(Z)-Ethyl 2-phenyl-1-(2-vinylphenyl)vinylcarbamates. Part 1: Synthesis and preliminary studies on their divergent transformation into benzo[c]phenanthridines and 2-phenyl-1,4-naphthoquinones

Treatment of N-carbethoxy-1-benzylideneisoquinolines with LDA gives N-ethoxycarbonyl-1-amino-1-(2-vinylphenyl)-2-phenylethylenes, which can easily be transformed into N-carbethoxy-1-amino-2-phenylnaphthalenes. Bischler-Napieralski reaction of these latter compounds affords the corresponding benzo[c]phenanthridines, while their hydrolysis and subsequent oxidation constitutes a novel route to 2-phenyl-1,4-naphthoquinones.     

Cesium fluoride and tetra-n-butylammonium fluoride mediated 1,4-N-->O shift of disubstituted phenyl ring of a bicalutamide derivative

A novel 1,4-N→O migration of a disubstituted phenyl ring was observed during N-methylation of a bicalutamide derivative, (2S)-2-(tert-butyldimethylsilanyloxy)-N-(4-cyano-3-trifluoromethylphenyl)-3-(4-fluorophenoxy)-2-methylpropionamide, in the presence of CsF-Celite/acetonitrile and desilylation of (2S)-2-(tert-butyldimethylsilanyloxy)-N-(4-cyano-3-trifluoromethylphenyl)-3-(4-fluorophenoxy)-2,N-dimethylpropionamide in tetra-n-butylammonium fluoride/THF. Both NMR and X-ray analysis confirmed the structure of the 1,4-N→O disubstituted phenyl ring migrated product.     

Synthesis of N,N-diethyldithiocarbamate functionalized 1,4-polyisoprene, from natural rubber and synthetic 1,4-polyisoprene

N,N-Diethyldithiocarbamate functionnalized 1,4-polyisoprenes were prepared from 1,4-polyisoprenes (natural or synthetic). The syntheses were performed by nucleophilic addition of N,N-diethyldithiocarbamate salts upon oxirane rings of epoxidized units according to a SN2 mechanism with ring opening. Studies on model molecules of epoxidized 1,4-polyisoprene units (1,2-epoxy-1-methylcyclohexane and 4,5-epoxy-4-methyloctane) were previously achieved to develop the procedure. The best yields were obtained at low temperature in polar medium, and more especially in water with sodium N,N-diethyldithiocarbamate (DEDT-Na) as reagent. A diastereospecific addition was noted when reaction was performed in water with DEDT-Na. Afterwards, the developed procedure was successfully generalized to epoxidized synthetic polyisoprenes and epoxidized natural rubber (in THF, then in latex medium). Excellent results were obtained in latex medium with epoxidized natural rubber (ENR) latices. As with the models, a diastereospecific addition of sodium N,N-diethyldithiocarbamate trihydrate onto epoxidized 1,4-polyisoprene units of ENR was observed at the condition to bring the latex medium to pH 8 before introduction of DEDT-Na. Influence of temperature, drc, and DEDT-Na concentration were successively examined to determine the best conditions of the addition on ENR latices.     

Rapid access to 3-(N-substituted)-aminoquinolin-2(1H)-ones using palladium-catalyzed C-N bond coupling reaction

A series of 3-(N-substituted)-aminoquinolin-2(1H)-ones have been synthesized by the palladium-catalyzed C-N coupling reaction starting from 3-bromoquinolin-2-(1H)-ones. Various nucleophiles including amines, amides, sulfonamides, carbamates and ureas have been used successfully. In all the cases, the reactions take place rapidly in 1,4-dioxane and proceed in good to excellent yield using palladium acetate as a catalyst, Xantphos as a ligand and Cs₂CO₃ as a base.     

Voltammetric sensing of sugar by an electrode covered with wheat germ agglutinin/chitin film

The binding between wheat germ agglutinin (WGA) and N-acetylglucosamine at the electrode covered with chitin film was investigated with voltammetry. Chitin, β-1,4-poly-N-acetylglucosamine, is one of the biolpolymers which have a high biocompatibility. WGA is immobilized to the surface of chitin film by the affinity of WGA to N-acetylglucosamine residue of chitin. To investigate the binding event of WGA on the chitin modified electrode, N-acetylglucosamine labeled with an electroactive compound was prepared. The binding causes the changes in the electrode response of labeled sugar. The peak current of labeled sugar decreased due to the specific binding with WGA on the chitin film modified at the electrode. N-Acetylglucosamine was successfully determined by using the competitive reaction with labeled sugar to WGA on the chitin film electrode.     

