Mild template synthesis of copper(II)-containing macrocyclic compounds in the CuII–1,2-diaminoethanedithione-1,2–ethanedione-1,2 and CuII–1,2-diamino-ethanedithione-1,2–butanedione-2,3 triple systems into Cu2[Fe(CN)6]-gelatin-immobilized matrix implantates

The complexing processes in the Cu^II–1,2-diaminoethanedithione-1,2–ethanedione-1,2 and Cu^II–1,2-diaminoethanedithione-1,2–butanedione-2,3 triple systems occuring in the copper(II)hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous alkaline solutions (pH~12) containing 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-1,2 under room temperature, and between MCl₂, 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-1,2 in the ethanol solutions, upon heating up to ~80 °C, have been studied. In both systems indicated, template synthesis occurs in the gelatin-immobililized matrix but does not occur in the ethanol solution. As a result of template synthesis, macrocyclic Cu^II chelates with 2,7-dithio-3,6-diazaoctadien-3,5-dithioamide-1,8 and its 4,5-dimethylsubstituted derivative are formed in the gelatin-immobililized matrix. 1,2-diaminoethanedithione-1,2 and ethanedione-1,2 or butanedione-2,3 are the ligand synthons in the processes indicated.     

Investigations in the imidazole series

The synthesis of derivatives of 2,3-dihydropyrrolo[1,2-a]imidazole from 1,2-dialkylimidazolines or 1,2-diarylkylimidazolines and phenacyl bromides with subsequent heating of the 1,2-disubstituted 3-phenacyl-imidazolinium bromides in aqueous or ethanolic solution in the presence of bases has been effected.For part XXXVIII, see [7].     

1,2和1,3-缩水内醚糖衍生物的制备, 构象及其糖苷化反应

吡喃糖的1,2-及1,3-缩水内醚苄醚由相应的吡喃糖的C-2氧负离子(对1,3-缩水内醚是C-3氧负离子)与连有氯原子的C-1经分子内关环反应而制备, 而有些吡喃糖的1,2-缩水内醚苄醚是由相应的吡喃糖的C-1氧负离子与连有对甲苯磺酰氧基的C-2经分子内关环(倒关环)反应而得。呋喃糖的1,2-缩水内醚苄醚只能用倒关环法合成。1,2-(或1,3-)缩水内醚糖的开环反应通常给出1,2-反式连接(对1,3缩水内醚是1,3反式连接)的糖苷键。1,2-及1,3-缩水内醚糖的构象分析是通过^1H NMR测定及分子力学计算的方法而完成的。     

Reductive metalation of 1,2-diaryl-substituted ethenes: synthetic applications

Reduction of 1,2-diaryl-substituted ethenes with Na metal in dry THF allowed easy access to a variety of 1,2-diaryl-1,2-disodiumethanes. These diorganometallic intermediates were elaborated into the corresponding 1,2-diarylethanes (aqueous work up), or cycloalkylated with 1,3-dichloropropanes. The last reaction led to a highly diastereoselective synthesis of trans-1,2-diaryl-substituted cyclopentanes.     

The Chemistry of Vicinal Diamines

Especially in the field of enantioselective synthesis , vicinal diamines (1,2-diamines) 1 and compounds easily prepared from them—such as 1,2-bisimines, 1,2-diamides, or imidazolidin-2-ones—are widely used by organic chemists. Various strategies have been developed to produce these compounds selectively. Many natural products and medicinal agents also contain a 1,2-diamino unit.     

Studies towards iodine-catalyzed dehydrative-cycloisomerization of pent-4-yne-1,2-diols to di- and tri-substituted furans

An efficient and single-step iodine catalyzed and metal-free synthesis of di and tri-substituted 2-methylfuran derivatives were achieved from 1-popargyl-1,2-diols. Stereospecific synthesis of starting 1,2-diols was achieved by indium mediated Barbier type propargylation on corresponding keto-alcohols or by sodium borohydride mediated reduction of 2-hydroxy-2-propargyl ketones. The furan synthesis proceeded through iodine mediated 5-exo-trig cyclization, dehydration and reductive deiodination. The method was applied to the synthesis of 2-methylfuran fused to phenanthrene, pyrene and acenaphthylene rings.     

