ChemInform Abstract: Synthesis and Application of Imidazole Derivatives. Synthesis of Pyrrolo(1,2‐a)benzimidazoles and Azepino(1,2‐a)benzimidazoles.

Abstract

Synthesis and Application of Imidazole Derivatives. Synthesis of Pyrrolo(1,2-a)benzimidazoles and Azepino(1,2-a)benzimidazoles. -N-Alkylation of the benzimidazoles (I) with the α-bromo esters ( II) followed by N-methylation yields the 1-alkoxycarbonylmethylbenzimidazolium iodides (V) which are hydrolyzed to give the acids (VI). These are converted into the corresponding imidazolides which undergo intramolecular cyclization upon treatment with triethylamine, forming the novel tricyclic pyrrolobenzimidazolones (VII). The lithium enolate of the dihydroazepinobenzimidazolone (VIII) reacts with the ketones (IX) to produce the alcohols (X). Treatment of (Xb) with thionyl chloride leads to the formation of the diphenylmethylene derivative (XI). The 6-substituted heterocycles (XIII) and (XV) are synthesized by reaction of the enone (VIII) with the acid anhydrides (XII) or the iso(thio) cyanates (XIV). Further reactions of (VIII) with electrophiles such as methyl vinyl ketone, benzenediazonium chlorides, or phenylselenenyl chloride are described in the original paper. -(OHTA, S.; NARITA, Y.; YUASA, T.; HATAKEYAMA, S.; KOBAYASHI, M.; KAIBE, K.; KAWASAKI, I.; YAMASHITA, M.; Chem.

Recent advances on the synthesis of azoles, azines and azepines fused to benzimidazole

“…Treatment of the latter salts 542 with N,N'-carbonyldiimidazole (CDI) in acetonitrile at room temperature followed by addition of Et 3 N and heating the mixture at 70 °C gave 7,8,9,10-tetrahydro-5H-azepino[1,2-a]benzimidazol-7-one derivatives 543 (Scheme 175). 31,292 Scheme 175 N-(Haloaryl)amidines 544 underwent heterocyclization when heated in DMF in the presence of sodium methoxide to give the 7,8,9,10-tetrahydro-6H-azepino[1,2-a]benzimidazole derivatives 545 in high yields (Scheme 176). …”