33599-86-9Relevant academic research and scientific papers
Intramolecular Cyclization of Vinyldiazoacetates as a Versatile Route to Substituted Pyrazoles
Drikermann, Denis,G?rls, Helmar,Kerndl, Valerie,Vilotijevic, Ivan
, p. 1158 - 1162 (2020/07/20)
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95percent. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- A nd tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents, this method constitutes a new entry to this valuable heterocyclic scaffold and may be of interest to all branches of the chemical industry.
Highly regioselective palladium-catalysed oxidative allylic C-H carbonylation of alkenes
Chen, Huoji,Cai, Congbi,Liu, Xiaohang,Li, Xianwei,Jiang, Huanfeng
supporting information; experimental part, p. 12224 - 12226 (2011/12/14)
Pd-catalysed direct oxidative carbonylation of allylic C-H bonds with carbon monoxide was first described. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalysed allylic carbonylation can be lifted, which provides a new route for accessing more synthetically useful β-enoic acid esters with high regioselectivity. The Royal Society of Chemistry 2011.
Regioselective ring opening and isomerization reactions of 3,4-epoxyesters catalyzed by boron trifluoride
Izquierdo, Javier,Rodriguez, Santiago,Gonzalez, Florenci V.
supporting information; experimental part, p. 3856 - 3859 (2011/09/19)
Efficient ring opening of 3,4-epoxyesters with alcohols to produce 4-alkoxy-3-hydroxyesters and their isomerization into 4-ketoesters using boron trifluoride as the catalyst are presented. Both transformations are simple and efficient methods for the synthesis of the above named synthetically useful compounds.
HPLC and GC-MS identification of the major organic constituents in New Zealand propolis
Markham, Kenneth R.,Mitchell, Kevin A.,Wilkins, Alistair L.,Daldy, Julia A.,Lu, Yinrong
, p. 205 - 211 (2007/10/03)
The major organic constituents of New Zealand sourced propolis have been identified and quantified in tincture solutions by a combination of HPLC and GC-mass spectrometry (MS). HPLC was the preferred method for the analysis of flavonoids because of their very low response factors in GC-MS. Flavonoid levels ranged from 30-40 mg ml-1. A distinctive characteristic of the flavonoids in New Zealand propolis is the unusually high proportion (ca 70%) of dihydroflavonoids, e.g. pinocembrin, pinobanksin and pinobanksin 3-acetate. Non-flavonoid components analysed by GC-MS comprised a range of aromatic compounds (3-7.5 mg ml-1), together with low levels (0.25-0.78 mg ml-1) of fatty acids. The former comprised mainly cinnamic acids and their esters, but also included the rare 5-phenyl-trans-trans-2,4-pentadienoic acid and the new natural product, 5-phenyl-trans-3-pentenoic acid. Both were synthesized to confirm their identity. Copyright
Reductive Cleavage Reaction of γ-Functionalized α,β-Unsaturated Esters and Halomethyls Mediated with Magnesium in Methanol
Pak, Chwang Siek,Lee, Eun,Lee, Ge Hyeong
, p. 1523 - 1530 (2007/10/02)
Reductive cleavage of various types of C-O and C-N bonds tethered to α,β-unsaturated esters and halomethyls was mediated with magnesium in methanol, which provided a facile method for the synthesis of δ-hydroxy or δ-amino β,γ-unsaturated esters and allylic alcohols.Regardless of the geometry (E or Z) of the α,β-unsaturated esters, 1a-b, 5a-c, 11, 13, and 23, the cleavage product obtained was exclusively the E isomer of the corresponding deconjugated hydroxy and amino esters.The steric bias and ring strain of 15, 17, and 21 gave rise to a product mixture of E and Z isomers.
