Abstract
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 benzotriazole-1-methanesulfonate/4-(dimethylamino)pyridine in CH2Cl2 or dicyclohexylcarbodiimide/4-(dimethylamino)pyridine in CH2Cl2 at ambient temperature. Yields of bis(pheophorbide) 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 CH2Cl2, while the metalation of the 6 and bacterial series macrocycles was carried out with a mixture of IMgBHT and lithium 2,2,6,6-tetramethylpiperidide in thiophene, all at ambient temperature. Both mono- and dimetalated derivatives were isolated and characterized in each case.
| Original language | English |
|---|---|
| Pages (from-to) | 1969-1974 |
| Number of pages | 6 |
| Journal | Journal of Organic Chemistry |
| Volume | 45 |
| Issue number | 10 |
| Publication status | Published - 1980 |
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ASJC Scopus subject areas
- Organic Chemistry
Cite this
Synthesis of covalently linked dimeric derivatives of chlorophyll a, pyrochlorophyll a, chlorophyll b, and bacteriochlorophyll a. / Wasielewski, Michael R; Svec, Walter A.
In: Journal of Organic Chemistry, Vol. 45, No. 10, 1980, p. 1969-1974.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Synthesis of covalently linked dimeric derivatives of chlorophyll a, pyrochlorophyll a, chlorophyll b, and bacteriochlorophyll a
AU - Wasielewski, Michael R
AU - Svec, Walter A.
PY - 1980
Y1 - 1980
N2 - 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 benzotriazole-1-methanesulfonate/4-(dimethylamino)pyridine in CH2Cl2 or dicyclohexylcarbodiimide/4-(dimethylamino)pyridine in CH2Cl2 at ambient temperature. Yields of bis(pheophorbide) 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 CH2Cl2, while the metalation of the 6 and bacterial series macrocycles was carried out with a mixture of IMgBHT and lithium 2,2,6,6-tetramethylpiperidide in thiophene, all at ambient temperature. Both mono- and dimetalated derivatives were isolated and characterized in each case.
AB - 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 benzotriazole-1-methanesulfonate/4-(dimethylamino)pyridine in CH2Cl2 or dicyclohexylcarbodiimide/4-(dimethylamino)pyridine in CH2Cl2 at ambient temperature. Yields of bis(pheophorbide) 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 CH2Cl2, while the metalation of the 6 and bacterial series macrocycles was carried out with a mixture of IMgBHT and lithium 2,2,6,6-tetramethylpiperidide in thiophene, all at ambient temperature. Both mono- and dimetalated derivatives were isolated and characterized in each case.
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M3 - Article
VL - 45
SP - 1969
EP - 1974
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 10
ER -