Trichodiene synthase. Synergistic inhibition by inorganic pyrophosphate and aza analogs of the bisabolyl cation.
摘要:
A series of aza analogs of the bisabolyl and alpha-terpinyl cations were tested as inhibitors of the sesquiterpene cyclase, trichodiene synthase. Both (R)- and (S)-16 and (R)- and (S)-13 as well as trimethylamine were only weak inhibitors when incubated alone. In the presence of inorganic pyrophosphate, itself a known competitive inhibitor of trichodiene synthase, all five amines showed strong cooperative competitive inhibition with an enhancement factor estimated to be 10-40. The apparent induced inhibition constant alpha-K(j) decreased in going from trimethylamine to the monoterpene analogs 13 and was strongest for the sesquiterpene analogs 16, indicating that both electrostatic and hydrophobic interactions are important in the binding of each intermediate analog. The cyclase showed little discrimination, however, between the individual enantiomers of each inhibitor.
Trichodiene synthase. Synergistic inhibition by inorganic pyrophosphate and aza analogs of the bisabolyl cation.
摘要:
A series of aza analogs of the bisabolyl and alpha-terpinyl cations were tested as inhibitors of the sesquiterpene cyclase, trichodiene synthase. Both (R)- and (S)-16 and (R)- and (S)-13 as well as trimethylamine were only weak inhibitors when incubated alone. In the presence of inorganic pyrophosphate, itself a known competitive inhibitor of trichodiene synthase, all five amines showed strong cooperative competitive inhibition with an enhancement factor estimated to be 10-40. The apparent induced inhibition constant alpha-K(j) decreased in going from trimethylamine to the monoterpene analogs 13 and was strongest for the sesquiterpene analogs 16, indicating that both electrostatic and hydrophobic interactions are important in the binding of each intermediate analog. The cyclase showed little discrimination, however, between the individual enantiomers of each inhibitor.
Stereoselective [4+2]‐Cycloaddition with Chiral Alkenylboranes
作者:Dongshun Ni、Brittany P. Witherspoon、Hong Zhang、Chen Zhou、K. N. Houk、M. Kevin Brown
DOI:10.1002/anie.202000652
日期:2020.7.6
A method for the stereoselective [4+2]‐cycloaddition of alkenylboranes and dienes is presented. This transformation was accomplished through the introduction of a new strategy that involves the use of chiral N‐protonated alkenyl oxazaborolidines as dieneophiles. The reaction leads to the formation of products that can be readily derivatized to more complex structural motifs through stereospecific transformations
Alkylhalovinylboranes: a new class of Diels–Alder dienophiles
作者:Pablo L. Pisano、Silvina C. Pellegrinet
DOI:10.1039/c8ra07089j
日期:——
The Diels–Alder reactions of alkylhalovinylboranes have been investigated theoretically and experimentally. Alkylhalovinylboranes presented higher reactivity than the corresponding dialkylvinylboranes. Although endo/exo selectivities were high for the reactions with cyclopentadiene, facial selectivities for the chiral analogues were low. Our results demonstrate that the replacement of an alkyl group
The present invention provides a compound represented by Formula (I)
(wherein R
1
and R
2
are the same or different, and each represents a hydrogen atom, substituted or unsubstituted lower alkyl and the like,
R
3
represents substituted or unsubstituted aryl, a substituted or unsubstituted aromatic heterocyclic group and the like,
R
4
and R
5
are the same or different, and each represents a hydrogen atom, halogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl and the like, proviso that they are not simultaneously hydrogen atoms, and
R
6
represents hydroxy or substituted or unsubstituted lower alkoxy), or a pharmaceutically acceptable salt thereof and the like.