- 1H AND 13C NMR SPECTRA OF TRANSFORMATION PRODUCTS OF GOSSYPOL IN SOLUTIONS
-
The complete cycle of the transformation of gossypol in solutions takes place in the measuring ampul of a NMR spectrometer.It has been established for the first time that, in methanol, gossypol is converted into stereoisomeric dilactol 15,15'-dimethyl ethers which change into dianhydrogossypol in chloroform and back into gossypol in aqueous acetone.The 1H and 13C NMR spectra of the main and intermediate products of the conversion of gossypol in the solvents mentioned have been studied in detail for the first time and a complete assignment of their resonance characteristics has been made.It has been shown that dianhydrogossypol is formed through intermediate stereoisomeric 15,15'-dimethyl ethers of the dilactol form of gossypol.
- Abdullaev, N. D.,Tyshchenko, A. A.,Nazarova, I. P.,Ul'chenko, N. T.,Yagudaev, M. R.,Glushenkova, A. I.
-
-
Read Online
- Stereoselective coupling of hemigossypol to form (+)-gossypol in moco cotton is mediated by a dirigent protein
-
The terpenoid gossypol, a secondary metabolite found in the cotton plant, is synthesized by a free radical dimerization of hemigossypol. Gossypol exists as an atropisomeric mixture because of restricted rotation around the central binaphthyl bond. The dimerization of hemigossypol is regiospecific in cotton. In the case of some moco cotton, the dimerization also exhibits a high level of stereoselectivity. The mechanism that controls this stereoselective dimerization is poorly understood. In this paper, we demonstrate that a dirigent protein controls this stereoselective dimerization process. A partially purified protein preparation from cotton flower petals, which by itself is unable to convert hemigossypol to gossypol, converts hemigossypol with a 30% atropisomeric excess into (+)-gossypol when combined with an exogenous laccase, which by itself produces racemic gossypol.
- Liu, Jinggao,Stipanovic, Robert D.,Bell, Alois A.,Puckhaber, Lorraine S.,Magill, Clint W.
-
-
Read Online
- Cascade Claisen Rearrangement: Rapid Synthesis of Polysubstituted Salicylaldehydes and Total Syntheses of Hemigossypol and Gossypol
-
A cascade Claisen rearrangement of a well-organized maltol propargyl ether for the construction of polysubstituted salicylaldehydes is reported. This reaction features high atom economy (100 %), as well as catalyst-free and gram-scale conditions. Based on this novel methodology, the total synthesis of hemigossypol, gossypol, and their analogues has been realized.
- Cao, Tongxiang,Kong, Yi,Luo, Kui,Chen, Lianfen,Zhu, Shifa
-
-
Read Online
- An expedient route for the practical preparation of optically active (-)-gossypol
-
A simple and practical procedure has been developed for the resolution of racemic gossypol. The commercially available l-amino acid esters have been employed as the resolving agents with the l-tryptophan methyl ester (l-Trp-OMe) as the best reagent of choice. The individual diastereoisomeric gossypol adducts derived from l-Trp-OMe are readily separated by a simple filtration step to give the (-)-diastereoisomeric adduct, and its (+)-diastereoisomeric adduct can be easily obtained by simple evaporation of the mother liquor. Acid hydrolysis of the separated adduct gave (-)-gossypol and (+)-gossypol, respectively, in high chemical yields (quantitatively) and in high enantiomeric excesses (>95%).
- Jiang, Hai-Xia,Cao, Xing-Xin,Huang, Hao,Jiang, Biao
-
-
Read Online
- Preparation method and intermediate of gossypol and derivative thereof
-
The invention discloses a preparation method and an intermediate of gossypol and derivatives thereof. The preparation method comprises the following steps: in a solvent, under the action of alkali, apalladium catalyst and a chiral ligand, carrying out a coupling reaction shown in the specification on a compound 6 and a double-boron reagent to obtain a compound (+)-7, wherein the structure of thechiral ligand is shown as a formula L1. The preparation method is simple, easy to operate and suitable for industrial production.
