138-12-5Relevant articles and documents
The Assignment of the Absolute Configuration of β-Chiral Primary Alcohols with Axially Chiral Trifluoromethylbenzimidazolylbenzoic Acid
Kriegelstein, Michal,Profous, David,P?ibylka, Adam,Canka?, Petr
, p. 12912 - 12921 (2020/11/23)
Axially chiral trifluoromethylbenzimidazolylbenzoic acid (TBBA) was used as a chiral derivatization agent for the assignment of the absolute configuration of β-chiral primary alcohols. The structures varied from simple aliphatic alcohols to complex cyclic systems and highly substituted sugar derivatives. The NMR-based method was successfully implemented to evaluate 17 compounds and displayed ΔδPM values higher than 0.1 ppm in most cases, which makes TBBA superior to MTPA and MPA and comparable to 9-AMA.
Contra-thermodynamic Hydrogen Atom Abstraction in the Selective C-H Functionalization of Trialkylamine N-CH3 Groups
Barham, Joshua P.,John, Matthew P.,Murphy, John A.
supporting information, p. 15482 - 15487 (2016/12/09)
We report a simple one-pot protocol that affords functionalization of N-CH3 groups in N-methyl-N,N-dialkylamines with high selectivity over N-CH2R or N-CHR2 groups. The radical cation DABCO+?, prepared in situ by oxidation of DABCO with a triarylaminium salt, effects highly selective and contra-thermodynamic C-H abstraction from N-CH3 groups. The intermediates that result react in situ with organometallic nucleophiles in a single pot, affording novel and highly selective homologation of N-CH3 groups. Chemoselectivity, scalability, and recyclability of reagents are demonstrated, and a mechanistic proposal is corroborated by computational and experimental results. The utility of the transformation is demonstrated in the late-stage site-selective functionalization of natural products and pharmaceuticals, allowing rapid derivatization for investigation of structure-activity relationships.
Functional characterization of recombinant hyoscyamine 6β-hydroxylase from Atropa belladonna
Li, Jing,Van Belkum, Marco J.,Vederas, John C.
experimental part, p. 4356 - 4363 (2012/08/28)
(-)-Hyoscyamine, the enantiomerically pure form of atropine, and its derivative scopolamine are tropane alkaloids that are extensively used in medicine. Hyoscyamine 6β-hydroxylase (H6H, EC 1.14.11.11), a monomeric α-ketoglutarate dependent dioxygenase, converts (-)-hyoscyamine to its 6,7-epoxy derivative, scopolamine, in two sequential steps. In this study, H6H of Atropa belladonna (AbH6H) was cloned, heterologously expressed in Escherichia coli, purified and characterized. The catalytic efficiency of AbH6H, especially for the second oxidation, was found to be low, and this may be one of the reasons why Atropa belladonna produces less scopolamine than other species in the same family. 6,7-Dehydrohyoscyamine, a potential precursor for the last step of epoxidation, was shown not to be an obligatory intermediate in the biosynthesis of scopolamine using purified AbH6H with an in vitro 18O labeling experiment. Moreover, the nitrogen atom in the tropane ring of (-)-hyoscyamine was found to play an important role in substrate recognition.
