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401.
402.
Novel pyrano[2,3-d]pyrimidine-2,4,7-triones were synthesized in 90–97% yield via a three-component reaction of an aromatic aldehyde, Meldrums acid, and barbituric acid in the presence of 10 mol % K2CO3 under microwave irradiation. This is the first protocol to be reported for the synthesis of title compounds and the significant features of the present protocol are simplicity, high yields, short reaction time, involvement of aqueous work-up procedure, environmentally benign nature, and no chromatographic purification. 相似文献
403.
Dr. Debangsu Sil Firoz Shah Tuglak Khan Prof. Dr. Sankar Prasad Rath 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14585-14597
The synthesis, structure, and properties of bischloro, μ‐oxo, and a family of μ‐hydroxo complexes (with BF4?, SbF6?, and PF6? counteranions) of diethylpyrrole‐bridged diiron(III) bisporphyrins are reported. Spectroscopic characterization has revealed that the iron centers of the bischloro and μ‐oxo complexes are in the high‐spin state (S=5/2). However, the two iron centers in the diiron(III) μ‐hydroxo complexes are equivalent with high spin (S=5/2) in the solid state and an intermediate‐spin state (S=3/2) in solution. The molecules have been compared with previously known diiron(III) μ‐hydroxo complexes of ethane‐bridged bisporphyrin, in which two different spin states of iron were stabilized under the influence of counteranions. The dimanganese(III) analogues were also synthesized and spectroscopically characterized. A comparison of the X‐ray structural parameters between diethylpyrrole and ethane‐bridged μ‐hydroxo bisporphyrins suggest an increased separation, and hence, less interactions between the two heme units of the former. As a result, unlike the ethane‐bridged μ‐hydroxo complex, both iron centers become equivalent in the diethylpyrrole‐bridged complex and their spin state remains unresponsive to the change in counteranion. The iron(III) centers of the diethylpyrrole‐bridged diiron(III) μ‐oxo bisporphyrin undergo very strong antiferromagnetic interactions (J=?137.7 cm?1), although the coupling constant is reduced to only a weak value in the μ‐hydroxo complexes (J=?42.2, ?44.1, and ?42.4 cm?1 for the BF4, SbF6, and PF6 complexes, respectively). 相似文献
404.
A Response to a Comment by G. Frenking and M. Hermann on: “The Quadruple Bonding in C2 Reproduces the Properties of the Molecule”
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405.
Gounder Thangamani J. Deshmukh Kalim Sadasivuni Kishor Kumar Ponnamma Deepalekshmi Goutham Solleti Venkateswara Rao K. Chidambaram K. Basheer Ahamed M. Nirmala Grace A. Faisal Muhammad Khadheer Pasha S. K. 《Mikrochimica acta》2017,184(10):3977-3987
Microchimica Acta - The authors describe the preparation of PVA/WPPy/hBNNP nanocomposite films by solution casting method from poly(vinyl alcohol) (PVA), water soluble polypyrrole (WPPy), and using... 相似文献
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409.
Molecular iodine efficiently catalyzes the four‐component tandem reaction of araldehydes, arylmethyl ketones, acetyl chloride, and acetonitrile to afford the corresponding β‐acetamido‐β‐aryl‐propiophenones. The new protocol gives high yields of the products, and the reactions go to completion within 10–15 min on a hot plate at 80–85°C. 相似文献
410.
A mild, efficient, green, and selective oxidation method of sulfides to sulfoxides or sulfones using H2O2 in the presence of catalytic amounts of sulfamic acid has been developed. Various substituted sulfides having functional groups such as alcohol, ester, and aldehyde are successfully and selectively oxidized without affecting the sensitive functionalities in good to excellent yields at room temperature. 相似文献