In the title compound, C40H34N2O2, the central piperidine ring adopts a half-chair conformation and the fused pyrrolidine rings adopt twisted envelope (with the C atom bearing the methylphenyl ring as the flap atom) and envelope (with the C atom bound to the N atom, common to the pyridinone and pyrrolidine rings being the flap atom) conformations. The mol­ecular structure features weak intra­molecular N—H⋯O and C—H⋯O inter­actions. In the crystal, O—H⋯O hydrogen bonds generate a C(7) chain along the b-axis direction. C—H⋯O inter­actions also occur.

In the title compound, C29H34N2O2, the central piperidine ring adopts a half-chair conformation, whereas the terminal one adopts a chair conformation. The mean plane of the central piperidine ring [maximum deviation = 0.384 (2) Å] makes dihedral angles of 64.82 (13) and 17.55 (13)° with the benzene rings. In the crystal, mol­ecules are linked into a tape along the b axis via C—H⋯O inter­actions, generating R 2 2(20) and R 2 1(6) graph-set motifs. C—H⋯π inter­actions are observed between the tapes.

In the title compound, C13H10N2O2S, the essentially planar 2H-chromene ring system [maximum deviation = 0.0297 (13) Å] and the thia­zole ring [maximum deviation = 0.0062 (11) Å] form a dihedral angle of 3.47 (5)°. In the crystal, N—H⋯N and C—H⋯O hydrogen bonds link the mol­ecules into two-dimensional networks parallel to the bc plane. C—H⋯π and π–π [centroid–centroid separation = 3.6796 (8) Å] inter­actions further stabilize the crystal structure.

In the title compound, C34H26F2N2O2S, an intra­molecular O—H⋯N hydrogen bond forms an S(5) ring motif. The piperidine ring adopts a chair conformation. The thia­zolidine ring and one of the pyrrolidine rings adopt envolope conformations with methyl­ene C atoms at the flap, whereas the other pyrrolidine ring adopts a half-chair conformation. The fluoro-substituted benzene rings form dihedral angles of 32.25 (10) and 38.27 (10)°, respectively, with the mean plane of the dihydro­acenaphthyl­ene ring system [maximum deviation = 0.043 (2) Å]. The dihedral angle between the fluoro-substituted benzene rings is 64.13 (14)°. In the crystal, mol­ecules are linked by weak C—H⋯O, C—H⋯F and C—H⋯S hydrogen bonds into a three-dimensional network.

In the title compound, C14H11N3O3, the chromene ring is almost planar, with a maximum deviation of 0.065 (2) Å from the mean plane for one of the C atoms. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops. The dimers are linked by C—H⋯N and C—H⋯O inter­actions into a three-dimensional network. An aromatic π–π stacking inter­action, with a centroid–centroid distance of 3.562 (10) Å, is also observed.

In the title compound, C34H28N2O2S, the piperidine ring adopts a chair conformation. One of the pyrrolidine rings adopts an envelope conformation with the methyl­ene C atom at the flap whereas the other pyrrolidine ring and the thia­zolidine ring adopt half-chair conformations. The mean plane of the dihydro­acenaphthyl­ene ring system [maximum deviation = 0.067 (1) Å] makes dihedral angles of 28.31 (5) and 31.32 (6)° with the two terminal benzene rings. An intra­molecular O—H⋯N hydrogen bond forms an S(5) ring motif. In the crystal, mol­ecules are linked by C—H⋯O and C—H⋯S hydrogen bonds into layers lying parallel to the ac plane.

Background

Coumarin derivatives exhibit a wide range of biological properties including promising antioxidant activity. Furthermore, microwave-assisted organic synthesis has delivered rapid routes to N- and O-containing heterocycles, including coumarins and thiazoles. Combining these features, the use of microwave-assisted processes will provide rapid access to a targeted coumarin library bearing a hydrazino pharmacophore for evaluation of antioxidant properties

Results

Microwave irradiation promoted 3 of the 4 steps in a rapid, convergent synthesis of a small library of hydrazinyl thiazolyl coumarin derivatives, all of which exhibited significant antioxidant activity comparable to that of the natural antioxidant quercetin, as established by DPPH and ABTS radical assays

Conclusions

Microwave dielectric heating provides a rapid and expedient route to a series of hydrazinyl thiazolyl coumarins to investigate their radical scavenging properties. Given their favourable properties, in comparison with known antioxidants, these coumarin derivatives are promising leads for further development and optimization.

