Synthesis of isatin thiosemicarbazones derivatives: in vitro anti-cancer, DNA binding and cleavage activities.

New derivatives of thiosemicarbazone Schiff base with isatin moiety were synthesized L1-L6. The structures of these compounds were characterized based on the spectroscopic techniques. Compound L6 was further characterized by XRD single crystal. The interaction of these compounds with calf thymus (CT-DNA) exhibited high intrinsic binding constant (k(b)=5.03-33.00×10(5) M(-1)) for L1-L3 and L5 and (6.14-9.47×10(4) M(-1)) for L4 and L6 which reflect intercalative activity of these compounds toward CT-DNA. This result was also confirmed by the viscosity data. The electrophoresis studies reveal the higher cleavage activity of L1-L3 than L4-L6. The in vitro anti-proliferative activity of these compounds against human colon cancer cell line (HCT 116) revealed that the synthesized compounds (L3, L6 and L2) exhibited good anticancer potency.

(Z)-N-Ethyl-2-(5-fluoro-2-oxoindolin-3-yl-idene)hydrazinecarbothio-amide.

In the title compound, C(11)H(11)FN(4)OS, an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, mol-ecules form chains through N-H⋯O hydrogen bonds, which are extended by N-H⋯S hydrogen bonds into an infinite three-dimensional network.

(E)-N-Ethyl-2-[(E)-3-(hy-droxy-imino)-butan-2-yl-idene]hydrazinecarbothio-amide.

In the crystal structure of the title compound, C(7)H(14)N(4)OS, mol-ecules are linked through N-H⋯S and O-H⋯N hydrogen bonds and C-H⋯S interactions, forming chains propagating along [21-1].

(Z)-N-Methyl-2-(5-nitro-2-oxoindolin-3-yl-idene)hydrazinecarbothio-amide.

In the title compound, C(10)H(9)N(5)O(3)S, an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked via N-H⋯S hydrogen bonds into a zigzag chain along the b axis. C-H⋯O inter-actions are observed between the chains.

(Z)-N-Methyl-2-(5-methyl-2-oxoindolin-3-yl-idene)hydrazinecarbothio-amide.

In the title compound, C(11)H(12)N(4)OS, an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, the mol-ecules form a helical chain along the a axis through an N-H⋯O hydrogen bond. These chains are extended by an N-H⋯S hydrogen bond and a C-H⋯π inter-action into a three-dimensional network.

(Z)-2-(2-Oxoindolin-3-yl-idene)-N-phenylhydrazinecarbothio-amide.

In the title compound, C(15)H(12)N(4)OS, the dihedral angle between the nine-membered indolin-2-one ring system and the phenyl ring is 2.72 (7)°. Intra-molecular cyclic N-H⋯O and C-H⋯S hydrogen-bonding inter-actions [graph set S(6)] are present, as are weak N-H⋯N inter-actions [graph set S(5)]. In the crystal, mol-ecules form centrosymmetric cyclic dimers through pairs of N-H⋯O hydrogen bonds [graph set R(2) (2)(8)] and these are extended by C-H⋯S inter-actions. The crystal structure also features weak C-H⋯π inter-actions.

Bis[2-(2-oxoindolin-3-yl-idene)-N-phenylhydrazinecarbothio-amidato-κ(3)O,N(2),S]nickel(II) dimethyl-formamide monosolvate.

The asymmetric unit of the title compound, [Ni(C(15)H(11)N(4)OS)(2)]·C(3)H(7)NO, contains one Ni(II) complex mol-ecule and one disordered dimethyl-formamide solvent mol-ecule. The Ni(II) ion is six-coordinated in a distorted octa-hedral geometry by two N, two O and two S atoms. An intra-molecular C-H⋯S hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked through inter-molecular N-H⋯S, N-H⋯O, C-H⋯N, C-H⋯O and C-H⋯S hydrogen bonds into infinite two-dimensional network parallel to the ab plane. The structure is further stablized by weak C-H⋯π inter-actions. The dimethylformamide solvent molecule is disordered over two sets of sites in a 0.514 (15):0.486 (15) ratio.

(Z)-2-(5-Chloro-2-oxoindolin-3-yl-idene)-N-methyl-hydrazinecarbothio-amide.

In the title compound, C(10)H(9)ClN(4)OS, an intra-molecular N-H⋯O hydrogen-bonding inter-action and an N-H⋯N inter-action generate ring motifs [graph sets S(6) and S(5), respectively]. In the crystal, mol-ecules form a chain through N-H⋯O hydrogen bonds, and these are extended by N-H⋯S hydrogen-bonding inter-actions into an infinite three-dimensional network. The crystal structure also exhibits weak C-H⋯π inter-actions.

