7149-90-8Relevant academic research and scientific papers
Monodentate Transient Directing Group Enabled Pd-Catalyzed Ortho-C-H Methoxylation and Chlorination of Benzaldehydes
Li, Feng,Zhou, Yirong,Yang, Heng,Wang, Ziqi,Yu, Qinqin,Zhang, Fang-Lin
supporting information, p. 3692 - 3695 (2019/05/24)
We report Pd-catalyzed ortho-C-H methoxylation and chlorination of benzaldehydes by employing monodentate transient directing groups (TDGs) as an alternative strategy to bidentate TDGs. More importantly, a single crystal of benzaldehyde imine ortho-cyclopalladium intermediate was successfully obtained, and its structure was unambiguously determined by X-ray diffraction, which clearly showed that it was a binuclear palladium species bridged by a pyridone ligand. The utility of this approach was further demonstrated through the synthesis of key intermediates of natural products and drugs.
Synthesis of oxygenated orthomethylbenzaldehydes via aryne [2+2] cycloaddition and benzocyclobutenol ring opening
Maturi, Mark M.,Ohmori, Ken,Suzuki, Keisuke
, p. 870 - 873 (2019/01/21)
Herein, a two-step procedure for the preparation of oxygenated ortho-methylbenzaldehyde derivatives, starting from commercially available bromoarenes, is described. The synthesis features the simultaneous and highly regioselective installation of both the methyl and the formyl group onto the benzene core via benzyne [2+2] cycloadditions with acetaldehyde lithium enolate to give the corresponding benzocyclobutenols in high yields. Bond-selective ring opening of the benzocyclobutenols under basic conditions in methanol delivers the title compounds.
First total synthesis of kipukasin A
Li, Chuang,Ding, Haixin,Ruan, Zhizhong,Zhou, Yirong,Xiao, Qiang
supporting information, p. 855 - 862 (2017/06/20)
In this paper, a practical approach for the total synthesis of kipukasin A is presented with 22% overall yield by using tetra-O-acetyl-β-D-ribose as starting material. An improved iodine-promoted acetonide-forming reaction was developed to access 1,2-O-is
IBX works efficiently under solvent free conditions in ball milling
Achar, Tapas Kumar,Maiti, Saikat,Mal, Prasenjit
, p. 12834 - 12839 (2014/04/03)
IBX (2-iodoxybenzoic acid), discovered in 1893, is an oxidant in synthetic chemistry whose extensive use is impeded by its explosiveness at high temperature and poor solubility in common organic solvents except DMSO. Since the discovery of Dess-Martin Periodinane in 1983, several modified IBX systems have been reported. However, under ball milling conditions, IBX works efficiently with various organic functionalities at ambient temperature under solvent free conditions. Also, the waste IBA (2-iodosobenzoic acid) produced from the reactions was in situ oxidized to IBX in the following step using oxone and thus reused for multiple cycles by conserving its efficiency (only ～6% loss after 15 cycles). This work describes an overview of a highly economical synthetic methodology which overcomes the problems of using IBX, efficiently in gram scale and in a non-explosive way. This journal is the Partner Organisations 2014.
Ethynylbenzenoid metabolites of Antrodia camphorata: Synthesis and inhibition of TNF expression
Buccini, Marco,Punch, Kathryn A.,Kaskow, Belinda,Flematti, Gavin R.,Skelton, Brian W.,Abraham, Lawrence J.,Piggott, Matthew J.
