No abstract

No abstract

No abstract

The chemical performance of 5-bromo-2-(bromoacetyl)-thiophene (1) was tested toward the reaction with numerous bi-nucleophilic reagents (namely; 2-aminobenzothiazoles, 2-aminothiazole, 2-aminotetrazole, 2-aminotriazole, 2-aminopyridines, 2-aminobenzimidazole and o-phenylenediamine). Therefore, a series of bridged nitrogen heterocycles bearing thiophene moiety 3, 5, 7, 9, 11, 13 and 15, respectively was synthesized. In addition, the reaction of 5-bromo-2-(bromoacetyl)-thiophene with the thiocarbamoyl compounds 17, 19 and/or 24 afforded the corresponding thienyl-thiazoles 18 or dithien-2-yl ketones 20 and 25, based on the reaction conditions. Treatment of 1 with 2-mercapto-4,6-dimethylnicotinonitrile was achieved to obtain the target dithien-2-yl ketone 28. The new synthesized scaffolds were examined for their antioxidant activity by means of ABTS antioxidant assay. The thienyl-thiazole scaffold 18c and 2-((2-[thiophen-2-yl]-2-oxoethyl)thio)nicotinonitrile derivative 27 displayed a reasonable radical scavenging activity.

No abstract

No abstract

Dihydro-5H-dibenzo[b,g]azonine-6,13-dione (2) has been used as a precursor in the synthesis of the indolo[2,3-e]dibenzo[b,g]azonine and tribenzo[b,g,j][1,6]diazacyclododecine ring systems 6 and 7 respectively via a Fischer indolization/periodate oxidation sequence. Fischer indolization of the (1,4-phenylenedihydrazono) derivative 8 gave the polycyclic system 9. The Schmidt reaction of 2 led to the formation of the benzimidazo[1,2-b] [2]benzazepine ring system 11. The Mannich reaction of 2 led to the spirocyclic system 15. The reactions of 2 with aldimines and aromatic aldehydes were also investigated.

The reaction of malononitrile with the tertiary Mannich base hydrochloride derived from acetophenone and some related compounds 1, 3, 5 and 7, in piperidine at 50°C afforded the pyrido[1,2-a]pyrimidine derivatives 2, tetrahydronaphthalene derivative 4 substituted quinolines 6 and benzopyran derivatives 8. While the condensation of malononitrile dimer with acetophenone, cyclohexanone and/ or α-tetralone Mannich bases hydrochloride 1, 3 and 9 gave the pyridine, isoquinoline and benzo[f]isoquinoline derivatives 10–12 in moderate to good yield.