An efficient protocol for the asymmetric construction of enantiomerically enriched tetrahydro-6H-benzo[c]chromenes and their derivatives has been developed. The corresponding products were obtained by the cascade double Michael addition of 3-nitro-2H-chromenes and their derivatives with α,β-unsaturated ketones catalyzed by a combination of a quinine-derived primary amine and benzoic acid. Throu...

Efficient kinetic resolution of racemic 3-nitro-2H-chromenes by bifunctional thiourea afforded optically active (R)-3-nitro-2H-chromene derivatives with moderate to good enantioselectivities, which simultaneously gave the multifunctional 3,4-diphenyl-3a-nitrobenzopyrano-[3,4-c]-pyrrolidine-1,1-dicarboxylate derivatives with four vicinal chiral carbon centers.

2-Dimethyl-2H-Chromenes, Coumarin Derivatives, Phase-Transfer Catalysis 2,2-Dimethyl-5H-pyrano(3,2-c)-l-benzopyrano-5-one(2) and 4H-2,3-dihydro-3-methyl-2methylene-furan-l-benzopyran-4-one (3), two new coumarin derivatives were synthesised from 4-hydroxycoumarin by treating with 3-chloro-3-methylbut-l-yne and 3-chlorobut-l-yne respectively, both reactions progressing via the phase-transfer cata...

Some new hydrazono 5a,b, thiosemicarbazono 6a-c, and oximo chromenes 7a-c were prepared via the reaction of the corresponding beta-chlorocarbaldehyde 3 with hydrazine, aromatic hydrazine, thiosemicarbazide and hydroxylamine hydrochloride, respectively. In addition, ether derivatives 8a-h were prepared from the corresponding aldoximes 7a-c. The new products were tested for anti-inflammatory and ...

In(OTf)3 catalyzed microwave-assisted alkenylation of methoxyphenols was investigated. Exclusive formation of either indenes or chromenes was observed depending on the position of the methoxy group on phenol. The structures of 1H-inden-4-ol derivatives (4a-e) and 4H-chromene derivatives (5a-j) were established by NMR ((1)H & (13)C) and high-resolution mass spectra, which were further supported ...

background: recently, the anti cancer effect of chromene derivatives in different cell types has been reported. in this study, we report some derivatives of dihydropyrano[c]chromenes with growth inhibitory and apoptotic activity against k562, chronic myeloid leukaemia (cml). methods: the cells were seeded in 96-well plates at 1×105 cells/well and treated with different concentrations of the dih...

The synthesis of 6H-benzo[c]chromenes from unactivated 2-bromo aryl benzyl ethers was studied through two approaches: (i) the transition-metal-free intramolecular dehydrohalide coupling via intramolecular homolytic aromatic substitution; and (ii) the intramolecular cyclization via direct C–H arylation catalysed by PdCl2(MeCN)2. Having developed the most efficient method, a 17-membered chromene ...

An organocatalytic [4 + 2] cascade annulation of salicylaldehydes and 1,3-bisarylsulfonylpropenes has been developed. This protocol enables the efficient straightforward synthesis a new series 3-sulfonyl-2-sulfonylmethyl-2H-chromenes that are useful for exploring pharmacologically valued compounds. Further reductive modifications result in 3-desulfonylated chromene or chromane derivatives. can ...

Silica-bonded n-propyltriethylene-tetramine (SBNPTT) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes. Chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oC under solvent-free conditions. The heterogeneous solid base showed much the same efficiency when u...