, p. 1100 - 1113 (2014/02/14)
An improved synthesis of the anti-inflammatory natural product antrocamphin A (2), involving a key Castro-Stephens reaction, is presented, along with the first total synthesis of its congener antrocamphin B (3). Approaches towards the more complex co-meta
Reaction of phenols with the 2,2-diphenyl-1-picrylhydrazyl radical. Kinetics and DFT calculations applied to determine ArO-H bond dissociation enthalpies and reaction mechanism
Foti, Mario C.,Daquino, Carmelo,Mackie, Iain D.,DiLabio, Gino A.,Ingold
experimental part, p. 9270 - 9282 (2009/04/07)
(Figure Presented) The formal H-atom abstraction by the 2,2-diphenyl-1-picrylhydrazyl (dpph?) radical from 27 phenols and two unsaturated hydrocarbons has been investigated by a combination of kinetic measurements in apolar solvents and density functional theory (DFT). The computed minimum energy structure of dpph? shows that the access to its divalent N is strongly hindered by an ortho H atom on each of the phenyl rings and by the o-NO2 groups of the picryl ring. Remarkably small Arrhenius pre-exponential factors for the phenols [range (1.3-19) × 105 M-1 s-1] are attributed to steric effects. Indeed, the entropy barrier accounts for up to ca. 70% of the free-energy barrier to reaction. Nevertheless, rate differences for different phenols are largely due to differences in the activation energy, Ea,1 (range 2 to 10 kcal/mol). In phenols, electronic effects of the substituents and intramolecular H-bonds have a large influence on the activation energies and on the ArO-H BDEs. There is a linear Evans-Polanyi relationship between E a,1 and the ArO-H BDEs: Ea,1/kcal x mol-1 = 0.918 BDE(ArO-H)/kcal x mol-1 - 70.273. The proportionality constant, 0.918, is large and implies a "late" or "product-like" transition state (TS), a conclusion that is congruent with the small deuterium kinetic isotope effects (range 1.3-3.3). This Evans-Polanyi relationship, though questionable on theoretical grounds, has profitably been used to estimate several ArO-H BDEs. Experimental ArO-H BDEs are generally in good agreement with the DFT calculations. Significant deviations between experimental and DFT calculated ArO-H BDEs were found, however, when an intramolecular H-bond to the O? center was present in the phenoxyl radical, e.g., in ortho semiquinone radicals. In these cases, the coupled cluster with single and double excitations correlated wave function technique with complete basis set extrapolation gave excellent results. The TSs for the reactions of dpph ? with phenol, 3- and 4-methoxyphenol, and 1,4-cyclohexadiene were also computed. Surprisingly, these TS structures for the phenols show that the reactions cannot be described as occurring exclusively by either a HAT or a PCET mechanism, while with 1,4-cyclohexadiene the PCET character in the reaction coordinate is much better defined and shows a strong π-π stacking interaction between the incipient cyclohexadienyl radical and a phenyl ring of the dpph? radical.
COMPOUNDS AND COMPOSITIONS USEFUL IN THE TREATMENT OF NEOPLASIA
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Page/Page column 49; 59, (2008/06/13)
There is described compounds for use in therapy, said compounds being defined by Formula (1): There is also described an anti-proliferative composition comprising one or more compounds according to Formula (1), and a method of treatment of neoplasia comprising the administration of such a compound or composition.
Synthetic study for two 2H-chromenic acids, 8-chlorocannabiorcichromenic acid and mycochromenic acid
Yamaguchi, Seiji,Nedachi, Masahiro,Maekawa, Mikiko,Murayama, Yohei,Miyazawa, Masahiro,Hirai, Yoshiro
, p. 29 - 41 (2007/10/03)
Two 2H-chromenes having a fully substituted benzene ring, 8-chlorocannabioreichromene (1) and mycochromenic acid (2), were synthesized by a condensation of salicylaldehydes with isopropylidenemalonate or the thermal cyclization of corresponding propargyl ethers.
Total synthesis of CRM646-A and -B, two fungal glucuronides with potent heparinase inhibition activities
Wang, Ping,Zhang, Zhaojun,Yu, Biao
, p. 8884 - 8889 (2007/10/03)
CRM646-A (1) and -B (2), two fungal glucuronides with a dimeric 2,4-dihydroxy-6-alkylbenzoic acid (orcinol p-depside) aglycone showing significant heparinase and telomerase inhibition activities, were synthesized for the first time. The successful approac
New approach for two chromene carboxylic acids having a fully substituted benzene ring
Yamaguchi, Seiji,Maekawa, Mikiko,Murayama, Yohei,Miyazawa, Masahiro,Hirai, Yoshiro
, p. 6971 - 6973 (2007/10/03)
Two chromene carboxylic acids having a fully substituted benzene ring, 8-chlorocannabiorcichromenic acid (1) and myco-chromenic acid (2), were synthesized via thermal cyclization of the corresponding four substituted phenyl propargyl ethers. Two chromene
