Palladium-catalyzed stereoselective decarboxylative[4+2]cyclization of 2-methylidenetrimethylene carbonates with pyrrolidone-derived enones:Straightforward access to chiral tetrahydropyran-fused spiro-pyrrolidine-2,3-diones

A novel asymmetric[4+2]cycloaddition of 2-methylidenetrimethylene carbonate with pyrrolidonederived enones has been achieved to produce the functionalized tetrahydropyran-fused spirocyclic scaffolds via palladium-catalysis.An array of enantioenriched spiro-pyrrolidine-2,3-diones bearing adjacent quaternary and tertiary stereocenters are obtained in high yields with excellent enantioselectivities(up to 96% yield and 99% ee).The further transformation of the product has been accomplished for the construction of medical interesting β^(2,2)-amino acids and β-lactams.Preliminary mechanistic research was well conducted.

Selective O-difluoromethylation of 1,3-diones using S-(difluoromethyl) sulfonium salt

A facile and highly efficient approach for selective O-difluoromethylation of 1,3-diones by recently developed bench-stable S-(difluoromethyl)sulfonium salt was described.And a broad range of difluoromthyl enol ethers were readily accessed in good to excellent yields under mild reaction conditions.Mechanistic studies revealed that the O-difluoromethylation reaction proceeds mainly via a difluorocarbene pathway.

Microwave-promoted Beller Synthesis of N-Substituted 2,3,3a,4,7,7a-Hexahydroisoindole-1,3-diones

A rapid and facile synthesis of N-substituted 2,3,3a,4,7,7a-hexahydroisoindole-l,3-dione derivatives via microwave-promoted Beller three-component domino reaction of α,β,-unsaturated aldehydes, amides and N-substituted maleimides was described.

6,7-dichlorobenzo[de]isochromene-1,3-dione的合成新方法

本文报道了6,7-dichlorobenzo[de]isochromene-1,3-dione的合成新方法。该路线简单易行,后处理方便,且产率较高,有较高的实用价值。

Cobalt-Catalyzed Switchable[4+1]and[4+1+1]Spirocyclization of Aromatic Amides with 2-Diazo-1H-indene-1,3(2H)-dione:Access to Spiro Indene-2,1'-isoindolinones and Spiro Isochroman-3,1'-isoindolinones

Herein,we report a condition-controlled divergent synthesis of spiro indene-2,1'-isoindolinones and spiro isochroman-3,1'-isoindolinones through cobalt-catalyzed formal[4+1]and[4+1+1]spirocyclization of aromatic amides with 2-diazo-1H-indene-1,3(2H)-dione.When the reaction is carried out under air in ethyl acetate,spiro indene-2,1'-isoindolinones are formed through Co(II)-catalyzed C—H/N—H[4+1]spirocyclization.When the reaction is run under O2 in CH3CN,on the other hand,spiro isochroman-3,1'-isoindolinones are generated through Baeyer-Villiger oxidation of the in situ formed spiro indene-2,1'-isoindolinones with O2 as a cheaper and environmental-friendly oxygen source.In general,these protocols have advantages such as using non-precious and earth-abundant metal catalyst,no extra additive,high efficiency and regioselectivity.A gram-scale synthesis and the removal of the directing group further highlight its utility.

Synthesis and Crystal Structure of a New Penta-coordinated Cu(Ⅱ) Complex:Cu(C_(17)H_(13)F_3O_3)_2·C_5H_5N

A new copper（II） complex 3, Cu（C17H13F3O3）2·C5H5N, has been synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group C2/c with a = 17.8511（7）, b = 17.4136（7）, c = 13.9425（7） A, β = 124.4830（10）°, V = 3572.5（3） A^3, Z = 4, C39H29CuF6NO6, Mr = 785.17,/7（000） = 1604, T = 292（2） K, Dc = 1.460 g/cm^3 and p = 0.691 mm^-1. The structure was refined to R = 0.0477 and wR = 0.1110 for 2935 observed reflections with I 〉 2σ（I）. For the title compound, X-ray analysis reveals that the copper（II） is penta-coordinated by four oxygen atoms from the corresponding 1-（4-（benzyloxy）phenyl）-4,4,4-trifluorobutane-1,3-dione ligands and one nitrogen atom of pyridine, forming a distorted square pyramidal geometry. It is found that the trifluoromethyl group, F（1）/F（1＇）, F（2）/F（2＇） and F（3）/F（3＇））, is disordered over two orientations in an approximate 3：1 ratio.

