合成重要中间体1,4位官能化化合物的简便方法

5,6-取代环烯醚2在乙腈的单重态氧反应有效的生成一系列1,4位官能化化合物3。1,4位官能化化合物为合成上重要的中间体。环烯醚2可以通过β-二酰基化合物1和1,3-二溴丙烷在稀碱(碳酸钾/丙酮)条件下缩合生成。     

A New Route to the Synthesis of Alpha-Alkyltetrahydrothiophene-1,1-Dioxide Compounds

Alpha-alkyltetrahydrothiophene-1,1-dioxide compounds have been prepared in relatively high yield through the reaction of 2-lithiotetrahydrothiophene-1,1-dioxide with primary alkyl halides.     

A New Route to Pyrrolidines: One-Step Cyclization of 1,4-Azido Alcohol Synthesis of 1,4-Dideoxy-1,4-Imino-L-Lyxitol

Several optically active 3,4-dihydroxy-2-hydroxymethyl pyrrolidines are potent α-glycosidase inhibitors; for example, 1,4-dideoxy-1,4-imino-D-lyxitol (1) is a powerful inhibitor of α-galactosidase.¹ Furthermore, pyrrolidine 1 can be easily converted into the indolizidine alkaloid swainsonine to which it is structurally related.² (-) Swainsonine exhibits α-D-mannosidase inhibitory activity and immunoregulatory activity. Certain swainsonine stereoisomers have glycosidase inhibitory activity as well, and therefore have attracted considerable interest.³ 1,4-Dideoxy-1,4-imino-L-lyxitol (2) (enantiomer of 1) could be of biological interest. This communication describes the first synthesis of 2, starting from D-ribonolactone.     

A Practical Route for the Synthesis of Prostaglandin D2 Metabolites

A convenient, efficient route for the total synthesis of 9α, 11β-dihydroxy-13,14-dihydro-15-oxo-PGF₂ 2, a new plasma metabolite of prostaglandin D₂ 1 is described.     

Fluorocontaining 1,3-Dicarbonyl Compounds in the Synthesis of Pyrimidine Derivatives

Hexafluoroacetylacetone reacts with urea (thiourea) to yield respectively 4,6-bis(hydroxy)-4,6-bis(trifluoromethyl)hexahydropyrimidin-2-one(thione). The dehydration of the products and also reaction of nonsymmetrical fluoroalkyl-containing 1,3-diketones with urea (thiourea) afford substituted pyrimidines. The condensation of fluorinated 3-oxoesters and 1,3-diketones with benzaldehyde and urea (thiourea) results in 5-alkoxycarbonyl(acyl)-4-hydroxy-2-oxo(thioxo)-6-phenyl-4-fluoroalkylhexahydropyrimidines that on dehydration furnish 5-alkoxycarbonyl(acyl)-2-oxo(thioxo)-4-phenyl-6-fluoroalkyltetrahydropyrimidines. Ethyl 7-nonafluorobutyl-5-phenyl-2,3-dihydrothiazolo[3,2-a]pyrimidine-6-carboxylate hydrobromide forms in reaction of dibromoethane with ethyl ether of 2-thioxo-4-phenyl-6-nonafluorobutyltetrahydropyrimidine.     

Regioselective Synthesis of New Triheterocyclic Compounds from 1,4-Benzodiazepine

As part of our program on the synthesis of new heterocyclic compounds, we report here a one-step synthesis of [1,2,4]triazolo[4,3-d][1,4]benzodiazepine 3 and [1,2,4]oxadiazolo[4,5-d][1,4]benzodiazepine 5 by 1,3-dipolar cycloaddition of nitrilimines and nitrile oxides with 1,4-benzodiazepines 1.     

邻芳基苯基膦酸酯的新合成路线

以磷酸苯酯为原料,经碱性重排、O-磺酰化和Suzuki偶联反应合成邻芳基苯基膦酸酯是一条方便合理的路线.     

A Convenient and Improved Procedure for the Cyanation of Enamines and 1,3-Dicarbonyl Compounds

The direct cyanation of enamines 2a-f using acylsubstituted cyanatobenzenes 1a-c and cyanatoanthraquinone 1d furnishes β-cyanoenamines 3a-f which upon hydrolysis afford the cyanoketones 4a,b. 2-Cyano-1,3-diketones 6a-c are obtained starting from compounds 5a-c and 1.     

