Timothy P. Forsyth

A novel approach to the synthesis of symmetrical and unsymmetrical porphyrin dimers

Abstract Methodology for synthesis of symmetrical or unsymmetrical porphyrin dimers linked at the meso positions with phenyl or stilbene functionalities is reported; 5-porphyrinyl-dipyrromethanes are key intermediates in this approach.

Syntheses and Spectroscopic Studies of Some Novel Porphyrin-Pyropheophorbide Dimers and Trimers with Fixed Distances

Abstract Syntheses and spectroscopic properties of pyropheophorbide-porphyrin dimers and a bis-pyropheophorbide-porphyrin trimer are described. Fluorescence spectroscopic data of the oligomers reveal that the macrocycles in the systems are only weakly coupled .

Chemical synthesis of a “GSA-pyrrole” and its reaction with Ehrlich's reagent

Abstract A rational chemical synthesis of 4-acetyl-2-(2-carboxyethyl)-5-methylpyrrole (5), the product formed when glutamate-1-semialdehyde (GSA, 2) is reacted with acetylacetone in the first step of the quantitative analysis for GSA in biological media. Rates of reaction of the GSA-pyrrole (5) with Ehrlichs reagent (the second step in GSA quantitation) are compared with the rates of the reactions of well-characterized “ALA-pyrroles” (3) and (4). Pyrrole (5) reacts more slowly with Ehrlichs reagent, and extinction coefficients for the corresponding Ehrlichs adducts were determined to be 46,000 for (3) and 865 for (5). These observations resolve the discrepancies observed in earlier quantitations of GSA and allow more accurate determinations of it in biological materials.

A novel biliverdin with an inverted pyrrole subunit

Abstract The synthesis and spectroscopic properties of a novel biliverdin 4 with one inverted pyrrole ring are described; the dipyrromethane 8 and a,c-biladiene 6 were the key intermediates in the synthesis of 4 .

Synthesis and structure of a 5,15-bis(4-pyridyl)purpurin

Abstract Base catalyzed cyclization of a 5,15-di(4-pyridyl)octaalkylporphyrin-5-acrylate 6 yields smoothly the corresponding purpurin 2 . Quaternization with methyl iodide yielded the corresponding cationic N,N′-dimethylpyridiniumpurpurin 3 ; X-ray crystallography of purpurin 2 , the first purpurin to be studied crystallographically, shows the two β-alkyl groups on the saturated ring of the purpurin have a syn configuration, and the macrocycle to have a slight saddle shape with a mean deviation of 0.230 A from the least-squares plane calculated for the core atoms.

Synthesis, Solution, Molecular and Crystal Structure of Bis[5-(coproporphyrinato-I tetraethylester)nickel(II)]1,2-ethane

Vilsmeier formylation of the oporphyrin-I tetraethyl ester Ni-complex (III) followed by reduction of the intermediary imine salt (IV) with NaBH4 gave the o-dimethylaminomethyl-coproporphyrin-I Ni-complex (V). Heating the latter in methyl iodide gave 65% of the ethane- bis-porphyrin (I), which has been characterized by NMR-spectroscopy and a molecular and crystal structure investigation. The crystal structure shows an extended structure of the bisporphyrin with a parallel arrangement of the porphyrin subunits. Crystal data: I - C90H106N8Ni2O16. Triclinic, a = 12.319(3) Å. b = 13.297(3) Å, c = 14.444(3) Å, α = 105.56(2)°, β = 100.82(2)°, γ = 112.98(2)°, V = 1981.0(7) Å3, Cu Kα radiation, λ = 1.54178 Å, space group P1̄, Z = 1, R = 0.07.