Deuteroporphyrin IX

The reactions of alkyl halides with Fe(II) deuteroporphyrin IX have been examined (Wade and Castro 1973). Three classes of reaction were observed (i) hydrogenolysis, (ii) elimination to alkenes, and (iii) coupling of alkyl free radicals. Further discussion has been given in Castro (1998). 

Experiments have been carried out to mimic the reactions of model systems for coenzyme F430 that is involved in the terminal step in the biosynthesis of methane, and that is able to dechlorinate CCI4 successively to CHCI3 and CH2CI2 (Krone et al. 1989). Nickel(I) isobacteriochlorin anion was generated electrolytically and used to examine the reactions with alkyl halides in dimethylformamide (Helvenston and Castro 1992). The three classes of reaction were the same as those observed with Fe(II) deuteroporphyrin IX that have already been noted. 

The NIS investigation of heme complexes includes various forms of porphyrins (deuteroporphyrin IX, mesoporphyrin IX, protoporphyrin IX, tetraphenylpor-phyrin, octaethylporphyrin, and picket fence porphyrin) and their nitrosyl (NO) and carbonyl (CO) derivatives, and they have been the subject of a review provided by Scheidt et al. [109]. 

Table 7.3.2 Standard (Std) solutions used for the determination of urinary porphyrin concentration. 1ST Deuteroporphyrin IX (2,4-bis-glycol)...

Table 5 Basicity of Substituted Deuteroporphyrin-IX Dimethyl Esters...

Early workers appeared to show that electrophilic substitution reactions could not be carried out on porphyrins, and began to question the aromaticity of porphyrins since this classical pre-requisite of aromatic character could not be accomplished. However, they had concentrated on reactions of metal-free systems, and since many electrophilic substitution reactions utilize acidic conditions (nitration, sulfonation), they were actually dealing with the non-nucleophilic porphyrin dication. But, as early as 1929, H. Fischer had realised that diacetylation of deuteroporphyrin-IX (Table 1) had to be carried out on a metal complex, such as the iron (III) derivative chelation with a metal ion which cannot be removed under the acid conditions of the subsequent reaction, effectively eliminates dication formation. A judicious choice of metal complex therefore needs to be made for any particular reaction. For example, though magnesium(II) produces an extremely reactive substrate for electrophilic substitution reactions, it is removed by contact with the mildest of acids and is, consequently, of little use for this purpose. 

Mossbauer data for 2,4 diacetyl deuteroporphyrin IX dimethyl ester and Fe(II) protoporphyrin IX obtained at 77 °K show isomer shifts... 

A more quantitative estimate of the pseudocontact shifts in DeutCN was obtained from comparison of the methylester resonances in DeutCN and deuteroporphyrin IX zinc(II) (114). Under identical conditions these resonances were both at —3.72 ppm from DSS in the diamagnetic complex, and at —3.78 and —3.82 ppm in DeutCN. The observed shift of ca. —0.08 ppm has to come almost entirely from pseudocontact coupling, since delocalization of unpaired spin density to these positions must be negligibly small, and a small change of the porphyrin ring current field, which might result from the zinc(II) vs. iron(III) substitution, would hardly be noticeable at the methylester positions either. With the assumption of an axially symmetrical g-tensor, and rj -values for the different protons of 10.0, 6.4, 5.7, and 4.5 A (Hoard (41)), one then estimates from the fj 3-dependence (Eq. 10) that the corresponding... 

Kurland et al. (64) observed hyperfine-shifted resonances of ferrimyoglobin between —20 and —90 ppm. Comparison with the spectra of the iron(III)-complexes with protoporphyrin IX, deuteroporphyrin IX, and mesoporphyrin IX seems to indicate that four of the low field resonances correspond to the four ring methyl groups. Additional lines at high fields from DSS were observed in ferrimyoglobin (116), and in high spin porphyrin-iron(III) complexes (Caughey et al. (19)). The observation... 

Fig. 7. The DTPA-ester of 2-[l-(2-hydroxyethoxy)ethyl]-4-vinyl-deuteroporphyrin (IX)...

Boronated protoporphyrin (2,4-(a,/Tdihydroxyethyl)deuteroporphyrin IX, BOPP, Fig. 8), a neutron capture agent, localizes in cerebral gliomas with a ratio of 400 1 as compared with normal brain tissue [116]. The manganese(III) complex of BOPP was investigated as a MRI contrast agent in the expectation that it would behave similarly to the free base BOPP and would act in the dual role of tumor detector and radiation sensitizer [117]. The 1 value for Mn-BOPP at... 

Similar to Gd-ATN-10 andMn-BOPP,KADTF,amanganese(III) complex of 2-[l-(2-hydroxyethoxy)ethyl]-4-vinyl-deuteroporphyrin (IX) attached to the radiation sensitizer KU2280 (Fig. 12), was conceived as both a method of detecting cancerous tumors and of treating them [123]. The Rj value for KADTF in water at 10.7 MHz and 37 °C is 7.15 mM 1 s 1 and the LD50 in mice was reported to be... 

In work that also involves the use of a Mn(III) porphyrin, Huang et al. published a report on the manganese chelate of the tetrakiscarborane carboxylate ester of 2,4-(a, P-dihydroxylethyl)deuteroporphyrin IX (MnBOPP, 9, Figure 2) [19]. The free-base form of this derivative, BOPP, has demonstrated potential as an agent for boron neutron capture therapy (BNCT) [75,76] and photodynamic therapy (PDT) [77] and is known to localize selectively in cerebral glioma tumors at ratios as high as 400 1 relative to normal brain tissue [19,78]. Like the free-base, MnBOPP also selectively localizes in tumor tissue. Specifically, it has been shown to enhance preferentially the... 

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