A New Route for Synthesis of Entecavir

2-Amino-1,9-dihydro-9-[(1S,3R,4S)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopen tyl]-6H-purin-6-one (entecavir, Scheme 1) is a novel carbocyclic 2-deoxyguanosine analog drug which has potent and selective anti hepatitis B virus (HBV) activity1-3. Entecavir is also effective against lamivudine-resistant YMDD mutants4. The US Food and Drug Administration (FDA) approved entecavir as a new preferred drug for the treatment of HBV after lamivudine in March, 2005. Scheme 1 The structure o…     

A Concise Route to a Key Intermediate in the Total Synthesis of Sempervirine1

Enantiopure γ-amino and γ-hydroxy-β-ketosulfones have been synthesized in high yields from α-diazoketones derived from the α-amino and α-hydroxy acid chiral pools.     

1'-碘代二茂铁甲醛合成的新方法

二茂铁甲醛是有机合成化学中一个重要的中间体,利用它可以合成各种功能二茂铁衍生物.然而异环取代的二茂铁甲醛因合成难度较大使其应用受到限制,1'-碘代二茂铁甲醛分子内因为有较多的反应活性点,从而被广泛应用到功能金属有机分子的设计合成中.合成该物质的传统方法不仅路线长,且需要使用昂贵的金属有机试剂.我们利用改进后的合成方法,以二茂铁为起始原料经三步反应合成了1'-碘代二茂铁甲醛.该方法不仅缩短了合成路线,简化了反应条件,且避免使用苛刻的反应条件和贵重的有机锂(锡)试剂,是目前合成该化合物最简单的方法.     

A New Route for the Synthesis of Substituted Pyridazines

Condensation of 4‐acetyl‐5,6‐diphenyl‐2,3‐dihydropyridzin‐3‐one (1) with dimethylformamide dimethylacctal (DMFDMA) afforded the enaminone 2. This could be converted into the pyrazolylpyridazine derivative 4 on reaction with hydrazine hydrate and into pyridazinylpyridazinone 7a,b via coupling with aromatic diazonium salts and subsequent treatment with active methylene compounds. The reaction of 6 with dimethyl acetylenedicarboxylate in the presence of triphenylphosphine afforded the pyridazinylpyridazine derivative 8. Compound 1 converted into 9 upon reflux in acetic acid in the presence of ammonium acetate and afforded 10 on reflux in acetic acid.     

二茂铁基α—二酮合成的新途径

本文报道根据Corey和Seebach“羰基反应活性逆转”原理合成二茂铁基α-二酮的新途径。用锂化二茂铁基二噻烷与一个酯反应,再经HgCl_2-CdCO_3水解得到标题化合物。共合成16种酰基二茂铁基二噻烷和13种二茂铁基α-二酮化合物。除两种外,其余均为新二茂铁衍生物。所有产物的结构都由元素分析、IR和~1H NMR谱确定。本文讨论了反应中二茂铁衍生物在结构及性质上的特点和产物的IR和~1H NMR谱。     

Convenient and Short Route to a Key Intermediate in the Synthesis of Forskolin

The intermediate 2, previously used in several synthetic sequences toward forskolin (1), has been synthesized from enone 3. The key step in the sequence is the 1,3-oxidative rearrangement of the tertiary alcohol 5, which allowed the easy introduction of the keto group at C-6 of 2.     

A New Route for the Synthesis of N-Substituted Diketopiperazine Derivatives

Eight N-substituted diketopiperazines (DKPs) were synthesized by solid-phase protocols. The introduction of iminodiacetic acid (Ida) and followed another α-amino acid residue as the precursor of DKP framework made the present synthesis to be very facile and efficient.     

含硫—硫键的新型苯胺类化合物的合成

通过一条新的合成路线得到了一个已知化合物5-氨基-1,4-二氢苯唑并[d]-1',2'-二硫因(1). 同时成功地合成了一个新的类似化合物9-氨基-1,2,3,4,5,6,7,8-八氢-2,3,6,7-四硫代蒽(2). 目标化合物及其中间体的结构经¹H, ¹³C NMR, MS, IR确证, X单晶衍射测定了化合物9-硝基-1,2,3,4,5,6,7,8-八氢-2,3,6,7-四硫代蒽(10)的结构.     

反式-1,4-二芳基环己烷类液晶的合成及性能研究

合成了一系列反式－1，4－二芳基环己烷类液晶化合物，总收率11．0％－27．5％，较文献收率有显著提高；并用IR和1H NMR进行了结构鉴定，通过配方研究，发现该系列化合物具有低阈值的特性，应用前景广阔。