Ruthenium(II) Complex-Based Tetradentate Schiff Bases: Synthesis, Spectroscopic, Antioxidant, and Antibacterial Investigations.

In this work, we describe the synthesis of novel Ruthenium (II) complex-based salen Schiff bases. The obtained Ruthenium (II) complexes are characterized using usual spectroscopic and spectrometric techniques, viz., IR, UV-Vis, NMR (1H and 13C), powder X-ray diffraction, and HRMS. Further techniques, such as DTA-TGA and elemental analysis, are used to well establish the structure of the obtained complexes. Octahedral geometries are tentatively proposed for the new Ru(II) complexes. The measured molar conductance for the Ruthenium (II) complexes shows their electrolytic nature (4.24-4.44 S/m). The new Ru(II) complexes are evaluated for their antioxidant and antibacterial activities. The DPPH radical scavenging, FRAP, and total antioxidant capacity (TAC) assays show that the obtained complexes are more potent than the used positive control. They also exhibit promising antibacterial responses against pathogen bacteria: [RuH2L3Cl2] exhibits an important inhibition against Bacillus subtilis DSM 6633, with an inhibition zone of 21 ± 1.41 mm with an MIC value of 0.39 mg/mL, and Proteus mirabilis INH, with 16.50 ± 0.70 mm and an MIC value of 0.78 mg/mL, while [RuH2L2Cl2] exerts interesting antibacterial effects versus Bacillus subtilis DSM 6633 (21 ± 1.41 mm) and Proteus mirabilis INH (25.5 ± 0.70 mm) with equal MIC values of 0.97 mg/mL.

Optimization of Insecticidal Triterpene Derivatives by Biomimetic Oxidations with Hydrogen Peroxide and Iodosobenzene Catalyzed by MnIII and FeIII Porphyrin Complexes.

Semisynthetic functionalized triterpenes (4α,14-dimethyl-5α,8α-8,9-epoxycholestan-3ß-yl acetate; 4α,14-dimethyl-5α-cholest-8-ene-3,7,11-trione; 4α,14-dimethyl-5α-cholesta-7,9(11)-dien-3-one and 4α,14-dimethyl-5α-cholest-8-en-3ß-yl acetate), previously prepared from 31-norlanostenol, a natural insecticide isolated from the latex of Euphorbia officinarum, have been subjected to oxidation with hydrogen peroxide (H2 O2 ) and iodosobenzene (PhIO) catalyzed by porphyrin complexes (cytochrome P-450 models) in order to obtain optimized derivatives with high regioselectivity. The main transformations were epoxidation of the double bonds and hydroxylations of non-activated C-H groups and the reaction products were 25-hydroxy-4α,14-dimethyl-5α-cholesta-7,9(11)-dien-3ß-yl acetate (59 %), 25-hydroxy-4α,14-dimethyl-5α-cholest-8-ene-3,7,11-trione (60 %), 4α,14-dimethyl-5α,7ß-7,8-epoxycholest-9(11)-en-3-one (22 %), 8-hydroxy-4α,14-dimethyl-5α-cholest-9(11)-ene-3,7-dione (16 %), 12α-hydroxy-4α,14-dimethyl-5α,7ß-7,8-epoxycholest-9(11)-en-3-one (16 %), and 4α,14-dimethyl-5α,8α-8,9-epoxycholestan-3ß-yl acetate (26 %), respectively. We also investigated the insect (Myzus persicae, Rhopalosiphum padi and Spodoptera littoralis) antifeedant and postingestive effects of these terpenoid derivatives. None of the compounds tested had significant antifeedant effects, however, all were more effective postingestive toxicants on S. littoralis larvae than the natural compound 31-norlanostenol, with 4α,14-dimethyl-5α,8α-8,9-epoxycholestan-3ß-yl acetate being the most active. The study of their structure-activity relationships points out at the importance of C3 and C7 substituents.

Controlled Dimroth Rearrangement in the Suzuki-Miyaura Cross Coupling of Triazolopyridopyrimidines.

Polynitrogen heterocycles are often subject to Dimroth rearrangement which consists of ring opening, bond rotation, and ring closure. In this note, we report a synthesis of two new families of triazolopyridopyrimidines. Successful functionalization via a Suzuki-Miyaura coupling was performed with total control of triazole (Dimroth) isomerization based on the judicious choice of reaction conditions.

Synthesis and biological evaluation of 9α- and 9ß-hydroxyamino-parthenolides as novel anticancer agents.

A series of 9α-hydroxyamino-parthenolides 3-10, 9ß-hydroxyamino-parthenolides 11-13 and 9α-hydroxy-1ß,10α-epoxyamino-parthenolides 15-19 were efficiently synthesized starting from 9α-hydroxyparthenolide 1 and 9ß-hydroxyparthenolide 2, which were isolated from Anvillea radiata. Compounds 1-13 and 15-19 were evaluated for their in vitro anticancer activity by the MTT colorimetric assay against one murine and six human cancer cell lines. This work provides new details about the structural requisites for anticancer activity.