Bis{2-[3-(hy-droxy-imino-κN)butan-2-yl-idene]-N-methyl-hydrazinecarbothio-amide-κN,S}nickel(II) dichloride.

The asymmetric unit of the title compound, [Ni(C(6)H(12)N(4)OS)(2)]Cl(2), contains two independent Ni(II) complex cations and four chloride anions. Each Ni(II) ion is six-coordinated in a distorted octa-hedral geometry by four N atoms from the two imine and two oxime groups and two S atoms from the thione group. In the crystal, the cations and anions are linked through N-H⋯Cl and O-H⋯Cl hydrogen bonds into infinite chains propagating along [10[Formula: see text]]. Weak inter-molecular C-H⋯O and C-H⋯Cl hydrogen bonds are also observed.

Bis{N-ethyl-2-[3-(hy-droxy-imino-κN)butan-2-yl-idene]hydrazinecarbothio-amide-κN,S}nickel(II) dichloride.

In the title complex, [Ni(C(7)H(14)N(4)OS)(2)]Cl(2), the Ni(II) ion is six-coordinated in a distorted octa-hedral geometry by four N atoms from the two imine and two oxime groups, and two S atoms from the thione groups. Two chloride ions complete the asymmetric unit. In the crystal, mol-ecules are linked through N-H⋯Cl and O-H⋯Cl hydrogen bonds into an infinite chain propagating along [101].

(Z)-2-(5-Fluoro-2-oxoindolin-3-yl-idene)-N-phenyl-hydrazinecarbothio-amide.

The title compound, C(15)H(11)FN(4)OS, crystallizes with three independent mol-ecules (A, B and C) in the asymmetric unit. The dihedral angles between the nine-membered 5-fluoro-indolin-2-one ring system and the benzene ring are 22.14 (11), 12.56 (11) and 3.70 (11)° in mol-ecules A, B and C, respectively. In all three mol-ecules, intra-molecular cyclic N-H⋯O and C-H⋯S hydrogen-bonding inter-actions [graph set S(6)] are present in the N-N-C-N chain between the ring systems. In the crystal, the A mol-ecules form centrosymmetric cyclic dimers through inter-molecular N-H⋯O hydrogen bonds, which are linked into a supramolecular chain along [100] via C-H⋯F interactions; each type of hydrogen bond has graph set graph set R(2) (2)(8). A similar chain stabilised by similar interactions and also along [100] but, comprising alternating molecules of B and C is found. The latter chains are connected via C-H⋯S interactions, forming a layer with a zigzag topology parallel to (001).

2-Amino-3-nitro-benzoic acid.

The title compound, C(7)H(6)N(2)O(4), is approximately planar (r.m.s. deviation = 0.026 Šfor the 13 non-H atoms). The mol-ecular structure is stabilized by intra-molecular N-H⋯O hydrogen bonds, which generate S(6) ring motifs. In the crystal, mol-ecules are linked via inter-molecular N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds into a three-dimensional network.

(E)-2-[(E)-3-(Hy-droxy-imino)-butan-2-yl-idene]-N-methyl-hydrazinecarbothio-amide.

In the title compound, C(6)H(12)N(4)OS, an intra-molecular N-H⋯N hydrogen-bond is present giving rise to an S(5) ring motif. In the crystal, double-stranded chains propagating along [10[Formula: see text]] are formed via pairs of O-H⋯S and N-H⋯S hydrogen bonds. The chains are further stabilized by C-H⋯S interactions.

Novel modified ultrasonication technique for the extraction of lycopene from tomatoes.

Lycopene extraction was carried out via the ultrasonic assisted extraction (UAE) with response surface methodology (RSM). Sonication enhanced the efficiency of relative lycopene yield (enhancement of 26% extraction yield of lycopene in 6 replications at 40.0 min, 40.0 °C and 70.0% v/w in the presence of ultrasound), lowered the extraction temperature and shortened the total extraction time. The extraction was applied with the addition of oxygen-free nitrogen flow and change of water route during water bath sonication. The highest relative yield of lycopene obtained was 100% at 45.0 °C with total extraction time of 50.0 min (30:10:10) and ratio of solvent to freeze-dried tomato sample (v/w) of 80.0:1. Optimisation of the lycopene extraction had been performed, giving the average relative lycopene yield of 99% at 45.6 min, 47.6 °C and ratio of solvent to freeze-dried tomato sample (v/w) of 74.4:1. From the optimised model, the average yield of all-trans lycopene obtained was 5.11±0.27 mg/g dry weight. The all-trans lycopene obtained from the high-performance liquid chromatography (HPLC) chromatograms was 96.81±0.81% with 3.19±0.81% of cis-lycopenes. The purity of total-lycopene obtained was 98.27±0.52% with ß-carotene constituted 1.73±0.52% of the extract. The current improved, UAE of lycopene from tomatoes with the aid of RSM also enhanced the extraction yield of trans-lycopene by 75.93% compared to optimised conventional method of extraction. Hence, the current, improved UAE of lycopene promotes the extraction yield of lycopene and at the same time, minimises the degradation and isomerisation of lycopene.

