Rearrangements in Scholl reaction are mostly serendipitous. The design of molecular precursors is what seems to guide the course of rearrangement. This review consolidates different classes of precursors used in Scholl reaction and their accompanying rearrangements that include aryl migration, migration followed by cyclization and skeletal rearrangements involving ring expansion, ring contraction and both, under the reaction conditions. The attempt in collating heretofore-reported examples in this review is to guide designing appropriate precursors to predictably achieve complex molecular structures or nanographenes or defect-nanographenes via rearrangement. 相似文献
AbstractWe report an efficient green one-pot approach for the synthesis of eighteen novel dihydro-4H-benzo[g]chromene derivatives under ultrasound irradiation conditions. The three-component condensation reaction proceeded through Knoevenagel-Michael reaction of chosen active methylene compounds and 2-hydroxynaphthalene-1,4-dione with different substituted aldehydes in the presence of ammonium acetate in water and ethanol mixture at room temperature, which furnished high yields of products (91–98%) in a rapid reaction time of 5–15?min. This procedure offers 95% of the atom economy and 100% of carbon efficiency together with other eco-friendly benefits. 相似文献
We report design and subsequent fabrication of an intrinsically gain flattened Erbium doped fiber amplifier (EDFA) based on a highly asymmetrical and concentric dual-core fiber, inner core of which was only partially doped. Phase-resonant optical coupling between the two cores was so tailored through optimization of its refractive index profile parameters that the longer wavelengths within the C-band experience relatively higher amplification compared to the shorter wavelengths thereby reducing the difference in the well-known tilt in the gains between the shorter and longer wavelength regions. The fabricated EDFA exhibited a median gain ?28 dB (gain excursion below ±2.2 dB within the C-band) when 16 simultaneous standard signal channels were launched by keeping the I/P level for each at −20 dBm/channel. Such EDFAs should be attractive for deployment in metro networks, where economics is a premium, because it would cut down the cost on gain flattening filter head. 相似文献
An operationally simple, economical, and straightforward synthesis of diverse 4,5-disubstituted 1,2,3-thiadiazoles from α-enolicdithioesters has been achieved via nitrosation/reduction/diazotization/cyclization sequence in one-pot through the formation of cascade 1–2 (N–S) and 3–4 (C–N) bonds. Importantly, this is the first straightforward entry to highly functionalized 1,2,3-thiadiazoles from dithioesters. 相似文献
Russian Journal of General Chemistry - A new series of linear and angular alkyl substituted furochromanone derivatives have been synthesized in one pot microwave irradiation assisted process from... 相似文献
Addition of 2D GO to the TiO2 nanowires brings about progressive changes in the optical properties and photochemical hydrogen production. The composition with progressive addition of GO played a dramatic role in making the material blue shift. The blue shift may happen due to transition from O2− anti-bonding orbital to the Ti4+ lowest empty orbital and also the process of band shifting towards lower wavelength is attributed to quantum confinement effect which occurs due to the transformation of bulk titanate to nanostructure titanate. In this article, we present the results of TiO2 nanowires and its rGO composites. TiO2 with 30 mg rGO nanocomposite exhibits good UV-light induced hydrogen production unlike bare TiO2. Current studies explain how rGO addition can be employed for better hydrogen production.
Among the bioactive heterocyclic frameworks, nitrogen containing multisubstituted imidazoles are versatile building blocks of many naturally occurring products. Imidazoles possess wide range of biological properties including anticancer, anti-inflammatory, antimicrobial, and antihypertensive activities with potential applications in other sectors. Multicomponent reactions in combination with heterogeneous catalysts and nanocomposites have contributed significantly to organic synthesis in general and imidazoles, in particular with high functional group tolerance. Owing to their tunable properties, lower operational cost, thermal stability, recyclability, and easily separation from products, heterogeneous catalysts and nanocomposites are integral part of numerous pharmaceutical, agrochemical, and industrial processes. There has been increased focus on the development of green and sustainable catalytic procedures for the building of novel and biologically potent imidazole conjugates. This article emphasizes the recent advances in recyclable catalysts and protocols, and their merits for the synthesis of diverse multisubstituted imidazole conjugates by one-pot reaction approach and the catalyst and reactant interactions. 相似文献
The 1,4‐conjugate addition of indoles to nitro olefins was efficiently carried out using an environmentally benign catalyst, silica sulfuric acid, at ambient temperature. 相似文献
Journal of Solid State Electrochemistry - Ta2O5 is one of the promising anode materials for lithium ion battery application undergoing conversion reaction in combination with an extrinsic... 相似文献