- -
-
-
- Synthetic method of semi-gossypol, gossypol and analogues of semi-gossypol and gossypol
-
The invention discloses a synthetic method of semi-gossypol, gossypol and analogues of semi-gossypol and gossypol. According to the method, maltol containing substituents is taken as a raw material, and multi-stage reactions including coupling, rearrangement, reduction, oxidation and cyclization are carried out to synthesize semi-gossypol, gossypol and the analogues of semi-gossypol and gossypol.According to the method, the situation that gossypol is extracted from roots, stems, leaves and seeds of natural malva plant cotton is changed, and a new route for artificially synthesizing semi-gossypol, gossypol and the analogues of semi-gossypol and gossypol is created.
- -
-
-
- Method for preparing free gossypol by using gossypol acetate as raw material
-
The invention relates to a method for preparing free gossypol by using gossypol acetate as a raw material. According to the method, an intermolecular hydrogen bond between acetic acid and gossypol inthe gossypol acetate is destroyed by means of ultrasonic waves, and then the acetic acid is enabled to enter an aqueous solution or a saturated saline solution, so that the free gossypol is separatedfrom the acetic acid; the crude free gossypol is enabled to be subjected to recrystallization so as to obtain the high purity free gossypol; the whole preparation process is carried out at the room temperature, and the preparation time is short, so that the oxidation of a gossypol structure and the conversion between various isomers are effectively avoided; the method is low in raw material cost,short in process flow, good in repeatability, high in purity and safety, short in time and high in efficiency, and has certain economic value and practical value.
- -
-
Paragraph 0041-0076
(2018/07/30)
-
- Gossypol/ cotton and kapok alkone derivatives, their preparation and application of anti-tumor drug
-
The invention discloses a gossypol/ cotton ketone derivative. The structure of the derivative is shown as the specification. The invention also discloses a preparation method of the derivative and an application of the derivative in preparation of a medicament or a medicinal composition for treating tumors. The gossypol/ cotton ketone derivative has obvious anti-tumor activity, the toxicity of the derivative is reduced, the water solubility and the stability of the derivative under the physiological condition are improved, and the derivative is expected to be used as a novel anti-tumor candidate medicament.
- -
-
Paragraph 0110
(2016/11/07)
-
- Regioselective oxidative dehydrogenation under nonenzymatic conditions: A synthetic route to gossypol
-
A practical and scalable route was developed for the total synthesis of gossypol to allow for the construction of dozens of gossypol derivatives. tBuO2Ac was found to be a highly efficient oxidant for the polymerization of hemigossypol through a biosynthetic process under nonenzymatic conditions to give gossypol. Hemigossypol was synthesized on a gram scale by starting from commercially available carvacrol and dimethyl succinate and using a Stobbe condensation, an electrophilic cyclization, and the Michael addition of ortho-quinone methide as key steps. A practical route was developed for the total synthesis of racemic gossypol. tBuO2Ac was found to be a highly efficient oxidant for the polymerization of hemigossypol under nonenzymatic conditions to give gossypol. Hemigossypol was synthesized on a gram scale from commercially available carvacrol and dimethyl succinate. Copyright
- Li, Ling,Liu, Yuxiu,Wang, Qingmin
-
p. 8014 - 8021
(2014/01/06)
-
- Spectroscopic and Kinetic Studies of the Aldehyde-Lactol Tautomerization of Gossypol in Solution
-
1H NMR spectra of gossypol in C2H5OD solution show that an equilibrium between aldehyde 1 and lactol 2 tautomers is formed and that the aldehyde tautomer is predominant, whereas in C2H5OD-DCl solution (pH 2 equilibrium is studied by means of UV-VIS absorption spectroscopy and the results are compared with those of 1H NMR studies.Furthermore, the decrease of the absorbance at the long wavelength band in the spectrum of 1 is used to determine the kinetic parameters of aldehyde-lactol tautomerization in ethanol-HCl solution (pH 298 = (2.14 +/- 0.03)*10-2 dm3 mol-1 s-1; ΔH(excit.) = 64.0 +/- 3.4 kJ mol-1; ΔS(excit.) = -63 +/- 11 J mol-1 K-1; and the value of kinetic isotope effects, kH/kD = 5.6 at 55 deg C.A mechanism for aldehyde-lactol tautomerization of gossypol is proposed.
- Marciniak, Bronislaw,Schroeder, Grzegorz,Kozubek, Halina,Brzezinski, Bogumil
-
p. 1359 - 1362
(2007/10/02)
-