cis and trans Isomers distinguished by imidazole N-alkylation after Debus-Radziszewski reaction starting from 2,7-di-tert-butyl-pyrene-4,5,9,10-tetraone

• Published in: Tetrahedron Vol. 71; no. 21; pp. 3195 - 3202
• Main Authors: Ma, Bin-Bin, Peng, Yu-Xin, Zhao, Pei-Chen, Huang, Wei
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 27.05.2015; Elsevier
• Subjects: 1H NMR spectrum; aldehydes; chemical reactions; Chemistry; Chemistry, Organic; cis and trans Isomerism; cis-trans isomers; Imidazole/pyrene/imidazole core; N-alkylation; Organic semiconductor; Physical Sciences; Science & Technology; solubility; 1H NMR spectrum; Imidazole/pyrene/imidazole core; Organic semiconductor; N-alkylation; cis and trans Isomerism; GOLD NANOPARTICLES; PYRENE; CHROMOPHORES; DITHIOL; ELECTRODES; H-1 NMR spectrum; EFFICIENT
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/j.tet.2015.04.012

We report the design and synthesis of three new imidazo[5,4-f]2,7-di-tert-butyl-pyrene-imidazol derivatives prepared from 2,7-di-tert-butylpyrene-4,5,9,10-tetraone and respective aromatic aldehyde through Debus-Radziszewski reaction. It is noted that three pairs of cis and trans isomers (1–6) can be separated after double imidazole N-alkylation for the central fused imidazole/pyrene/imidazole core, because of their distinguishable molecular polarity and improved solubility. Successful separation of every cis and trans isomeric pair can be verified by the single-crystal structural and spectral proofs. To the best of our knowledge, the current study is the first structural and spectral investigation on the imidazole N-alkylation of imidazole/pyrene/imidazole based compounds after successful separation of cis and trans isomers. [Display omitted] Three pairs of cis and trans isomers with fused imidazole/pyrene/imidazole based compounds have been successfully separated after double imidazole N-alkylation, and they can be distinguished by 1H NMR spectra and X-ray single-crystal structures.