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Scolecite is one kind of natural zeolite. A three component Biginelli reaction using scolecite as a novel heterogeneous acid catalyst is demonstrated. The short reaction time, clean reaction conditions, consistent yields and minimum environmental effects are important features of the reaction.

A clean and simple synthesis of 6-amino-4-aryl-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles was accomplished in good to excellent yields via the one-pot three component condensation of 3-methyl-1-phenyl-2-pyrazolin-5-one, an aromatic aldehyde, and malononitrile catalysed by sulfamic acid in ethanol.

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A highly efficient, mild, and simple protocol is presented for the oxidative aromatization of Hantzsch 1, 4-dihydropyridines using the combination of Dess-Martin periodinane with molecular iodine or KBr. The in situ generated acetyl hypoiodite or bromite formed due to the reaction between Dess-Martin periodinane and molecular iodine or KBr respectively is supposed to be the responsible species for bringing about the oxidative aromatization of 1, 4-dihydropyridines.

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Other 6-membered heterocycles R 0670 Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazine and 1,3,4-Thiadiazine from Substituted Acetophenones and Acid Hydrazides Using [Hydroxy(tosyloxy)iodo]ben-zene. -(KARADE*, N. N.; KONDRE, J. M.; GAMPAWAR, S. V.; SHINDE, S. V.; Synth.