(Z)-2-(5-Chloro-2-oxoindolin-3-yl-idene)-N-phenyl-hydrazinecarbothio-amide.

In the title compound, C(15)H(11)ClN(4)OS, the dihedral angle between the nine-membered 5-chloro-indolin-2-one ring system and the benzene ring is 10.00 (6)°. Intra-molecular cyclic N-H⋯O and C-H⋯S hydrogen-bonding inter-actions [graph set S(6)] are present in the N-N-C-N chain between the ring systems. In the crystal, mol-ecules form centrosymmetric cyclic dimers through inter-molecular N-H⋯O hydrogen bonds [graph-set R(2) (2)(8)] and are extended by C-H⋯Cl inter-actions into infinite chains which propagate along [100].

(Z)-2-(5-Methyl-2-oxoindolin-3-yl-idene)-N-phenyl-hydrazinecarbothio-amide.

In the title compound, C(16)H(14)N(4)OS, the dihedral angle between the nine-membered 5-methyl-indolin-2-one ring system and the benzene ring is 10.21 (7)°. Intra-molecular cyclic N-H⋯O and C-H⋯S hydrogen-bonding inter-actions [graph set S(6)] are present within the N-N-C-N chain between the ring systems. In the crystal, mol-ecules form centrosymmetric cyclic dimers through pairs of N-H⋯O hydrogen bonds [graph set R(2) (2)(8)].

2-(5,6-Dihydro-benzimidazo[1,2-c]quinazolin-6-yl)phenol.

The asymmetric unit of the title compound, C(20)H(15)N(3)O, contains two independent mol-ecules, each of which is disordered over two sets of sites corresponding to a rotation of approximately 180° of the dihydro-benzimidazoquinazoline moiety, with refined site occupancies of 0.7479 (13) and 0.2521 (12) for both mol-ecules. The pyrimidine rings are in sofa conformations. In one mol-ecule, the hy-droxy-substituted benzene ring forms dihedral angles of 83.9 (3) and 82.4 (4)° for the major and minor components, respectively, with the mean plane of the benzimidazole ring system. The corres-ponding dihedral angles in the other mol-ecule are 88.31 (14) and 85.8 (6)°. In the crystal, mol-ecules are linked via inter-molecular O-H⋯N and N-H.·O hydrogen bonds into chains along [100].

2-(5,6-Dihydro-benzimidazo[1,2-c]quinazolin-6-yl)-5-methyl-phenol.

In the title compound, C(21)H(17)N(3)O, the imidazole ring is essentially planar, with a maximum deviation of 0.009 (1) Å. The mol-ecule is disordered over two sites corresponding to a rotation of approximately 180° with a refined occupancy ratio of 0.9180 (14):0.0820 (14). The central pyrim-idine ring makes dihedral angles of 5.02 (5), 3.97 (5) and 6.28 (5)°, respectively, with the planes of the imidazole and the terminal phenyl rings for the major component; the values for the minor component are 5.8 (7), 5.0 (6) and 8.5 (6)°, respectively. Part of the observed planarity is accounted for in terms of an intra-molecular N-H⋯O hydrogen bond. In the crystal, mol-ecules of the major component are connected by O-H⋯N hydrogen bonds, forming supra-molecular chains along the c axis.

(E)-2-{[1-Carb-oxy-2-(1H-indol-3-yl)ethyl-iminio]meth-yl}-6-hy-droxy-phenolate.

In the zwitterionic title compound, C(18)H(16)N(2)O(4), the dihedral angle between the planes of the benzene and indole rings is 26.38 (10)°. An intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked through N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds into infinite chains propagating in [010].

2-(5,6-Dihydro-benzimidazo[1,2-c]quinazolin-6-yl)-5-meth-oxy-phenol.

In the title quinazoline derivative, C(21)H(17)N(3)O(2), the benzimidazole unit makes dihedral angles of 8.29 (5) and 81.79 (5)° with the benzene rings of the quinazoline and meth-oxy-phenol units, respectively. The nitro-gen-containing six-membered ring adopts a half-chair conformation. In the crystal, the mol-ecules are linked through O-H⋯N hydrogen bonds into screw chains along the b axis; adjacent chains are further connected by N-H⋯O hydrogen bonds, thereby forming a two-dimensional network lying parallel to the bc plane. Weak C-H⋯π and π⋯π inter-actions with centroid-centroid distances of 3.5258 (8) and 3.7184 (7) Šare present and N⋯O [2.6816 (15) and 3.0519 (15) Å] short contacts also occur.