<sup>13</sup>C-NMR. Spectral Differences between Corresponding Methyl Esters, Phenyl Esters and 2-Substituted Chromones
作者:Urs Séquin
DOI:10.1002/hlca.19810640824
日期:1981.12.16
The 13C-NMR. spectra of 2-substitutedchromones (3) are compared with the data of the analogous methyl and phenylesters (1 and 2). The chemical shift differences found are most prominent for the C-atoms in β-position to the ester carbonyl and chromone C(2), respectively. These shift differences are discussed in terms of conformational differencesbetween the esters 1 and 2 and the analogous chromones
The Ru(II)-catalyzed C-H activation and annulation reaction of salicylaldehydes and disubstitutedalkynes affords chromones in high yields. This reaction works with terminal alkynes also and tolerates wide range of sensitive...
Chiral chromanols and their derivatives have been synthesized via a RuPHOX–Ru catalyzedasymmetrichydrogenation of chromones in high yields, >20 : 1 drs and with up to 99.9% ee. Control experiments show that the reaction undergoes two sequential asymmetrichydrogenation steps of the CC and CO double bonds. The reaction could be performed on a gram-scale with a relatively low catalyst loading (up to
通过RuPHOX-Ru催化色酮的不对称氢化,以高产率,> 20:1 drs和最高99.9%ee合成了手性苯甲酚及其衍生物。对照实验表明,该反应经历了C C和C O双键的两个连续的不对称氢化步骤。该反应可以以克级进行,具有相对较低的催化剂负载量(最高1000 S / C),并且所得产物可以转化为几种生物活性化合物。
Synthese von 2-Carbonyl-chromonen
作者:J. Schmutz、R. Hirt、H. Lauener
DOI:10.1002/hlca.19520350411
日期:1952.5.2
Es werden drei Wege der Synthesevon 2-Carbonylchromonen beschrieben: Oxydation von 2-Alkylchromonen mit SeO2, resp. CrO3; Spalten der Nitrone, resp. Anile von 2-Alkylchromonen; Spalten der Isonitrosoverbindungen von 2-Alkylchromonen.
Es werden drei Wege der Synthese von 2-Carbonylchromonenmitschöben:氧化von 2-Alkaylchromonen mit SeO 2,分别。CrO 3 ; Spalten der Nitrone,分别。Anile von 2-Alkaylchromonen; Spalten der Isonitrosoverbindungen von 2-Alkylchromonen。
Synthesis of Chromones through LiO<i>t</i>Bu/Air-Mediated Oxidation and Regioselective Cyclization of<i>o</i>-Hydroxyphenyl Propargyl Carbinols
作者:Shuai Zhang、Changfeng Wan、Qiang Wang、Baiqun Zhang、Lingfeng Gao、Zhenggen Zha、Zhiyong Wang
DOI:10.1002/ejoc.201201665
日期:2013.4
A cascade oxidativecyclization reaction for the synthesis of chromone derivatives was developed by using LiOtBu as a mediator and air as an oxidant. The reaction was carried out without the assistance of a transition metal under mild conditions to afford the chromones in good yields with high regioselectivities.