Facile synthesis of[1,2,4]triazino[4,3-b][1,2,4,5]tetrazepin derivatives by a one-pot reactions using 4-amino-3-hydrazinyl-6-methyl-1,2,4-triazin-5(4H)-one

4-Amino-3-mercapto-6-methyl-l,2,4-triazin-5（4H）-one 1 converted to 4-amino-6-methy-3-（methylthio）-1,2,4-triazin-5（4H）-one by methylation with methyl iodide.Controlled hydrazination of the resulting compound afforded 4-amino-3-hydrazinyl-6- methyl-l,2,4-triazin-5（4H）-one 2 as a building block,to the synthesis of some novel derivatives of[1,2,4]triazino- [4,3,b][1,2,4,5]tetrazepine 3-6,by the reaction with 3-chloropentane-2,4-dione,chloro acetonitrile,1,3-dichloroacetone,and methyl bromoacetate.This general synthetic procedure can be extended to the preparation of wide variety of tetrazepines using 1,2- bielectrophiles derivatives.

One stone three birds:Ni-catalyzed asymmetric allenylic substitution of allenic ethers,hydroalkylation of 1,3-enynes and double alkylation of enynyl ethers

The development of low-cost,earth-abundant and environmentally benign transition metal catalysts,which can catalyze multiple different types of asymmetric reactions,is an important objective in mod-ern asymmetric catalysis.Herein we demonstrate that a chiral Ni/P-Phos catalyst achieves three types of asymmetric reactions:allenylic substitution of racemic allenic ethers,1,4-hydroalkylation of prochiral 1,3-enynes and double alkylation of newly designed enynyl ether reagents.Three methods complement each other and produce various axially chiral allene derivatives bearing a pyrazolidine-3,5-dione unit,which is widely present in drugs and biologically active molecules with versatile pharmacological activities.

One-pot Synthesis of lO-Methyl-1,2,3,4,5,6,7,8,9,10-decahydroacridine-l,8-dione Derivatives under Microwave Heating without Catalyst

A series of 10-methyl-1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8-dione derivatives were synthesized by one-pot reaction of aldehyde, dimedone or 1,3-cyclohexanedione and methylamine in glycol or water under microwave heating without catalyst. The method has the advantage of short routine and reaction time, high yields as well as friendly environment. And the reaction was not only suitable for aliphatic and aromatic monoaldehyde, but also for aromatic dialdehyde.

An Efficient Synthesis of 3,3＇,4,4＇-Tetrahydro-4,4＇-bibenzo- [e][1,3]oxazine-2,2＇-dione Derivatives with the Aid of Low-valent Titanium

Synthesis of 3,3＇,4,4＇-tetrahydro-4,4＇-bibenzo[e][1,3]oxazine-2,2＇-diones via reaction of salicylidendphenylhy- drazone and triphosgene with the aid of low-valent titanium reagent is described. This method has the advantages of accessible starting materials, good yields and short reaction time.

Synthesis and Characterization of New 3-（3-Hydroxyphenyl）-4- alkyl-3,4-dihydrobenzo[e][1,3]oxazepine-1,5-dione Compounds

A series of 3-（3-hydroxyphenyl）-4-alkyl-3,4-dihydrobenzo[e][1,3]oxazepine-l,5-dione compounds with general formula CnH2n＋1CNO（CO）2C6H4（C6HnOH） in which n are even parity numbers from 2 to 18. The structure deter- minations on these compounds were performed by FT-IR spectroscopy which indicated that the terminal alkyl chain attached to the oxazepine ring was fully extended. Conforrnational analysis in DMSO at ambient temperature was carried out for the first time via high resolution 1H NMR and 13C NMR spectroscopy.

