43056-25-3Relevant academic research and scientific papers
Polyoxometalate catalyzed imine synthesis: Investigation of mechanistic pathways
Adhikary, Subhasis D.,Mandal, Debaprasad
supporting information, (2020/05/25)
The syntheses of imines by oxidative coupling of primary alcohols and amines were achieved by using 2 molpercent polyoxometalate (POM) Na12[WZn3(H2O)2(ZnW9O34)2] (Zn–WZn3) catalyst in the presence of t-BuOK and di-oxygen with excellent conversion (up to 100percent) and selectivity (up to 100percent). Non-noble metal-based POM catalyst in the presence of base represents a new reaction protocol for the selective synthesis of imine from both aromatic and aliphatic primary amines with functional group tolerance. Control experiment shows the formation of di-oxygen bind Zn–WZn3 activated species. The electron-density of POM is mostly situated on the surface oxygen atoms of W–O–W bonds which can engage the alcoholic OH group and helps for the imine selectivity in the second step of imine synthesis.
An Efficient Mesoporous Cu-Organic Nanorod for Friedl?nder Synthesis of Quinoline and Click Reactions
Elavarasan, Samaraj,Bhaumik, Asim,Sasidharan, Manickam
, p. 4340 - 4350 (2019/08/12)
Within the green chemistry context, heterogeneous catalysis for the synthesis of N-heterocycles from renewable resources using non-precious metals has garnered great interest in terms of economic and environmental perspectives. Herein, we present a triazine functional hierarchical mesoporous organic polymer (HMOP) with nanorod morphology together with large BET surface area ～1218 m2 g?1, huge pore volumeγτ“;6 mL g?1 and dual micro/mesopore architectures. Subsequent Cu-coordination with nitrogen atoms of the HMOP provides a robust catalyst (Cu-HMOP) to accomplish multi-step cascade reactions for preparation of N-heterocycles by different routes. For instance, the Cu-HMOP efficiently catalyzes one-pot sequential multi-step oxidative dehydrogenative coupling of 2-aminobenzyl alcohol with diverse aromatic ketones to afford corresponding quinolines in excellent isolated yields (up to 97 %). Secondly, the present catalyst exhibits good aerobic oxidative dehydrogenation activity of amines to imines. Thirdly, for “click” reaction involving azides-alkynes, the Cu-HMOP produced quantitative yield for 1,4-disubstituted 1,2,3-triazole derivatives at room temperature using water as solvent. Verification of active metal leaching by a hot filtration test as well as reusability of the retrieved Cu-HMOP catalysts shows a consistent activity in the multi-component quinoline synthesis as model reaction.
Substituent effects on the stretching vibration of C═N in multi-substituted benzylideneanilines
Wang, Linyan,Cao, Chaotun,Cao, Chenzhong
supporting information, (2019/05/29)
Forty-nine samples of 3,4′/4,3′/3,3′-disubstituted benzylideneanilines (XBAYs) and 52 samples of multi-substituted XBAYs were synthesized, and their infrared absorption spectra were recorded in this paper. On the basis of the stretching vibration frequencies νC═N of C═N bridging bond of 158 samples of substituted XBAYs (including 57 samples of 4,4′-disubstituted XBAYs from reference and 101 samples of substituted XBAYs synthesized in this paper), an extensional research of substituent effects on the νC═N values from 4,4′-disubstituted XBAYs to multi-substituted XBAYs was made. A modified equation for quantifying the νC═N values of multi-substituted XBAYs was obtained (shown as Equation (3)). Equation (3) indicates that the excited-state substituent constant of Y and the substituent specific cross-interaction effect between X and X cannot be ignored for the quantitative regression analysis of the νC═N values of multi-substituted XBAYs. Compared with Equation (1), Equation (3) has a wider application and more accuracy in quantifying the νC═N values of substituted XBAYs.
Silica gel supported sodium hydrogen sulfate as an efficient and reusable heterogeneous catalyst for the synthesis of imines in solvent-free conditions under microwave irradiation
Gopalakrishnan, Mannathusamy,Sureshkumar, Purushothaman,Kanagarajan, Vijayakumar,Thanusu, Jeyaraman,Govindaraju, Ramalingam
, p. 299 - 303 (2007/10/03)
This synthesis of imines has been carried out efficiently by the condensation of carbonyl compounds with amines in the presence of silica gel supported sodium hydrogen sulfate (NaHSO4.SiO2) as a heterogeneous catalyst under microwave irradiation in solvent-free conditions. NaHSO4.SiO2 can be recovered and re-used up to ten times by simple washing with diethyl ether after each use and activated in an oven at 120°C for 1 h, thus rendering the process more economical.
