Synthesis of covalently linked dimeric derivatives of chlorophyll a, pyrochlorophyll a, chlorophyll b, and bacteriochlorophyll a
Bis(chlorophyllide) ethylene glycol diesters were prepared for each of the title compounds. Pheophytins a and b isolated from alfalfa and bacteriochlorophyll a isolated from R. sphaeroides were treated with 80% aqueous trifluoroacetic acid to yield the corresponding pheophorbides. Pyropheophorbide was prepared by a literature procedure. Carbonic anhydride and benzotriazole-1-methanesulfonate activation methods were used in the esterification of the pheophorbides with ethylene glycol at ambient temperature. Each method yielded 75%+ of the pheophorbide ethylene glycol monoester. These monoesters were treated with equimolar amounts of the corresponding pheophorbide by using benzotriazol-1-methanesulfonate/4-(dimethylamino)pyridine in CH/sub 2/Cl/sub 2/ or dicyclohexylcarbodiimide/4-(dimethylamino)pyridine in CH/sub 2/Cl/sub 2/ at ambient temperature. Yields of bis(phenophorbide) ethylene glycol diesters averaged about 50% for the former method and 70% for the latter method. Insertion of the magnesium atoms into the a series macrocycles was accomplished with iodomagnesium 2,6-di-tert-butyl-4-methylphenolate, IMgBHT, in CH/sub 2/Cl/sub 2/, while the metalation of the b and bacterial series macrocycles was carried out with a mixture of IMgBHT and lithium 2,2,6,6-tetramethylpiperidide in thiophen, all at ambient temperature. Both mono- and dimetalated derivatives were isolated and characterized in each case.
- Research Organization:
- Argonne National Lab., IL
- OSTI ID:
- 5134441
- Journal Information:
- J. Org. Chem.; (United States), Journal Name: J. Org. Chem.; (United States) Vol. 45:10; ISSN JOCEA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
BINDING ENERGY
CARBOXYLIC ACIDS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHLOROPHYLL
COMPLEXES
ELECTRONS
ELEMENTARY PARTICLES
ENERGY
ESTERS
FERMIONS
GLYCOLS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
LEPTONS
LITHIUM COMPLEXES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
SYNTHESIS
VALENCE