Convenient Synthesis of Spiro[benzo[d]pyrrolo[2,1-b]thiazole- 3,2＇-indenes] Derivatives via Three-Component Reaction

The three-component reaction of N-phenacylbenzothiazolium bromides, aromatic aldehydes and indane-l,3- dione in ethanol at room temperature in the presence of triethylamine as base afforded functionalized spiro[benzo- [d]pyrrolo[2,1-b]thiazole-3,2＇-indenes] in good yields and with high diastereoselectivity. The 1H NMR data and sin- gle crystal structure clearly indicated that the obtained spiro compounds predominately have one diastereoisomer.

Catalyst-free and atom-economical 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines:Facile synthesis of isoquinoline-fused spirocycles

A highly efficient and environmentally benign 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines with 5-alkenyl thiazolones and 2-arylidenindane-1,3-diones is developed for the construction of congested quaternary spiro-carbon centers.All these transformations can be smoothly performed in ethanol at room temperature,providing a catalyst-free and atom-economical access to diversely substituted novel isoquinoline-fused spirocycles in almost quantitative yields with high diastereoselectivities.The promising anti-tumor activity of these structurally novel spirocyclic compounds is reported as well.

Synthesis of New 2-Phenylpyrano[3,2-b]phenothiazin- 4（6H）-one Derivatives

A new synthesis of 2-phenylpyrano[3,2-b]phenothiazin-4（6H）-one derivatives was reported. First 2,10-diacetyl-3-hydroxyphenothiazine （2） was converted into their benzoyloxy esters （3a--3j） using different aro- matic carboxylic acids in the presence of phosphorous oxychloride in pyridine. Benzoyloxy esters were converted into their 1,3-diones （4a--4j） by using dry KOH in pyridine via Baker-Venkataraman transformation reaction. The 1,3-diones thus obtained were cyclised to pyranophenothiazines （Sa--Sj） by refluxing in an acetic acid/HCl mixture.

Diastereoselective synthesis of spiro[chromane-3,30-indolines]and spiro[chromane-3,20-indenes]via DBU promoted formal[4+2]cycloaddition reaction

A new DBU-catalyzed formal[4+2]cycloaddition between ortho-hydroxyphenyl-substituted para-quinone methides and electron-deficient dienophiles including 3-methyleneoxindoles and 2-aryldeneindene-1,3-diones was established.A wide range of functionalized spiro[chromane-3,30-indolines]and spiro[chromane-3,20-indenes]were successfully synthesized in good yields and with high diastereoselectivity.The features of the reaction included readily available substrates,mild reaction conditions,convenient methodology and good functional group tolerance.

红葱的化学成分研究

目的研究红葱Eleutherine americana的化学成分。方法采用硅胶柱色谱、Sephadex LH-20柱色谱及重结晶等方法,分离纯化红葱的化学成分,通过MS、NMR等波谱技术确定化合物结构。结果确定了7个化合物的结构,分别为9-hydroxy-8-methoxy-1-methyl-1,3-dihydronaphtho[2,3-c]furan-4-O-β-D-glucopyranoside(1)、eleutherinoside A(2)、豆甾醇-3-O-β-D-葡萄糖苷(3)、kadsuric acid(4)、豆甾醇(5)、1,2-二羟基-8-甲氧基-3-甲基蒽醌(6)、9-methoxy-1,3-dimethyl-1H-naphtho[2,3-c]pyran-5,10-dione(7)。结论化合物1为新化合物,命名为红葱新苷。化合物3～5为首次从该植物中分离得到,化合物6和7为首次获得的新天然产物。

Iodine catalyzed synthesis of the chromene derivatives in one-pot

Iodine catalyzed one-pot reactions of salicylaldehyde and dimolecular 1H-indene-l,3（2H）-dione, barbituric acids, 4-hydro- xycoumarin, or 4-hydroxy-6-methylpyran-2-one were performed and provided a rapid, convenient and general approach to synthesize the chromene derivatives. 2-（11-Oxo-10,11-dihydroindeno[1,2-b]chromen-10-yl）-lH-indene-1,3（2H）-diones P1-P4 and 10-（4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl）-3-methylpyrano[4,3-b]chromen-1（1OH）-ones P8-P9 were unprecedentedly prepared and structurally identified by NMR and Mass. The confirmation of structure by single crystal X-ray crystallography is reported for P3.