二氧化碳与环氧化物的共聚反应

自1969年Inoue用ZnEt₂/H₂O的混合物作催化剂由二氧化碳与环氧化物合成聚碳酸酯以来,化学家们在催化剂体系的设计与合成方面进行了大量研究。目前,这条合成聚碳酸酯的绿色合成路线已日渐成熟。本文综述了近5年来环氧化物与二氧化碳反应合成聚碳酸酯的研究成果,主要考察催化剂的催化活性对共聚反应的影响以及反应机理研究。     

Reactions of 1,2-diaza-1,3-dienes with thiol derivatives: a versatile construction of nitrogen/sulfur containing heterocycles

The synthesis of substituted 2,3-dihydro-1,4-thiazines, fused cycloalkyl-1,4-thiazines, 1,4-benzothiazines and fused cycloalkyl-1,4-benzothiazines by 1,4-addition of 1,2-aminothiols to 1,2-diaza-1,3-dienes bearing carboxylate, carboxamide, or phosphorylated groups and subsequent internal heterocyclization is described. The reaction of carboxylated 1,2-diaza-1,3-butadienes with 2-(butylamino)ethanethiol affords 1,4-thiazinan-3-ones. The solid-phase reaction of polymer-bound 1,2-diaza-1,3-butadienes with 1,2-aminothiols produces 2,3-dihydro-1,4-thiazines and 1,4-benzothiazines.     

A new three-carbon synthon for efficient synthesis of benzannelated and 1-(2-arylethenyl) heterocycles

The novel three-carbon synthon 1-(1H-1,2, 3-benzotriazol-1-yl)-3-chloroacetone for the synthesis of benzothiazoles, pyrido[1,2-a]indoles, and styryl-substituted indolizines and imidazo[1,2-a]pyridines is reported. The proposed routes are a general and efficient approach for heterocyclizations followed by benzannelations or attachment of arylethenyl pharmacophores.     

Synthesis of substituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines and 4-oxo-3,4-dihydroquinazoline-2-thioles

We have developed a liquid-phase synthesis of combinatorial libraries of new disubstituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines and trisubstituted 4-oxo-3,4-dihydroquinazoline-2-thioles. The former were prepared using two general procedures: (i) cyclization of substituted methyl anthranilates with isothiocyanates, or (ii) cyclization of substituted 2-(methylcarboxy)benzeneisothiocyanates with primary amines or hydrazines. 4-Oxo-3,4-dihydroquinazoline-2-thioles were prepared by S-alkylation of disubstituted 4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazolines with alkyl or aryl halides. The hydrolysis of methyl benzimidazo[1,2-c]quinazoline-6(5H)-thione-3-carboxylate led to the corresponding acid. This acid was utilized in the synthesis of new benzimidazo[1,2-c]quinazoline-6(5H)-thione-3-carboxamide and S-substituted 6-mecaptobenzimidazo[1,2-c]quinazoline-3-carboxamide libraries.     

Synthesis of seven- and eight-membered [1,2-a] alicyclic ring-fused benzimidazoles and 3-aziridinylazepino[1,2-a]benzimidazolequinone as a potential antitumour agent

Azepino and azocino[1,2-a]benzimidazoles were obtained either by treatment of 1-nitrophenyl-2-azacycloalkanes via a one-pot catalytic hydrogenation/acetylation or by treatment of the acetamides generated in the latter reaction with performic acid. This represents the first facile synthesis of eight-membered [1,2-a] alicyclic ring-fused benzimidazoles. 3-Methoxy-azepino[1,2-a]benzimidazole was elaborated to the novel potential cytotoxin, 3-(N-aziridinyl)-7,8,9,10-tetrahydro-6H-azepino[1,2-a]benzimidazole-1,4-dione. The synthesis included clarification of the reactivity of methoxy-substituted benzimidazoles towards nitration.     

One-Pot Three-Component Synthesis of 3-Aminoimidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridines and -pyrazines in the Presence of Silica Sulfuric Acid

Summary. The synthesis of 3-aminoimidazo[1,2-a]pyridines and 3-aminoimidazo[1,2-a]pyrazines through a condensation reaction of 2-aminopyridine or 2-aminopyrazine, aldehyde, and alkyl or aryl isocyanide in high yields at room temperature in the presence of silica sulfuric acid is described.     

