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 (−).

Determination of the absolute stereochemistry of the fungal metabolite (R)-(−)-2-(4′-hydroxyphenyl)-2-hydroxyethanoic acid (pisolithin B)

1991 ◽  
Vol 69 (5) ◽  
pp. 772-778 ◽  
Author(s):  
Youla S. Tsantrizos ◽  
Kelvin K. Ogilvie
Keyword(s):  
Absolute Configuration ◽  
Lithium Aluminum Hydride ◽  
Optical Rotation ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Fungal Metabolite ◽  
H Nmr ◽  
The Absolute ◽  
Absolute Stereochemistry

The antifungal antibiotic pisolithin B (p-hydroxymandelic acid, 2-(4′-hydroxyphenyl)-2-hydroxyethanoic acid, 1a) was shown to have the absolute (R) configuration. The stereochemistry was established via comparison of its optical rotation to that of its synthetic (R) and (S) enantiomers. The synthetic samples were prepared by the stereospecific reduction of the prochiral α-keto acid, p-hydroxybenzoylformic acid (2-(4′-hydroxyphenyl)-2-oxoethanoic acid, 2a), with (R) or (S)-2,2′-dihydroxy-1,1′-binaphthyl lithium aluminum hydride (BINAL-H). The absolute configuration and enantiomeric purity of both products were determined using the 1H NMR of their isobutyl esters in the presence of the chiral solvating agent (R)-(−)-2,2,2-trifluoro-1-(9-anthryl)ethanol. Key words: pisolithin B, p-hydroxymandelic acid, antifungal, absolute configuration.

scholarly journals Assignment of Absolute Configuration of Bromoallenes by Vacuum-Ultraviolet Circular Dichroism (VUVCD)

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1296
Author(s):  
Taiki Umezawa ◽  
Nakaba Mizutani ◽  
Koichi Matsuo ◽  
Yuugo Tokunaga ◽  
Fuyuhiko Matsuda ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Vacuum Ultraviolet ◽  
Specific Rotation ◽  
Ultraviolet Region ◽  
Cotton Effects ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
Absolute Stereochemistry ◽  
Unambiguous Assignment

A new application of vacuum-ultraviolet circular dichroism (VUVCD), which enables the measurement of CD spectra in the vacuum-ultraviolet region (140–200 nm), for the assignment of the absolute configurations of bromoallenes is described. Bromoallene moieties are found in natural products obtained from many marine organisms. To date, the absolute configuration of bromoallenes has been assigned almost exclusively with Lowe’s rule, which is based on specific rotation. However, exceptions to Lowe’s rule have been reported arising from the presence of other substituents with large specific rotations. For the unambiguous assignment of the absolute configuration of the bromoallene moiety with its characteristic absorption wavelength at 180–190 nm due to the π–π* transition, VUVCD was applied to four pairs of bromoallene diastereomers prepared by modifying the synthetic scheme of omaezallene. The VUVCD spectra clearly showed positive or negative Cotton effects around 180–190 nm according to the configuration of the bromoallene employed, revealing the potential of VUVCD for determining absolute stereochemistry.

Absolute Stereochemistry of (-)-Wieland-Miescher Ketone as Established by the X-ray Crystallographic and CD Exciton Chirality Methods

1992 ◽  
Vol 57 (7) ◽  
pp. 1459-1465 ◽  
Author(s):  
Nobuyuki Harada ◽  
Tatsuo Sugioka ◽  
Hisashi Uda ◽  
Takeo Kuriki
Keyword(s):  
Structure Analysis ◽  
Absolute Configuration ◽  
X Ray ◽  
The Absolute ◽  
Absolute Stereochemistry

The 8aR absolute stereochemistry of Wieland-Miescher ketone (-)-I was established by the X-ray structure analysis of its bis(4-bromobenzoate) derivatives (1R,6R,8aR)-(+)-IV and (1R,6S,8aR)-(-)-V. The absolute configuration of (-)-I was corroborated further by the application of the CD exciton chirality method to bis(4-bromobenzoates) (+)-IV and (-)-V.

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.

