Antioxidant action of a lipophilic nitroxyl radical, cyclohexane-1-spiro-2'-(4'-oxyimidazolidine-1'-oxyl) -5'-spiro-1"-cyclohexane, against lipid peroxidation under hypoxic conditions

Facile, regio- and diastereoselective synthesis of spiro-pyrrolidine and pyrrolizine derivatives and evaluation of their antiproliferative activities

A number of novel spiro-pyrrolidines/pyrrolizines derivatives were synthesized through [3+2]-cycloaddition of azomethine ylides with 3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones 2a–n. Azomethine ylides were generated in situ from the reaction of 1H-indole-2,3-dione (isatin, 3) with N-methylglycine (sarcosine), phenylglycine, or proline. All compounds (50 μM) were evaluated for their antiproliferative activity against human breast carcinoma (MDA-MB-231), leukemia lymphoblastic (CCRF-CEM), and ovarian carcinoma (SK-OV-3) cells. N-α-Phenyl substituted spiro-pyrrolidine derivatives (5a–n) showed higher antiproliferative activity in MDA-MB-231 than other cancer cell lines. Among spiro-pyrrolizines 6a–n, a number of derivatives including 6a–c and 6i–m showed a comparable activity with doxorubicin in all three cell lines. Among all compounds in three classes, 6a, 6b, and 6m, were found to be the most potent derivatives showing 64%, 87%, and 74% antiproliferative activity in MDA-MB-231, SK-OV-3, and CCRF-CEM cells, respectively. Compound 6b showed an IC₅₀ value of 3.6 μM in CCRF-CEM cells. These data suggest the potential antiproliferative activity of spiro-pyrrolidines/pyrrolizines.

4-Phenyl-1,2,4-tri-aza-spiro-[4.4]non-1-ene-3-thione

In the title compound, C12H13N3S, the 4,5-di-hydro-3H-1,2,4-triazole system is nearly planar [maximum deviation = 0.014 (2) Å], while the cyclo-pentane ring adopts a half-chair conformation. The dihedral angle between the mean plane of the 4,5-di-hydro-3H-1,2,4-triazole-3-thione ring and the phenyl ring is 85.49 (14)°, with the S atom 0.046 (1) Å out of the former plane. The crystal structure is stabilized only by van der Waals inter-actions. The investigated crystal was found to be a non-merohedral two-component twin by a 180° rotation about c*, with a refined value of the minor twin fraction of 0.12203 (18).

Effects of Different Phases of Cigarette Smoke on Lipid Peroxidation and Membrane Structure in Liposomes

This paper discloses for the first time the effects of the gas phase (GP) and the tar of cigarette smoke on lipid peroxidation (LPO) and on the structure of different lipid regions in liposomes. The LPO development was analysed in terms of the total unsaturation of lipids (double-bond, DB, content) and the formation of dienic conjugates (DC), ketodienes (KD), and malonic dialdehyde (MDA). As expected, the exposure of liposomes to either the GP or the tar led to a significant decrease in the DB content. However, the formation of oxidation products revealed different dynamics: MDA generation was inhibited, while the formation of DC and KD increased during the first few hours of the LPO development followed by its inhibition. The smoke constituents exhibited opposite effects on the structure of the lipid bilayer of liposomes: the GP markedly enhanced the microviscosity of liposomal membranes, whereas the tar caused a drastic lowering of microviscosity.

4-Phenyl-1,2,4-triazaspiro[4.5]dec-1-ene-3-thione

In the title compound, C₁₃H₁₅N₃S, the 4,5-di­hydro-3H-1,2,4-triazole ring is nearly planar [maximum deviation = 0.020 (1) Å], while the cyclo­hexane ring adopts a chair conformation. The dihedral angle between the 4,5-di­hydro-3H-1,2,4-triazole ring and the phenyl ring is 74.68 (7)°. No specific inter­molecular inter­actions are discerned in the crystal packing.

Microwave assisted synthesis of some new heterocyclic spiro-derivatives with potential antimicrobial and antioxidant activity

Homophthalic anhydride reacts with different aromatic amines to produce N-substituted homophthalimides. Bromination of the latter produces 4,4-dibromo-homophthalimide derivatives that can be used as precursors for spiro-derivatives. The dibromo derivatives react with different binucleophilic reagents to produce several spiro-isoquinoline derivatives. Reaction of the dibromo derivatives with malononitrile produces dicyanomethylene derivatives which react with different binucleophiles to produce new spiro-derivatives. Structures of the newly synthesized compounds are proved using spectroscopic methods such as IR, 1H-NMR and 13C-NMR. The newly synthesized compounds were tested for their antimicrobial and antioxidant activities, showing weak or no antimicrobial activity. On the other hand select compounds showed promising antioxidant activities.