Pyrrolic Compounds Research Articles

Pukeleimide C, a novel pyrrolic compound from the marine cyanophyte [formula omitted][formula omitted

The crystal structure of pukeleimide C, a novel pyrrolic compound from a shallow-water variety of the marine blue-green alga Lyngbya majuscula , is reported.

The chemistry of pyrrolic compounds. XXXIX. Dihydro and monohydrated derivatives of protoporphyrin IX

Rational syntheses of the dihydro [(1d), (1e)] and monohydrated [(1b), (1c)] derivatives of protoporphyrin IX dimethyl ester have been completed. It has also been shown that the latter isomers [(1b), (1c)] can be obtained either from haematoporphyrin IX dimethyl ester (1a) by partial dehydration, or from diacetyldeuteroporphyrin IX dimethyl ester (1f) by partial reduction followed by dehydration and reduction.

Chemistry of pyrrolic compounds. XLI. The synthesis of the phaeophorbides c1 and c2 methyl esters

Phaeophorbide c1, the magnesium-free derivative of chlorophyll c1, has been synthesized as the methyl ester (1c) by means of the copper acetate cyclization of an appropriately substituted bilene-b salt. Similar syntheses of phaeophorbide c2 methyl ester (1d) and isophaeophorbide c1 methyl ester (1g) have been completed. Comparison of these synthetic compounds with natural material both as the metal free derivative and as the magnesium chelate has substantiated the accepted structures for the chlorophylls c.

The chemistry of pyrrolic compounds. XL. A new synthesis of protoporphyrins III and XIII and a 1H N.M.R. study of the preferred pathway of electron delocalization in the porphyrin macrocycle

The synthesis of protoporphyrins III and XIII as the dimethyl esters has been completed by an oxidative cyclization of biladiene-ac intermediates. Protoporphyrin III has been converted into deuteroporphyrin III and measurements of the proton coupling constant in the allylic unit, CH3-C=C-H, of this latter porphyrin point to the double bond of this system having a significantly diminished bond order. This finding is in accord with the view that the π-electron delocalization pathway in the porphyrin macrocycle involves the periphery of the molecule.

The Radiation Chemistry of Some Simple Pyrroles

Pyrrole, the monomethylpyrroles, and 2,5-dimethylpyrrole have been ..gamma..-irradiated. Gaseous products have been quantitatively determined and liquid and residual products have been qualitatively identified. The products indicate that several types of reactions occur including ring rupture, cleavage of bonds external to the pyrrole ring, ring substitution, and intramolecular rearrangement. A brief comparison is made among radiolysis, photolysis, mass spectral ionization, and pyrolysis reactions of pyrrole compounds.

ChemInform Abstract: MO Studies of Configuration and Conformation. Part 3. Conformations of Some 2‐Substituted Furan, Thiophene and Pyrrole Carbonyl Compounds.

Conformations of nine 2-substituted furan, thiophene and pyrrole compounds have been studied by EHT methods. The preferred conformations of furan derivatives were trans form, which were mainly stabilized by electrostatic interactions. For thiophenes, electronic conjugation between the ring S and carbonyl oxygen was dominant, while for pyrroles both the electrostatic and conjugation effects were operative in determining the preferred conformations. Results of EHT calculation agreed well with experimentally determined preferences.

Physiologically Active Substances from Marine Sponges IV: Heterocyclic Compounds

Several guanidine compounds were synthesized by the reaction of acid chlorides of thiophene and furan with guanidines. Some of these compounds showed antibiotic and cytotoxic activities. Series of pyrrole compounds were synthesized and found to have significant antibiotic activity.

β‐substitution of simple pyrroles in metal‐assisted reactions with kthyl diazoacetate

AbstractThe reaction of N‐methylpyrrole with ethyl diazoaeelate, assisted by copper bronze or copper powder, as described previously by a number of researchers, produces not only ethyl N‐melhylpyrrole‐2‐acetate (3), but also heretofore unrecognized ethyl N‐melhylpyrrole‐3‐acetate (4); the ratio of 3/4 was ca. 84/16. Promotion of this reaction with other transition metal catalysts furnished differing proportions of 3 and 4, indicating that the metal is intimately involved in the substitution process. Certain agents, notably cupric fluoborate, cupric trifluoromelhylsullonate, palladous acetate, and (π‐C3H5 PdCI)2, were particularly active in this reaction and gave β‐substi‐lulion to the extent of ca. 35‐45%. Other pyrrole compounds, namely 1,2‐dimethylpyrrole, 1,3‐dimethylpyrrole, 3, and pyrrole, were also found (in preliminary work) to undergo β‐substi‐tution in their reaction with copper carbenoids.

The chemistry of pyrrolic compounds. XXXVIII. The synthesis of hexahydroporphyrin a and related compounds

A procedure is described which allows the synthesis of porphyrins substituted with an α-hydroxy terpenoid side chain. Of particular significance is the preparation of the hexahydro derivative of porphyrin a, the iron-free prosthetic group of cytochrome oxidase.

