Specific Optical Rotation and Absolute Configuration of Flexible Molecules Containing a 2-Methylbutyl Residue

2020 ◽  
Vol 2020 (30) ◽  
pp. 4768-4774
Author(s):  
Jia-Min Lu ◽  
Bei-Bei Yang ◽  
Li Li
Keyword(s):  
Absolute Configuration ◽  
Optical Rotation ◽  
Specific Optical Rotation ◽  
Flexible Molecules

Synthesis of anisomycin. Part I. The stereospecific synthesis of N-benzoyl-2-(p-methoxybenzyl)-3-hydroxy-4-carboxamido pyrrolidine and the absolute configuration of anisomycin

1968 ◽  
Vol 46 (7) ◽  
pp. 1101-1104 ◽  
Author(s):  
C. M. Wong
Keyword(s):  
Infrared Spectra ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Specific Rotation ◽  
Stereospecific Synthesis ◽  
Specific Optical Rotation ◽  
Synthetic Compound ◽  
The Absolute ◽  
Hydrolysis Of ◽  
Absolute Stereochemistry

L-Tyrosine was converted stereospecifically to N-benzoyl-2-(p-methoxybenzyl)-3-hydroxy-4-cyanopyrrolidine (10) which had a specific optical rotation [Formula: see text]. Anisomycin was converted also to N-benzoyl-2-(p-methoxybenzyl)-3-hydroxy-4-cyanopyrrolidine (16) which had a specific rotation [Formula: see text]. The infrared spectra of the synthetic compound and the derivative of anisomycin were superimposable with each other. This result showed that the absolute configuration of the three asymmetric centers in (10) of synthetic origin were 2S, 3S, 4S, and those in (16) were 2R, 3R, 4R. Thus, anisomycin should have the absolute stereochemistry 2R, 3S, 4S as depicted in the structure (2). Hydrolysis of the hydroxy nitriles (8) and (10) gave an identical amide (3) which should have the absolute stereochemistry 2S, 3S, 4R as shown in structure (3).

scholarly journals Synthesis and structural reconfirmation of bacillamide B

2015 ◽  
Vol 13 (14) ◽  
pp. 4271-4277 ◽  
Author(s):  
Xue Sun ◽  
Yi Liu ◽  
Jun Liu ◽  
Guofeng Gu ◽  
Yuguo Du
Keyword(s):  
Absolute Configuration ◽  
Optical Rotation ◽  
Specific Optical Rotation ◽  
The Absolute

Synthesis of bacillamide B was accomplished, the absolute configuration was reconfirmed as S, and the specific optical rotation was revised to (−).

scholarly journals Absolute Configuration Sensing of Chiral Aryl- and Aryloxy-Propionic Acids by Biphenyl Chiroptical Probes

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 154
Author(s):  
Stefania Vergura ◽  
Stefano Orlando ◽  
Patrizia Scafato ◽  
Sandra Belviso ◽  
Stefano Superchi
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Environmental Pollutants ◽  
Red Shift ◽  
Electronic Circular Dichroism ◽  
Configuration Assignment ◽  
Clear Sign ◽  
The Absolute ◽  
Circular Dichroïsm

The absolute configuration of chiral 2-aryl and 2-aryloxy propionic acids, which are among the most common chiral environmental pollutants, has been readily and reliably established by either electronic circular dichroism spectroscopy or optical rotation measurements employing suitably designed 4,4′-disubstituted biphenyl probes. In fact, the 4,4′-biphenyl substitution gives rise to a red shift of the diagnostic electronic circular dichroism signal of the biphenyl A band employed for the configuration assignment, removing its overlap with other interfering dichroic bands and allowing its clear sign identification. The largest A band red shift, and thus the most reliable results, are obtained by employing as a probe the 4,4′-dinitro substituted biphenylazepine 3c. The method was applied to the absolute configuration assignment of 2-arylpropionic acids ibuprofen (1a), naproxen (1b), ketoprofen (1c) and flurbiprofen (1d), as well as to the 2-aryloxypropionic acids 2-phenoxypropionic acid (2a) and 2-naphthoxypropionic acid (2b). This approach, allowing us to reveal the sample’s absolute configuration by simple optical rotation measurements, is potentially applicable to online analyses of both the enantiomeric composition and absolute configuration of these chiral pollutants.

scholarly journals Immunochemical studies on blood groups LXII. Fractionation of hog and human A, H, and AH blood group active substance on insoluble immunoadsorbents of Dolichos and Lotus lectins.

1976 ◽  
Vol 143 (2) ◽  
pp. 422-436 ◽  
Author(s):  
M E Pereira ◽  
E A Kabat
Keyword(s):  
Blood Group ◽  
Optical Rotation ◽  
Gastric Mucin ◽  
Specific Optical Rotation ◽  
Dolichos Biflorus ◽  
Blood Group A ◽  
Analytical Properties ◽  
Group Substance ◽  
Group A

The purified lectins from Lotus tetragonolobus and Dolichos biflorus were coupled to Sepharose 2B to make insoluble adsorbents for purification and fractionation of blood group A and H active glycoproteins. With both adsorbents, hog gastric mucin A + H blood substance (HGM), purified by phenol-ethanol precipitation, yielded fractions showing only A, only H, or AH activities. The AH fraction was obtained when the adsorbent column was overloaded with HGM and its A and H specificities seem to be carried on the same molecules since they were not separable by chromatography on either column. However A and H specificities of blood group substance from the stomach of a presumably heterozygous individual hog were both on the same molecules as they too could not be fractionated on either column. Analytical properties of the isolated fractions were generally similar to those of the unfractionated material, the purfied A substances had a higher galactosamine/fucose ratio than did the H substances. Although the original A + H showed very little specific optical rotation, the separated A and H substances rotated positively and negatively, respectively. The lectin-Sepharose adsorbents have also proven useful in isolating A or H substances directly from the crude commercial hog gastric mucin. Blood group A2 substance from a human ovarian cyst yielded two fractions on the Lotus-Sepharose column; the effluent did not interact with the Lotus lectin but precipitated the Ulex and Dolichos lectins and anti-A, and appears to contain type 1 H determinants. The other fraction reacted with Lotus and Ulex lectin as well as with Dolichos and anti-A.

