Gerold Haake

A useful preparation of pyrroles from α,β-unsaturated sulfones

Abstract The addition of alkyl isocyanoacetate to α,β-unsaturated sulfones, which are easily obtained from olefins, affords a convenient access to pyrroles with unusual substitution patterns.

A Taylor made lipophilic chlorin for Photodynamic Tumor Therapy

Abstract A new chlorin dicarboxylic acid 3 has been synthesized from the porphyrin 1 by amide acetal Claisen rearrangement. The chemical purity, photophysical properties, and its lipophilicity make the chlorin 3 promising camdidate for application in Photodynamic Tumor Therapy (PDT).

An improved method for the preparation of formyldeuteroporphyrins : synthesis of biologically relevant porphyrins

Abstract Pure 3 and 8 formyldeuteroporphyrin dimethylester isomers 3a,b have been prepared in high yield by formylation of readily accessible deuteroporphyrin dimethylester 1 with trimethyl orthoformate in trifluoroacetic acid and subsequent chromatographic separation of the mixture of isomers. The formyl-porphyrins can be transformed into synthetically and biologically useful derivatives.

Selective synthesis and photophysical properties of tailor-made chlorins for photodynamic therapy

Photodynamic therapy (PDT) is a promising approach for the treatment of cancer, and is presently being evaluated worldwide. PDT is based on the ability of photosensitizers to accumulate selectively in tumor tissue. On irradiation fluorescence of the sensitizer allows tumor localization. Singlet oxygen formed by sensitization causes tumor destruction. Hematoporphyrin derivatives and Photofrin IIR, at the present the only practically used sensitizers in PDT, absorb light only weakly ((epsilon) approximately equals 5.000 at (lambda) equals 620 nm). It has been shown that Photofrin IIR is a multicomponent mixture of different porphyrins with only a few therapeutically active components. In contrast to porphyrins, chlorins and azachlorins have ideal photophysical properties with strong absorption ((epsilon) approximately equals 50.000) in a spectral region ((lambda) equals 650 nm) where tissue transmits much better. Molecular properties of porphinoid structures, which are responsible for tumor uptake and tumor enrichment, are connected with lipophilicity and aggregation behavior. Therefore our aim was to synthesize well defined chlorins with lipophilic properties similar to those of the active fractions of Photofrin IIR.