An efficient method is presented for the synthesis of chromeno[2,3-d]pyrimidine/chromeno[4,3-b]chromene derivatives via pTSA-catalyzed cyclization of 1,3-dimethylbarbituric acid/4-hydroxycoumarin, electron-rich arenes, and various salicylaldehydes.
We demonstrate two distinct photomechanical responses (i.e. photomechanical bending and photosalient bursting) of two new 1,3-dimethylbarbituric acid derivative crystals based on tailoring their substituents and the modulation of their spacers.
CS-(M3SP)2-NH2·HSO4, was successfully utilized as a promoter in the synthesis of (±)-spiro[indoline-3,4′-pyrazolo[3,4-b]quinoline]dione and (±)-spiroindoline-pyrano[2,3-c]quinolone derivatives.
Synthetic protocols access to complex dispiro[indene-2,3′-cyclopentane-1′,5′′-pyrimidines], dispiro[indoline-3,3′-cyclopentane-1′,5′′-pyrimidines] and spiro[cyclopenta[c]indeno[1,2-b]chromene-3,5′-pyrimidines] in good yields and with high diastereoselectivity was developed.
Unusual, highly complex and valuable spirocyclic compounds were produced through domino radical addition, intramolecular cyclization and ring opening instead of usual migration to the difunctionalization products of olefins.