3,4-ِdihydropyrano[c]chromene derivatives were synthesized using sulfonic acid functionalized silica (sio2-pr-so3h) as a highly efficient heterogenous solid acid catalyst via one-pot three-component condensation of aromatic aldehydes with malononitrile and 4-hydroxycoumarin in excellent yields.

In the title compound, C(17)H(14)O(6)S, the 2H-chromene ring is essentially planar, with a maximum deviation of 0.016 (1) Å. The dihedral angle between the 2H-chromene and the benzene rings is 54.61 (5)°. The C atom of the meth-oxy group is close to coplanar with its attached ring [deviation = 0.082 (2) Å]. In the crystal, mol-ecules are connected via C-H⋯O hydrogen bonds, forming sheets lying ...

In the title compound, C(20)H(14)BrN(3)O(3)S, the mol-ecule adopts an E configuration about the central C=N double bond. The chromene ring system and the thia-zole ring are approximately planar [maximum deviations = 0.029 (3) and 0.007 (3) Å, respectively]. The chromene ring system is inclined at angles of 7.37 (12) and 13.90 (13)° with respect to the thia-zole and benzene rings, respectively, ...

In the title compound, C(22)H(18)N(2)O(2), the pyran ring of the chromene unit is fused with an isoxazole ring, which adopts an N-envelope conformation with the N atom lying 1.3291 (14) Å from the mean plane of the remaining ring atoms [maximum deviation = 0.341 (2) Å]. The dihedral angle between the isoxazole and chromene units is 43.74 (8)° and that between the iosxazole ring and the naphthal...

In the title compound, C(20)H(19)N O(2)S(2),the 3Hbenzo-chromene ring system is nearly planar, with a maximum deviation of 0.036 (2) Å, and the piperidine ring adopts a chair conformation: the bond-angle sum for its N atom is 358.7°. The dihedral angle between the 3H-benzo[f]chromene ring and the piperidine ring is 89.07 (8)°. In the crystal, C-H⋯O hydrogen bonds lead to [010] C(6) chains and w...

An unexpected transformation of 2H-chromene-3-carboxaldehydes to coumarin derivatives, mediated by NHC, is reported.

Although salicylaldehyde azine (3) was reported in 1985 as the single product of the reaction of ethyl 2-oxo-2H-chromene-3-carboxylate (1) with hydrazine hydrate, we identified another main reaction product, besides 3, which was identified as malono-hydrazide (4). In the last two decades, however, some articles have claimed that this reaction afforded exclusively hydrazide 2 and they have repo...

In the asymmetric unit of the title compound, C(16)H(11)FO(5)S, the 2H-chromene ring is essentially planar, with a maximum deviation of 0.040 (2) Å. The dihedral angle between the 2H-chromene ring and the 4-fluoro-phenyl ring is 2.17 (8)°. One of the sulfonamide O atoms is approximately coplanar with the benzene ring [C-C-S-O torsion angle = 166.00 (14)°], whereas the other O atom lies well bel...

The synthesis of 2-benzylamino-8-methoxy-4H-chromene-3-carbonitriles 7(a-e) has been realized in four steps, via reductive amination from the 2-amino-8-methoxy-4H-chromene-3-carbonitrile 4 as key intermediate platform with para- and meta-substituted benzaldehydes 5(a-e), good overall yields. physicochemical properties also their aldimines 6(a-e) precursors have determined using Swiss ADME serve...

In the title compound, C17H19NO2S2, the 2H-chromene ring system is nearly planar, with a maximum deviation of 0.0383 (28) Å, and the piperidine ring adopts a chair conformation. The 2H-chromene ring makes dihedral angles of 32.89 (16) and 67.33 (8)°, respectively, with the mean planes of the piperidine ring and the carbodi-thio-ate group. In the crystal, C-H⋯O and weak C-H⋯S hydrogen bonds link...