In the present research, silica bonded n-propyl-1,3,5-triazine-2,4,6-triamine (SPTT) was synthesized by direct incorporation of chloropropyl groups through co-condensation of tetraethyl orthosilicate (TEOS) and 3-chloropropyl trimethoxysilane (CPTMS) and subsequent grafting the melamine onto the propyl groups via simple nucleophilic substitution reaction. The catalyst has been characterized by ...

na2so4 as an inexpensive and effective catalyst has provided a green protocol for the synthesis of tetrahydrobenzo[b]pyran, pyrano[2,3-d]pyrimidinone and dihydropyrano[3,2c]chromene derivatives from the three-component domino reaction of aromatic aldehydes and malononitrile with 4-hydroxycoumarin/ dimedone/ barbituric acid in ethanol/water as a mixture of solvent that, this mixture entirely is ...

Na2SO4 as an inexpensive and effective catalyst has provided a green protocol for the synthesis of tetrahydrobenzo[b]pyran, pyrano[2,3-d]pyrimidinone and dihydropyrano[3,2c]chromene derivatives from the three-component domino reaction of aromatic aldehydes and malononitrile with 4-hydroxycoumarin/ dimedone/ barbituric acid in ethanol/water as a mixture of solvent that, this mixture entirely is ...

Na2SO4 as an inexpensive and effective catalyst has provided a green protocol for the synthesis of tetrahydrobenzo[b]pyran, pyrano[2,3-d]pyrimidinone and dihydropyrano[3,2c]chromene derivatives from the three-component domino reaction of aromatic aldehydes and malononitrile with 4-hydroxycoumarin/ dimedone/ barbituric acid in ethanol/water as a mixture of solvent that, this mixture entirely is ...

Pyridine-functionalized MCM-41 catalyzed reactions between tetracyanoethylene and various activated CH-acid compounds are described. These reactions afford the corresponding pyran annulated heterocyclic ring systems in high yields at room temperature within a few minutes. The work-up procedure is very simple and the products do not require further purification. The catalyst can be recycled and ...

Sodium citrate as a highly efficient catalyst is developed for the synthesis of functionalized 2-amino-3-cyano-4H-pyrans and pyran-annulated heterocycles. This method involves one-pot three-component reaction aromatic aldehydes, malononitrile 1,3-dicarbonyl compounds with EtOH: H2O (1:1 v/v) solvent under room temperature. protocol presents several advantages such shorter time, utilization eco-...

The unicellular organism, Noctiluca, has been examined with the electron microscope. The nucleus is small compared to the very large size of the cell, but the nuclear border has an organization which indicates an active nucleocytoplasmic exchange. Whereas annuli are missing over most parts of the nuclear membrane proper, there are "annulated vesicles" in a layer inside the nuclear membrane. The...

The synthesis of C2-symmetrical bis(β-enamino-pyran-2,4-dione) derivative 3 connected via 1,6-hexylene linker was reported for the first time. X-ray structures and Hirshfeld studies new bis- β-enamino-pyran-2,4-dione along with two structurally related pyran-2,4-dione derivatives 2a,b were discussed. A comparative analysis different intermolecular contacts affecting crystal stability presented....