Intramolecular Aminolactonization for Synthesis of Furoindolin-2-One

Propellanes are polycyclic compounds in which tricyclic systems share one carbon–carbon single bond. Propellane frameworks that consist of larger sized rings are found in a variety of natural products. As an approach to the stereoselective synthesis of the propellane framework, one of the efficient methods is forming several rings in a single operation. Lapidilectine B (1) is composed of a propellane framework and was synthesized through the oxidative cyclization of trisubstituted alkenes. When the alkene with an ester moiety was treated with N-iodosuccinimide (NIS), iodocyclization proceeded to give the cyclic carbamate. On the other hand, when PhI(OAc)2 was allowed to react in the carboxyl form, a furoindolin-2-one structure corresponding to the A-B-C ring of lapidilectine B (1) was produced. Furthermore, when Pd(OAc)2 catalyst was used for cyclization under oxidative conditions, the product yield was improved.

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

A regioselective method for the synthesis of 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones – close structural analogs of naturally occurring vasicinone alkaloids – is described. The procedure is based on PIFA-initiated oxidative 5-exo-trig cyclization of 2-(3-butenyl)quinazolin-4(3Н)-ones, in turn prepared by thermal cyclocondensation of the corresponding 2-(pent-4-enamido)benzamides. The products obtained have a good natural product likeness (NPL) score and therefore can be useful for the design of natural product-like compound libraries.

Synthesis of 1,3,4-Oxadiazoles by Iodine-mediated Oxidative Cyclization of Methyl Ketones with 4-Phenylsemicarbazide

An efficient one-pot method to access 5-amino-2-benzoyl-1,3,4-oxadiazoles via I2/DMSO promoted oxidative cyclization of 4-phenylsemicarbazide with (het)aryl methyl ketones under mild conditions was developed. This reaction proceeds smoothly with a wide range of methyl ketones containing different functional groups to give the corresponding products in moderate yields under mild conditions.

Aerobic Oxidation Reactivity of Well-Defined CoII and CoIII Aminophenol Complexes

This article describes the synthesis and reactivity studies of three cobalt complexes bearing aminophenol-derived ligands without nitrogen substitution: CoII(tBu2APH)2(tBu2AP)2 (1), Co2III(tBu2APH)2(tBu2AP)2(μ-tBu2BAP)2 (2), and CoIII(tBu2AP)3 (3) (tBu2APH = 2-amino-4,6-di-tert-butylphenol, tBu2AP = 2-amino-4,6-di-tert-butylphenolate, μ-tBu2BAP = bridging 2-amido-4,6-di-tert-butylphenolate). Stoichiometric reactivity studies of these well-defined complexes demonstrate the catalytic com-petency of both CoII and CoIII complexes in the aerobic oxidative cyclization of tBu2APH with tert-butyl isonitrile. Reactions with O2 reveal the aerobic oxidation of CoII complex 1 to generate the CoIII species 2 and 3. UV-visible time-course studies and EPR spectroscopy indicate that this oxidation proceeds through a ligand-based radical intermediate. These studies repre-sent the first example of well-defined cobalt-aminophenol complexes that participate in catalytic aerobic oxidation reactions and highlight a key role for a ligand radical in the oxidation sequence.

Synthesis, characterization and antimicrobial activity of novel tetrazoles clubbed with pyrimidine

An attempt was made to synthesize pyrimidine tetrazole derivatives of pharmaceutical interest by oxidative cyclization of chalcones with adequate yield and purity, prompted by the diversity of their wider usage and the fact that they are an integral part of genetic content. The present work involves the reaction of 5-(2,6-dimethylphenyl)-1H-tetrazole with acetic anhydride to yield 1-[5-(2,6-dimethylphenyl)-1H-tetrazol-1-yl] ethanone (1) and which then treated with different aromatic aldehydes in presence of alkaline medium to chalcones (2a-f). Reaction of chalcones (2a-f) with urea and thiourea to produce 5-[5-(2,6-dimethylphenyl)-1H-tetrazol-1-yl]-4-(substituted aryl ) pyrimidin-2-ol (3a-f) and 5-[5-(2,6-dimethylphenyl)-1H-tetrazol-1-yl]-4-(substituted aryl) pyrimidin-2-thiol (4a-f) respectively. All compounds were characterized by infrared spectroscopy (IR), H nuclear magnetic resonance (NMR), and mass spectrometry (MS) to prove the structure and assessed in vitro for their efficacy as antibacterial and antifungal activity against four bacteria. The compounds 3c, 3d and 3f and compounds 4c, 4d and 4f possess very good activity against and E. coli and the compounds 3e, 3c and 3a and compounds 4e,4b and 4c possess very good activity against fungi and .