A convenient method for the synthesis of substituted thioureas

A convenient method for the synthesis of substituted thioureas by the reaction of primary amines with molybdenum dialkyl dithiocarbamates has been developed. Primary amines on reaction with 0.5 equiv of molybdenum xanthate produce the corresponding thioureas in moderate to good yields in short times. Similar reactions with propargylamine or 2-aminoethanol produce cyclic thiaoxazolidine and oxazolidine derivatives, respectively.     

A convenient one-pot synthesis of substituted 2-pyrone derivatives

2-Pyrone derivatives were prepared in a one step procedure from readily available (chlorocarbonyl)phenyl ketene and 1,3-diketones such as 2,4-pentanedione, 1,3-diphenyl-1,3-propanedione, 1-phenyl-1,3-butanedione, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-dimethyl-pyrimidine-2,4,6-trione and ethyl 2,4-dioxopentanoate. A mechanism is presented to account for the formation of the products. This method provides an easy route to prepare 3,4,5,6-tetrasubstituted 2-pyrones in good to excellent yields and in a short experimental time.     

金属催化合成呋喃衍生物的最新进展

综述了近几年来利用金属催化合成多取代呋喃环的方法。分两大类介绍：一是通过对呋喃环进行结构改造,即呋喃金属试剂在过渡金属催化下与卤化物或酰氯发生偶联反应得到,或呋喃卤化物与金属试剂、烯烃、炔烃偶联得到;二是以非环状化合物为前体进行呋喃环的构筑,即在金属试剂催化下,1,2-联烯基酮、β-碘代-β-烯酮、叁键在α,β-、β,γ-、γ,δ-的炔酮、4-炔-2-烯醇可以关环得到多取代的呋喃产物。此外,在Ru~2(OAc)~4催化下,α-叠氮酮与炔烃反应得到金属卡宾中间体,然后关环也可得到取代呋喃产物。     

A convenient synthesis of substituted γ-pyrones

An efficient and general synthetic method for various 2-mono- and 2,6-disubstituted γ-pyrones has been developed. This utilizes the $\text{C}$-acylation (70–85%) of β-methoxy-α,β-enone lithium enolates $\text{4}$ by acid chlorides $\text{3}$ followed by the acid-catalyzed cyclization (>80%) of the resulting enols $\text{5}$ to γ-pyrones $\text{6}$.     

A novel and convenient method for the synthesis of substituted naphthostyrils

3-Pyrrolyl-6-fluoro-naphthostyril 13 was synthesized via a base-catalyzed intramolecular cyclization of oxindole precursor 2 (Y=H). Derivatization of 2 (Y=I) through a one-pot reaction give 5-substituted naphthostyrils. This method allows convenient access to 3,5,6-trisubstituted naphthostyrils which may serve as a new template for CDK2 inhibition.     

New synthesis of substituted isoindolines from furans via epoxyisoindolines

The preparation of substituted N-arylisoindolines 3 from simple furan derivatives 1 is reported. Oxatricycloadducts 2, readily accessible by intramolecular Diels-Alder reaction are susceptible to acidic reagents yielding aromatized products 3 by a ring-opening reaction via intermediate carbocation.     

A convenient synthesis of a substituted phthalocyanine compound

A new substituted tetra-(4-octanethiol-5-nitro)phthalocyaninatocopper complex was synthesized by nucleophlic substitution of tetra-(4-bromo-5-nitro)phthalocyaninatocopper where the bromo activated by an ortho-nitro group is easily substituted by 1-octanethiol.     

A new and convenient synthesis of substituted benzobarrelenes

Bromination of 3-bromo-6,7-benzobicyclo [3.2.1] octa-2,6-diene at ?50°C gave anti-tribromo adduct (5) in essentially quantitative yield. The double dehydrobromination of (5) was achieved using potassium tert.- butoxide to give 2-bromo-benzobarrelene (7). Reaction of (7) with n-BuLi and subsequent quenching with CH₃I, CO₂, and dimethylformamide afforded the corresponding substituted benzobarrelenes in high yield.     

