituted 4-hydroxyl group in suitably protected 4-hydroxy-L- prolines. Similar displacements with azide ion followed by reduction provide convenient routes to cis- and trans- 4-amino-L-proline. A less satisfactory pathway to cis-4-aminoproline is reduction of a 4- oximinoproline derivative. In the course of the syntheses, which involve a variety of protecting groups, 45 new L-proline derivatives have been prepared. Unexpected side reactions were the formation of cis-4-hydroxyprolinamide by the action of ammonia on trans-4- bromoproline, and the reduction by sodium borohydride of N- benzyloxycarbonyl-4-oximinoproline methyl ester to N-benzyloxycar- bonyl-4-oximinoprolinol.

THE INFRARED FREQUENCIES AND INTENSITIES OF THE HYDROXYL BAND OF ORTHO-ALKYL PHENOLS IN THE VAPOR PHASE

1962 ◽  
Vol 40 (1) ◽  
pp. 111-121 ◽  
Author(s):  
K. U. Ingold
Keyword(s):  
Vapor Phase ◽  
Hydroxyl Group ◽  
Trans Isomers ◽  
Polar Solvents ◽  
Cis And Trans Isomers ◽  
Stretching Vibration ◽  
Alkyl Phenols ◽  
Infrared Frequencies ◽  
Cis And Trans ◽  
Hydroxyl Band

The infrared frequencies and intensities of the fundamental stretching vibration of the hydroxyl group have been measured for a number of ortho-alkyl phenols in the vapor phase over a range of temperatures. Both quantities have been shown to depend on internal steric and environmental factors. The differences in enthalpy between the cis and trans isomers of several 2-tert-alkyl phenols have been measured, and it is concluded that the latter are not significantly stabilized relative to the former by solvation in non-polar solvents.

Azido(imidazole)bis(acetylacetonato)cobalt(III) Complexes — Facile trans ⇋ cis Interconversion in Solution

1985 ◽  
Vol 40 (4) ◽  
pp. 470-476 ◽  
Author(s):  
J. K. Das ◽  
K. C. Dash
Keyword(s):  
Nmr Spectra ◽  
Equilibrium Mixture ◽  
Biologically Active ◽  
Trans Isomers ◽  
Active Ligand ◽  
Azide Ion ◽  
Cis And Trans Isomers ◽  
Neutral Base ◽  
Cis And Trans ◽  
C Nmr

A number of mixed-ligand complexes of cobalt(III) containing coordinated azide ion, acetyl- acetonatc anion and the neutral base imidazole and, having the general formula [Co(acac)2(N3)(Im)] (Im = imidazole or its derivatives) have been synthesised by the reaction of K[trans-Co(acac)2(N3)2] with the biologically active ligand imidazole or its derivatives. IR and electronic spectra alongwith 1H and 13C NMR spectra have been employed to characterise the complexes and determine their geometry. In contrast to the stable trans-[Co(acac)2(NO2)(Im)] complexes, these azido complexes arc shown to undergo facile trans ⇋ cis interconversion in CHCl3 solution. The NMR spectra (1H and 13C) can be interpreted by assuming the presence of an equilibrium mixture of the cis- and trans-isomers in solution.

Photochemistry of 2-(2-Furyl)-benzimidazole (Fuberidazole)

1992 ◽  
Vol 47 (10) ◽  
pp. 1431-1437 ◽  
Author(s):  
M. J. Melo ◽  
Fernando Pina ◽  
António L. Maçanita ◽  
Eurico C. Melo ◽  
Christiane Herrmann ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Acidic Medium ◽  
Fluorescence Emission ◽  
Trans Isomers ◽  
Significant Similarity ◽  
Cis And Trans Isomers ◽  
Low Concentrations ◽  
Cis And Trans ◽  
Kinetics Of

The photodegradation of 2-(2-Furyl)-benzimidazole (Fuberidazole 1) has been reinvestigated employing advanced HPLC—UV/VIS technique and fluorescence emission and excitation spectroscopy in methanol at natural pH, in acidic medium and in aqueous solutions at pH 7 and 3, and four main products benzimidazole-2-carboxylic acid 3, its methyl ester 2, 1-methoxy benzimidazole 5, methyl 4-oxo-2-benzimidazole crotonate 7 (cis and trans isomers) besides benzimidazole 4 and 2,2′-bibenzimidazole 6 and other side products have been isolated and characterized. The kinetics of the photodegradation process was followed independently by HPLC—UV and fluorescence emission showing a significant similarity of the curve habit; this allows to monitor a photodegradation at very low concentrations (5·10-5-5·10-6Μ). The quantum yield of disappearance of Fuberidazole has been determined.

