The synthesis of ventiloquinone L, the monomer of cardinalin 3

Readily available ethyl-4-acetoxy-6,8-dimethoxynaphthalene-2-carboxylate was converted into 1-[3-allyl-4-(benzyloxy)-6,8-dimethoxy-2-naphthyl)-1-ethanol in seven steps. Subjection of this compound to Wacker oxidation conditions provided 5-benzyloxy-7,9-dimethoxy-1,3-dimethyl-1H-benzo[g]isochromene in good yield. Hydrogenation of the isochromene afforded (+/-)-cis-7,9-dimethoxy-1,3-dimethyl-1H-benzo[g]isochroman-5-ol as the major product, which was readily converted into ventiloquinone L.     

Stereoselective synthesis of biologically active tetronic acids

(4R)-3-Amino-4-trimethylsilyloxy-2-alkenoates (R)-3, obtained from O-trimethylsilyl protected optically active cyanohydrins (R)-1 via the Blaise reaction, are hydrolyzed under mildly acidic conditions to give optically active tetronic acids (R)-4 without racemization. From the follow-up reactions of (R)-4 investigated, only methylation with diazomethane afforded the biologically active tetronic acid derivative (R)-5a without racemization whereas acylation and reductive alkylation, respectively, resulted in partial racemization or failed on the whole.     

Recent advances in the synthesis of biologically active spirooxindoles

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具生物活性有机磷化合物的设计与合成

对氨基膦酸及磷肽的合成作了研究,同时考察了引入二氟次甲基及三氟甲基的方法。在此基础上研究成功基于[1,2]不对称诱导及[1,3]质子转移反应的手性合成方法。对多官能团的氨基膦酸及磷肽也作了研究。此外还制备了具1,1-双膦酸基的多种碳环化合物,对含磷酰基,特别对既含磷酰基又含三氟甲基的多种杂环化合物的合成方法与反应机理进行了报导。     

Short-step synthesis of optically and biologically active exo-brevicomin

Optically and biologically active (IR,5S,7R)-(+)-exo-brevicomin was synthesized in the six-step sequence starting from diethyl (S,S)-(−)-tartrate.     

Selective methodologies for the synthesis of biologically active piperidinic compounds

The synthesis of optically active substituted piperidines has been achieved by using four different methodologies. The first one is an intramolecular nucleophilic displacement of activated alcohol moieties that was used to build up the piperidine ring of (-)-prosophylline and (-)-slaframine, and the second one is a ring-closing metathesis of unsaturated amines which was employed in the synthesis of (+)-sedamine and 4a,5-dihydrostreptazoline. The third methodology is the alpha-functionalization of N-Boc piperidines which was particularly useful in the synthesis of argatroban, and the fourth one is a ring expansion of prolinols to 3-chloropiperidines or 3-hydroxypiperidines which was utilized to synthesize (-)-paroxetine, (-)-pseudoconhydrine, the piperidine ring of (-)-velbanamine and (+)-zamifenacin.     

The Grandberg reaction in the synthesis of biologically active compounds

The review is focused on the Grandberg synthesis, namely, the synthesis of tryptamines from arylhydrazines and γ-halocarbonyl compounds, as an exceptionally useful and efficient methodology to access biologically active indole heterocycles.     

Ultrasonic-promoted three-component synthesis of some biologically active 1,2,5,6-tetrahydropyrimidines

Multicomponent reactions and organic synthesis with ultrasonic activation have been used as key methods for the synthesis of tetrahydropyrimidine derivatives. The three-component condensation of 1,3-diarylprop-2-en-1-one with ammonia and aldehydes/acetone or N-substituted gamma-pyridones under ultrasonic irradiation was developed as a rapid and efficient solution-phase method for the high-yielding preparation of 2-aryl(hetaryl)-4,6-diaryl-1,2,5,6-tetrahydropyrimidines and 2,4-diaryl-1,5,9-triazaspiro[5.5]undec-1-enes. The described synthetic protocol provides rapid access to novel and diversely substituted tetrahydropyrimidines libraries. The simple, primary biological screening showed 98% of inhibitory activity against Mycobacterium tuberculosis for one of tetrahydropyrimidines synthesized.     