The asymmetric unit of the title compound, C27H45ClO, consists of two crystallographically independent mol­ecules. In both mol­ecules, the three cyclo­hexane rings in the steroid fused-ring systems adopt chair conformations, while the cyclo­pentane ring adopts a half-chair conformation in one mol­ecule and an envelope conformation in the other. In the crystal, the mol­ecules are linked into a two-dimensional network by weak C—H⋯O hydrogen bonds. The crystal studied is a nonmerohedral twin with a refined ratio of twin components of 0.264 (3):0.736 (3).

The asymmetric unit of the title compound, C30H48ClN3O, contains two mol­ecules, A and B. In both mol­ecules, the three cyclo­hexane rings in the steroid fused ring systems adopt chair conformations, while the cyclo­pentane rings adopt envelope and twist conformations in mol­ecules A and B, respectively. In mol­ecule B, the cyano group is disordered over two orientations with refined site-occupancies of 0.593 (8) and 0.407 (8). An intra­molecular C—H⋯N inter­action forms an S(10) ring in both mol­ecules. In the crystal, mol­ecules are linked by N—H⋯O, C—H⋯O and C—H⋯N inter­actions, resulting is chains propagating along the a-axis direction.

The asymmetric unit of the title complex, {[Mn(C20H10Br2N3O5)(H2O)]·(CH3)2NCHO}n, consists of one MnIII ion, one (E)-5-bromo-N-[2-(5-bromo-2-oxidobenzyl­idene­amino)-4-nitro­phen­yl]-2-oxidobenzamidate ligand (Schiff base), one water mol­ecule and an N,N-dimethyl­formamide mol­ecule. The coordination geometry around the MnIII ion is a distorted octa­hedron, being surrounded by two O and two N atoms from the Schiff base, which are positioned in the equatorial plane. The water mol­ecule and the O atom of the carbonyl group from the adjacent MnIII complex are situated at the axial positions, leading to a polymeric chain along the c axis. In the crystal, the complex and N,N-dimethyl­formamide mol­ecules are connected via O—H⋯O, C—H⋯O and C—H⋯Br hydrogen bonds, forming a three-dimensional network.

In the title compound, C27H21NO, the piperidine ring adopts a chair conformation. The mean plane through the piperidine ring makes dihedral angles of 49.27 (5) and 63.07 (5)° with the naphthalene ring systems. In the crystal, mol­ecules are linked into dimers via pairs of inter­molecular C—H⋯O inter­actions, generating ten-membered R 2 2(10) ring motifs. C—H⋯π inter­actions further stabilize the crystal structure.

In the asymmetric unit of the title compound, C16H11FO5S, 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-fluoro­phenyl 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 below the plane [C—C—S—O = −61.35 (17)°]. In the crystal, mol­ecules are connected by weak C—H⋯O hydrogen bonds, forming two-dimensional networks parallel to the ac plane.

The asymmetric unit of the title compound, C32H51N3O3, consists of two crystallographically independent mol­ecules, A and B; the 2-methyl­pentane group of mol­ecule A and the propane group of mol­ecule B are each disordered over two sets of sites, with refined site-occupancies of 0.825 (5):0.175 (5) and 0.630 (18):0.370 (18), respectively. In both mol­ecules, the three cyclo­hexane rings in the steroid fused ring systems adopt chair conformations while the cyclo­pentane rings adopt envelope and twist conformations in mol­ecules A and B, respectively. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds link the two independent mol­ecules together, generating R 2 1(7) and R 2 2(8) ring motifs.

In the title mol­ecule, C19H20N2O4·H2O, the benzimidazole ring system is essentially planar [maximum deviation = 0.013 (11) Å] and is inclined to the 4-meth­oxy­phenyl ring by 30.98 (5)°. In the crystal, O—H⋯O and O—H⋯N hydrogen bonds involving the water mol­ecule link neighbouring mol­ecules, forming a two-dimensional network lying parallel to the bc plane. There are also C—H⋯π and π–π inter­actions present. The latter involve inversion-related benzimidazole rings with centroid–centroid distances of 3.5552 (8) and 3.7466 (8) Å.

In the title compound, C26H25FO5, the terminal cyclo­hexane rings of the xanthene ring system adopt half-boat conformations. The 4H-chromene ring make a dihedral angle of 87.94 (5)° with the xanthene ring system and its carbonyl O atom lies above the xanthene O atom. In the crystal, mol­ecules are linked into ribbons propagating along the a-axis direction by C—H⋯O hydrogen bonds. Aromatic π–π stacking inter­actions [centroid–centroid distance = 3.7367 (12) Å] also occur.

In the title compound, C17H14O6S, 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 meth­oxy group is close to coplanar with its attached ring [deviation = 0.082 (2) Å]. In the crystal, mol­ecules are connected via C—H⋯O hydrogen bonds, forming sheets lying parallel to the bc plane. Weak C—H⋯π inter­actions are also observed.