PREPARATION AND STEREOCHEMISTRY OF 1,2-O-(2′-HYDRO0XY-ETHYLIDENE)- AND 1,2-O-(HYDROXYISOPROPYLIDENE)-GLYCEROLS

1966 ◽  
Vol 44 (15) ◽  
pp. 1787-1793 ◽  
Author(s):  
P. A. J. Gorin ◽  
T. Ishikawa
Keyword(s):  
Hydrogen Bonding ◽  
Chemical Synthesis ◽  
Infrared Absorption ◽  
Hydroxyl Group ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Absorption Studies ◽  
Cis And Trans

The cis- and trans-isomers of 1,2-O-(2′-hydroxyethylidene)-glycerol (I and II) and 1,2-O-(hydroxyisopropylidene)-glycerol (V and VI) were prepared and their configurations assigned by stereospecific chemical synthesis. Equilibration of 1,2-O-(2′-cis-hydroxyethylidene)-L-glycerol (I) in acidified chloroform gave mainly 1,3-O-(2′-cis-hydroxyethylidene)-glycerol (III). In the 1,2-O-(hydroxyisopropylidene)-glycerol series, equilibration data and infrared absorption studies showed that hydrogen bonding of the O-(hydroxyisopropylidene) hydroxyl group was more pronounced in the cis-isomers.

scholarly journals Identification of Anthocyanin Compounds in Butterfly Pea Flowers (Clitoria ternatea L.) by Ultra Performance Liquid Chromatography/Ultraviolet Coupled to Mass Spectrometry

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4539
Author(s):  
Nguyen Minh Thuy ◽  
Vo Minh ◽  
Tran Ben ◽  
My Tuyen Thi Nguyen ◽  
Ho Ha ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Ultra Performance Liquid Chromatography ◽  
Negative Ion ◽  
Trans Isomers ◽  
Clitoria Ternatea ◽  
Flower Extract ◽  
Cis And Trans Isomers ◽  
Butterfly Pea ◽  
Cis And Trans

Butterfly pea flower have great sensory attraction, but they have not yet been used widely in Vietnam. Extracts of butterfly pea flowers can be used conveniently as a natural blue colorant for food products. In this study, the identification of anthocyanin compounds in butterfly pea flowers was performed by UPLC coupled with a UV and Mass spectrometer instrument. Positive and negative ion electrospray MS/MS chromatograms and spectra of the anthocyanin compounds were determined. By analyzing the chromatograms and spectra for each ion, five anthocyanins were identified in the butterfly pea flower extract; these were delphinidin-3-(6”‐p-coumaroyl)-rutinoside, cyanidin 3-(6”-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl) glucose in both cis- and trans- isomers, cyanidin-3-(p-coumaroyl-glucoside) and delphinidin-3-pyranoside. Additionally, based on their intensity, it was determined that cyanidin-3-(p-coumaroyl-glucoside) was the most abundant anthocyanin, followed by cyanidin 3-(6”-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl-glucoside), delphinidin-3-(6”-p-coumaroyl)-rutinoside and delphinidin-3-pyranoside. In this study, cyanidin derivatives were discovered in butterfly pea flower extract, where these compounds had not been detected in previous studies.

Unveiling the coexistence of cis- and trans-isomers in the hydrolysis of ZrO2: A coupled DFT and high-resolution photoelectron spectroscopy study

2020 ◽  
Vol 153 (24) ◽  
pp. 244308
Author(s):  
Ali Abou Taka ◽  
Mark C. Babin ◽  
Xianghai Sheng ◽  
Jessalyn A. DeVine ◽  
Daniel M. Neumark ◽  
...  
Keyword(s):  
High Resolution ◽  
Photoelectron Spectroscopy ◽  
Spectroscopy Study ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Hydrolysis Of
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