New Routes to Oxindole Derivatives

Summary. A new, practical synthesis of the antirheumatic oxindole derivative, tenidap, has been elaborated. The new approach has initiated studies on the mechanism of the acylation reactions of oxindoles. Methods have been developed for the synthesis of 1-[alkoxy(or aryloxy)carbonyl]- and 1,3-di[alkoxy(or aryloxy)carbonyl]oxindoles starting from oxindoles. The route designed for tenidap has provided a facile access to several analogues, too.On another front, new reaction conditions are described, which turn Wenkerts synthesis of 3-alkyloxindoles (by Raney nickel induced alkylation of oxindoles with alcohols) into a highly efficient synthetic tool. The method has been extended to the synthesis of 3-alkyloxindoles from isatins and to the preparation of 3-(-hydroxyalkyl)oxindoles from oxindoles and isatins.     

New Synthetic Routes to 1,3,4-Thiadiazole Derivatives

Different new 1,3,4-thiadiazolopyridine derivatives (6, 8, 20, 28, and 42) were synthesized from 5-cyanomethyl-1,3-4-thiadiazole (1) and activated nitriles. Also, spiro indolono-thiadiazolopyridine (12) was obtained from the reaction of (1) with 2-(2-oxoindolin-3-ylidene)malononitrile (10). Other heterocyclic derivatives at position-5 in the thiadiazole ring were obtained for possible use as antimicrobial agents.     

Novel One-Pot Synthesis of New Oxindole Derivatives Catalyzed by PTSA

The one-pot synthesis of spirooxindoles via three-component reaction of urea, isatin, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of p-toluenesulfonic acid in acetonitrile has been carried out.

An Efficient Synthesis for Some New Heterocyclic Compound‐fused Oxindole Derivatives

An efficient and rapid procedure for the synthesis of novel oxindole derivatives is described. The process employs a condensation reaction of 3‐(bis(methyl thio)methylene)indolin‐2‐one and dinucleophiles such as 1,2‐phenylene diamine, propylene diamine, 2‐aminoethanol, ethylene‐1,2‐dithiol, 2‐mercaptoethanol, (1S,2S)‐cyclohexane‐1,2‐diamine, 2‐aminoethanthiol, 2,3‐diaminomaleonitrile, 2‐aminobenzenethiol, (3,4‐diaminophenyl)(phenyl)methanone, and ethane‐1,2‐diole in the presence of triethylamine under solvent‐free conditions at 60°C.     

New Routes to Fused Isoquinolines

Treatment of 6,7‐diethoxy‐3,4‐dihydroisoquinoline ( 8 ) and its 1‐methyl derivative 12 with hydrazonoyl halides 10 in the presence of Et₃N in THF under reflux afforded the corresponding 5,6‐dihydro‐1,2,4‐triazolo[3,4‐a]isoquinolines 11 and 13 , respectively, in high yield (Schemes 2 and 3). The products are formed via regioselective 1,3‐dipolar cycloaddition of the intermediate nitrilimines 9 with the isoquinoline C=N bond. Reaction of 6,7‐diethoxy‐3,4‐dihydroisoquinoline‐1‐acetonitrile ( 4a ) with ethyl α‐cyanocinnamates 15 in the presence of piperidine in refluxing MeCN yielded benzo[a]quinolizin‐4‐ones 16 (Scheme 4). Under the same conditions, 12 and arylidene malononitriles 19 reacted to give benzo[a]quinolizin‐4‐imines 20 (Scheme 5). Instead of 15 and 19 , mixtures of an aromatic aldehyde, and ethyl cyanoacetate or malononitrile, respectively, can be used in a one‐pot reaction.     

New Routes to Multicomponent Oxide Glasses

Multicomponent oxide glasses can be produced not only by melting methods but also by hydrolysis and condensation of alkoxide complexes with several metals. This requires temperatures only up to the transformation range of the glass in question, usually 500–600 °C. The process does not pass through the molten phase. It is possible to obtain glasses or polycrystalline substances, depending on the composition. The method is particularly suitable for the production of thin, transparent multicomponent oxide layers of almost any composition on substrates. Some of these layers provide protection against climatic attack or against oxidation.     

