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 ...

In the title compound, C(18)H(15)ClN(2)O(2), the five-membered isoxazole ring adopts an envelope conformation [the deviation of the N atom is 0.3154 (15) Å] and the six-membered pyran ring adopts a half-chair conformation. The mean plane through all atoms of the isoxazole ring forms dihedral angles of 47.98 (8)° with the mean plane of the chromene ring system and 75.10 (9)° with the chloro-benz...

An enantioselective Pd-catalyzed 6-endo-trig reaction for the synthesis of 2-aryl-chromenes has been developed. A systematic optimization of a TADDOL-derived ligand set resulted in the identification of a novel monodentate phosphoramidite-palladium catalyst that accesses 2-aryl-2H-chromenes with high yield and enantioselectivity under mild conditions. The products obtained from this method can ...

In the title coumarin derivative, C(13)H(12)O(4), the 2H-chromene ring system is essentially planar [maximum deviation = 0.047 (1) Å]. An intra-molecular hydrogen bond is observed between the hy-droxy and the ketonic O atoms. In the crystal, pairs of inter-molecular C-H⋯O hydrogen bonds link inversion-related mol-ecules into dimers. Additional inter-molecular C-H⋯O hydrogen bonds further inter-...

In the title compound, C(17)H(12)O(4), the chromene unit is approximately planar, the maximum deviation from the mean plane being 0.0166 Å. The attached phenyl ring makes a dihedral angle of 53.2 (1)° with the fused ring system. The packing of the mol-ecules in the crystal structure is governed by C-H⋯O and O-H⋯O hydrogen-bonding inter-actions.

2H-Chromene is an important structural motif that exists in natural products and non-natural compounds possessing interesting biological activities. In this investigation, a highly efficient approach toward 2H-chromenes has been developed based on palladium-catalyzed coupling of N-tosylhydrazones and β-bromostyrenes. The mechanism of this reaction is proposed that involves the formation of viny...

In the title compound, C14H15N3O2, one of the methyl C atoms of the tert-butyl group lies almost in the plane of the chromene ring system [deviation = -0.097 (2) Å], one lies above and one lies below [deviations = 1.460 (3) and 1.006 (3) Å, respectively]. The C-C-N-N torsion angle is 142.33 (17)°. In the crystal, moelcules are linked by weak C-H⋯O hydrogen bonds to generate C(6) chains propagat...

The reaction of dimethyl acetylenedicarboxylate with OH-acid such as 2-naphthol in the presence of trimethyl or triphenyl phosphite under solvent-free conditions produce oxaphosphaphenanthrene derivatives in good yields. Also, the reaction of dimethyl acetylenedicarboxylate and trimethyl phosphite in the presence of 1-naphthol leads to succinate derivatives in excellent yields. Using triethyl p...

The carbene complex 5-(2,2-dimethyl-2H-chromene)methoxylmethylene chromium pentacarbonyl will undergo a benzannulation reaction with phenylacetylene, 1-pentyne, 3-hexyne, and trimethylsilylacetylene to give 7-hydroxy-10-methoxy-3H-naphtho[2.1-b]pyrans as the primary product. These compounds are difficult to obtain pure due to their sensitivity to air. If the benzannulation reaction is performed...

In the title compound, C(29)H(22)O(4), the chromene ring is almost planar with a small puckering [0.143 (2) Å]. The crystal structure is stabilized by C-H⋯O and C-H⋯π inter-actions. Edge-to-face (centroid-centroid distances of 3.894 and 3.673 Å) and face-to-face (centroid-centroid distance of 3.460 Å) π-π-ring electron inter-actions are also observed.