具有抗HIV活性的螺环缩酮类化合物合成研究: Didemnaketals C(1)～C(8)片段 的合成

以天然薄荷酮为原料,立体选择性地合成了具有抗艾滋病活性的化合物DidemnaketalsAC(1)～C(8)片段,(3S,5R,6S)-3-甲基-5,6-丙酮化物-7-氧代-辛酸甲酯及其6R异构体。     

Total synthesis of (-)-21-isopentenylpaxilline

[structure: see text] The total synthesis of (-)-21-isopentenylpaxilline (1) has been achieved. Key elements of the synthesis include the stereocontrolled construction of the advanced eastern hemisphere (-)-5, a highly efficient union of the eastern and western fragments (-)-5 and 4, respectively, exploiting our 2-substituted indole synthesis, and a new protocol for the construction of ring C.     

Hydrothermal Synthesis,Crystal Structure and Thermal Properties of a Novel Samarium Complex with 1D Nano-chain Structure

1 Introduction The design and construction of metal-organic polymers has been a field of rapid growth in materials chemistry because of their intriguing topologies and potential applications as functional materials[1―6]. In     

Synthesis of 2-(4-Aminocarbonyl-2-thiazoyl)-1,4-anhydro-D-ribitol,and-D-arabitol

The syntheses of 2-(4-aminocarbonyl-2-thiazoyl)-1,4-anhydro-D-ribitol 10 and 2-(4-aminocarbonyl-2-thiazoyl)-1,4-anhydro-D-arabitol 11 have been accomplished via the construction of thiazoyl moiety from the cyanohydrins 2 and 3.     

Total synthesis of 10-norparvulenone and of O-methylasparvenone using a xanthate-mediated free radical addition-cyclization sequence

[reaction: see text] A short synthesis of (+/-)-10-norparvulenone and (+/-)-O-methylasparvenone was developed starting from commercially available m-methoxyphenol, hinging on a xanthate-mediated addition-cyclization sequence for the construction of the alpha-tetralone subunit.     

An expedient route to the Calabar bean alkaloids (-)-physovenine and (-)-physostigmine

An expedient route to the Calabar bean alkaloids (-)-physovenine and (-)-physostigmine has been devised using a chiral building block which was originally designed for diastereocontrolled construction of aldohexoses.     

Synthesis of indolo[1,2-f]phenanthridines from palladium-catalyzed reactions of arynes

A novel convenient approach for the construction of indolo[1,2-f]phenanthridine was developed from the reaction of arynes with 1-(2-bromophenyl)-1H-indole in the presence of palladium catalyst.     

Total syntheses of enantiomerically enriched R-(+)- and S-(-)-deplancheine

Total syntheses of indoloquinolizidine alkaloid (+/-)-, R-(+)-, and S-(-)-deplancheine are described here. The synthesis features an enantioselective intramolecular formal aza-[3 + 3] cycloaddition for the construction of the quinolizidine CD-ring. This application serves to introduce a new synthetic strategy for the synthesis of indoloquinolizidine alkaloids.     

Maltodextrins as new chiral selectors in the design of potentiometric, enantioselective membrane electrodes

Maltodextrins (dextrose equivalent (DE) 4.0-7.0, 13.0-17.0, and 16.5-19.5) are proposed as novel chiral selectors for the construction of potentiometric, enantioselective membrane electrodes. The potentiometric, enantioselective membrane electrodes can be used reliably for the assay of S-captopril as raw material and in pharmaceutical formulations such as Novocaptopril tablets, by use of direct potentiometry. The best response was obtained when maltodextrin with higher DE was used for construction of the electrode. The best enantioselectivity and time-stability was achieved for the lower DE maltodextrin. L-proline was found to be the main interferent for all the proposed electrodes. The surface of the electrodes can be regenerated by simply polishing; this furnishes a fresh surface ready for use in a new assay.     

Eco-friendly synthesis of 1,8-naphthyridine 5-aryl-1,3,4-oxadiazole derivatives under solvent-free solid-state conditions and their antimicrobial activity

Research on Chemical Intermediates - A simple and highly efficient green synthetic procedure has been described for the construction of...     