THE REACTION OF UNSATURATED CARBOHYDRATES WITH CARBON MONOXIDE AND HYDROGEN: V. ABSOLUTE STEREOCHEMISTRY OF ANHYDRODEOXYHEPTITOLS FROM 3,4,6-TRI-O-ACETYL-D-GLUCAL. STEREOCHEMISTRY OF HYDROFORMYLATION. CONFORMATIONAL ANALYSIS

1965 ◽  
Vol 43 (5) ◽  
pp. 1375-1381 ◽  
Author(s):  
Alex Rosenthal ◽  
Hans J. Koch
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Carbon Monoxide ◽  
Absolute Configuration ◽  
Sodium Iodide ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Dicobalt Octacarbonyl ◽  
The Absolute ◽  
Compound Ii ◽  
Absolute Stereochemistry

3,4,6-Tri-O-acetyl-D-glucal reacted with carbon monoxide and hydrogen in the presence of dicobalt octacarbonyl to yield a mixture of two epimeric anhydrodeoxyheptitols, namely, 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-D-manno-heptitol (I) and 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-D-gluco-heptitol (II). De-O-acetylation of the mixture, followed by chromatographic separation, yielded crystalline 2,6-anhydro-3-deoxy-D-manno-heptitol (III) and 2,6-anhydro-3-deoxy-D-gluco-heptitol (IV). Reaction of the mixture of heptitols (I) and (II) with p-bromobenzenesulfonyl chloride, followed by fractional crystallization of the brosylates, gave pure 4,5,7-tri-O-acetyl-2,6-anhydro-1-O-(p-bromophenylsulfonyl)-3-deoxy-D-gluco-heptitol (VII). The absolute configuration of (VII) has been previously established by X-ray crystallographic analysis. The absolute configuration of (III) was established by correlation with that of (VII). The conversion of compound (II) into various derivatives is described.Reaction of 3,4,6-tri-O-acetyl-D-glucal with carbon monoxide and deuterium afforded 2,6-anhydro-3-deoxy-D-manno-heptitol-1,1,3-2H3 (XIII) and 2,6-anhydro-3-deoxy-D-gluco-heptitol-1,1,3-2H3 (XIV). Examination of the nuclear magnetic resonance (n.m.r.) spectra of the normal and deuterated anhydrodeoxyheptitols confirmed the structural assignments and showed that cis addition to the double bond took place to give (XIV).Comparison of the exchange reaction of sodium iodide with 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-1-O-tosyl-D-gluco-heptitol (VIII) and with 4,5,7-tri-O-acetyl-2,6-anhydro-3-deoxy-1-O-tosyl-D-manno-heptitol (XV) revealed that the equatorial primary tosyloxy group of (VIII) was exchanged by iodine twice as readily as the axial primary tosyloxy group of (XV).

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.

scholarly journals Absolute Stereochemistry of the β-Hydroxy Acid Unit in Hantupeptins and Trungapeptins

2016 ◽  
Vol 11 (1) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Deepak Kumar Gupta ◽  
Gary Chi Ying Ding ◽  
Yong Chua Teo ◽  
Lik Tong Tan
Keyword(s):  
Amino Acid ◽  
Structural Feature ◽  
Absolute Configuration ◽  
Hydroxy Acid ◽  
Hplc Analysis ◽  
The Absolute ◽  
Absolute Stereochemistry ◽  
Common Structural Feature ◽  
Acid Unit

The β-hydroxy/amino acid unit is a common structural feature of many bioactive marine cyanobacterial depsipeptides. In this study, the absolute stereochemistry of the β-hydroxy acid moieties in hantupeptins and trungapeptins were determined through their synthesis and HPLC analysis of the Mosher ester derivatives. Synthesis of two3-hydroxy-2-methyloctanoic acid (Hmoa) stereoisomers, (2 S,3 R)-Hmoa and (2 S,3 S)-Hmoa, were achieved using diastereoselective asymmetric method and the retention times of all four Hmoa isomers were established indirectly by RPLC-MS analysis of their Mosher ester derivative standards. Based on the retention times of the standards, the absolute configuration of the Hmoa unit in hantupeptin C (3) and trungapeptin C (6) was assigned as (2 R,3 S)- and (2 S,3 R)-Hmoa, respectively. The use of the Mosher's reagents, coupled with HPLC analysis, provided a viable alternative to the absolute stereochemical determination of β-hydroxy acid units in depsipeptides.

ChemInform Abstract: A Stereospecific Synthesis and Unambiguous Assignment of the Absolute Configuration of (-)-erythro-Mefloquine Hydrochloride (I).

ChemInform ◽  
2014 ◽  
Vol 45 (21) ◽  
pp. no-no
Author(s):  
Gang Zhou ◽  
Xian Liu ◽  
Xueying Liu ◽  
Huifang Nie ◽  
Shengyong Zhang ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Stereospecific Synthesis ◽  
The Absolute ◽  
Unambiguous Assignment

(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.

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