排序方式: 共有49条查询结果,搜索用时 984 毫秒
11.
The cycloaddition of o-quinodimethane, from 1,3-dihydrobenzo(c)-S,S dioxide, to 5,6-dihydroquinoline yields a mixture of adducts isomeric at the newly created ring junction. The cycloadducts can be dehydrogenated to the fully aromatic 1-azabenzanthracene. 相似文献
12.
A selective, rapid and simple reduction of azobenzenes to diphenylhydrazines using borane-THF is described. 相似文献
13.
We have synthesized a series of novel coplanar chromophores in which heteroarenes, namely, thiophene, benzothiophene, and carbazole, were fused to neighboring phenylene ring(s) through intramolecular annulation via sp(3)-hybridized carbon atoms bearing two p-tolyl groups as peripheral substituents. The molecular configurations of the pi-conjugated backbones were determined by X-ray crystallographic analysis; the heteroarene-fused molecular frameworks of these novel molecules exhibit nearly coplanar conformations. [structure: see text] 相似文献
14.
Highly Enantioselective Formation of α‐Allyl‐α‐Arylcyclopentanones via Pd‐Catalysed Decarboxylative Asymmetric Allylic Alkylation 下载免费PDF全文
Dr. Ramulu Akula Dr. Robert Doran Prof. Patrick J. Guiry 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(29):9938-9942
A highly enantioselective Pd‐catalysed decarboxylative asymmetric allylic alkylation of cyclopentanone derived α‐aryl‐β‐keto esters employing the (R,R)‐ANDEN‐phenyl Trost ligand has been developed. The product (S)‐α‐allyl‐α‐arylcyclopentanones were obtained in excellent yields and enantioselectivities (up to >99.9 % ee). This represents one of the most highly enantioselective formations of an all‐carbon quaternary stereogenic center reported to date. This reaction was demonstrated on a 4.0 mmol scale without any deterioration of enantioselectivity and was exploited as the key enantioselective transformation in an asymmetric formal synthesis of the natural product (+)‐tanikolide. 相似文献
15.
Satish S. More Akula Raghunadh Ramanathan Shankar Navin B. Patel Dinesh S. Bhalerao Unniaran K. Syam Kumar 《Helvetica chimica acta》2014,97(3):404-413
The first total synthesis of the α‐oxo amide‐based natural product, N‐(3‐guanidinopropyl)‐2‐(4‐hydroxyphenyl)‐2‐oxoacetamide ( 3 ), isolated from aqueous extracts of hydroid Campanularia sp., has been achieved. The α‐oxo amide 12 , prepared via the oxidative amidation of 1‐[4‐(benzyloxy)phenyl]‐2,2‐dibromoethanone ( 9a ) with 4‐{[(tert‐butyl)(dimethyl)silyl]oxy}butan‐1‐amine ( 10a ), has been used as the key intermediate in the total synthesis of 3 as HBr salt. On the way, an expeditious total synthesis of polyandrocarpamide C ( 2c ), isolated from marine ascidian Polyandrocarpa sp., was carried out in four steps. 相似文献
16.
Hee‐Jeong Cha Se‐Yeun Hwang Da‐Som Lee Akula Ravi Kumar Yong‐Uk Kwon Moritz Voß Eva Schuiten Uwe T. Bornscheuer Frank Hollmann Deok‐Kun Oh Jin‐Byung Park 《Angewandte Chemie (International ed. in English)》2020,59(18):7024-7028
Long‐chain aliphatic amines such as (S,Z)‐heptadec‐9‐en‐7‐amine and 9‐aminoheptadecane were synthesized from ricinoleic acid and oleic acid, respectively, by whole‐cell cascade reactions using the combination of an alcohol dehydrogenase (ADH) from Micrococcus luteus, an engineered amine transaminase from Vibrio fluvialis (Vf‐ATA), and a photoactivated decarboxylase from Chlorella variabilis NC64A (Cv‐FAP) in a one‐pot process. In addition, long chain aliphatic esters such as 10‐(heptanoyloxy)dec‐8‐ene and octylnonanoate were prepared from ricinoleic acid and oleic acid, respectively, by using the combination of the ADH, a Baeyer–Villiger monooxygenase variant from Pseudomonas putida KT2440, and the Cv‐FAP. The target compounds were produced at rates of up to 37 U g?1 dry cells with conversions up to 90 %. Therefore, this study contributes to the preparation of industrially relevant long‐chain aliphatic chiral amines and esters from renewable fatty acid resources. 相似文献
17.
Naveenkumar Akula Neha Sharma Apurva Lohegaonkar Satishchandra B. Ogale Moumita Majumdar 《化学:亚洲杂志》2020,15(5):585-589
The organosilicon reagent 1,4‐bis‐(trimethylsilyl)‐1,4‐diaza‐2,5‐cyclohexadiene 2 plays the binary role of the simultaneous reduction of GeCl2.dioxane 1 dissolved in oleylamine to Ge nanocrystals and the formation of graphitic sheets under hot‐injection conditions. This colloidal synthetic route to germanium nanocrystals embedded on N‐doped graphitic nanosheets Ge/NG is free of any template or catalyst and involves easy purification techniques. The Ge/NG/C obtained after carbonization has been explored for anode performance in lithium‐ion batteries. Both Ge/NG and Ge/NG/C can be obtained on a gram scale and are bottleable under argon for months. 相似文献
18.
An efficient and high yielding synthesis of N-substituted pyrrolidines and piperidines is described. 相似文献
19.
Rare earth element substituted bismuth ferrites (BiFeO3) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi
x
La1−x
FeO3 (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of
these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz
to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz).
All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature
shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds
to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity
as well as ε′ are found to be maximum for the sample x=0.2 at room temperature. 相似文献
20.
CoFe2O4-BaTiO3 composites were prepared using conventional ceramic double sintering process with various compositions. Presence of two phases
in the composites was confirmed using X-ray diffraction. The dc resistivity and thermoemf as a function of temperature in
the temperature range 300 K to 600 K were measured. Variation of dielectric constant (ɛ′) with frequency in the range 100 Hz to 1 MHz and also with temperature at a fixed frequency of 1 kHz was studied. The ac
conductivity was derived from dielectric constant (ɛ′) and loss tangent (tan δ). The nature of conduction is discussed on the basis of small polaron hopping model. The static value of magnetoelectric
conversion factor has been studied as a function of magnetic field. 相似文献