32659-20-4Relevant academic research and scientific papers
A detailed view on 1,8-cineol biosynthesis by Streptomyces clavuligerus
Rinkel, Jan,Rabe, Patrick,Zur Horst, Laura,Dickschat, Jeroen S.
supporting information, p. 2317 - 2324 (2016/11/17)
The stereochemical course of the cyclisation reaction catalysed by the bacterial 1,8-cineol synthase from Streptomyces clavuligerus was investigated using stereospecifically deuterated substrates. In contrast to the well investigated plant enzyme from Salvia officinalis, the reaction proceeds via (S)-linalyl diphosphate and the (S)-terpinyl cation, while the final cyclisation reaction is in both cases a syn addition, as could be shown by incubation of (2-13C)geranyl diphosphate in deuterium oxide.
Identification of geranic acid, a tyrosinase inhibitor in lemongrass (Cymbopogon citratus)
Masuda, Toshiya,Odaka, Yuka,Ogawa, Natsuko,Nakamoto, Katsuo,Kuninaga, Hideki
experimental part, p. 597 - 601 (2009/05/30)
Lemongrass is a popular Asian herb having a lemon-like flavor. Very recently, potent tyrosinase inhibitory activity has been found in lemongrass in addition to various biological activities reported in the literature. The aim of the present study is to identify the active compounds in the lemongrass. An assay-guided purification revealed that one of the active substances was geranic acid. Geranic acid has two stereoisomers, which are responsible for the trans and cis geometry on the conjugated double bond. Both isomers are present in the active ethyl acetate-soluble extract of the lemongrass, and their IC 50 values were calculated to be 0.14 and 2.3 mM, respectively. The structure requirement of geranic acid for the potent tyrosinase inhibitory activity was investigated using geranic acid-related compounds.
Observations on the direct amidocyclopropanation of alkenes using organozinc carbenoids
Motherwell, William B.,Bégis, Guillaume,Cladingboel, David E.,Jerome, Laure,Sheppard, Tom D.
, p. 6462 - 6476 (2008/02/04)
A series of amidocyclopropanes were prepared by direct amidocyclopropanation of alkenes, using organozinc carbenoids generated from readily available diethoxymethylamides. The amidocyclopropanation of monosubstituted alkenes led to selective formation of the trans-amidocyclopropane in most cases, but with more substituted alkenes, the stereochemical outcome of the cyclopropanation reactions was unpredictable. The amidocyclopropane products can be readily elaborated to structurally interesting cyclopropane containing amino acids or amino alcohols.
Mechanism of the Asymmetric Isomerization of Allylamines to enamines Catalyzed by 2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl-Rhodium Complexes
Inoue, Shin-Ichi,Takaya, Hidemasa,Tani, Kazuhide,Otsuka, Sei,Sato, Tsuneo,Noyori, Ryoji
, p. 4897 - 4905 (2007/10/02)
Cationic Rh complexes containing the 2,2′-bis(diphenylphosphino)-1,1′-binahthyl lgand catalyze a highly enantioselective isomerization of diethylgeranylamine or -nerylamine to give (R)- or (S)-citronellal (E)-diethylenamine in >95% ee. A new, nitrogen-triggered mechanism is postulated for the double-bond-migration reaction on the basis of 1H and 31P NMR stdies, kinetic measurements, and deuterium-labeling experiments. The initial nitrogen-coordinated allylamine-Rh+ complex causes a four-centered hydride elimination from C(1) via dissociative mechanism to generate a transien iminium-RhH complex. Delivery of the hydrogen from Rh to C(3) gives the enamine η3complex. The latter, having an aza-allyl structure, serves as the chain carrier in the catalytic cycle. The BINAP-Rh+ complexes differetiate efficiently the enantotopic C(1) hydrogens of the allylamines through interaction with the adjacent nitrogen atoms. The overall 1,3-hydrogen shift occurs in a suprafacial manner from an s-trans-type conformer of the flexible substrates. The origin of the chiral recognition has been interpreted n terms of the chiral environments of the BINAP-based Rh+ complexes.
Carbon-Carbon Bond Formation at the γ-Position of Dienolates via the Germanium Masked Dienolates
Yamamoto, Yoshinori,Hatsuya, Satoshi,Yamada, Jun-ichi
, p. 1639 - 1640 (2007/10/02)
Trapping of the lithium dienolate (1), derived from 3-methyl-2-butenoate, with Me3GeX (X = Br or Cl gives the α-germylated derivative (2), which reacts with various electrophiles at the γ-position.