Synthesis of N-linked glycan derived from Gram-negative bacterium, Campylobacter jejuni

Recent research has revealed the presence of asparagine (Asn)-linked (N-linked) glycoproteins in certain prokaryotes. In this paper, we describe the chemical synthesis of a novel N-glycan derived from Campylobacter jejuni, a heptasaccharide composed of Asn-linked bacillosamine (Bac), repeating GalNAc, and branching Glc, namely GalNAc-α(1,4)-GalNAc-α(1,4)-[Glc-β(1,3)-]GalNAc-α(1,4)-GalNAc-α(1,4)-GalNAc-α(1,3)-Bac. The synthesis started from a Bac-acceptor, which was consecutively glycosylated with 4-O-pentafluoropropionyl (PFP) protected donors to give heptasaccharide. Reduction of azide groups was followed by debenzylation to complete the synthesis of the target oligosaccharide.     

Synthesis of conjugated 2 and 2,5-(ethenyl) and (ethynyl)phenylethynyl thiophenes: fluorescence properties

Nano conjugated thienylethenyl and thienylethynyl compounds with controlled structure and dimensions have been efficiently prepared, by heterocoupling reaction between 1,4-(thienylethynyl)phenylacetylene (or thienylethenyl)phenylacetylene and 2- or 2,5-dihalothiophene. Conjugated 1,4-di(2-thienylethynylphenyl)- (or 2-thienylethenylphenyl)-1,3-butadiyne were obtained by the homocoupling of the terminal acetylenes in excellent yield. The end-capped (N,N-dimethylaminophenyl)- and [3,5-di(trimethylsilylethynyl)-1-ethynyl]-2,5-di(phenylethynyl)_nthiophene were obtained by the heterocoupling between the corresponding terminal acetylene and 2,5-di(iodo)thiophene, catalyzed by the bis(triphenylphosphine)palladium and cuprous iodide system in excellent yield.     

Synthesis and structure of N-(4-dialkylaminophenyl)hexafluoro-1,4-naphthoquinone 4-imines

The reaction of heptafluoro-1-naphthol with N,N-dialkyl-p-nitrosoanilines or N,N-dialkyl-p-phenylenediamines in the presence of HIO₃ gave the corresponding polyfluorinated N-aryl-1,4-naphthoquinone 4-imine derivatives which exist in solution as equilibrium mixtures of Z and E isomers. 2,3,5,6,7,8-Hexafluoro-N-(4-dimethylaminophenyl)-1,4-naphthoquinone 4-imine in crystal has exclusively the Z-isomer structure.     

Synthesis of a novel tetrahydroisoquinoline pentacyclic framework

N-Acyliminium cyclization of 6-substituted (3R^∗,6R^∗,11aS^∗)-3-arylmethyl-pyrazino[1,2-b]isoquinoline-1,4-diones gave with very good yields a novel tetrahydroisoquinoline pentacyclic core framework (29), while this reaction failed in all-cis-isomers to give instead conjugated enamines by deprotonation. Electronic and steric factors that govern the approach to both diastereomers from 6-substituted pyrazino[1,2-b]isoquinoline-1,4-diones have been studied.     

Reaction of (1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile with N-arylisoindolines

In a multistep reaction, 3,3′-(2-aryl-2H-isoindol-1,3-ylene)-di-(1,4-naphthoquinone-2-carbonitriles) 13a-f have been formed in 25-61% yield from a series of N-arylisoindolines 8a-f with (1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile (1) in aerated pyridine. The structure of one of these products (13f) has been unambiguously confirmed by a single crystal X-ray structure analysis. Under otherwise the same conditions, 2-(3-methoxyphenyl)-isoindoline (8g) and 1 gave 38% of [4-(2,3-dihydro-1H-isoindol-2-yl)-2-methoxyphenyl]-1,3-dioxoindan-2-ylidene)acetonitrile (15). Rationales for these conversions involving the known rearrangement of the radical anion of 1 into the radical anion of 1,4-naphthoquinone-2,3-dicarbonitrile (3) are presented.     

