One-pot synthesis of 2-substituted indoles from 2-aminobenzyl phosphonium salts. A formal total synthesis of arcyriacyanin A

The reaction of (2-aminobenzyl) triphenylphosphonium bromide with aromatic aldehydes or alpha,beta-unsaturated aldehydes under microwave-assisted conditions constitutes a new synthesis of 2-substituted indoles in high yields (81-97%) in a one-pot reaction. The adduct from indole-4-carboxaldehyde was an advanced intermediate in the synthesis of arcyriacyanin A.     

New multi-1,2,3-selenadiazole aromatic derivatives

The aromatic polyketones 3a-d are versatile compounds for the synthesis of the multi-1,2,3-selenadiazole aromatic derivatives 1a-d. The preparation starts with the reaction between the multi-bromomethylene benzene derivatives 2a-d and 4-hydroxy- acetophenone to give compounds 3a-d which are transformed through the reaction with semicarbazide hydrochloride or ethyl hydrazine carboxylate into the corresponding semicarbazones derivatives 4a-d or hydrazones 5a-d. The reaction with selenium dioxide leads to regiospecific ring closure of semicarbazones or hydrazones to give the multi- 1,2,3-selenadiazole aromatic derivatives in high yield.     

An Efficient Synthesis of 4‐Naphthylpyrimidin‐2‐amine Derivatives under Solvent‐Free Conditions

A simple, efficient, and mild protocol for the synthesis of 4‐naphthylpyrimidin‐2‐amine derivatives under solvent‐free conditions by the reaction of aromatic aldehydes (or 1‐naphthaldehyde), 2‐acetylnaphthalene (or aromatic ketones), guanidine carbonate, and sodium hydroxide was reported. The advantages of this protocol include short reaction time, mild reaction conditions, easy workup, high yields, and environmental friendliness.     

New many fold 1,2,3‐selenadiazole aromatic derivatives

The many fold aromatic ketones 2a‐d are versatile compounds for the synthesis of the many fold 1,2,3‐selenadiazole aromatic derivatives 5a‐d . The preparation starts with the reaction between the many fold bromomethylene benzene derivatives 1a‐d and 4‐hydroxyacetophenone, which are transformed through the reaction with semicarbazide hydrochloride or ethylhydrazine carboxylate into the corresponding semicarbazones derivatives 3a‐d or hydrazones 4a‐d . The reaction with selenium dioxide leads to regiospecific ring closure of semicarbazones or hydrazones to give the many fold 1,2,3‐selenadiazole aromatic derivatives in high yield.     

无溶剂条件下三聚氰胺-Br_3催化一锅法合成1-氨基烷基-2-萘酚(英文)

A facile and efficient method has been developed for the synthesis of 1-amidoalkyl-2-naphthols via the one-pot multi-component condensation of 2-naphthol with aromatic aldehydes and acetamide or thioacetamide in the presence of melamine-Br3 under solvent-free conditions. There are several advantages to this reaction, including high yields, short reaction time, and high catalytic efficiency.     

Synthesis of 2-amino-3-cyano 4-<Emphasis Type="Italic">H</Emphasis>-chromenes containing quinoline in water: computational study on substituent effects

An efficient, high yielding and environmentally benign strategy to the synthesis of new 2-amino-3-cyano-4-H-chromene derivatives, via one-pot three-component reaction involving malononitrile, various α- or β-naphthol and appropriate aromatic aldehydes including 2-chloroquinoline-3-carbaldehydes in the presence of morpholine in water, was achieved. During the development of the synthesis five new chromene derivatives were fruitfully synthesized. It was found that employing this approach, aromatic aldehydes bearing electron-withdrawing groups give higher yields of the corresponding products in shorter reaction times. This observation was in agreement with topological analysis of calculated electron density functions using density functional theory and quantum theory of atoms in molecules approaches.     

Aqueous Synthesis of N-Phenyl/alkyl-2-quinolinone-3-carboxylic Acids from Coumarin-3-carboxylic Acids

An efficient, ecofriendly aqueous synthesis of aromatic/aliphatic amines with coumarin-3-carboxylic acid in a one pot reaction in a sealed tube or InCl₃/ H₂O in open vessel to afford N-phenyl/alkyl-2-quinolinones is achieved. This method provides high yield of products in shorter time, making it a useful process for the synthesis of structurally diversified 2-quinolinones from corresponding coumarins.     