Identification of d- or di-∝-Tocopherol in Pharmaceuticals, Food Supplements, or Feed Supplements: A Collaborative Study

1975 ◽  
Vol 58 (3) ◽  
pp. 585-594
Author(s):  
Stanley R Ames ◽  
Emma-Jane E Drury
Keyword(s):  
Vitamin E ◽  
Oxidation Product ◽  
Optical Rotation ◽  
Collaborative Study ◽  
Food Supplements ◽  
Tocopheryl Acetate ◽  
Specific Optical Rotation ◽  
Feed Supplements ◽  
Before And After ◽  
Optical Rotations

Abstract A collaborative study was conducted to evaluate a method for identifying d- or dl-∝-tocopherol in pharmaceuticals, food supplements, or feed supplements. The sample is extracted and saponified, the extraneous color is removed by chromatography, and the sample is assayed for vitamin E. Optical rotations are determined before and after formation of the ferricyanide oxidation product. The specific optical rotation of the oxidation product is negligible for the dJ-form and +25.5° for the d-form. Statistical analysis of the data reported by 8 collaborators for the standard d-∝-tocopheryl acetate and for 6 unknown samples indicates a significant interaction between laboratories and samples. The mean coefficients of variation among laboratories for the determinations of the corrected specific optical rotation of the standard and the rotation ratio for the unknown samples containing d-∝-tocopherol were 11.7 and 21.6%, respectively, for all laboratories and 5.8 and 11.8%, respectively, for experienced laboratories. This identification test for vitamin E is acceptable for determining the form of vitamin E as either d or dl, but is not acceptable for accurately determining mixtures of the 2 forms. The method has been adopted as official first action for the identification of d- or dl-∝-tocopherol.

scholarly journals Chiral Resolution and Absolute Configuration of 3α,6β-Dicinnamoyloxytropane and 3α,6β-Di(1-ethyl-1H-pyrrol-2-ylcarbonyloxy)tropane, Constituents of Erythroxylum Species

2014 ◽  
Vol 9 (1) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Marcelo A. Muñoz ◽  
Solange Arriagada ◽  
Pedro Joseph-Nathan
Keyword(s):  
Stationary Phase ◽  
Natural Product ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Normal Phase ◽  
Vibrational Circular Dichroism ◽  
Chiral Resolution ◽  
Case Characteristic ◽  
The Absolute

Chiral resolution of (±)-3α,6β-dicinnamoyloxytropane (1) and (±)-3α,6β-di(1-methyl-1 H-pyrrol-2-ylcarbonyloxy)tropane (2), prepared by esterification of (±)-3α,6β-tropanediol (3), was achieved using an amylose-derived HPLC stationary phase and normal phase conditions. The corresponding vibrational circular dichroism (VCD) spectra provided the absolute configuration of the enantiomers as (-)-(3 R,6 R)-1, (+)-(3S,6S)- 1, (-)-(3 R,6 R)-2 and (+)-(3S,6S)- 2. In each case, characteristic VCD bands for the absolute configuration determination of the 3α,6β-tropandiol esters were observed. While the absolute configuration of natural 1, previously isolated from Erythroxylum hypericifolium, could not be established due to the lack of literature optical rotation values, that of catuabine E, previously isolated from E. vacciniifolium, is now assigned as (-)-(3 R,6 R)-2 by comparison with the optical rotation values of the prepared samples and the reported rotation of the natural product.

(3aS,5aR,6R,8aR)-3a-Hydroxy-5a-methyl-6-[(1R,2E,4R)-1,4,5-trimethyl-2-hexen-1-yl]-3a,4,5,5a,6,7,8,8a-octahydro-2H-cyclopenta[e]benzofuran-2-one

2007 ◽  
Vol 63 (11) ◽  
pp. o4196-o4196
Author(s):  
Wen-liang Wang ◽  
Hong-wen Tao ◽  
Wei Sun ◽  
Qian-Qun Gu ◽  
Wei-Ming Zhu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Absolute Configuration ◽  
Title Compound ◽  
Optical Rotation ◽  
Side Chain ◽  
Compound C ◽  
Extended Chain ◽  
Halotolerant Fungus ◽  
The Absolute

The title compound, C21H32O3, also known as dimethylincisterol A3, was isolated from halotolerant fungus THW-18. It is composed of three fused rings and a side chain. In the crystal structure, the molecules interact with each other via O—H...O hydrogen bonds, resulting in an extended chain along the b axis. The absolute configuration was assigned from the measured optical rotation and reference to the literature.

Temperature dependence of specific optical rotation of an aqueous levoglucosan solution

2018 ◽  
Vol 67 (11) ◽  
pp. 2155-2156
Author(s):  
A. V. Orlova ◽  
N. N. Kondakov ◽  
Yu. F. Zuev ◽  
L. O. Kononov
Keyword(s):  
Temperature Dependence ◽  
Optical Rotation ◽  
Specific Optical Rotation
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