A new strategy for synthesizing the steroids with side chains from steroidal sapogenins: synthesis of the aglycone of OSW-1 by using the intact skeleton of diosgenin

The protected aglycone of saponin OSW-1, a new antitumor natural product, was synthesized in 13 linear steps in 9.5% overall yield by utilizing the intact skeleton of diosgenin. This strategy demonstrated a higher efficiency than the routine synthesis of steroids with side chains.     

Facile green synthesis of 16-dehydropregnenolone acetate (16-DPA) from diosgenin

Chromium- and MnO₂-free green synthesis of industrially important steroidal drug intermediate 16-dehydropregnenolone acetate (16-DPA) starting from diosgenin is reported. The reaction sequence involves three steps: acetolysis followed by acetylation, oxidation, and hydrolysis. In the first step, Ac₂O was used both as reagent and solvent in combination with a Lewis acid (AlCl₃), which led to considerable reduction of high temperature and pressure requirements of earlier processes. The oxidation step was made catalytic with the use of KMnO₄(5 mol%) in the presence of co-oxidant NaIO₄, leading to less waste generation (of chromium, MnO₂, etc.). Minimization of the temperature, pressure, time consumption, and use of nontoxic solvents makes the process very handy and simple.     

绿色合成--21世纪的有机合成

绿色合成,作为当代有机合成发展的一个重要学科前沿,已成为化学发展的一个方向.从催化剂、绿色溶剂、合成手段、合成方法、计算机辅助绿色合成等方面综述了近年来国内外实现绿色合成的有效途径,并对绿色合成的目标进行了探讨.参考文献35篇.     

绿色化学与有机合成及有机合成中的原子经济性

本文概述了有机合成和绿色化学的关系, 并介绍了原子经济性的概念及其在有机合成中的重要性。对21 世纪的化学发展提出了希望。     

A highly efficient synthesis of 22-deoxy-OSW-1 by utilizing the intact skeleton of diosgenin

22-Deoxy-OSW-1 (1), an analogue of OSW-1 with the potent anticancer activity, was synthesized by utilizing the intact skeleton of diosgenin in 11 steps in 13.7% overall yield. This synthesis demonstrated an effective and reasonable synthetic strategy for bioactive steroids with side chains.     

Synthesis of pennogenyl saponins using three methods

The synthesis of pennogenyl saponins using three important methods of glycosylation is reported in this article. Six correlative compounds (7–12) were first synthesized. As donors (1–6), glycosyl halide, trichloroimidate, and thioglycoside were chosen to study their reaction with the acceptor pennogenin. In these reactions the difference in steric hindrance between 3-OH and 17-OH of pennogenin was utilized skillfully and only the 3-hydroxyl group of pennogenin could be connected with each kind of donors selectively. There was no reaction at the 17-hydroxyl group, which had no protection. The characteristic above makes it convenient to synthesize compounds of pennogenyl saponins. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 348–350, July–August, 2007.     

Synthesis of New 13-O-Acylavermectin Bl Aglycones

Six new 13-O-acylavermectin Bl aglycones(3-8) were synthesized from avermectin B1 aglycone and their bioactivities were evaluated against Spodoptera exigua, Spodoptera eridania, Tetranychus urticae and Aphis fabae.     

Diazocarbonyl and Related Compounds in the Synthesis of Azoles

Diazocarbonyl compounds have found numerous applications in many areas of chemistry. Among the most developed fields of diazo chemistry is the preparation of azoles from diazo compounds. This approach represents a useful alternative to more conventional methods of the synthesis of azoles. A comprehensive review on the preparation of various azoles (oxazoles, thiazoles, imidazoles, pyrazoles, triazoles, and tetrazoles) from diazocarbonyl and related compounds is presented for the first time along with discussion of advantages and disadvantages of «diazo» approaches to azoles.     

Anti-inflammatory,antioxidant and antiangiogenic activities of diosgenin isolated from traditional medicinal plant,Costus speciosus (Koen ex.Retz.) Sm

Costus speciosus is an important medicinal plant widely used in several indigenous medicinal formulations. The present study was conducted to evaluate the in vitro anti-inflammatory, antioxidant and antiangiogenic activities of diosgenin isolated from C. speciosus. The diosgenin was isolated from C. speciosus by HPTLC and its biological activities were studied by different protocols. The results demonstrated that LPS stimulated TNF-α generation in RAW 264.7 macrophage culture supernatant up to 3.7-fold of the control and that sample treatment (50 μg/mL) resulted in a highly significant inhibitory effect on LPS-stimulated TNF-α (p < 0.01) in a similar manner to methotrexate inhibitory effect. The tested sample possessed an effective antioxidant scavenging affinity against DPPH radicals as compared with the standard antioxidant activity of vitamin C. The results presented here may suggest that diosgenin isolated from C. speciosus possess anticancer, apoptotic and inhibitory effects on cell proliferation.     

利用薯蓣皂甙元完整骨架合成澳洲茄胺

澳洲茄胺1是中药龙葵生物活性成分澳洲茄碱和澳洲茄边碱的甙元, 具有抗肿瘤等生物活性. 利用薯蓣皂甙元的完整骨架, 以16-羟基甾体皂甙元的溴代开环反应为关键反应, 经9步反应, 以21%的总收率完成了澳洲茄胺1的合成.     

Synthesis of 5(6)-dihydro-OSW-1 by using the intact skeleton of tigogenin

5(6)-Dihydro-OSW-1 (1), an analogue of OSW-1 with the potent anticancer activity, was synthesized by utilizing the intact skeleton of tigogenin in 13 steps in 9.0% overall yield. This synthesis demonstrated an effective and reasonable synthetic strategy for bioactive steroids with side chains as compared with their routine synthesis.     

