Studies in the Naphthalene Series. III. Synthesis of Apogossypol Hexamethyl Ether<sup>1</sup>

Edwards, J. D.; Cashaw, Jesse L.

doi:10.1021/ja01566a071

Cited by 29 publications

(19 citation statements)

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“…Almost two decades passed after Adams' initial studies before the structure postulated by Adams for gossypol was confirmed through gossypol's total synthesis, completed by Edwards and colleague (36)(37)(38). With gossypol's structure now firmly established, researchers turned to improving cottonseed's meal and oil quality by developing methods to remove gossypol and other gossypol-like pigments.…”

mentioning

confidence: 99%

Reaction chemistry of gossypol and its derivatives

Kenar

2006

J Americ Oil Chem Soc

107

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Gossypol, a complex polyphenolic compound, is a naturally occurring highly colored yellow pigment found in the small intercellular pigment glands in the leaves, stems, roots, and seed of cotton plants. In cottonseed, gossypol contributes to its toxicity and therefore it is regarded as an unwanted processing component. It was not until its antitumor and male infertility activities were discovered that gossypol was considered as a valueadded natural product from cottonseed with useful physiological and chemical properties. These serendipitous discoveries created much excitement, and an enormous amount of research on gossypol has ensued. Since then, much research has focused on the preparation of suitable gossypol derivatives for medicinal applications. This review summarizes current knowledge about gossypol, its stereochemistry, tautomerism, and the many varied reactions the gossypol molecule can undergo.

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confidence: 99%

Reaction chemistry of gossypol and its derivatives

Kenar

2006

J Americ Oil Chem Soc

107

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“…Stobbe condensation of 6a with (CH,CO,Et),/t-BuOK [7] provided a half-ester which, after cyclodehydratation with Ac,O followed by saponification [3], was converted into the hydroxynaphthalenecarboxylic acid 7a in 60% overall yield. Reduction of 7a with LiAlHJTHF [3] gave the (hydroxymethy1)naphthol 8a in 91 YO yield. Attempts for thermal dimerization of 8a under the conditions described for a similar synthetic gossypol precursor [3] gave a tarry material.…”

Section: R=hmementioning

confidence: 99%

“…Reduction of 7a with LiAlHJTHF [3] gave the (hydroxymethy1)naphthol 8a in 91 YO yield. Attempts for thermal dimerization of 8a under the conditions described for a similar synthetic gossypol precursor [3] gave a tarry material. The phenolic coupling of 8a into the binaphthalenediol 9a was achieved with (t-Bu),O,/C,H,Cl [S] rings of 2 by intramolecular cyclization.…”

Section: R=hmementioning

confidence: 99%

“…and reextracted with Et20 (3 x 200 ml). Evaporation of the solvent gave an oily residue which was further subjected, without purification, to cyclodehydratation with Ac20/AcONa and saponification with 10% NaOH in MeOH according to [3]. Crystallization from C6H6 or C6H6/hexane gave 7a (28.4 g, 60%), 7c (28.0 g, 47%), or 7d (29.6 g, 41 %), resp.…”

Section: 4-bis(benzyloxy)-2-isopropylbenzaldehyde (6d)mentioning

confidence: 99%

“…3-(Hydroxymethyl)-S-isopropyl-6,7-dimethoxy-I-naphthol @a), 7-(Benzyloxy)-3-(hydroxytnethyl)-S-isopropyl-6-methoxy-I-naphthol (tic), and 6,7-Bis(benzyloxy) -3-(hydroxymethyl) -5-isopropyl-l-naphthol(8d). Reduction of 7a, 7b, or 7d (0.087 mol) with LiAIH, (0.493 mol) in dry THF (700 ml) according to [3] gave 8a (21.9 g, 91 %), 8c (25.0 g, 82%), and 8d (34.3 g, 92%), resp. (7.3 g, 0.05 mol) in C6H5CI (600 ml) was heated under reflux for 9 h. Evaporation of the solvent and crystallization from C6H6 gave 9a (12.7 g, 92%), 9c ( Il-dicarbaldehyde (2b).…”

Section: 4-bis(benzyloxy)-2-isopropylbenzaldehyde (6d)mentioning

confidence: 99%

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Synthesis of Gossypol Analogues

Ognyanov

Petrov

Tiholov

et al. 1989

Helvetica Chimica Acta

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Dedicated to the memory of Professor Dr. Pierre CrahhP (24. XI. 88) Two gossypol analogues 2a and 2b were synthesized for biological evaluation as male contraceptive agents. The naphthol 8c was prepared by analogy with a known procedure starting from 3-isopropylcatechol (3). (t-Bu)?02-Mediated phenolic coupling of 8c furnished the binaphthol9c which, after pyrane ring closure, deprotection, and selective bisformylation with SnCI,/CI,CHOCH,, gave the target compound 2a. The corresponding tetrahydroxy analogue 2b was prepared in a similar way.

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Dirigierende Proteine aus Baumwolle (Gossypium sp.) für die atropselektive Synthese von Gossypol

Effenberger

Bin

et al. 2015

Angewandte Chemie

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Gossypol dient der Abwehr von Schädlingen und Pathogenen in Baumwollpflanzen. Seine Biosynthese umfasst die oxidative Kupplung von Hemigossypol, die zu zwei Atropisomeren führt. In vivo dominiert (+)‐Gossypol, was auf eine stereochemisch kontrollierte Biosynthese schließen lässt. Ziel dieser Studie waren die Identifizierung der Faktoren für die Bildung von (+)‐Gossypol sowie die Untersuchung ihres Potenzials für die Synthese asymmetrischer Biaryle. Die Kupplung von Hemigossypol mit Laccase und O2 als Oxidationsmittel in Gegenwart eines dirigierenden Proteins (DIR) von Gossypium hirsutum (GhDIR4) verläuft atropselektiv. (+)‐Gossypol wurde mit >80 % ee erhalten, während in Abwesenheit von GhDIR4 nur racemisches Gossypol entstand. Die Identifizierung von GhDIR4 unterstreicht die Bedeutung von DIRs im Sekundärstoffwechsel von Pflanzen und könnte ein erster Schritt zur Entwicklung von DIRs für die Synthese axial‐chiraler Binaphthyle sein.

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Studies in the Naphthalene Series. III. Synthesis of Apogossypol Hexamethyl Ether¹

Cited by 29 publications

References 1 publication

Reaction chemistry of gossypol and its derivatives

Reaction chemistry of gossypol and its derivatives

Synthesis of Gossypol Analogues

Dirigierende Proteine aus Baumwolle (Gossypium sp.) für die atropselektive Synthese von Gossypol

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Studies in the Naphthalene Series. III. Synthesis of Apogossypol Hexamethyl Ether1

Cited by 29 publications

References 1 publication

Reaction chemistry of gossypol and its derivatives

Reaction chemistry of gossypol and its derivatives

Synthesis of Gossypol Analogues

Dirigierende Proteine aus Baumwolle (Gossypium sp.) für die atropselektive Synthese von Gossypol

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Studies in the Naphthalene Series. III. Synthesis of Apogossypol Hexamethyl Ether¹