نتایج جستجو برای: friedländer hetero annulation

تعداد نتایج: 5992  

Journal: :Organic letters 2015
Santhivardhana Reddy Yetra Santigopal Mondal Eringathodi Suresh Akkattu T Biju

The N-heterocyclic carbene (NHC)-organocatalyzed enantioselective annulation reaction of pyrazolones with α,β-unsaturated aldehydes proceeding via the chiral α,β-unsaturated acyl azolium intermediates under oxidative conditions is presented. The reaction afforded dihydropyranone-fused pyrazoles in moderate to good yields and good er values under operationally simple and base-free conditions.

Journal: :Organic & biomolecular chemistry 2016
A Sagar Venkata Nagarjuna Babu Anand H Shinde Duddu S Sharada

A reactive cyclic iminium induced one-pot Groebke-Blackburn-Bienayme (GBB) double annulation cascade (DAC) for the synthesis of skeletally diverse DHIQ salts has been described. The key features of this protocol are transition-metal and solvent-free, mild reaction conditions, robust method, one-step construction of two privileged heterocyclic rings, clean reaction profile and operational simpli...

2013
Lynnie Trzoss Jing Xu Michelle H Lacoske Emmanuel A Theodorakis

An enantioselective synthesis of the core framework of neurotrophic Illicium majucin-type sesquiterpenes is described here. This strategy is based on an organocatalyzed asymmetric Robinson annulation and provides an efficient approach for a diversity-oriented synthesis of Illicium natural products that holds remarkable therapeutic potential for neurodegenerative diseases.

Journal: :Chemical communications 2013
Junjun Tian Zhengjie He

A phosphine-catalyzed [3+2] annulation reaction of α-substituted allenoates with ester-activated α,β-unsaturated imines is reported, which provides new and efficient access to highly functionalized cyclopentenes bearing one all-carbon quaternary center. This reaction also expands the scope of the famous Lu [3+2] cycloaddition reaction.

Journal: :Organic letters 2011
Yen-Ju Cheng Chiu-Hsiang Chen Yu-Ju Ho Shu-Wei Chang Henryk A Witek Chain-Shu Hsu

Nitrogen-bridged donor-acceptor multifused dithienopyrrolobenzothiadiazole (DTPBT) and dibenzothiadiazolopyrrolothiophene (DBTPT) were successfully synthesized by intramolecular Cadogan annulation. The electron-deficient benzothiadiazole unit in DTPBT can be converted to benzoselenadiazole and quinoxaline moieties through reduction/cyclization to generate dithienopyrrolobenzoselenadiazole (DTPB...

Journal: :Journal of veterinary internal medicine 2009
C Carlos Sampedrano V Chetboul J Mary R Tissier M Abitbol F Serres V Gouni A Thomas J-L Pouchelon

BACKGROUND A mutation in the sarcomeric gene coding for the myosin-binding protein C gene has been identified in a colony of Maine Coon cats with hypertrophic cardiomyopathy (MyBPC3-A31P mutation). However, the close correlation between genotype and phenotype (left ventricular hypertrophy [LVH] and dysfunction) has never been assessed in a large population, particularly in heterozygous (Hetero)...

Journal: :Chemical communications 2012
Xue-Song Xu Zhen-Wu Li Yi-Jun Zhang Xiao-Shui Peng Henry N C Wong

The first total synthesis of (±)-pallambins C and D has been accomplished in a linear 38 step reaction from (±)-Wieland-Miescher ketone. The key conversions are featured as follows: a Grob fragmentation-intramolecular aldol cyclization and a thiourea/palladium-catalyzed carbonylative annulation.

Journal: :Organic & biomolecular chemistry 2016
Shuai-Shuai Li Wei-Huan Li Guo-Tai Zhang Ying-Qi Xia Chen-Fei Liu Fu Su Xiao-Mei Zhang Lin Dong

A novel one-pot synthesis of π-conjugated polycyclic compounds, which could undergo further facile transformation to form complex polycyclic heteroarene compounds, has been realized between 7-azaindoles and α,β-unsaturated ketones. This distinctive cascade process proceeds via a rhodium(iii)-catalyzed alkylation/copper-catalyzed radical annulation-aromatization pathway.

Journal: :Journal of the American Chemical Society 2008
Nathan D Shapiro F Dean Toste

A convenient gold(III)-catalyzed synthesis of azepines from the intermolecular annulation of propargyl esters and alpha,beta-unsaturated imines is reported (19 examples, 55-95% yield). This formal [4 + 3]-cycloaddition reaction is proposed to proceed via a stepwise process involving intramolecular trapping of an allyl-gold intermediate.

Journal: :Chemical communications 2012
Soji Shimizu Tatsuya Otaki Yoko Yamazaki Nagao Kobayashi

A β,β-sp(3)-hybridized subphthalocyanine analogue, dibenzosubtriazachlorin, was synthesized, and its significantly split Q band absorptions in longer and shorter wavelength regions relative to those of subphthalocyanines were revealed. The effect of benzo-annulation to a subtriazachlorin structure on the position of the split Q bands as well as the electronic structures was also investigated.

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