Experimental and Theoretical Investigation of an Azaoxyallyl Cation-Templated Intramolecular Aryl Amination Leading to Oxindole Derivatives

Herein, development and detailed investigation of a S_N′-type intramolecular aromatic substitution reaction involving α-arylazaoxyallyl cation intermediate, is disclosed. The study showcased that while α-aryl-α-chlorohydroxamate could be activated by a combination of base and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) into the corresponding azaoxyallyl cations, it could further emerge into a π-extended species involving the adjacent α-aryl moiety, and this transition is contingent on electronic effects of the aromatic ring as well as on α-substituents. An effective activation of the α-aromatic ring could pave the path for intramolecular Ar(Csp²)-N bond formation towards oxindoles. Control experiments and DFT calculations suggested that a non-pericyclic nucleophilic amination pathway is most likely operative and precluded the possibility of concerted or electrophilic amination mechanism. HFIP as the reaction solvent plays pivotal roles in the transformation.     

Two New Oxindole Alkaloids from Ervatamia yunnanensis

ErvalanIiaYunnanensiSTsianghasbeenusedasafolkmedicineinChinaforthetreatmentofhypertensi0n'.Aspart0fourc0ntinuingpr0gramonthestudyofplant-derivedbioactivecomp0unds,thechemicaIconstituents0fE.yunnanensI1vgrowinginYunnanwereinvestigated.Intheprevi0uspaper,werep0rtedthestructuresofind0lealkal0ids;l9S-hydr0xy-tacamine,tabernaemontanine,l7-demethoxy-c0rynoxineB,l7-demethoxy-hydr0c0rynoxineB,20-epi-ervatamine,19,2O-dehydroervatamine,includinganewone,l9S-hydroxy-16-epi-tacaminefr0mthisspecies'.T…     

New Routes to (E)-Halophosphaalkenes

Abstract

Starting from dihalophosphaalkenes Mes?P=CHal₂ (Hal = Cl, Br, I) we have been developing methodologies for the synthesis of (E)-Mes?P=CHHal, which can be converted to reactive phosphaalkenyl metal reagents. Dibromophosphaalkene 1 was reacted with n-butyllithium at -120 °C, furnishing 2 after chlorination of the intermediate carbenoid. Compound 2 was transformed to the (E)-chlorophosphaalkene 3 as shown (SCHEME 1).     

Nucleophilic Addition of Oxindole to Pyrroloquinoxalinetriones

Russian Journal of Organic Chemistry - 3-Aroyl-5-phenylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones reacted with 2-oxindole to give products of addition of the C3H group of the enol form of...     

New Routes to Poly(Alkylene Sulfidoselenides)

A procedure was developed for preparing mixed poly(alkylene sulfidoselenides) by simultaneous dissolution of sulfur and selenium in basic reducing systems NaOH (KOH)-N₂H₄·H₂O-H₂O, followed by alkylation of the resulting solutions with bielectrophilic agents.     

Synthetic Routes to α-Aminoacids Derivatives. Part I. Carbomethoxylation of Metalated N-Nitrosoamines

N-nitrosoamines are well known to undergo α-metalation when treated with appropriate strong bases^1,2.     

Routes to New Aromatic Polycarbonates with Special Material Properties

Polycarbonate together with the acrylonitrile/butadiene/styrene copolymers, and the poly amides constitute the leading groups of engineering thermoplastics; for polycarbonate in particular, continued dynamic growth is prophesized. The underlying reason for this lies not only in its outstanding combination of technical properties and excellent price/performance balance, but also in the chemical and physical potential inherent in the basic structure of polycarbonate. The following review demonstrates with examples how this potential can be used in the development of new polycarbonates through the incorporation of alternative monomers, changes in the linear structure, end group variation, addition of special additives, and blending. The main emphasis of this articles lies in the development of polycarbonates resistant to high temperature, with a good balance of technologically valuable properties. For scientific and practical interests a new criterion is offered for polycarbonates having both high-temperature stability and impact strength. “One must not only make a discovery, but also realize that a discovery has been made.” Hermann Schnell [1]