Solar thermochemical reactionsⅢ:A convenient one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles catalyzed by high surface area SiO_2 and induced by solar thermal energy

A simple,convenient and efficient method for the synthesis of 1,2,4,5-tetrasubstituted imidazole derivatives using benzoin,an aromatic aldehyde,an aromatic amine in the presence of ammonium acetate catalyzed by high surface area SiO_2 and induced by free solar thermal energy was reported.     

Straightforward three-component synthesis of diarylmethylpiperazines and 1,2-diarylethylpiperazines

Several functionalized diarylmethylpiperazines and 1,2-diarylethylpiperazines have been synthesized in moderate to high yield according to a one-step three-component coupling between an aromatic or a benzylic organozinc reagent, a piperazine derivative, and an aromatic aldehyde. The procedure can be extended to the synthesis of benzylpiperazine derivatives or β-arylethylpiperazines toward the use of paraformaldehyde or aliphatic aldehydes.     

Synthesis of poly(benzoxazinone)s by direct polycondensation of dicarboxylic acids with bis(anthranilic acid)s

A convenient method for the synthesis of poly(benzoxazinone)s of high molecular weights has been developed. These polymers were prepared readily by direct polycondensation of aromatic dicarboxylic acids containing phenyl ether structures with bis(anthranilic acid)s using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensations proceeded smoothly and were completed within several hours at 140°C to produce poly(benzoxazinone)s with inherent viscosities up to 2.6 dL/g. The synthesis of 2-substituted benzoxazinones by the reaction of aromatic carboxylic acids or dicarboxylic acid with anthranilic acid in PPMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(benzoxazinone)s showed 10% weight loss in air and nitrogen around at 440 and 460°C, respectively.     

Catalytic asymmetric synthesis of optically active allenes from terminal alkynes

CuBr and ZnI(2) have been developed as catalysts or subcatalysts for the efficient asymmetric synthesis of axially chiral allenols with up to 97% ee from readily available propargylic alcohols, aliphatic or aromatic aldehyde, pyrrolidine, and commerically available ligands. The alcohol unit in the terminal alkynes plays a very important role for ensuring high enantioselectivity via coordination.     

Highly selective reaction of alpha-halo-alpha,beta-unsaturated esters with ketones or aldehydes promoted by SmI2: an efficient alternative access to Baylis-Hillman adducts

A samarium diiodide promoted addition of aromatic or aliphatic beta-substituted-alpha-halo-alpha,beta-unsaturated esters 1 or 3 to both ketones (in THF) and aldehydes (in acetonitrile) led to (Z)-2-(1-hydroxyalkyl)-2,3-alkenoates 2 and 4 in good yields and very high stereoselectivity. This method constitutes an efficient and valuable alternative to the synthesis of Baylis-Hillman adducts. A mechanism is proposed to explain this transformation.     

Microwave-assisted four-component, one-pot condensation reaction: an efficient synthesis of annulated pyridines

A one-pot, effective synthesis of pyridines by a modified Kr?hnke procedure is described. Polysubstituted annulated pyridines were synthesized in high yields by four-component, one-pot cyclocondensation reactions of N-phenacylpyridinium bromide, aromatic aldehydes, acetophenones or cyclic ketones in the presence of ammonium acetate and acetic acid, assisted by microwave irradiation. In this procedure, cyclic ketones with two alpha-CH(2) groups yield annulated pyridines with additional alpha-benzylidene groups, which are derived in situ from double aldol condensation of cyclic ketones with two moles of aromatic aldehydes.     

2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate as an efficient coupling reagent for the amidation and phenylhydrazation of carboxylic acids at room temperature

The synthesis of amides and phenylhydrazides from the reaction of corresponding carboxylic acids with primary aliphatic, aromatic amines or phenylhydrazine in the presence of triethylamine or diisopropylethyl amine as a base using 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) proceeds smoothly under mild conditions to afford the corresponding amides or phenylhydrazides in good to high yields in ethyl acetate at room temperature.     

