The Infrared Spectra of Gossypol<sup>1a</sup>

O’Connor, Robert T.; Haar, P. Von der; DuPré, Elsie F.; Brown, Linda; Pominski, C. H.

doi:10.1021/ja01638a023

Cited by 29 publications

(11 citation statements)

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“…This proved to be t h e case as indicated in T a b l e 11. T h e ratio of erythro isomer ( l l ) / t h r e o isomer (12) increases in comparison with t h e ratio of 5/6 (cf. entries 2,4, and 5 of Table I1 vs. 9, 12, and 13 of T a b l e I, respectively).…”

Section: Reactions Of Pent-3-en-2-yl-9-bbn (9)mentioning

confidence: 97%

“…The reaction of cortyllithium and -magnesium compounds also proceeds via Sa (entries 1, 2, 5, and 8). The erythro selectivity does not so much depend upon the steric bulk of the R' group (entries [9][10][11][12], but that of the R group exerts a strong influence upon the selectivity (entries 13 and 14). The 1,3-diaxial interaction between the R group and the bridgehead proton of the 9-BBN ringzb and the 1,2 axial-equatorial interaction between the R group and the Me group in Sa increase with the steric bulk of R group.…”

Section: Scheme 11 Cyclic Transition-state Geometrymentioning

confidence: 99%

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Diastereofacial selectivity in the reaction of allylic organometallic compounds with imines. Stereoelectronic effect of imine group

Yamamoto¹,

Komatsu²,

Maruyama³

1985

J. Org. Chem.

107

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The diasterofacial selectivity in the reaction of crotyl organometallic compounds (4) (M = Li+, Mg, B, and Sn) with imines (3) is investigated. The reaction of ordinary imines produces the erythro isomer (5) predominantly regardless of the metal (M). With increase of the steric bulk of the R group or with aryl substituent in the R' group, the threo isomer (6) predominates in the reaction of crotyl-9-BBN. The ratio of erythro (ll)/threo (12) in the reaction of pent-3-en-2-yl-9-BBN (9) is higher than the ratio of erythro (5)Ithreo (6) in the reaction of crotyl-9-BBN itself. On the basis of these observations, the transition-state geometry is discussed.

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Section: Reactions Of Pent-3-en-2-yl-9-bbn (9)mentioning

confidence: 97%

Section: Scheme 11 Cyclic Transition-state Geometrymentioning

confidence: 99%

Diastereofacial selectivity in the reaction of allylic organometallic compounds with imines. Stereoelectronic effect of imine group

Yamamoto¹,

Komatsu²,

Maruyama³

1985

J. Org. Chem.

107

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“…2) and to the reaction conditions that influence the equilibrium between gossypol's tautomeric forms. Typical alkali-mediated methylation procedures are not practical because of gossypol's instability toward alkali, and over the years several procedures that use diazomethane, methyl iodide, and dimethyl sulfate have been developed (33,(93)(94)(95). Adams and coworkers used dimethyl sulfate to methylate gossypol (9), and, depending on the reaction conditions, gossypol can be methylated to provide a tetramethyl ether product 6, or two distinct isomeric hexamethyl ethers 7a (red form) and 7b (white form) (Fig.…”

Section: Gossypol Reactionsmentioning

confidence: 99%

Reaction chemistry of gossypol and its derivatives

Kenar

2006

J Americ Oil Chem Soc

109

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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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“…The infrared spectrum of herqueinone, Fig. 1, shows a band at 3.1 µ, characteristic of a hydrogen-bonded hydroxyl (3). For example, salicylaldehyde shows the band from the stretching vibration of the hydroxyl at 3.05 µ.…”

mentioning

confidence: 99%

Structural Features of Herqueinone, a Red Pigment From Penicillium Herquei

Harman¹,

Cason²,

Stodola³

1955

J. Org. Chem.

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Isolation of a red pigment from P . herquei has been reported in an earlier paper (1). Further examination of this pigment and purification by adsorption chromatography has verified its homogeneity and the empirical formula CmHzoO,, although there remains the possibility of a slightly Merent ratio of hydrogen to carbon. Since the infrared spectrum of this pigment indicates the presence of a t least one carbonyl group, and since Burton (2) has applied the name, herquein, to a yellow acid also isolated from P . herqwi, the name herqueinone is proposed for the red pigment with a coppery lustre, which is the subject of the present study.The infrared spectrum of herqueinone, Fig. 1, shows a band at 3.1 p, characteristic of a hydrogen-bonded hydroxyl (3). For example, salicylaldehyde shows the band from the stretching vibration of the hydroxyl a t 3.05 p . The absence of absorption in the 5.5-6 p region and occurrence of a strong band at 6.1 p suggests carbonyl in an aromatic or quinonoid system which also contains hydroxyl. Among the few types of carbonyl compounds absorbing beyond 6 p are hydroxyphenyl aldehydes (3) and ketones (4), and 2-hydroxy-l14-naphthoquinones (5). Ettlinger (5) has noted that 2-hydroxy-1 , 4-naphthoquinones and their 3-alkyl derivatives are characterized by bands at 2.95-3.1 p, 5.98-6.08 p, and 6.23-6.3 p. The spectrum of herqueinone exhibits bands in each of these three regions; however, all efforts to secure carbonyl derivatives of herqueinone have been unsuccessful. The 1,2-naphthoquinones (5) show a shorter wavelength band, below 6 p, as do all types of y-and &lactones. Further indication of absence of a 1,2-quinone system is furnished by failure of herqueinone to react with o-phenylenediamine under conditions which yield a quinoxaline with

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The Infrared Spectra of Gossypol^1a

Cited by 29 publications

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Diastereofacial selectivity in the reaction of allylic organometallic compounds with imines. Stereoelectronic effect of imine group

Diastereofacial selectivity in the reaction of allylic organometallic compounds with imines. Stereoelectronic effect of imine group

Reaction chemistry of gossypol and its derivatives

Structural Features of Herqueinone, a Red Pigment From Penicillium Herquei

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The Infrared Spectra of Gossypol1a

Cited by 29 publications

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Diastereofacial selectivity in the reaction of allylic organometallic compounds with imines. Stereoelectronic effect of imine group

Diastereofacial selectivity in the reaction of allylic organometallic compounds with imines. Stereoelectronic effect of imine group

Reaction chemistry of gossypol and its derivatives

Structural Features of Herqueinone, a Red Pigment From Penicillium Herquei

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The Infrared Spectra of Gossypol^1a