Showing papers by "Raymond Bonnett published in 1984"
TL;DR: In this article, coal porphyrins may be derived in part from fungal and bacterial cytochromes, and a Porphyrin Index as a parameter for coalification is proposed.
27 citations
TL;DR: In this article, the isolation and characterisation of a homologous series of gallium polyalkylporphyrins from a large scale extraction of a bituminous coal (Daw Mill) from the Carboniferous is described.
Abstract: The isolation and characterisation of a homologous series of gallium polyalkylporphyrins from a large scale extraction of a bituminous coal (Daw Mill) from the Carboniferous is described. About 0.2 µg/g of metalloporphyrin fraction is obtained. The homologous series extends from C26 to C32. It is proposed that the homologues arise by fragmentation (thermal cracking, protodesubstitution on a mineral surface) of etioporphyrin III or its metal complexes during the coalification process.Evidence in support of this is provided by a survey of bituminous coals of increasing rank, where the predominating carbon number decreases in the range C30 to C26 as rank increases. The amount of metal-loporphyrins extracted also decreases with increasing rank : only traces are detected in anthracites.
18 citations
TL;DR: In this paper, the first X-ray structure analysis for an isoindole with a simple substitution pattern was carried out, which provided information bearing on the aromaticity of the nucleus.
Abstract: 1-Phenylisoindole reacts with the Vilsmeier reagent to give 1-(NN-dimethylaminomethylidene)-3-phenylisoindole (4), which on basic hydrolysis furnishes 1-formyl-3-phenylisoindole (5). X-Ray structure analyses have been carried out on (4) and (5). The latter structure is the first available for an isoindole with a simple substitution pattern, and provides information bearing on the aromaticity of the isoindole nucleus.
9 citations
01 Jan 1984
TL;DR: The term bilin is now formally assigned1 to the unsubstituted parent (1), and the naturally occurring derivatives so far known are all dihydroxy derivatives of this, essentially in the bis lactam, bilindione, tautomeric form as discussed by the authors.
Abstract: The bile pigments have long been familiar as products of haem catabolism in the animal kingdom. In recent years their importance in the plant world — notably as biliproteins, such as phycoerythrin, phycocyanin, and phytochrome — has become increasingly evident. In a very real sense the name “bile pigment” is inappropriate for these substances, and it is perhaps more fitting to use the terms “linear tetrapyrrole” or “bilindione” to refer to the series as a whole.The term bilin is now formally assigned1 to the unsubstituted parent (1), and the naturally occurring derivatives so far known are all dihydroxy derivatives of this, essentially in the bis lactam, bilindione, tautomeric form. The commonest oxidation levels are the bilindione or verdin system (2) and the 10,23-dihydrobilindione or rubin system (3).