Ultrafast fabrication of fluorescent organic nanoparticles with aggregation-induced emission feature through the microwave-assisted Biginelli reaction

Zheng

Macro Chemistry & Physics

et al. 2021

In the synthesis of traditional AIE-active polymers with conjugate or multi-benzene system, the troublesome process is still faced such as consuming time, high temperature, catalysis, no water or vacuum, and so on. In this study, the polydihydropyrimidone derivatives ( PDPMDs) with AIE properties are facilely synthesized by the introduction of 4-dihydropyrimidone rings onto non-AIE-active intermediate polyureas (PUs) in Biginelli reaction. It is found that the unsymmetrical L-lysine ethyl diisocyanate and butylenediamine played a very important role in the smooth preparation and fluorescence enhancement of PDPMDs. Compared with the intermediate PUs, the fluorescence of PDPMDs is significantly enhanced (35-fold increase), which is mainly due to the intramolecular aggregation of dihydropyrimidone rings on PUs chains. At the same time, with the increase of the content of dihydropyrimidone rings, the fluorescence intensity of PDPMDs also increases, and the emission wavelength shows an obvious red shift.

Section: Molecular Design For Aie-active Pdpmdsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polyurea Modified with 4‐Dihydropyrimidone‐2‐ketone Rings by Biginelli Reaction and its Boostered AIE Characteristic

Zheng

Macro Chemistry & Physics

et al. 2021

“…In this context, the microwave irradiation technique can be utilized to synthesize DHMPs as it involves rapid and uniform heating, leading to the improvement in the reaction rate and selectivity to a greater extent compared to conventional heating. 22,23 Besides, aldehyde, dicarbonyl compounds, and urea are excellent absorbers of microwave radiation; it is a perfect choice to utilize the microwave irradiation technique for Biginelli reaction. 24 To date, a few catalysts are available on the utilization of microwave irradiation in Biginelli reaction using a solid acid catalyst such as ferric chloride hexahydrate, 25 FeCl 3 supported nanopore silica, 26 Cu(OTf) 2 27 etc.…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Acid-Functionalized Mesoporous Polymer

Changmai¹,

Rajkumari²,

das³

et al. 2021

Preprint

Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwave irradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDX were employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1 ), high surface area (90.44 m2 g -1 ) and mesoporous nature of the catalyst effectively promoted the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98 %) as compared to conventional heating (15-25 % yield) under our optimized reaction conditions such as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesized Biginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalyst was investigated up to 5 successive cycles and it showed great stability towards the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields.

Section: Introductionmentioning

confidence: 99%

Microwave-assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Using Acid-Functionalized Mesoporous Polymer

Changmai

Rajkumari

Das

et al. 2021

CMIC

Background: In recent years, 3,4-dihydro-pyrimidin-2-(1H)-ones (DHPMs) have attracting significant attention due to their diverse range of biological properties such as antibacterial, antiviral, antitumor, anti-inflammatory, calcium channel block etc. Taking into account, in this present work a polymer based solid acid catalyst is employed for the microwave-assisted synthesis of DHPMs. Introduction: Multicomponent reactions (MCRs) are attracting utmost attention as it promotes the formation of several bonds in a single process with diverse advantages. Biginelli reaction is the top-ranked example of MCR for the synthesis of dihydropyrimidinones (DHPMs). Solid catalysts are considered as a significant tool for MCRs as they are non-toxic, easy to handle, high selectivity, easy separation process and reusable. Methods: DHPMs synthesis was carried out using acid functionalized mesoporous polymer (AFMP) catalyst under microwave irradiation and solvent-free condition. Results: AFMP showed good to excellent DHPMs yield (89-98%) under the optimized reaction conditions: 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 500 W. Conclusion: We have successfully utilized microwave-assisted AFMP catalyzed the synthesis of DHPMs under solvent-free condition via Biginelli approach. The catalyst is recyclable and reusable up to 5 consecutive reaction cycles with no significant loss in catalytic activity.