Iridium-catalyzed [2 + 2 + 2] cycloaddition of α,ω-diynes with nitriles

[Ir(cod)Cl](2)/DPPF or BINAP efficiently catalyzed the cycloaddition of α,ω-diynes with nitriles to give pyridines. The reaction can accommodate a very wide range of nitriles. Both aliphatic and aromatic nitriles smoothly reacted with α,ω-diynes to give pyridines. Ten equivalents of unactivated aliphatic nitrile were enough to give the product in high yield. Aliphatic nitriles bearing an acetal or amino moiety could be used for the reaction. The highly regioselective cycloaddition of unsymmetrical diyne bearing two different internal alkyne moieties was achieved. The observed regioselectivity could be reasonably explained by considering the different reactivities of the α-position in iridacyclopentadiene. Regioselective cycloaddition was successfully applied to the synthesis of terpyridine and quinquepyridine. This chemistry was extended to a new and efficient synthesis of oligoheteroarenes. Five aromatic or heteroaromatic rings were connected in a single operation. [Ir(cod)Cl](2)/chiral diphosphine catalyst can be applied to enantioselective synthesis. Kinetic resolution of the racemic secondary benzyl nitrile catalyzed by [Ir(cod)Cl](2)/SEGPHOS gave a central carbon chiral pyridine in 80% ee. The mechanism was analyzed on the basis of the B3LYP level of density functional calculations.     

芳烃酰基化后还原制备芳香醇的工艺进展

芳烃制备高附加值精细化学品芳香醇(9-芴甲醇),一直以来存在产物选择性低以及合成成本高等问题。基于此,本文主要综述了芳烃酰基化后还原合成芳香醇的工艺,包括第一步采用Friedel-Crafts酰基化反应、Vilsmeier-Haack反应、Reimer-Tiemann反应、Duff反应等过程将芳烃酰基化合成芳香醛/酮;第二步通过金属氢化物还原、催化加氢还原、活泼金属还原、Cannizarro反应、Meerwein-Ponndorf-Verley还原反应等过程将芳香醛/酮还原合成芳香醇。在总结和归纳各种工艺过程优缺点的基础上,提出了合理的芳香醇制备工艺,为9-芴甲醇产业化制备技术的开发提供帮助。     

Novel multicomponent one-pot synthesis of tetrahydro-1H-1,5-benzodiazepine-2-carboxamide derivatives

A new approach to the design of multicomponent reactions is introduced. As a result, the novel one-pot synthesis of 2,3,4,5-tetrahydro-1 H-1,5-benzodiazepine-2-carboxamide derivatives using an aromatic diamine, a linear or cyclic ketone, an isocyanide, and water in the presence of a catalytic amount of p-toluenesulfonic acid at ambient temperature in high yields is described.     

Radiation resistant amorphous–all aromatic polyarylene ether sulfones: Synthesis,characterization, and mechanical properties

The synthesis and characterization of amorphous, aromatic, polyaryl ethers has been investigated. Detailed synthesis procedures are provided. The main thrust of these activities was to synthesize polymers which could serve as castable amorphous matrix resins for carbonfiber composites and which would be highly resistant to radiation degradation. It was important that these polymers not contain any aliphatic groups in order to contrast their behavior with the commercially available Bisphenol-A polysulfones. The approach taken was to synthesize a series of statistical or random copolymers derived from hydroquinone and biphenol together with 4,4′-dichlorodiphenyl sulfone. In order to produce copolymers of high molecular weight, modified techniques were developed which utilized potassium carbonate as a weak base and N-methyl-2-pyrrolidone as the aprotic dipolar solvent. Detailed procedures are provided in this paper for the synthesis of high molecular weight copolymers of this type. In addition, stress-strain, dynamic mechanical properties and preliminary electron beam (e-beam) degradation studies are reported significantly. Improved mechanical property retention after e-beam exposure was observed with the all aromatic polyether sulfones.     

A convenient preparation of thioether functionalized porphyrins

This paper describes a convenient and high yielding three-step approach for the synthesis of trans-tetraphenylporphyrins possessing two thioethers in the ortho positions, which will facilitate the synthesis of more elaborate and complex porphyrin architectures. Their synthesis is realized by a double nucleophilic aromatic substitution of 2 equiv of a thiolate on 2,6-dichlorobenzaldehyde to generate a bis-thioether substituted benzaldehyde. This aldehyde is then condensed with 2 equiv of pyrrole to give a dipyrromethane, which in the final step reacts with an aromatic aldehyde to give a series of thioether-substituted trans-tetraphenylporphyrins.     

VO(acac)_2 catalyzed condensation of o-phenylenediamine with aromatic carboxylic acids/aldehydes under microwave radiation affording benzimidazoles

Vanadyl acetylacetonate,VO（acac）₂,has been found to be very effective catalyst for synthesis of a variety of benzimidazoles under solvent-free condition.The methodology involves the exposure of a mixture of o-phenylenediamine and a selected aromatic carboxylic acid/aldehyde to microwave radiation without the use of any solvent or supporting agents.The benzimidazoles were obtained in quick time with high yields.