scholarly journals A Facile Route to alpha-Hydrazinopropionic Acid of High Optical Purity. The Absolute Configuration of alpha-(4,5,6,7-Tetrahydroindazolyl-1- and -2)propionic Acid.

1975 ◽  
Vol 29b ◽  
pp. 93-98 ◽  
Author(s):  
Håkan Gustafsson ◽  
Carmen H. G. Vogt ◽  
Curt R. Enzell ◽  
O. Smidsrød ◽  
O. Dahl ◽  
...  
Keyword(s):  
Propionic Acid ◽  
Absolute Configuration ◽  
Optical Purity ◽  
High Optical Purity ◽  
The Absolute ◽  
Hydrazinopropionic Acid ◽  
Facile Route

Total synthesis and establishment of the absolute stereochemistry of (+)-mostueine. Addition of chiral nucleophiles to 3,4-dihydro-2-methyl-9-(p-toluenesulfonyl)-β-carbolinium iodide

1992 ◽  
Vol 70 (12) ◽  
pp. 2922-2928 ◽  
Author(s):  
Allan W. Rey ◽  
Walter A. Szarek ◽  
David B. MacLean
Keyword(s):  
Total Synthesis ◽  
Indole Alkaloid ◽  
Optical Purity ◽  
Ring System ◽  
Asymmetric Induction ◽  
Iminium Salt ◽  
High Optical Purity ◽  
The Absolute ◽  
Absolute Stereochemistry ◽  
Mediated Reduction

A highly convergent synthesis of the pentacyclic indole alkaloid (+)-mostueine (1) is described. The key step involved the coupling of the dianion derived from (1′S)-3-(1′-hydroxyethyl)-4-methylpyridine (4) with the iminium salt 3,4-dihydro-2-methyl-9-(p-toluenesulfonyl)-β-carbolinium iodide (3). Low asymmetric induction (15% de) at the C-1 position of the β-carboline ring system (C-3 of mostueine) was obtained. The nonfermenting baker's yeast-mediated reduction of 3-acetyl-4-methylpyridine provided the hydroxyethylpyridine component in acceptable yield (67%) and high optical purity (99.0% ee). This synthesis of 1 has established that the absolute stereochemistry of mostueine is (3S, 19R).

The absolute configurations of ( - )-angolensin and some related 1,2-diarylpropanes

1965 ◽  
Vol 18 (11) ◽  
pp. 1791 ◽  
Author(s):  
JW Clark-Lewis ◽  
RW Jemison
Keyword(s):  
Propionic Acid ◽  
Butyric Acid ◽  
Absolute Configuration ◽  
The Absolute

(-)-Angolensin has been converted into (+)-(2S)-1-(2,4-dimethoxyphenyl)-2-(4-methoxyphenyl)propane, an analogue of (+)-(2S)-1-(2,4,6-trimethoxyphenyl)-2-(3,4-dimethoxyphenyl)propane. The stereochemistry of angolensin is thereby correlated with that of catechin and epicatechin. Oxidation of (+)-(2S)-1-(2-hydroxy-4-methoxyphenyl)-2-(4-methoxyphenyl)propane gave (+)-3-(4-methoxyphenyl)- butyric acid, in agreement with the established absolute configuration of (-)-angolensin. The (+)-butyric acid was also prepared by resolution of the synthetic racemate with quinine, and by homologation of (-)-2-(4-methoxyphenyl)propionic acid.

Antioestrogenic and antifertility compounds. II. Synthesis of optically active 2,3-Bis(p-methoxyphenyl)alk-1-enes

1970 ◽  
Vol 23 (1) ◽  
pp. 119
Author(s):  
DJ Collins ◽  
JJ Hobbs
Keyword(s):  
Propionic Acid ◽  
Absolute Configuration ◽  
Optically Active ◽  
The Absolute

The enantiomers of 2,3-bis(p-methoxyphenyl)but-1-ene were synthesized by different routes. The laevo isomer, [α]D -73.6�, was derived by conversion of (+)-erythro-2,3-bis(p-methoxyphenyl)butylamine into (+)-erythro-l-N,N-dimethyl- amino-2,3-bis(p-methoxyphenyl)butane, and pyrolysis of the corresponding quaternary hydroxide. The absolute configuration of 2,3-bis(p-methoxyphenyl)but-1-ene was established as (+)-(R) by synthesis of the dextro isomer, [α]D + 72.50�, from (+)-(S)-2-(p-methoxyphenyl)propionic acid via (+)-(S)-3-(p-methoxyphenyl)butan-2-one. It follows that the absolute configuration of (+)-eryihro- 2,3-bis(p-methoxyphenyl)butylamine is (2R,3S). (-)-2,3-Bis(p-methoxyphenyl)pent-1-ene, [α]D -49.5�, was synthesized from (+)-erythro-2,3-bis-(p-methoxyphenyl)pentylamine.

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