Syntheses of thiophene appended N-confused phlorin isomersShow others and affiliations
2021 (English)In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, Vol. 25, no 10N12, p. 997-1003Article in journal (Refereed) Published
Abstract [en]
A doubly confused thiapentapyrrane NSP-5 was synthesized by acid-catalysed condensation. Subsequent oxidation with DDQ did not afford the expected thiasapphyrin-like product. Instead, two tetrapyrrolic macrocycles, i.e. neo-N-confused phlorin (1) and N-confused phlorin-II (2) were obtained in the yields of 14% and 18%, respectively. The compounds were characterized by NMR, HRMS, and X-ray diffraction analyses. Single crystal structures clearly reveal that the thienyl units are not embedded into the macrocycles, but appended as meso-substituents, and the C-meso-N and C-meso-C-beta cyclization modes can be clearly revealed by the crystal structures of 1 and 2, respectively. The observation that the thienyl unit is not involved in oxidative cyclization may be related to the relatively low reactivity of the thiophene moiety compared with the more electron-rich pyrrole unit. These results indicate that oxidative cyclization of linear thiaoligopyrranes containing terminal thiophene units may be developed as an effective approach for synthesizing nonconjugated macrocycles like phlorin analogues.
Place, publisher, year, edition, pages
World Scientific Pub Co Pte Ltd , 2021. Vol. 25, no 10N12, p. 997-1003
Keywords [en]
porphyrinoid, N-confused porphyrin, phlorin, calixphyrin
National Category
Organic Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-306412DOI: 10.1142/S1088424621500905ISI: 000718931500014Scopus ID: 2-s2.0-85116867245OAI: oai:DiVA.org:kth-306412DiVA, id: diva2:1620688
Note
QC 20211216
2021-12-162021-12-162022-06-25Bibliographically approved