Tandem Knoevenagel-cyclocondensation

Keywords Aldehydes, malononitrile, C-H activated acids, urea, organocatalyst, ethanol-water (1 1), room temperature, tandem Knoevenagel-cyclocondensation, one-pot three-component reaction, chemoselectivity, functionalized 2-amino-3-cyano-4//-pyrans and pyran annulated heterocycles... [Pg.227]

Keywords Salicylic aldehydes, malononitrile, cyclic secondary amines/thiols, sodium formate, ethanol, room temperature, one-pot multicomponent reaction, tandem Knoevenagel-cyclocondensation, benzopyrano[2,3- f pyrimidmes/2-amino-4-arylsulfanyl-4//-chromene-3-corbonitriles... [Pg.231]

A series of tetrasubstituted thiazole derivatives 28 has been prepared via a multi-component tandem protocol <07T10054>. Reaction of bis(aroylmethyl)sulfides 23 with aryl aldehydes and ammonium acetate in 1 2 1 ratio under solvent-free microwave irradiation affords 28 in good yields. This reaction presumably starts with Knoevenagel condensation of sulfide with 2 equiv. of aryl aldehydes to give 24. Michael addition with ammonia and concomitant cyclocondensation lead to 26. Base-catalyzed ring opening of 26 to 27 and ring... [Pg.222]

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