Total synthesis of everninomicin 13,384-1--Part 3: synthesis of the DE fragment and completion of the total synthesis

The stereoselective construction of the DE fragment (2) of everninomicin 13,384-1 (1) is reported. From the two possible ways of inserting the DE fragment between the A1B(A)C and FGHA2 domains of the natural product, the sequence involving the DEFGHA2 segment was found to be the most viable. This coupling was followed by attachment of a suitably protected and activated A1B(A)C fragment which led, after orthoester construction and final deprotection to the targeted everninomicin 13,384-1 (1), completing the total synthesis of this complex naturally occurring substance.     

Aza-Prins-pinacol approach to 7-azabicyclo[2.2.1]heptanes: syntheses of (+/-)-epibatidine and (+/-)-epiboxidine

The syntheses of (+/-)-epibatidine and (+/-)-epiboxidine have been accomplished from commercial 2-methoxy-3,4-dihydro-2H-pyran. A recently developed aza-Prins-pinacol rearrangement was employed for the construction of the key 7-azabicyclo[2.2.1]heptane skeleton of these targets.     

General approach for the stereocontrolled construction of the beta-lactam ring in amino acid-derived 4-alkyl-4-carboxy-2-azetidinones

The first general approach toward the asymmetric synthesis of 4-alkyl-4-carboxy-2-azetidinones derived from amino acids is described. The stereoselective construction of the beta-lactam ring was achieved through base-mediated intramolecular cyclization of the corresponding N(alpha)-chloroacetyl derivatives bearing (+)- or (-)-10-(N,N-dicyclohexylsulfamoyl)isoborneol as chiral auxiliary (ee up to 82%).     

Solid-phase synthesis of indolizidine and quinolizidine derivatives

An efficient method for the construction of simple indolizidine and quinolizidine derivatives on solid support has been developed. An intramolecular tandem Michael reaction initiated by the nucleophilic attack of a suitably placed amino group on the tethered Wittig condensation products between 4- or 5-aminoaldehydes attached to a trityl chloride resin and 4-[(4-methylphenyl)sulfonyl]-1-(triphenylphosphoranylidene)-2-b utanon e is the key step.     

An expeditious protocol for synthesis of Baylis–Hillman derived piperazine derivatives and evaluation of their AChE inhibition

Research on Chemical Intermediates - The highly efficient and eco-economical “on water” method has been developed for the rapid construction of highly functionalized...     

Catalyst-controlled regiodivergent 1,2-difunctionalization of alkenes with two carbon-based electrophiles

Regiodivergent catalysis provides an efficient strategic approach for the construction of architecturally different molecules from the same starting materials. In this field, the intermolecular regiodivergent 1,2-difunctionalization of alkenes with two electrophiles is still a challenging task. A ligand-controlled, nickel-catalyzed regiodivergent dicarbofunctionalization of alkenes using both aryl/vinyl halides and acetals as electrophiles under mild reductive reaction conditions has been accomplished. This study provides a general approach to accessing both β-methoxyl esters and γ-methoxyl esters from readily available acrylates,aryl halides and acetals. Experimental mechanistic evidence supports that the difference in regioselective outcomes is attributed to the ligand tuning the reactivity of the nickel catalyst, which results in different catalytic cycles operating for these two reaction conditions.     

Effects of Anchimeric Assistance in Phosphonium Enolates Chemistry

Russian Journal of General Chemistry - Phosphonium enolates are key intermediates of phosphine-catalyzed reactions extensively used in current organic synthesis for construction of...     

Synthesis of 5-Substituted-3-[ (2＇R,4＇R)-4＇-Hydroxy-2＇-hydroxymethyl tetrahydrofuran-4＇-yl ]-1,2,4-oxadiazoles and Their Epimers

The syntheses of 5-substituted-3-[(2＇ R＇ 4＇ R)-4v -hydroxy-2＇-hydroxymethyltetrahydrofuran-4＇-yl]-1, 2,4-oxadiazoles and their epimers were accomplished with the aid of the construction of 1, 2, 4-oxadiazoles by condensation of O-acylated cyanohydrins with hydroxylamine via intramolecular transacylation and subsequent cyclization.     

Total synthesis of (-)-histrionicotoxin 285A and (-)-perhydrohistrionicotoxin

Starting from commercially available ( S)-glycidol, and via a common intermediate, the total synthesis of (-)-histrionicotoxin 285A and (-)-perhydrohistrionicotoxin has been achieved. Key to this synthesis was the efficient construction of a six-membered, chiral, cyclic nitrone.