Synthesis of N-substituted 1,2,3,4-tetrahydrobenz[g]isoquinoline-5,10-diones

The synthesis of 1,2,3,4-tetrahydrobenz[g]isoquinoline-5,10-dione hydrochlorides is reported starting from 1,4-dihydrobenz[g]isoquinoline-3(2H)-ones or ethyl (3-aminomethyl-1,4-dimethoxynaphth-2-yl)acetates. A third strategy relies on the synthesis of the title compounds via an N-protected 2-(3-bromomethyl-1,4-dimethoxynaphth-2-yl)ethylamine. The synthesized 1,2,3,4-tetrahydro-benz[g]isoquinoline-5,10-diones are a new class of quinones, which have not been reported yet.     

New and clean synthesis of N-substituted pyrroles under microwave irradiation

N-Substituted homochiral pyrrole derivatives were synthesized by the ring-closure reaction of cis-1,4-dichloro-2-butene with various amine compounds on a silica surface under microwave irradiation.     

Thermal ring-opening reaction of N-polynitromethyl tetrazoles: facile generation of nitrilimines and their reactivity

Thermal ring-opening reaction of N-(R-dinitromethyl)-5-nitrotetrazoles (R=NO₂, F, Cl) yielded highly reactive N-(R-dinitromethyl)-nitrilimine intermediates under mild conditions. These species underwent facile and regiospecific reaction with nitriles and acetylenes to afford the corresponding nitrotriazoles and nitropyrazoles in 50-90% yields. Treatment of N-(chlorodinitromethyl)-5-nitrotetrazole with the excess of azide led to a unique compound with the molecular formula C₂N₁₄. Based on the analytical data, it was assigned a structure of diazidomethylenecarbonohydrazonic diazide.     

Reaction of N-arylcarbamoyl-1,4-benzoquinone imines with sodium azide

N-Arylcarbamoyl-1,4-benzoquinone imines reacted with sodium azide in completely regioselective fashion according to the 1,4-addition pattern with formation of 1-(3-azido-4-hydroxyphenyl)-3-arylureas. The reaction of N-arylcarbamoyl-2,6-dichloro-3,5-dimethyl-1,4-benzoquinone imines with sodium azide afforded N-arylcarbamoyl-2,6-diazido-3,5-dimethyl-1,4-benzoquinone imines as a result of nucleophilic substitution of the chlorine atoms.     

Synthesis of the end-capped 5-(N,N-dimethylamino)naphthyl-1-ethynyl derivatives and their 1,4-di[5-(N,N-dimethylamino)naphthyl]-1,3-butadiynes: anti rotamer structure

A new family of the end-capped 5-(N,N-dimethylamino)naphthylethynyl chains were synthesized, as terminal acetylenes or poly(yne) structures, by heterocoupling between 5-iodo-N,N-dimethylnaphthalen-1-amine and 2-methyl-3-butyn-2-ol or 4-(5-iodo-1-naphthyl)-2-methyl-3-butyn-2-ol, catalyzed by the palladium-copper system. Catalytic homocoupling of the terminal acetylenes, affords to 1,4-dinaphthyl-1,3-butadiyne nanostructures. X-ray diffraction analysis of 1,4-di(α-naphthyl)-1,3-butadiyne shows that the naphthalene rings are in the anti configuration along the acetylene axis. All the conjugated compounds show an important fluorescent emission radiation.     

Oxidative addition of trifluoromethanesulfonamide to cycloalkadienes

Reactions of trifluoromethanesulfonamide with cyclopentadiene, cyclohexa-1,3- and -1,4-dienes, cyclohepta-1,3,5-triene, and cycloocta-1,3-diene in the presence of t-BuOCl-NaI were studied. Trifluoromethanesulfonamide added at one double bond of cyclopentadiene and cyclohexa-1,3-diene in regio- and stereoselective fashion to give N-(5-iodocyclopent-2-en-1-yl)trifluoromethanesulfonamide and trans-N,N′-cyclohex-3-ene-1,2-diylbis(1,1,1-trifluoromethanesulfonamide), respectively. The reaction with cyclohexa-1,4-diene involved both isolated double bonds to produce N,N′-(2-chloro-5-iodocyclohexane-1,4-diyl)bis(1,1,1-trifluoromethanesulfonamide) which underwent halophilic reduction of the CHI group by the action of NaI and elimination of HCl, leading to N,N′-(cyclohex-2-ene-1,4-diyl)bis(1,1,1-trifluoromethanesulfonamide). Under analogous conditions, cyclohepta-1,3,5-triene was oxidized to benzaldehyde, while no reaction with trifluoromethanesulfonamide occurred.     

