Synthesis of near-IR absorbing/emitting porphyrazine derivatives with tunable solubility

S. Lee, A. J.P. White, D. J. Williams, A. G.M. Barrett*, Brian M Hoffman

*Corresponding author for this work

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

We report the synthesis of porphyrazines (pzs), or tetraazaporphyrins, of the form H2[pz(An;B4-n)], where A is [S(CH2)3COOR]2 (R = n-Pr, H) and B is a fused β,β′-diisopropyloxybenzo group, including the compounds with n = 4 (6), n = 3 (7) and the trans compound with n = 2 (8) (Scheme 1). The synthesis employs Linstead crossover macrocyclization of dimethyl 6,7-dicyano-5,8-dithia-6(Z)-dodecenedioate, MNT(C4O2Me)2 (2), with 1-imino-4,7-bis(1-methylethoxy)-1H-isoindole-3-amine (4). These pigments were characterized by 1H NMR, 13C NMR, absorbance/fluorescence spectroscopy, mass spectrometry, and microanalysis. An X-ray crystal structure of 8 is presented. Of particular note, 6-8 display intense near-IR absorbance and dual UV-visible/near-IR emission which are very important in potential biomedical applications, both for cancer therapy (photodyanamic therapy, PDT) and cancer diagnosis (optical tumor imaging). For example, the trans-porphyrazine 8 has an intense long-wavelength absorption at ca. 800 nm (log ε = 4.18) and S1 fluorescence at ∼820 nm, where mammalian tissue is effectively penetrated by light. Transformation of the ester group permits a wide range of functionality and solubility to be generated without change in optical properties. As an example, hydrolysis of these compounds by LiOH in THF/H2O gives the corresponding carboxylato-functionalized pigments 9-11, which are described. The last of these dissolves without aggregation in fetal calf serum.

Original languageEnglish (US)
Pages (from-to)461-465
Number of pages5
JournalJournal of Organic Chemistry
Volume66
Issue number2
DOIs
StatePublished - Jan 26 2001

ASJC Scopus subject areas

  • Organic Chemistry

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