New directions in the synthesis of biologically active analogs of luliberin

Chemistry of Natural Compounds -     

Control of the synthesis of some biologically active substances by thin-layer chromatography

Summary The aim of this investigation was the synthesis of -aryl propionic acids which might be expected to have antiinflammatory activity. The total synthesis of -(4-benzoylphenyl)--methyl propionic acid was monitored by thin-layer chromatography. The adsorption of the compounds of interest was found to be dependent upon the polarity of the eluting solvents. The observed retentions were mathematicaly analysed, and the system that showed the best separation of reactants evaluated. A least squares method was used to determine the best geometric curve expressing the relationship between values for R_f and eluent composition.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Total chemical synthesis of biologically active vascular endothelial growth factor

Efficient access: the 204-residue covalent-dimer vascular endothelial growth factor with full mitogenic activity was prepared from three unprotected peptide segments by one-pot native chemical ligations. The covalent structure of the synthetic VEGF was confirmed by precise mass measurement, and the three-dimensional structure of the synthetic protein was determined by high-resolution X-ray crystallography.     

Pronounced ionic liquid effect in the synthesis of biologically active isatin-3-oxime derivatives under acid catalysis

An efficient method was developed for the preparation of isatin-3-oxime derivatives with Bronsted and/or Lewis acids in imidazolium-based ionic liquids. Isatin-3-oxime bearing the electron donating methoxy group was equally obtained in good yields. The pronounced ionic liquid effect avoids the direct formation of isatin in the acidified media and the reaction leads exclusively to isatin-3-oxime derivatives.     

Developing novel organocatalyzed aldol reactions for the enantioselective synthesis of biologically active molecules

Aldol reaction is one of the most important methods for the formation of carbon-carbon bonds. Because of its significance and usefulness, asymmetric versions of this reaction have been realized with different approaches in the past. Over the last decade, the area of organocatalysis has made significant progresses. As one of most studied reactions in organocatalyses, organocatalyzed aldol reaction has emerged as a powerful tool for the synthesis of a large number of useful products in optically enriched forms. In this review, we summarize our efforts on the development of novel organocatalyzed aldol reactions for the enantioselective synthesis of biological active molecules. Literatures closely related to our studies are also covered.     

Microwaves in organic synthesis: Facile synthesis of biologically active pyridazinone and iminopyridazine derivatives

Condensation of Wittig reagents 1a,b with arylhydrazones 2a,b by conventional and by microwave heating techniques furnished the corresponding pyridazines 3a‐e . The arylhydrazones 7a,b were allowed to react with 1a,b under the same conditions to produce the pyridazinones 10a,b and iminopyridazines 11a,b respectively. On the other hand, the arylhydrazones 12a‐c reacted with 1a to afford the pyridazinones 13a‐c . Treatment of 3b with dimethylformamide dimethyl acetal (DMFDMA) produced the adduct 15 . The utility of microwave heating technique led to the reduction of the reaction times to few minutes and to the improvement of the yields of the products. The in vitro biological activity of some newly prepared compounds against four types of fungi was studied.     

Highly stereo and regiocontrolled synthesis of both racemic and optically active (−)-blastmycinone

Two highly stereo and regioselective synthetic pathways are reported to prepare both racemic and unnatural (?)-Blastmycinone, starting from readily available β-angelica lactone derivatives.     

Chemical properties of cyanoacetanilides and synthesis of biologically active compounds around them

The review compiles and systematizes the published data on the application of cyanoacetanilides in the organic synthesis, and the biological activity of compounds obtained on the basis of cyanoacetanilides is described.