Atom-economic Approach to the Synthesis of α-(Hetero)aryl-substituted Furan Derivatives from Biomass

An atom-economic ring construction approach to the synthesis of α-(hetero)arylfurans based on renewable furanic platform chemicals has been developed. Corresponding compounds have been prepared in good to excellent yields via [2+2+2] and [4+2] cycloaddition reactions using metal-catalyzed or photoredox protocols. Easily available HMF-based 2-hydroxymethyl-5-ethynylfuran and 2-hydroxymethyl-5-cyanofuran were used as starting materials. A synthetic route with an improved carbon economy factor has been implemented to achieve sustainability aim. The possible application of arylfurans as molecular conductors has been investigated by DFT calculations, which revealed excellent charge transfer properties. As a future perspective, integration of biomass processing strategy into manufacturing of molecular electronics was pointed out to achieve the aim of sustainability.     

多组分连续流动高选择性合成(Z)-N-乙烯基环N,O-缩醛衍生物

本工作发展了一种三组分在连续流动技术下高效制备(Z)-N-乙烯基环N,O-缩醛衍生物的合成方法. 以廉价易得原料为反应起始物, 在连续流动技术下发生可控的串联环化反应, 反应经历一个独特的分子内重排过程形成C—O和 C—N键. 最终, 高选择、精准合成含氮、氧六元环和七元环杂环分子, 两步合成仅需50 min. 连续流动合成技术的运用避免了多组分反应中两组分反应不彻底和副反应等问题, 提供了一种高选择性组装多组分可替代的合成方法, 产率高达96%, 为化工原料高值转化利用提供借鉴.     

Synthesis and photovoltaic properties of copolymers with a fluoro quinoxaline unit

Two novel accepter units, namely, difluoroquinoxaline and monofluoroquinoxaline, were prepared and used for the synthesis of the conjugated polymers containing electron donor–acceptor pairs for use in organic photovoltaics. The introduction of a fluorine atom into the quinoxaline moiety resulted in polymers with lowered highest occupied molecular orbital (HOMO) energy levels; this increased the open circuit voltage of the devices based on the synthesized polymers. The conjugated polymers containing difluoroquinoxaline and monofluoroquinoxaline, namely, thiophene and benzodithiophene, were synthesized using the Stille polymerization reaction to produce PEHBQxF2, PEHBQxF1, PEHBDTQxF2, and PEHBDTQxF1. The HOMO energy levels of PEHBQxF2, PEHBQxF1, PEHBDTQxF2, and PEHBDTQxF1 were determined to be −5.66, −5.52, −5.54, and −5.39 eV, respectively. The device with PEHBDTQxF2/PC₇₁BM (1:2, w/w) and containing diiodooctane (3 vol %) exhibited the best photovoltaic performance, with its V_OC being 0.79 V, J_SC being 10.44 mA/cm², FF being 68%, and PCE being 5.58%. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 821–830     

Total synthesis of bryostatins: the development of methodology for the atom-economic and stereoselective synthesis of the ring C subunit

Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for the stereoselective assembly of the ring C subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the ring C subunit of bryostatins.     

Synthesis and thermal properties of diblock copolymers utilizing non-covalent interactions

Diblock copolymers of poly(styrene) and poly(ethylene oxide) were prepared utilizing a bisterpyridine ruthenium complex as non-covalent interaction for the connection of the two blocks. Apart from the synthesis and characterization of four metallo-supramolecular block copolymers, first studies on the thermal properties of the block copolymers have been performed. A complex crystallization behavior was observed and is described in a qualitative fashion. The influence of the metal complex on the thermal stability of the metallo-supramolecular block copolymers remains a question for further investigation.     

General,Straightforward, and Atom-Economical Synthesis of Vinyl Triflimides

Vinyl triflimides were only accessible recently and their chemistry is yet to be discovered. Herein, we describe a general, straightforward and atom-economical synthesis of these materials from alkynes and triflimide. A vast array of terminal and internal alkynes with broad spectrum of functionalities could be employed to generate various di- and trisubstituted vinyl triflimides regiospecifically with high to specific stereoselectivity. Moreover, the protocol could be conducted on gram scale using terminal and internal alkynes. Preliminarily attempts to probe the unprecedented reactivity of vinyl triflimides revealed part of its chemical properties.     

6-氨基己酸的合成与表征——综合性多步有机合成实验

介绍了以环己酮为原料,通过肟化、贝克曼重排和水解开环等3步合成6-氨基己酸的过程,样品经过纯化后,通过1H NMR和13C NMR确证结构。本实验和有机合成课程结合紧密,内容覆盖肟化、重排、水解开环等基本操作,适合作为学生综合实验。     

Purification of the total steroidal saponins from fenugreek seeds (Trigonella foenum-graecum L.) using aqueous two-phase system and determination of diosgenin content using micellar electrokinetic chromatography method

The total steroidal saponins, particularly its major steroidal sapogenin (diosgenin), are the main active principles of fenugreek seed extract. In this study, an ethanol-salt aqueous two-phase system (ATPS) was explored for the purification of the total steroidal saponins, and the process conditions were optimized by response surface methodology (RSM). Under the optimized conditions, the RSM predicted recovery of the total steroidal saponins in the top phase of ATPS was 97.9%, which agreed with the average experimental recovery (98.3 ± 4.2% (n = 6)). Moreover, a rapid micellar electrokinetic chromatography (MEKC) method was developed for the determination of diosgenin from extracts. The diosgenin content in the ATPS top phase extract was 3-fold higher than that in crude extract, suggesting this ATPS having a great potential for purification pharmacological active ingredients from fenugreek seeds.