Microwave-assisted Hantzsch thiazole synthesis of N-phenyl-4-(6-phenylimidazo[2,1-b]thiazol-5-yl)thiazol-2-amines from the reaction of 2-chloro-1-(6-phenylimidazo[2,1-b]thiazol-5-yl)ethanones and thioureas

N-Phenyl-4-(6-phenylimidazo[2,1-b]thiazol-5-yl)thiazol-2-amines (6a-q) have been synthesized by the Hantzsch thiazole reaction of 2-chloro-1-(6-phenylimidazo[2,1-b]thiazol-5-yl)ethanones (4a-e) with suitably substituted thioureas using microwave heating. The ethanones (4a-e) were prepared by the reaction of 6-phenylimidazo[2,1-b]thiazoles (3a-e) with chloroacetylchloride in refluxing 1,4-dioxane whereas the thiazoles (3a-e) were synthesized by the reaction of 2-bromo-1-phenylethanones (2a-e) with thiazol-2-amine in refluxing acetone.     

Features and applications of reactions of α,β-unsaturated N-acylbenzotriazoles with amino compounds

Promoted by triethylamine, α,β-unsaturated N-acylbenzotriazoles reacted with amino compounds in a variety of ways. Thus, N-cinnamoylbenzotriazoles reacting with aromatic amines afforded novel addition products β-benzotriazolyl amides 3, which might be normally formed from the alternative but unknown 1,4-addition of benzotriazole to N-cinnamoylamides. The type 3 compounds could also result from the reaction between N-crotonoylbenzotriazole and aliphatic amines. However, normal 1,4-addition could occur between α,β-unsaturated aliphatic N-acylbenzotriazoles and aromatic amines, leading to β-amino N-acylbenzotriazoles 4 in good yields. In addition, exclusive 1,2-addition of aliphatic amines to N-cinnamoylbenzotriazoles gave excellent yields of cinnamides 5. Accordingly, three possible routes were proposed to rationalize the formation of compounds 3-5. Finally, with o-phenylenediamine and o-aminothiophenol as the substrates, the 1,4- and 1,2-addition to α,β-unsaturated N-acylbenzotriazoles could take place concurrently and the corresponding heterocycles 1,5-benzodiazepine-2-one and 1,5-benzothiazepine-4-one were constructed, respectively.     

Ugi three-component coupling reaction for the synthesis of 2-(6-oxo-11-phenyl-7,8-dihydrobenzo[b]pyrrolo[1,2-d][1,4]diazocin-5(6H)-yl)-2-phenylacetamide derivatives

A three-component, four center Ugi reaction of 3-(1-(2-aminophenyl)-5-phenyl-1H-pyrrol-2-yl)propanoic acid with aromatic aldehyde and t-butyl isocyanide has been achieved to produce a novel class of N-tert-butyl-2-(6-oxo-11-phenyl-7,8-dihydrobenzo[b]pyrrolo[1,2-d][1,4]diazacine-5(6H)-yl)-2-phenylacetamides in moderate to good yields.     

Oxidative trifluoroacetamidation of (1<Emphasis Type="Italic">E</Emphasis>,3<Emphasis Type="Italic">E</Emphasis>)-1,4-diphenylbuta-1,3-diene and 1,1,4,4-tetraphenylbuta-1,3-diene

Reactions of trifluoroacetamide with (1E,3E)-1,4-diphenylbuta-1,3-diene and 1,1,4,4-tetraphenylbuta-1,3-diene in the oxidative system t-BuOCl–NaI have been studied. The reaction with (1E,3E)-1,4-diphenylbuta-1,3-diene afforded three products, N,N′-(phenylmethylene)bis(trifluoroacetamide), 3-chloro-4-iodo- 2,5-diphenyl-1-(trifluoroacetyl)pyrrolidine, and trifluoro-N-[(3E)-2-hydroxy-1,4-diphenylbut-3-en-1-yl]acetamide, with a high overall yield. 1,1,4,4-Tetraphenylbuta-1,3-diene failed to react with trifluoroacetamide.