Syntheses of porphyrins bearing cyclopentane rings
Porphyrins occurring in petroleum deposits have long been believed to be derived by the degradation of chlorophyll over the course of time. Zinc(II) porphyrins bearing unsubstituted beta positions can be mercurated at those positions and the adjacent meso position. Palladium/olefin reaction with the dimercurated porphyrins produce products possessing a 5-membered isocyclic ring bridging the beta and meso positions. In Chapter 1 a novel synthesis of deoxophylloerythroetioporphyrin and deoxophylloerythrin methyl ester, two degradation products of chlorophyll found in petroporphyrins, are described. Chapter 2 deals with the synthesis of carbon-13 enriched a,c-biladienes which are used to establish the origin of the meso-carbons and meso-substituents. With these results a possible mechanistic pathway for the formation of porphyrins by copper(II) mediated cyclizations of 1',8'-dimethyl-a,c-biladienes is proposed. Also discussed is the cyclization of a,c-biladienes in the presence of a variety of chelating agents and oxidants. Chapter 3 is devoted to NMR spectroscopy. The NMR spectra of variety of N,N-dialkyl meso-substituted porphyrins is described. Nuclear Overhauser enhancement difference spectra allow complete assignment of the spectra. Low temperature experiments are also used to observe the rotational barrier about the porphyrin N,N-dialkyl bond. Chapter 4 discusses observations of a noval substituent orientation in the REIMER-TIEMANN reaction of 5-unsubstituted pyrrole-2-carboxylates. The final Chapter presents a discussion of the scope and limitations of the mercuration reaction along with a variety of useful applications using mercurated porphyrin intermediates.
- Research Organization:
- California Univ., Davis (USA)
- OSTI ID:
- 6165396
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020500 -- Petroleum-- Products & By-Products
023000* -- Petroleum-- Properties & Composition
CARBOXYLIC ACIDS
CATALYSTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLOROPHYLL
COPPER
ELEMENTS
GEOLOGIC DEPOSITS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
KINETICS
MAGNETIC RESONANCE
METALS
MINERAL RESOURCES
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PETROLEUM DEPOSITS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
REACTION KINETICS
RESONANCE
RESOURCES
SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
TRANSITION ELEMENTS
ZINC