(1R,4R,6S,7R)-5,5-Di-bromo-1,4,8,8-tetra-methyl-tri-cyclo-[5.4.1.0(4,6)]dodecan-12-one.

The title compound, C16H24Br2O, was synthesized from the reaction of ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from two fused seven-membered rings and an additional three-membered ring. In both mol-ecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.

9α-Hy-droxy-12-{[4-(4-hy-droxy-phen-yl)piperazin-1-yl]meth-yl}-4,8-dimethyl-3,14-dioxatri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one.

The title compound, C25H34N2O5, was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3, 14-dioxa-tri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which in turn was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule comprises a ten-membered ring fused to a five-membered ring with an additional ep-oxy ring system fused to the ten-membered ring. The five-membered ring also carries a 4-hy-droxy-phenyl-piperazin-1-ylmethyl substituent. The ten-membered ring adopts an approximate chair-chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy-droxy group forming the flap. Two C atoms in the phenyl ring and the O atom of the hydroxyl group are disordered over two sites, with an occupancy ratio of 0.53 (5):0.47 (5). An intra-molecular O-H⋯N hydrogen-bond stabilizes the mol-ecular conformation. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules into zigzag chains running along the a-axis direction.

(1S,2R,3S,6S,7R)-3,7,11,11-Tetra-methyl-6,7-epoxybi-cyclo-[5.4.0]undecane-2-ol.

The title compound, C15H26O2, was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the Atlas cedar (cedrus atlantica). The mol-ecule is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The seven- and six-membered rings each have a twist-boat conformation. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into zigzag chains running along the b-axis direction.

1-[(1S,6R,7S,9R)-8,8-Di-bromo-5,5,9-tri-methyl-tri-cyclo-[4.4.0.1(7,9)]decan-1-yl]ethanone.

The title compound, C16H24Br2O, was synthesized by three steps from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from essential oil of the Atlas cedar cedrus atlantica. The asymmetric unit contains two independent mol-ecules with almost identical conformations. Each mol-ecule is built up from two fused six-membered rings, one having a chair conformation and the other a boat conformation, and an additional three-membered ring arising from the reaction of himachalene with di-bromo-carbene. In the crystal, there are no significant intermolecular interactions present. The absolute structure of the title compound was confirmed by resonance scattering.

12-{[4-(4-Bromo-phen-yl)piperazin-1-yl]meth-yl}-9α-hy-droxy-4,8-dimethyl-3,14-dioxatri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one.

The title compound, C25H33BrN2O4, was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3,14-dioxa-tri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule is built up from two fused five- and ten-membered rings with an additional ep-oxy ring system and a bromo-phenyl-piperazine group as a substituent. The ten-membered ring adopts an approximate chair-chair-chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy-droxy group forming the flap. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation. The crystal packing features C-H⋯O hydrogen bonds, which link the mol-ecules into zigzag chains running along the b-axis direction.

(1S,3R,8R,10R)-2,2-Di-bromo-3,7,7,10-tetra-methyl-tri-cyclo-[6.4.0.0(1,3)]dodecan-9-one.

The title compound, C16H24Br2O was synthesized by three steps from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from essential oil of the Atlas cedar (Cedrus atlantica). The mol-ecule is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The six-membered ring shows a chair conformation. One C atom in the seven-membered ring and two methyl groups attached to the ring are disordered over two sets of sites, with an occupancy ratio of 0.658 (7):0.342 (7).

(1S,3R,8R,9S,11R)-2,2,10,10-Tetra-chloro-3,7,7,11-tetra-methyl-tetra-cyclo-[6.5.0.0(1,3).0(9,11)]trideca-ne.

The title compound, C(17)H(24)Cl(4), was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzocyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule is built up from fused six- and seven-membered rings and two three-membered rings from the reaction of ß-himachalene with dichloro-carbene. The six-membered ring shows a chair conformation, whereas the seven-membered ring displays a boat conformation.

(1S,3R,8R,9R,10S)-2,2-Dibromo-3,7,7,10-tetra-methyl-9ß,10ß-ep-oxy-3,7,7,10-tetra-methyl-tricyclo-[6.4.0.0(1,3)]dodeca-ne.

The title compound, C16H24Br2O, was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzocyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus atlantica). The mol-ecule contains fused six- and seven-membered rings, each linked to a three-membered ring. The six-membered ring has a half-chair conformation, while the seven-membered ring displays a chair conformation. The dihedral angle between the mean planes through the six- and seven-membered rings is 39.55 (12)°. The two three-membered rings, linked to the six- and seven-membered rings, are nearly perpendicular to the six-membered ring, making dihedral angles of 78.6 (2) and 80.5 (2)°, respectively. The absolute structure was established unambiguously from anomalous dispersion effects. In the crystal, each mol-ecule is linked to its symmetry-equivalent partner by C-H⋯O hydrogen bonds, forming zigzag chains parallel to [100].