Indium-mediated allenylation of arylacyl bromides in a route for the synthesis of substituted furans

A three-step, single purification procedure has been developed for the concise synthesis of substituted furans from arylacyl bromides.     

Indium trichloride catalyzed efficient one-pot synthesis of highly substituted furans

A one-pot synthesis of the substituted furans 3 could be achieved in good yields by reacting but-2-ene-1,4-diones 1 with acetoacetates 2 in the presence of a catalytic amount of InCl₃ (20 mol %) using i-PrOH as solvent at 80-90 °C for 4-8 h. InCl₃ was observed to give the optimum results among the various Lewis acids examined.     

Gold(I)-catalyzed synthesis of highly substituted furans

Cationic triphenylphosphinegold(I) complexes are excellent catalysts for a cascade reaction of propargyl-Claisen rearrangement and heterocyclization to synthesize tri- and tetrasubstituted furans. Starting from easily accessed propargyl vinyl ethers, the furans are obtained in 72-99% yield. [reaction: see text]     

Solution-phase synthesis of 2-cyano and 2-amido aziridinyl peptides

Starting from a library of 2-l-α-amino acyl (E)-acrylonitriles, different short 2-cyano and 2-amido aziridinyl peptides, potential protease inhibitors, were obtained under parallel solution-phase conditions. The transformations include careful selection of conditions for aziridine deprotection and cyano group partial hydrolysis.     

A convenient synthesis of 4-aminoaryl substituted cyclic imides

An efficient one-step synthesis of 4-nitro-N-aryl substituted glutarimides, succinimides and maleimides in polyphosphoric acid is described together with the subsequent reduction to the corresponding anilines. The scope and limitation of this cyclocondensation are presented.     

A convenient sonochemical synthesis of vicinally substituted 3-hydroxylaminopyridines

A method of synthesis of vicinally substituted N-(3-pyridyl)hydroxylamines by reducing the corresponding nitropyridines with Zn/NH₄Cl/EtOH under ultrasonication is proposed. Ultrasound irradiation increases the yields of these hydroxylamines and facilitates their isolation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 365–367, February, 1993.     

A convenient preparation of 3-substituted furans: synthesis of perillene and dendrolasin

A variety of 3-substituted furans, including the natural products perillene and dendrolasin, are obtained in good yield via reductive annulation of 1,1,1-trichloroethyl propargyl ethers using catalytic Cr(II) regenerated by Mn/TMSCl. [reaction: see text]     

A convenient synthesis of substituted piperazines via aminomercuration-demercuration of diallylamines

cis and trans-2,6-Bis[bromomercuriomethyl]piperazines II which bear equal or different substituents at each nitrogen are obtained in the reaction of N-substituted diallylamines with mercury(II) acetate and aryl-amines followed by a double decomposition process with potassium bromide. Their reduction with sodium borohydride lead to the corresponding 1,4-disubstituted cis- and trans-2,6-dimethylpiperazines III. Steric factors account for the remarkable stereoselectivity observed in the preparation of compounds IIIi-IIIn in which a 3:1 cis to trans isomer ratio is found.     

A convenient method for the synthesis of substituted 2-alkylthio-3-cyano-4,6-dimethyl-5-phenylcarbamoyl-1,4-dihydropyridines

Substituted 2-alkylthio-3-cyano-4,6-dimethyl-5-phenylcarbamoyl-1,4-dihydropyridines were obtained by successive reaction of acetaldehyde with cyanothioacetamide and acetoacetanilide, -chloracetamide or phenacyl bromide in the presence of piperidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 345–347, March, 2000.     

A convenient synthesis of substituted 3-bromotetrahydrofurans from homoallylic alcohols

Substituted 3-bromotetrahydrofurans were prepared from homoallylic alcohols via bromination and cyclization in methanol in the presence of potassium carbonate.     

Palladium-catalyzed one-pot synthesis of highly substituted furans by a three-component annulation reaction

A new three-component cyclization-coupling reaction catalyzed by palladium was developed, producing polysubstituted furans in good yields from readily available substrates. The reaction conditions and the scope of the process were examined, and a possible mechanism is proposed.