Inclusion complexes of the natural product gossypol. The formation of different gossypol polymorphs on decomposition of channel type inclusion complexes

The existence of seven gossypol polymorphs has been established. Two of them are obtained by direct crystallization from solution. The remaining five polymorphs are the products of desolvation of channel type complexes (tubulates). Each isostructural group of the complexes on decomposition gives one polymorph. Gossypol thus possesses specific peculiarities in terms of the decomposition of its tubulates, and also the absence of thermotropic polymorphic transitions.     

棉酚及其衍生物在溶剂中的氢转移

本文利用~1HNMR法研究棉酚及其胺类衍生物(双苯胺棉酚,双丁基棉酚和双嘧啶棉酚)在不同溶剂(CDCl_3,DMSO-d_6,C_6D_6,CD_3COCD_3,DMF-d_7 等)中和不同的酸碱环境下的氢转移(即结构互交).实验表明,棉酚、双苯胺棉酚、双丁基棉酚和双嘧啶存在着三种不同的异构体.这些异构体在同一溶剂不同环境下可以并存或者相互转变.     

Sorption of Ammonia, Methylamine and Methanol by the P3 Polymorph of Gossypol. Synthesis of Unsymmetrical Monoamine Derivatives of Gossypol by a Solid-state Reaction

The P3 polymorph of gossypol has wide, empty channels andstrongly absorbs linear amines. One of the two gossypol aldehydegroups is located near the channel wall. This situation allowsreaction of the amines with half of a gossypol molecule,yielding unsymmetric monoaminoderivatives of gossypol in highyield and by a simple, solid-state method.     

近红外反射光谱法(NIRS)测定棉仁粉中蛋白质和棉酚含量的研究

选用49份不同蛋白质和棉酚含量的陆地棉种质资源和188份陆地棉重组近交系为材料,以多年份、多地点种植收获的种子材料组成原始样品集,分别对棉仁粉中蛋白质含量和棉酚含量进行化学测定,采用改进的偏最小二乘法(Modified PLS)和(2,4,4,1)的数学转换方法建立近红外反射光谱(NIRS)定标模型,以寻找棉籽蛋白质含量和棉酚含量的快速测定方法。结果表明,蛋白质含量的定标决定系数(RSQ=0.933)和交叉检验决定系数(1-VR=0.929)较高,定标标准误差(SEC=0.623)和交互校验标准误差(SECV=0.638)较小,预测模型的建模效果较好,可替代化学分析。棉酚含量预测模型的RSQ,1-VR,SEC和SECV分别为0.836,0.811,0.074和0.079,模型预测效果略差于蛋白质模型,但仍可用于棉仁粉中棉酚含量的测定。     

Chemiluminescence Determination of Gossypol by Oxidation with N‐Bromosuccinimide

A chemiluminescence (CL) phenomenon was observed when gossypol was injected into a reaction mixture of N‐bromosuccinimide (NBS) and alkaline dichlorofluorescein (DCF). Based on this phenomenon, a rapid and sensitive method for the determination of gossypol was established. Under the optimum conditions, the linear range was from 1.0 × 10^?9 to 1.0 × 10^?6 M. The detection limit was 1.0 × 10^?10 M. The method has been applied to the determination of gossypol in cottonseed, cottonseed oil, pharmaceutical and biological fluids with satisfactory results. The possible CL reaction mechanism was discussed briefly.     

Inclusion of molecular iodine into channels of the organic zeolite-like gossypol

Gossypol has been obtained in the zeolite-like form by desolvation of the 1:1 unstable solvate with dichloromethane. It demonstrates a high potential for an uptake of molecular iodine from the environment. In a case of single crystals a stable inclusion compound (gossypol)₈·I₂, preserving the crystal structure of the zeolite-like form, has been prepared. The iodine molecules occupy large cavities of the channels and are inclined as confirmed by the absence of a strong dichroism. The iodine molecules can be removed with the help of vacuum giving back to the zeolite-like form. Supplementary Data relating to this article are deposited with the Cambridge Crystallographic Data Centre as supplementary publication No. CCDC 226180.     

Spectroscopic and semiempirical studies of new Schiff base of gossypol with allylamine in solution

The Schiff base of racemic gossypol with allylamine (GSBAL) has been studied by FT-IR, ¹H and ¹³C NMR spectroscopy as well as by the PM5 semiempirical method. The spectroscopic methods have shown that GSBAL Schiff base exists in chloroform solution as enamine–enamine tautomer. The structure of GSBAL and the hydrogen bonds within this structure have been calculated to show that the allyl groups are out-of-planes of naphthalene rings. The strongest intramolecular hydrogen bond within the structure of GSBAL is formed between O₇H–N₁₆ atoms and it belongs to the medium strong bonds. The other hydrogen bonds, although very weak, play a very important role in stabilising the GSBAL enamine–enamine structure.     

Synthesis and anti-HIV-1 activity of the conjugates of gossypol with oligopeptides and D-glucosamine

A series of novel gossypol derivatives were synthesized and screened for their in vitro anti-HIV- 1I activity. The results showed that replacing the aldehyde groups of gossypol with certain oligopeptides and Dglucosamine not only reduced the cytotoxicity of gossypol derivatives but also enhanced their antiviral activity against HIV-1. Interestingly, D-glucosamine derivative of gossypol that lacked the COONa group also exhibited the same potent anti-HIV-1 activity as oligopeptide derivatives with the COONa group. These compounds blocked the entry of HIV-1ⅢB into target cell. which was similar to T20. Furthermore, the molecular docking analysis rationalized their anti-HIV-1 activity. The results also implied that certain oligopeptides and D-glucosamine were important moities to prepare gossypol derivatives as HIV- 1 entry inhibitors besides certain amino acids.     

Crystal structure of the product of a condensation reaction of (±)-gossypol with (R)-(+)-1-phenylethylamine. Why do diastereoisomeric diaminogossypols cocrystallize?

The crystal structure of a compound obtained in a condensation reaction of (±)-gossypol with (R)-(+)-phenylethylamine has been determined by X-ray structure analysis. The crystals of C₄₆H₄₈O₆N₂·(C₄H₈O₂)₂ are monoclinic, space groupP2₁,a=21.243(3),b=8.666(1),c=28.651(4) Å, =108.24(1)⁰,V=5009(3) ³,Z=4,D _x=1.195 g cm^–3, (CuK )=0.66 mm^–1,T=292 K. The structure has been solved by direct methods and refined to the finalR value of 0.091 for 4290 observed reflections and 1049 parameters. There are two diastereoisomeric molecules of the host and four solvent molecules in the asymmetric unit. The host molecules are H-bonded into chains with diastereoisomeric molecules alternating along the chain. The fact that the host prefers the association mode in which molecules with a different configuration of the 2,2-binaphthyl moiety are H-bonded explains why separation of diastereoisomeric diaminogossypols by fractional crystallization has been unsuccessful. The 1,4-dioxane molecules are accommodated in infinite channels but only every second guest molecule in a channel is H-bonded to the host. Supplementary Data relevant to this article have been deposited with the British Library as Supplementary Publication No. SUP 82167 (27 pages).