The absolute configuration of the side chain diol moiety of the poison-frog alkaloid pumiliotoxin B

Toxicon ◽  
1984 ◽  
Vol 22 (3) ◽  
pp. 489-490
Author(s):  
H.P. Kolm
Keyword(s):  
Absolute Configuration ◽  
Side Chain ◽  
Poison Frog ◽  
The Absolute

The absolute configuration of the side chain diol moiety of the poison-frog alkaloid pumiliotoxin B

1982 ◽  
Vol 23 (42) ◽  
pp. 4369-4370 ◽  
Author(s):  
Motokazu Uemura ◽  
Katsuhiko Shimada ◽  
Takashi Tokuyama ◽  
John W. Daly
Keyword(s):  
Absolute Configuration ◽  
Side Chain ◽  
Poison Frog ◽  
The Absolute

Absolute configuration at C(20) of the derivatives of 21-nor-5α-cholane-20,24-diol

1980 ◽  
Vol 45 (9) ◽  
pp. 2443-2451
Author(s):  
Vladimír Pouzar ◽  
Miroslav Havel
Keyword(s):  
Absolute Configuration ◽  
Side Chain ◽  
Chemical Correlation ◽  
The Absolute ◽  
Derivatives Of

Derivatives of 21-nor-5α-cholane-20,24-diol XI and XIX were prepared by stepwise construction of the side-chain in the position 17β. Their absolute configuration at C(20) was determined on the basis of chemical correlation with the derivatives of 21-nor-5α-cholan-20-ol, XVI and XXIV. The absolute configuration of alcohols XVI and XXIV was determined from the ratio of the yields in which they are formed during the reduction of ketone X and using the benzoate rule. To compounds XI-XVIII the configuration 20R and to compounds XIX-XXVI the configuration 20S has been assigned.

(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.

Pterins. VIII. The absolute configuration at C 6 of natural 2-Amino-6-[(1'R,2'S)- 1',2'-dihydroxypropyl]-5,6,7,8-tetrahydropteridin-4(3H)-one (L-erythro-5,6,7,8-tetrahydrobiopterin)

1982 ◽  
Vol 35 (4) ◽  
pp. 785 ◽  
Author(s):  
WLF Armarego ◽  
P Waring ◽  
B Paal
Keyword(s):  
Hydrochloric Acid ◽  
Absolute Configuration ◽  
Side Chain ◽  
Methyl Group ◽  
Convenient Synthesis ◽  
The Absolute

The conformation of the side chain of 5,6,7,8-tetrahydrobiopterint (6) in 0.5 M DCl/D2O is predominantly quasi-equatorial (deduced from 3J (13C4a, 1H6) 1.1 HZ), and is the same as that of the methyl group in 2-methyl-1,2,3,4-tetrahydroquinoxaline and in 2-amino-6-methyl-5,6,7,8-tetrahydropteridin-4(3H)-one in the same solvent. Because (-)-(2S)-2-methyl-1,2,3,4-tetrahydroquinoxaline(4) and (-)-(6S)-2-amino-6-methyl-5,6,7,8-tetrahydropteridin-4(3H)-one (5) have the same conformation and negative c.d. spectra (O 248 nm and 263 nm respectively) as does the natural 5,6,7,8, tetrahydrobiopterin (O minimum at 265 nm) in 0.1 M hydrochloric acid, then the absolute conformations of the tetrahydropyrazine rings and the absolute configurations at the chiral centres C2, C6, and C6 of compounds (4), (5) and (6) respectively are the same. Hence the absolute configuration at C6 in natural 5,6,7,8 tetrahydrobiopterin is R.� A convenient synthesis of biopterin on a gram scale is described.

scholarly journals Total Synthesis of Decahydroquinoline Poison Frog Alkaloids ent-cis-195A and cis-211A

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7529
Author(s):  
Takuya Okada ◽  
Naizhen Wu ◽  
Katsuki Takashima ◽  
Jungoh Ishimura ◽  
Hiroyuki Morita ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Absolute Configuration ◽  
Mirror Image ◽  
Poison Frog ◽  
Dendrobates Pumilio ◽  
Frog Species ◽  
The Common ◽  
The Absolute ◽  
Absolute Stereochemistry

The total synthesis of two decahydroquinoline poison frog alkaloids ent-cis-195A and cis-211A were achieved in 16 steps (38% overall yield) and 19 steps (31% overall yield), respectively, starting from known compound 1. Both alkaloids were synthesized from the common key intermediate 11 in a divergent fashion, and the absolute stereochemistry of natural cis-211A was determined to be 2R, 4aR, 5R, 6S, and 8aS. Interestingly, the absolute configuration of the parent decahydroquinoline nuclei of cis-211A was the mirror image of that of cis-195A, although both alkaloids were isolated from the same poison frog species, Oophaga (Dendrobates) pumilio, from Panama.

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