نتایج جستجو برای: n substituted pyrroles

تعداد نتایج: 1008175  

Journal: :Journal of nematology 1992
S R Koenning S C Anand G O Myers

Alternate planting dates and periodic destruction of the previous year's soybean crop as well as 1-year bare fallow were used to establish a range of population densities ofHeterodera glycines for the subsequent year. Soybean cultivar Coker 156 (susceptible, moderately tolerant) was compared to cultivars Essex (susceptible, intolerant) and Bedford (resistant) to evaluate tolerance at different ...

2017
Richard C. Larock Nam H. Lee

A method is provided for preparing benzoprostacyclins by the free-radical-catalyzed tandem alkene insertion into a 1,4-bisoxy-substituted cyclopent-2-ene intermediate.

Journal: :Folding & design 1997
P Armand K Kirshenbaum A Falicov R L Dunbrack K A Dill R N Zuckermann F E Cohen

BACKGROUND Short sequence-specific heteropolymers of N-substituted glycines (peptoids) have emerged as promising tools for drug discovery. Recent work on medium-length peptoids containing chiral centers in their sidechains has demonstrated the existence of stable chiral conformations in solution. In this report, we explore the conformational properties of these N alpha chiral peptoids by molecu...

Journal: :Molecules 2004
Plamen A Angelov Iliyan I Ivanov Atanas P Venkov

A series of novel 11b-substituted 1,6,7,11b-tetrahydropyrimido[6,1-a]- isoquinoline-2,4-diones and 4-thioxo-1,3,4,6,7,11b-hexahydropyrimido[6,1-a]isoquinolin-2- ones were synthesized, utilizing two alternative strategies for ring closure of tetrahydroisoquinoline intermediates obtained from N-phenethyl enaminones.

Journal: :Journal of nematology 1997
S Chen D W Dickson T E Hewlett

Effects of tannic acid on hatching of Heterodera glycines eggs were determined in vitro using three batches of eggs obtained from greenhouse cultures in Florida or from naturally infested field soil in Minnesota. A quadratic model fits the percentage egg hatch. Hatch increased with increasing tannic acid concentrations from 0 to about 39 mg/liter, then declined with further increases in concent...

Journal: :Molecules 2013
Benjamin L Harris Jonathan M White

Selenium substituents which are disposed β to an electron deficient centre, such as a carbocation p-orbital, or the π* orbital of an electron deficient p-system, interact in a stabilising way by a combination of C-Se hyperconjugation (σ(Se-C)-π* interaction), and a through-space homoconjugative n(Se)-π* interaction. The relative importance of these two modes of interaction is dependant on the e...

2017
Alexei Nikolaevich Kiselev Olga Konstantinovna Grigorova Alexei Dmitrievich Averin Sergei Aleksandrovich Syrbu Oskar Iosifovich Koifman Irina Petrovna Beletskaya

The arylation of mono-, di- and tetra-meso-bromophenyl-substituted porphyrins with the heteroarenes containing "acidic" C-H bonds, such as benzoxazole, benzothiazole and N-methylimidazole was studied in the presence of three alternative catalytic systems: Pd(dba)2/DavePhos/Cs2CO3, Pd(PPh3)4/PivOH/K2CO3 and Pd(OAc)2/Cu(OAc)2/PPh3/K2CO3. The first catalytic system was found to be successful in th...

2017
Anastasia Sergeevna Kostyuchenko Tatyana Yu Zheleznova Anton Jaroslavovich Stasyuk Aleksandra Kurowska Wojciech Domagala Adam Pron Alexander S Fisyuk

New photoluminescent donor-acceptor-donor (DAD) molecules, namely 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles were prepared by palladium-catalyzed coupling from readily available compounds such as ethyl 3-decyl-2,2'-bithiophene-5-carboxylate and aryl halides. The obtained compounds feature increasing bathochromic shifts in their emission spectra with increasing a...

2015
Xiaofeng Lu Jibin Sun Shangxi Zhang Longfei Ma Lei Liu Hui Qi Yongliang Shao Xiangfeng Shao

A series of donor-acceptor type co-crystals of fullerene (as the acceptor) and arylthio-substituted tetrathiafulvalene derivatives (Ar-S-TTF, as the donor) were prepared and their structural features were thoroughly investigated. The formation of co-crystals relies on the flexibility of Ar-S-TTF and the size matches between Ar-S-TTF and fullerene. Regarding their compositions, the studied co-cr...

Journal: :Chemical communications 2012
Lixin Li Wenchao Chen Wenguo Yang Yuanhang Pan Hongjun Liu Choon-Hong Tan Zhiyong Jiang

A bicyclic guanidine-catalyzed Michael addition of 3-benzyl substituted oxindoles to N-maleimides has been developed to produce oxindole derivatives with a quaternary carbon chiral center at the 3-position in excellent yields and enantio- and diastereoselectivities. This is the first incorporation of N-benzylic α-branched succinimides into 3,3-disubstituted oxindoles.

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