2,2-Dichloro-3,7,7,11-tetra-methyl-10-aza-tetra-cyclo-[6.5.0.0(1,3).0(9,11)]trideca-ne.

The title compound, C16H25Cl2N, was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzocyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule is built up from fused six- and seven-membered rings linked to two three-membered rings. The six-membered ring shows a half-chair conformation, whereas the seven-membered ring displays a boat conformation. The dihedral angle between the mean planes through the six- and seven-membered rings is 59.8 (2)°. The two three-membered rings lie to one side and each is nearly perpendicular to the six-membered ring, forming dihedral angles of 83.2 (2) and 86.0 (2)°. The absolute structure was established unambiguously from anomalous dispersion effects. No specific inter-molecular inter-actions are noted in the crystal structure.

(1S,3S,8R,9S,11R)-10,10-Di-bromo-3,7,7,11-tetra-methyl-tetra-cyclo-[6.5.0.0(1,3).0(9,11)]trideca-ne.

The title compound, C17H26Br2, was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from fused six- and seven-membered rings and two appended three-membered rings. In both mol-ecules, the six-membered ring has a screw boat conformation, whereas the seven-membered ring displays a boat conformation. No specific inter-molecular inter-actions were discerned in the crystal packing.

(1S,3R,8R,11S)-11-Bromo-10-bromo-methyl-2,2-di-chloro-3,7,7-tri-methyl-tricyclo-[6.4.0.0(1,3)]dodec-9-ene.

The title compound, C16H22Br2Cl2, was synthesized from ß-him-achalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule is built up from fused six- and seven-membered rings and an appended three-membered ring. The six-membered ring has a half-chair conformation, whereas the seven-membered ring displays a chair conformation. The dihedral angle between the two best plane through each ring is 59.5 (2)°. No specific inter-molecular inter-actions were discerned in the crystal packing.

1,10,10-Trimethyl-5-phenyl-3-oxa-4-aza-tri-cyclo-[5.2.1.0(2,6)]dec-4-en-2-ol.

The title compound, C17H21NO2, was synthesized by the reaction of (1R)-(+)-3-benzyl-camphor and hydroxyl-amine. The oxazole ring makes a dihedral angle of 23.42 (16)° with the phenyl ring. The six-membered ring of the norboryl group adopts a boat conformation, whereas each of the five-membered rings of the norboryl group displays a flattened envelope conformation, with the C atom carrying the methyl groups representing the flap for both rings. In the crystal, mol-ecules are linked into zigzag chains propagating along the b axis by O-H⋯N hydrogen bonds.

(1S,3S,8R,10R,11R)-3,7,7,10-Tetra-methyl-tri-cyclo-[6.4.0.0(1,3)]dodecan-11-ol.

The title compound, C16H28O, was synthesized by three steps from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus atlantica). The mol-ecule is built up from fused six- and seven-membered rings and an appended three-membered ring. The six-membered ring has twist-boat conformation, whereas the seven-membered ring displays a chair conformation. In the crystal, mol-ecules are linked into chains propagating along the a-axis direction by O-H⋯O hydrogen bonds.

(1S,3R,8R)-2,2-Di-chloro-3,7,7,10-tetra-methyl-tri-cyclo-[6.4.0.0(1,3)]dodec-9-en-11-one.

The title compound, C16H22Cl2O, was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule is built up from fused six- and seven-membered rings and an additional three-membered ring arising from the reaction of himachalene with di-chloro-carbene. The six-membered ring has an envelope conformation, with the C atom belonging to the three-membered ring forming the flap, whereas the seven-membered ring displays a screw-boat conformation; the dihedral angle between the rings (all atoms) is 59.65 (14)°.

(1S,3S,8R,9S,11R)-10,10-Di-chloro-3,7,7,11-tetra-methyl-tetra-cyclo[6.5.0.0(1,3).0(9,11)]trideca-ne.

The title compound, C17H26Cl2, was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from fused six- and seven-membered rings and two three-membered rings from the reaction of ß-himachalene with di-chloro-carbene. In both mol-ecules, the six-membered ring has a half-chair conformation, whereas the seven-membered ring displays a boat conformation. The absolute configuration was established from anomalous dispersion effects.

(1S,3R,8R,9S,11R)-2,2-Di-bromo-10,10-di-chloro-3,7,7,11-tetra-methyl-tetra-cyclo-[6.5.0.0(1,3).0(9,11)]trideca-ne.

The title compound, C17H24Br2Cl2, was synthesized from ß-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule contains fused six-, seven- and two three-membered rings. The six-membered ring has a half-chair conformation, while the seven-membered ring displays a boat conformation. The absolute structure was unambiguously established from anomalous dispersion effects. The crystal packing exhibits no short inter-molecular contacts.