18917-77-6Relevant academic research and scientific papers
Identification and Quantification of a Phytotoxic Metabolite from Alternaria dauci
Leyte-Lugo, Martha,Pe?a-Rodriguez, Luis M.,Poupard, Pascal,Richomme, Pascal
, (2020)
Alternaria dauci is the causal agent of Alternaria leaf blight (ALB) in carrot (Daucus carota) crops around the world. However, to date, A. dauci has received limited attention in its production of phytotoxic metabolites. In this investigation, the bioassay-guided isolation of the extract from liquid cultures of A. dauci resulted in the isolation of two metabolites identified as α-acetylorcinol (1) and p-hydroxybenzoic acid (2), based on their spectroscopic data and results from chemical correlation reactions. Testing of both metabolites in different assays showed an important phytotoxic activity for p-hydroxybenzoic acid (2) when tested in the leaf-spot assay on parsley (Petroselinum crispum), in the leaf infiltration assay on tobacco (Nicotiana alata) and marigold (Tagetes erecta), and in the immersion assay on parsley and parsnip (Pastinaca sativa) leaves. Quantification of the two metabolites in the crude extract of A. dauci kept at different times showed that p-hydroxybenzoic acid (2) is one of the first metabolites to be synthesized by the pathogen, suggesting that this salicylic acid derivative could play an important role in the pathogenicity of the fungus.
Aldehyde to Ketone Homologation Enabled by Improved Access to Thioalkyl Phosphonium Salts
Fragis, Meghan,Deobald, Jackson L.,Dharavath, Srinivas,Scott, Jeffrey,Magolan, Jakob
supporting information, p. 4548 - 4552 (2021/06/28)
Phosphines were previously unusable as Pummerer-type nucleophiles due to competing redox chemistry with sulfoxides. Here we circumvent this problem to achieve a formal phosphine Pummerer reaction that offers thioalkyl phosphonium salts that, in turn, give rise to diverse vinyl sulfides via Wittig olefinations. Thirty vinyl sulfides are thus prepared from (alkylthioalkyl)triphenyl phosphonium salts and aldehydes. The hydrolysis of these vinyl sulfides offers an efficient and versatile two-step one-carbon homologation of aldehydes to ketones.
Direct Asymmetric Reductive Amination for the Synthesis of Chiral β-Arylamines
Huang, Haizhou,Liu, Xiaoyan,Zhou, Le,Chang, Mingxin,Zhang, Xumu
supporting information, p. 5309 - 5312 (2016/04/26)
The highly efficient and direct asymmetric reductive amination of arylacetones catalyzed by an iridium complex for the preparation of enantiomerically pure β-arylamines is described. The monodentate phosphoramidite ligand exhibits superb reactivity (TONs of up to 20 000) and enantioselectivity (up to 99 % ee). Additives played important roles in this reductive coupling reaction. Asymmetric reductive coupling of a ketone and an amine is a straightforward and atom-economic approach for preparing optically enriched amines. The highly efficient and direct asymmetric reductive amination of arylacetones, catalyzed by an iridium complex, supplies enantiomerically pure β-arylamines. The new phosphoramidite ligands reported show superb reactivity and enantioselectivity in this reductive coupling. M.S.=molecular sieves, TFA=trifluoroacetic acid.
Gold-catalyzed construction of two adjacent quaternary stereocenters via sequential C-H functionalization and aldol annulation
Yu, Zhunzhun,Qiu, Haile,Liu, Lu,Zhang, Junliang
supporting information, p. 2257 - 2260 (2016/02/12)
Herein, a novel and efficient gold-catalyzed intermolecular C(sp2)-H functionalization (Friedel-Crafts alkylation) and aldol annulation strategy is presented. This cascade process allows the synthesis of a series of indanol and tetrahydronaphthalenol derivatives with two adjacent quaternary stereocenters. The attractive reaction features are the use of readily available starting materials, good diastereoselectivity, good functional-group tolerance and mild reaction conditions. Furthermore, preliminary results indicate that this transformation is amenable to enantioselectivitive synthesis with further chiral ligand screening and design.
Synthesis of carbocyclic analogs of dehydroaltenusin: Identification of a stable inhibitor of calf DNA polymerase α
Ková?ová, Silvia,Adla, Santosh Kumar,Maier, Luká?,Babiak, Michal,Mizushina, Yoshiyuki,Paruch, Kamil
, p. 7575 - 7582 (2015/09/07)
Syntheses of carbocyclic analogs of dehydroaltenusin tautomers are reported. Both target compounds, cDHA (2,8-dihydroxy-6-methoxy-10a-methyl-10,10a-dihydrophenanthrene-3,9-dione) and cDHAs (4′,5-dihydroxy-6′-methoxy-2-methylspiro[cyclohexa[2,5]diene-1,1′-
Zheda-phos for general α-monoarylation of acetone with aryl chlorides
Li, Pengbin,Lue, Bo,Fu, Chunling,Ma, Shengming
supporting information, p. 1255 - 1259 (2013/06/27)
A new, readily available, and air-stable monophosphine ligand, i.e., Zheda-Phos, has been developed for the general and highly effective palladium-catalyzed monoarylation of acetone with aryl chlorides. The reaction rate is of first-order dependence with the aryl chloride. Copyright
Use of conjugated dienones in cyclialkylations: Total syntheses of arucadiol, 1,2-didehydromiltirone, (±)-hinokione, (±)-nimbidiol, sageone, and miltirone
Majetich, George,Liu, Shuang,Fang, Jing,Siesel, David,Zhang, Yong
, p. 6928 - 6951 (2007/10/03)
Functionalized hydrophenanthrenes can be prepared using a cyclialkylation-based strategy. These annulations are highly dependent on the directing effects of the arene substitutents and on conformational considerations. The utility of this methodology was featured in the syntheses of six diterpenoids.
The synthesis and biological activity of two analogs of the anti-HIV alkaloid michellamine B
Upender,Pollart,Liu,Hobbs,Olsen,Chao,Bowden,Crase,Thomas,Pandey,Lawson,Dawson
, p. 1371 - 1385 (2007/10/03)
Two simplified analogs of the dimeric naphthalenyltetrahydroisoquinoline alkaloid michellamine B [4',4''-didesmethoxy-2',2''-didesmethylmichellamine B and 6,8-dihydroxy-5-(1',1''-dihydroxy-2',2''-binaphthalen-4'-yl)-1R,3R-dim ethyl-1,2,3,4-tetrahydroisoqu
TOTAL SYNTHESIS OF MICHELLAMINES A-C: IMPORTANT ANTI-HIV AGENTS
Hoye, Thomas R.,Chen, Minzhang,Mi, Liang,Priest, Owen P.
, p. 8747 - 8750 (2007/10/02)
Michellamines A-C have been prepared by total synthesis in 7 and 16 linear steps from known and commercial materials, respectively.Key steps include i) palladium(0)-mediated biaryl coupling, ii) silver oxide promoted oxidative 1-naphthol coupling to an atropisomeric mixture of cross-ring quinones (indigoids), and iii) simultaneous per-debenzylation/reductive bleaching to the central 2,2'-binaphthol.
On the Synthesis of Some Chlorinated Isocoumarins
Chatterjea, J. N.,Bhakta, C.,Mukherjee, Sanat K.
, p. 888 - 890 (2007/10/02)
The dihydroisocoumarin(V) and the isochroman(XII) have been synthesised during experiments on the synthesis of some natural chlorinated isocoumarins.