Functionalization of Heterocycles through 1,2-Metallate Rearrangement of Boronate Complexes

Over the last decade, 1,2-metallate rearrangement of boronate complex has been dominating the literature of organoboron chemistry for the construction of very important C−C and C−boron bonds. Owing to the coordinative unsaturated nature of the boron atom, a nucleophile can attack on boron center for the formation of a boronate complex, which triggers 1,2-migration under electrophilic activation at the α-carbon. Apart from using stochiometric electrophilic activating reagents, several catalytic methods using transition metals in the presence or absence of light have been reported. The 1,2-migration of boronate complexes allows synthesis of many different classes of racemic and chiral compounds including a wide range of substituted heterocycles. Synthesis of chiral and achiral substituted heterocycles by using 1,2-metallate rearrangement of boronate complexes has been extensively reported by several groups owing to its prevalence in medicinal chemistry. This minireview highlights the methods known to date for the synthesis of heteroaryls by using 1,2-migration of boronate complexes, organized in a chronological manner.     

Propriétés chimiques du benzisosélénazole-1,2

The nitration and the bromination of 1,2-benzisoselenazole give mono derivatives at 5- or 7-position. With potassium amide 3-amino-1,2-benzisoselenazole is obtained from the unsubstituted ring. We observe a ring opening by action of organolithium compounds. We describe also the synthesis of functional derivatives at the 3-position from 3-styryl-1,2-benzisoselenazole and selenonaphthenequinone.     

手性1,2-二苯基-1,2-乙二胺及其衍生物在不对称合成中的应用

含有C2 对称轴的1,2-二胺在不对称合成中得到了广泛的应用.综述了手性1,2-二苯基-1,2-乙二胺及其衍生物的合成,以及作为手性辅助基和手性配体在不对称合成中的应用.     

Highly efficient synthesis of 1,2-disubstituted acetylenes derivatives from the cross-coupling reactions of 1-bromoalkynes with organoalane reagents

A Highly efficient route for the synthesis of 1,2-disubstituted acetylene derivatives has been developed by palladium catalyzed cross-couplings of alkynyl halides with (hetero)aryl aluminium reagents under mild conditions. This has given corresponding cross-coupling products good to excellent isolated yields of up to 99%. The aryls bearing electron-donating or electron-withdrawing groups in either alkynylhalides or arylaluminum substrates gave cross-coupling products good yields. This process was simple and easily performed, which provides an efficient method for the synthesis of 1,2-disubstituted acetylenes derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.     

A mild and variable synthesis of α-ketoesters

The ZnCl₂ promoted addition of 1,2-diethoxy-1,2-disilyloxyethylene 1 with electrophiles such as aldehydes, ketones, α,β-unsaturated ketones or tertiary alkyl halides allows for a simple synthesis of α-ketoesters.     

A novel method of synthesis of 1,2-diketones from 1,2-diols using N-bromosuccinimide

A simple and convenient procedure is reported for the synthesis of benzils and aliphatic 1,2-diketones of cyclic and open chain compounds from corresponding hydrobenzoins and 1,2-diols by refluxing with N-bromosuccinimide in carbon tetrachloride in presence or absence of pyridine.     

Diversified assembly of perfluoroalkyl-substituted furans and 2,5-dihydrofuran-2-ols

We have developed a facile and effective synthesis of 3-iodofurans from 3-monosubstituted 1,2-allenyl perfluoroalkyl ketones or 2-hydroxy-4-iodo-2,5-dihydrofurans from 3,3-disubstituted 1,2-allenyl perfluoroalkyl ketones. The perfluoroalkyl substituent and the amount of water in the solvent are important for the success of this electrophilic cyclization.     

Building block synthesis of predominantly (E) symmetrical and unsymmetrical 1,2-difluorostilbenes from 1,2-dibromo-1,2-difluoroethene

An efficient synthesis of predominantly (E) symmetrical or unsymmetrical 1,2-difluorostilbenes based on the Suzuki–Miyaura palladium-catalyzed cross-coupling reaction of arylboronic acids with predominantly (E)-1,2-dibromo-1,2-difluoroethene in the presence of Cs₂CO₃ in toluene is described. The reaction preserved the stereochemistry of the building block and performed in good yield independently of the electron-withdrawing or electron-donating character of the substituents.