Oxidation of 3β,28-Diacetoxy-18-lupen-21-one with Peroxy Acids: A Way to Des-E-lupane Derivatives

1993 ◽  
Vol 58 (10) ◽  
pp. 2505-2516 ◽  
Author(s):  
Eva Klinotová ◽  
Martin Rejzek ◽  
Hana Zůnová ◽  
Jan Sejbal ◽  
Jiří Klinot ◽  
...  
Keyword(s):  
Alkaline Medium ◽  
Peracetic Acid ◽  
Lead Tetraacetate ◽  
Epoxy Derivative ◽  
Oxidative Removal ◽  
Acid Catalyzed ◽  
Peroxy Acids ◽  
Strong Acids

Oxidation of 3β,28-diacetoxy-18-lupen-21-one (I) and its 18β, 19β-epoxy derivative III with peracetic acid, catalyzed with strong acids, proceeds with cleavage of the bond between C-19 and C-21 under formation of E-seco derivatives with hydroxyl and isobutyryl groups on C-18 (spiro lactones V - VII and acid VIII). Oxidative removal of the isobutyryl fragment in spiro lactone VI by treatment with lead tetraacetate leads to the tetranor derivative - keto lactone XI which in an alkaline medium loses formaldehyde from C-17 to give des-E acid XVI.

Mechanism of Acid-Catalyzed Epoxidation of Alkenes with Peroxy Acids

1997 ◽  
Vol 62 (15) ◽  
pp. 5191-5197 ◽  
Author(s):  
Robert D. Bach ◽  
Carlo Canepa ◽  
Julia E. Winter ◽  
Paul E. Blanchette
Keyword(s):  
Acid Catalyzed ◽  
Peroxy Acids ◽  
Epoxidation Of Alkenes

Highly active and durable flowerlike Pd/Ni(OH)2 catalyst for the electrooxidation of ethanol in alkaline medium

RSC Advances ◽  
2016 ◽  
Vol 6 (76) ◽  
pp. 72722-72727 ◽  
Author(s):  
Jiatai Zhong ◽  
Duan Bin ◽  
Bo Yan ◽  
Yue Feng ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Alkaline Medium ◽  
Dissociative Adsorption ◽  
Water Molecules ◽  
Highly Active ◽  
Oxidative Removal ◽  
Adsorption Of Water

Ni(OH)2 plays the key role in promoting the dissociative adsorption of water molecules and subsequent oxidative removal of poisonous intermediates on neighbor palladium sites.

Synthesis of 2,24-Diepicastasterone and 3,24-Diepicastasterone as Potential Brassinosteroid Metabolites of the Cockroach Periplaneta americana

2002 ◽  
Vol 67 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Brunhilde Voigt ◽  
Andrea Porzel ◽  
Günter Adam ◽  
Dieter Golsch ◽  
Waldemar Adam ◽  
...  
Keyword(s):  
Periplaneta Americana ◽  
Reference Standards ◽  
Water Addition ◽  
X Ray ◽  
Epoxy Derivative ◽  
Metabolic Conversion ◽  
Acid Catalyzed

Investigations of the metabolic conversion of the phytohormone 24-epicastasterone (1) in the cockroach Periplaneta americana (L.) required the synthesis of 2,24-diepicastasterone (4), 3,24-diepicastasterone (7b) and 2-dehydro-3,24-diepicastasterone (9) as reference standards. 2,24-Diepicastasterone (4) was synthesized from 2α,3α-epoxy derivative 2 as well as from the 2β,3β-epoxy-22,23-diol 3 by acid-catalyzed water addition to the epoxy function leading to the desired 2β,3α-trans functionality. 3,24-Diepicastasterone (7b) was prepared by NaBH4-reduction of the 3-oxo derivative 6. Upon deprotection conditions from the ketol acetonides 6 and 8 in both cases 2-dehydro-3,24-diepicastasterone (9) was obtained. The structure of 2,24-diepicastasterone (4) was confirmed by X-ray analysis.

Structure and the properties of 18α,19βH-ursane derivatives with a lactone bridge to ring E

1980 ◽  
Vol 45 (5) ◽  
pp. 1366-1378 ◽  
Author(s):  
Eva Klinotová ◽  
Hana Skorkovská ◽  
Jiří Protiva ◽  
Alois Vystrčil
Keyword(s):  
Alkaline Medium ◽  
Hydroxy Acid ◽  
Lead Tetraacetate

Oxidation of ketolactone II in alkaline medium led predominantly to hydroxy acid VI with an oxabicycloheptane arrangement of the E ring. Further oxidation of hydroxy acid VI with lead tetraacetate or the pyrolysis of its diacetate, VII, gave ketone XV which on further oxidation gave either lactone XVIII or XXIV, depending on conditions. The structure of both lactones was confirmed by reduction to tetrol XIX or pentol XXV, from lactone XXIV diketone XXXI was also obtained.

Decomposition of peracetic acid catalyzed by vanadium complexes

1985 ◽  
Vol 34 (8) ◽  
pp. 1749-1752
Author(s):  
A. P. Makarov ◽  
A. E. Gekhman ◽  
O. Ya. Polotnyuk ◽  
I. I. Moiseev
Keyword(s):  
Peracetic Acid ◽  
Vanadium Complexes ◽  
Acid Catalyzed
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