The title compound, C11H15NO6S, features a distorted tetra­hedral geometry for the S atom. One of the sulfonamide O atoms is approximately coplanar with the benzene ring [C—C—S—O torsion angle = −160.81 (7)°], whereas the other lies well below the plane [C—C—S—O = −29.66 (8)°]. In the crystal, O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into chains parallel to the b axis.

In the title compound, C21H24N2O3, the mean planes of the benzene ring and the benzimidazole ring system form a dihedral angle of 69.94 (7)°. The ethyl group atoms of the ethano­ate fragment are disordered over two sets of sites, with refined occupancies of 0.742 (6) and 0.258 (6). In the crystal, there are weak C—H⋯N hydrogen bonds which connect mol­ecules into chains along the b axis. A weak inter­molecular C—H⋯π inter­action is also observed.

In the title compound, C38H30N2O2, the acenaphthyl­ene ring is close to being planar [maximum deviation = 0.1047 (11) Å]. The dihedral angles between the three benzene rings and the acenaphthyl­ene system are 39.47 (3), 37.65 (3) and 44.47 (3)°. An intra­molecular O—H⋯N inter­action forms an S(5) hydrogen-bond ring motif. In the crystal, mol­ecules are linked into [101] chains by a set of C—H⋯O inter­actions.

In the title compound, C38H28F2N2O2, the piperidine ring adopts a chair conformation and the pyrrolidine ring adopts an envelope conformation with the spiro C atom as the flap atom. The naphthalene ring system makes dihedral angles of 39.89 (8), 35.33 (8) and 46.45 (8)° with the two fluoro-substituted benzene rings and the phenyl ring, respectively, while the dihedral angle between the two fluoro-substituted benzene rings is 75.21 (10)°. An intra­molecular O—H⋯N hydrogen bond generates an S(5) ring. In the crystal, mol­ecules are connected by C—H⋯O hydrogen bonds, forming supra­molecular chains propagating along the c-axis direction. Weak C—H⋯π inter­actions further consolidate the structure.

In the title compound, C36H32N2O4S, the piperidine ring adopts a chair conformation, while the five-membered pyrrolidine (with a C atom as the flap atom) and thia­zolidine (with the S atom as the flap atom) rings adopt envelope conformations. The naphthalene ring system makes dihedral angles of 18.82 (5) and 40.92 (5)° with the two meth­oxy-substituted benzene rings. In the crystal, centrosymmetrically-related mol­ecules are linked into dimers via pairs of C—H⋯O and C—H⋯N hydrogen bonds. An intra­molecular O—H⋯N hydrogen bond is also observed. The crystal structure is further stabilized by C—H⋯π inter­actions.

The asymmetric unit of the title compound, C21H26O4S, consists of two independent mol­ecules. In both mol­ecules, intra­molecular O—H⋯O hydrogen bonds stabilize the mol­ecular structure. In the crystal, each mol­ecule and its symmetry-related mol­ecule by twofold rotation form a dimer through a pair of inter­molecular C—H⋯O hydrogen bonds. In one of the mol­ecules, the thio­phene group is disordered over two sets of sites with occupancies of 0.735 (3) and 0.265 (3).

In the title compound, C20H14BrN3O3S, the mol­ecule adopts an E configuration about the central C=N double bond. The chromene ring system and the thia­zole 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 thia­zole and benzene rings, respectively, while the thia­zole ring makes a dihedral angle of 12.58 (15)° with the benzene ring. In the crystal, mol­ecules are connected by N—H⋯O hydrogen bonds, forming C(8) supra­molecular chains along the c axis.

In the title compound, C15H8Cl2N2O2, the mol­ecule adopts an E configuration about the central C=N double bond. The isoindoline ring is essentially planar, with a maximum deviation of 0.019 (2) Å. The dihedral angle between the isoindoline ring and the dichloro-substituted benzene ring is 6.54 (9)°. An intra­molecular C—H⋯O hydrogen bond occurs. A short Cl⋯Cl contact of 3.4027 (9) Å is present in the crystal structure. The crystal packing is further stabilized by weak C—H⋯π inter­actions.

The asymmetric unit of the title compound, C27H30N2O2, comprises two independent mol­ecules. The dihedral angles between the phenyl rings in the two mol­ecules are 55.59 (8) and 55.39 (8)°. The piperidine rings adopt chair conformations. The crystal structure is stabilized by weak inter­molecular C—H⋯O and C—H⋯N hydrogen bonds. The crystal studied was a non-merohedral twin with a domian ratio of 0.75 (2):0.25 (2).