Recent Progress in Determining the Chemical Structure of Chlorophyll.

Steele, Catherine C.

doi:10.1021/cr60065a001

Cited by 8 publications

(6 citation statements)

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“…The structures of pheophytin a (chlorophyll a lacking the magnesium) and 18,18-dimethylchlorin ( H 2 C ) are shown in Figure for comparison. The synthetic gem-dimethylchlorins differ from chlorophylls in four regards: The synthetic gem-dimethylchlorins lack (1) the “tadpole” shape of natural chlorophylls, which have a tetrapyrrole body of ∼15 Å x 15 Å and phytyl tail of ∼20 Å in length; (2) the waxy character of chlorophylls noted by early chemists; , (3) any of the three stereocenters of the chlorophyll macrocycle and the three stereocenters of the phytyl chain; , and (4) the significant molecular weight imparted by the natural substituents; indeed, the phytyl unit (C 20 H 40 O, 297 Da) provides ∼1/3 of the total mass of chlorophylls. In this latter regard, the formula weight of H 2 C (C 22 H 20 N 4 , 340 Da) is less than half that of the natural macrocycle pheophytin a (C 55 H 74 N 4 O 5 , 871 Da).…”

Section: Development Of De Novo Syntheses Of Gem-dialkylchlorinsmentioning

confidence: 99%

“…198 Whereas chlorins typically afford a less stable metal chelate than porphyrins, removal of copper from chlorins remains a challenge. Treatment of the crude reaction product with a mixture of TFA and H 2 SO 4 afforded a mixture of two free base macrocycles (16,17). 162 Both macrocycles were 17oxochlorins, wherein the 17-methylene group of the pyrroline ring had undergone oxidation presumably during the coppermediated oxidative cyclization process.…”

Section: Battersbymentioning

confidence: 99%

“…15 The monumental accomplishments in this era have been reviewed. 16–21 The absolute configuration of the six stereocenters of chlorophyll a was finally settled by the late 1960s. 22–24 …”

Section: Introductionmentioning

confidence: 99%

“…Fischer carried out incisive studies to determine the molecular structure of chlorophyll a , − which was in hand by 1940 (albeit without stereochemical information), and embarked on the synthesis before the structure had been fully deciphered . The monumental accomplishments in this era have been reviewed. − The absolute configuration of the six stereocenters of chlorophyll a was finally settled by the late 1960s. − …”

Section: Introductionmentioning

confidence: 99%

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De NovoSynthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World

2015

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Woodward reported his infamous synthesis of chlorin e 6 trimethyl ester, a known synthetic precursor to chlorophyll a. [59][60][61][62][63][64]124 The work was posited on a half-century of intensive studies by many investigators in tetrapyrrole chemistry and began a decade after the close of Fischer's lifetime of research 125−128 (which included an uncompleted synthetic program directed toward chlorophylls 15 ). Indeed, "he read all the umpteen papers on the chlorophylls written by Willstaẗter and Fischer, including the experimental parts." 129 The Woodward synthesis of chlorin e 6 trimethyl ester required 46 steps, of which 24 were spent on converting the sole precursor, Knorr's pyrrole, to the four pyrroles destined to form rings A−D; 7 additional steps accrued to obtain the dipyrromethanes that constitute the Eastern and Western halves (Scheme 13, the step numbers are identical to those shown in ref 64.). The first step formed the Knorr pyrrole (in several kg quantities), the next 24 steps were divided into four parallel paths, whereas the remaining 21 steps proceeded in linear fashion. Remarkable features of the synthesis include the directed intramolecular joining (via an imine) of the Eastern and Western halves (step 33), construction of the acrylate Scheme 10. Hydrogenation of a Porphyrin to Form a Chlorin Scheme 11. Representative meso-Tetraarylchlorins Scheme 12. Methyl Pyropheophorbide a

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Section: Development Of De Novo Syntheses Of Gem-dialkylchlorinsmentioning

confidence: 99%

Section: Battersbymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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De NovoSynthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World

2015

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“…The structure and chemical properties of extracted chlorophyll are now known rather completely, largely as a result of the investigations of Willstattér, Stoll, Fischer, and Conant. The subject has recently been reviewed by Fischer (30) and by Steele (73). Figure 9 shows the probable formula for chlorophyll a (30).…”

Section: Chemical Properties Of Chlorophyllmentioning

confidence: 99%