Stereo and chemical course of acid-catalyzed double bond migration of cholesta-5,7-dien-3β-ol to 5α-cholesta-8,14-dien-3β-ol

2000 ◽  
pp. 1697-1703 ◽  
Author(s):  
Hideharu Seto ◽  
Shozo Fujioka ◽  
Hiroyuki Koshino ◽  
Suguru Takatsuto ◽  
Shigeo Yoshida
Keyword(s):  
Double Bond ◽  
Double Bond Migration ◽  
Acid Catalyzed

Remote double bond migration via rhodium catalysis: a novel enone transposition

1976 ◽  
Vol 98 (22) ◽  
pp. 7102-7104 ◽  
Author(s):  
Paul A. Grieco ◽  
Mugio Nishizawa ◽  
Nebojsa Marinovic ◽  
William J. Ehmann
Keyword(s):  
Double Bond ◽  
Rhodium Catalysis ◽  
Double Bond Migration

ChemInform Abstract: Double-Bond Migration in Pyrano(4,3-b)pyrylium Cations.

ChemInform ◽  
2010 ◽  
Vol 25 (8) ◽  
pp. no-no
Author(s):  
F. M. DEAN ◽  
M. MALKI ◽  
L. J. O'KEEFFE
Keyword(s):  
Double Bond ◽  
Double Bond Migration

scholarly journals Oxepinamide F biosynthesis involves enzymatic d-aminoacyl epimerization, 3H-oxepin formation, and hydroxylation induced double bond migration

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Liujuan Zheng ◽  
Haowen Wang ◽  
Aili Fan ◽  
Shu-Ming Li
Keyword(s):  
Cytochrome P450 ◽  
Double Bond ◽  
Biosynthetic Pathway ◽  
Hydroxyl Group ◽  
Cytochrome P450 Enzyme ◽  
Double Bond Migration ◽  
Feeding Experiments ◽  
Aspergillus Ustus ◽  
P450 Enzyme ◽  
Derivatives Of

Abstract Oxepinamides are derivatives of anthranilyl-containing tripeptides and share an oxepin ring and a fused pyrimidinone moiety. To the best of our knowledge, no studies have been reported on the elucidation of an oxepinamide biosynthetic pathway and conversion of a quinazolinone to a pyrimidinone-fused 1H-oxepin framework by a cytochrome P450 enzyme in fungal natural product biosynthesis. Here we report the isolation of oxepinamide F from Aspergillus ustus and identification of its biosynthetic pathway by gene deletion, heterologous expression, feeding experiments, and enzyme assays. The nonribosomal peptide synthase (NRPS) OpaA assembles the quinazolinone core with d-Phe incorporation. The cytochrome P450 enzyme OpaB catalyzes alone the oxepin ring formation. The flavoenzyme OpaC installs subsequently one hydroxyl group at the oxepin ring, accompanied by double bond migration. The epimerase OpaE changes the d-Phe residue back to l-form, which is essential for the final methylation by OpaF.

scholarly journals Structure Determination of Two New Monocillin I Derivatives

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500
Author(s):  
Jixun Zhan ◽  
E. M. Kithsiri Wijeratne ◽  
A. A. Leslie Gunatilaka
Keyword(s):  
Double Bond ◽  
Acid Solution ◽  
Beauveria Bassiana ◽  
Structure Determination ◽  
Spectroscopic Data ◽  
Enzymatic Process ◽  
Acid Catalyzed ◽  
Hydrolysis Of

Biotransformation of monocillin I (1) by Beauveria bassiana ATCC 7159 was investigated. Two new derivatives 2 and 3 were isolated and identified on the basis of the spectroscopic data. Compounds 2 and 3 are synthesized by hydration at 10,11-double bond and hydrolysis of 14,15-epoxide, respectively. The R configuration of 11-OH in 2 was established by the modified 2-methoxy-2-trifluoromethylphenylacetic acid (MTPA) method. The conversion of 1 to 2 and 3 was reconstituted in an acid solution, indicating that the formation of 2 and 3 is an acid-catalyzed instead of an enzymatic process.

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