The chemistry of pyrrolic compounds. XXXV. Further observations on the chemistry of Spirographis porphyrin and its isomer: the oxidation offormylporphyrins

Evidence is presented which indicates that a mixture of hydriodic acid, acetic acid and air achieves the oxidation of formylporphyrins through the agency of peroxyacetic acid. The mechanism of the reaction is discussed. The oxidation of Spirographis porphyrin and its isomer are described and the product of these oxidations related to a methoxycarbonyldeuteroporphyrin of known structure. Improvements are recorded for the synthesis of Spirographis porphyrin and related compounds.

The chemistry of pyrrolic compounds. XXXIV. Vinylporphyrins from derivatives of 2'-hydroxyethylporphyrins

The bromo, chloro and methanesulphonate derivatives of 2'-hydroxyethylporphyrins are readily converted in high yield into the corresponding vinylporphyrins by treatment with sodium hydroxide in refluxing aqueous pyridine.

The chemistry of pyrrolic compounds. XXXVII. Monobenzoporphyrins: The rhodoporphyrin of petroleum deposits

A monobenzoporphyrin has been prepared from porphyrin derivatives containing a fused cyclo-hexanone ring. The cyclohexanone system can be constructed either before or after the porphyrin macrocycle has been synthesized. The spectroscopic properties of the monobenzoporphyrin are described and these support the proposal that such a species constitutes the rhodo-type series of porphyrins which have been isolated from some petroleum deposits.

Chemistry of pyrrolic compounds. XXXVI. Some aspects of the chemistry of 2'-hydroxypropionate porphyrins: new syntheses of harderoporphyrin trimethyl ester, 'S-411 porphyrin' trimethyl ester and related compounds

The 2?-hydroxypropionate porphyrins (1h) and (2g) were obtained by sodium borohydride reduction of the corresponding keto esters. Dehydration of (1h) and (2g) led to the acrylate esters (1b) and (2b) respectively; fragmentation of both the hydroxyl and carboxyl functions in (1h) and (2g), by way of a cyclic intermediate, furnished the vinylporphyrins (1a) and (2a) respectively. The synthesis of the 2?- hydroxypropionate porphyrin (9a), a possible biogenetic precursor of protoporphyrin-IX, was achieved.

Chromatography on Florisil in the quantitative estimation of urinary and other porphyrins.

We describe the use of Florisil chromatography to purify and fractionate porphyrins into uro-, copro-, and protoporphyrins before their measurement by quantitative fluorometry. Porphyrinogens in fresh urine may be rapidly oxidized to porphyrins by chloranil, or slowly in weakly alkaline solution, before the sample is applied to the Florisil column. Aliquots of the separate ammoniacal eluates may be lyophilized for additional fractionation by direct thin-layer chromatographic analysis if desired. The behavior of delta-aminolevulinic acid, porphobilinogen, and other pyrrole compounds in this system is also described.

ChemInform Abstract: CHEMISTRY OF PYRROLIC COMPOUNDS. XXX. APPROACH TO THE SYNTHESIS OF PORPHYRIN A

AbstractChemistry of Pyrrolic Compounds.

The chemistry of pyrrolic compounds. XXXIII. The synthesis of a β-nitroporphyrin

The first preparation of a β-nitroporphyrin is described.

The synthesis of 3-substituted pyrrole-2,4-dicarboxylic acid esters: Reaction of methyl isocyanoacetate with aldehydes.

A one-step synthesis of dimethyl 3-substituted pyrrole-2, 4-dicarboxylates by the reaction of methyl isocyanoacetate with various aldehydes in the presence of DBU was carried out. Furthermore, the reaction mechanism was investigated; it was found that the methyl α-isocyanoacrylate compound is a key intermediate of the pyrrole compound.

The chemistry of pyrrolic compounds. XXXII. Synthesis of isocoproporphyrin tetramethyl ester and related compounds

The acetylporphyrin (la) has been prepared by the oxidative cyclization of an intermediate bilene-b salt. By standard procedures this porphyrin has been converted into the ethyl (lb) (isocoproporphyrin tetramethyl ester), vinyl (lc), hydroxyethyl (1d) and deacetyl (1e) derivatives. These compounds have been reported to occur in the faeces of animals suffering from certain porphyric conditions.

Chemistry of pyrrolic compounds. XXXI. Porphyrins of biosynthetic significance between uroporphyrinogen III and coproporphyrinogen III

The four heptacarboxylic acid porphyrins (2b-e) and the four pentacarboxylic acid porphyrins (2f-i) which can be derived by the decarboxylation of the acetic acid side chains of uroporphyrin 111 have been prepared by ring synthesis and characterized as their methyl esters.

Chemistry of pyrrolic compounds. XXX. An approach to the synthesis of porphyrin a

Synthesis of the porphyrin (1e) has been achieved by the oxidative cyclization of an appropriately substituted 1,19-dideoxy-1,19- dimethylbilene-b. It is hoped to use this tetrapyrrole to complete the synthesis of porphyrin a, the prosthetic group of cytochrome oxidase. New syntheses of Spirographis porphyrin and its isomer are reported. 2,4-Diacetyl- and 4-acetyl-2-methoxycarbonyl-deutero-porphyrin IX dimethyl ester have been prepared through bilene-b intermediates constructed in the ?east-west? rather than the ?north-south? mode.