نتایج جستجو برای: n substituted pyrroles

تعداد نتایج: 1008175  

Journal: :Chemical communications 2013
Xiaofeng Ma Qin Tang Jun Ke Jichao Zhang Cong Wang Haibo Wang Yuxue Li Huawu Shao

An effective and facile method for the synthesis of 2,2-di-substituted perhydrofuro[2,3-b]pyran (and furan) derivatives is described. The cyclization of 1,2-cyclopropanated sugars with olefins in the presence of BiCl3 is highly diastereoselective. 2,2-Di-substituted cyclization products were obtained in good to excellent yields.

Journal: :Molecules 2006
Marijana Hranjec Grace Karminski-Zamola

A series of novel benzimidazole derivatives 3-10 were synthesized. Benzimidazolyl-substituted acrylonitriles 3 and 4 underwent a photochemical dehydrocyclization reaction to give the corresponding mono- and dicyano-substituted benzimidazo[1,2-a] quinolines 5 and 6. Pinner reaction of these compounds did not give the expected mono- and diamidines, but rather only compounds 7-10, with amido group...

Journal: :Chemical communications 2011
Kazuhiro Yonehara Keigo Kamata Kazuya Yamaguchi Noritaka Mizuno

A divanadium-substituted phosphotungstate TBA(4)[γ-HPV(2)W(10)O(40)] (TBA = tetra-n-butylammonium) could act as an effective homogeneous catalyst for the H(2)O(2)-based oxidative bromination.

Journal: :Chemical communications 2007
Milan Kivala Corinne Boudon Jean-Paul Gisselbrecht Paul Seiler Maurice Gross François Diederich

A series of donor-acceptor molecules, featuring intense low-energy intramolecular charge-transfer bands, was prepared by regioselective [2 + 2] cycloaddition between 7,7,8,8-tetracyanoquinodimethane (TCNQ) and N,N-dialkylanilino-substituted (DAA-substituted) alkynes, followed by ring opening of the initially formed cyclobutenes.

2014
Andreas Gansäuer Andreas Okkel Lukas Schwach Laura Wagner Anja Selig Aram Prokop

An operationally simple, convenient, and mild strategy for the synthesis of triazole-substituted titanocenes via strain-driven 1,3-dipolar cycloadditions between azide-functionalized titanocenes and cyclooctyne has been developed. It features the first synthesis of titanocenes containing azide groups. These compounds constitute 'second-generation' functionalized titanocene building blocks for f...

Journal: :Journal of nematology 1988
R D Riggs D P Schmitt G R Noel

Tests of Heterodera glycines on differential host plants to determine races were run in Arkansas, Illinois, and North Carolina to check the uniformity of results of the test. Methods used at the three locations varied somewhat. Results indicate that the race test is highly variable. Isolates previously identified as race 1 were identified as race 1 or race 3; those identified as race 2 were ide...

Journal: :Chemical communications 2014
Victor Gray Anders Lennartson Phasin Ratanalert Karl Börjesson Kasper Moth-Poulsen

Red-shifting the absorption of norbornadienes (NBDs), into the visible region, enables the photo-isomerization of NBDs to quadricyclanes (QCs) to be driven by sunlight. This is necessary in order to utilize the NBD-QC system for molecular solar thermal (MOST) energy storage. Reported here is a study on five diaryl-substituted norbornadienes. The introduced aryl-groups induce a significant red-s...

Journal: :Journal of nematology 1977
R D Riggs M L Hamblen L Rakes

The reproductive abilities of four races of Heterodera glycines were compared on soybean cultivars by using single cyst or mass inoculations. Progeny transfers were used to determine changes in reproduction of H. glycines. Reproduction of all races (1, 2, 3, 4) was best on 'Lee' and poorest on P1 88788. The size of females produced and numbers of eggs/female of the different races varied with t...

2010
Tilman Lechel Irene Brüdgam Hans-Ulrich Reissig

A series of trifluoromethyl-substituted 3-alkoxypyridinol derivatives has been deprotected to furnish pyridine-3,4-diol derivatives in good yields. The X-ray crystal structure analysis proved that a 1:1 mixture of pyridine-3,4-diols and their pyridin-4-one tautomers exist in the solid state. Subsequent conversion into bis(perfluoroalkanesulfonate)s were smoothly achieved. The obtained compounds...

Journal: :Dalton transactions 2010
Ming-Hui Qi Li-Xiong Shao Min Shi

The PdCl(2)-promoted reactions of methylenecyclopropanes (MCPs) 1 bearing diaryl substituents on the terminal double bond were carefully investigated. The solvents employed significantly affected the reaction outcomes. It was found that dimeric allylpalladium(ii) complexes 2a-2f can be obtained as the sole products in acceptable to good yields under mild reaction conditions with THF as the solv...

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