619-42-1Relevant articles and documents
The tremulanes, a new group of sesquiterpenes from the aspen rotting fungus Phellinus tremulae
Ayer,Cruz
, p. 7529 - 7534 (1993)
A series of new sesquiterpenes, the tremulanes, possessing a previously unreported substituted perhydroazulene carbon skeleton, has been isolated from liquid cultures of the aspen (Populus tremuloides) rotting fungus Phellinus tremulae. The structures were determined by NMR techniques (1H- 1H COSY, HMQC, and HMBC) and other physical methods including, in the case of tremulenolide A (6), X-ray crystallography. The chemical correlation of tremulenediol A (10) with tremulenolide A (6) is described as is the correlation of tremulenedial (8) with tremulenediol B (11). The absolute configuration of the compounds is assigned by application of the olefin octant rule to the allylic alcohol tremulenediol A (10). These new sesquiterpenes do not obey the biogenetic isoprene rule and it is suggested that they may not be derived from farnesyl pyrophosphate.
Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
Wang, Jingjing,Jiang, Feng,Tao, Chaofu,Yu, Han,Ruhlmann, Laurent,Wei, Yongge
supporting information, p. 2652 - 2657 (2021/04/21)
The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications.
Ni-NiO heterojunctions: a versatile nanocatalyst for regioselective halogenation and oxidative esterification of aromatics
Bhardwaj, Nivedita,Goel, Bharat,Indra, Arindam,Jain, Shreyans K.,Singh, Ajit Kumar,Tripathi, Nancy
, p. 14177 - 14183 (2021/08/16)
Herein, we report a facile method for the synthesis of Ni-NiO heterojunction nanoparticles, which we utilized for the nuclear halogenation reaction of phenol and substituted phenols usingN-bromosuccinimide (NBS). A remarkablepara-selectivity was achieved for the halogenated products under semi-aqueous conditions. Interestingly, blocking of thepara-position of phenol offeredortho-selective halogenation. In addition, the Ni-NiO nanoparticles catalyzed the oxidative esterification of carbonyl compounds with alcohol, diol or dithiol in the presence of a catalytic amount of NBS. It was observed that the aromatic carbonyls substituted with an electron-donating group favoured nuclear halogenation, whereas an electron-withdrawing group substitution in carbonyl compounds facilitated the oxidation reaction. In addition, the catalyst was magnetically separated and recycled 10 times. The tuned electronic structure at the Ni-NiO heterojunction controlled selectivity and activity as no suchpara-selectivity was observed with commercially available NiO or Ni nanoparticles.