Reaction between alkyl isocyanides and 3-formylchromones in the presence of monocyclic unsaturated acyl compounds: Competition between Friedel-Crafts acylation and Diels-Alder cycloaddition

The highly reactive alkylaminofurochromenone intermediate, produced from the reaction between 3-formylchromones and alkyl isocyanides, was trapped by monocyclic unsaturated acyl compounds such as maleic anhydride or maleimide derivatives to yield new types of organic fluorophores 4-(alkylamino)-1H-furo[3,4-b]xanthene-1,3,10-triones or 4-(alkylamino)chromeno[2,3-f]isoindole-1,3,10(2H)-triones, which exhibited strong sky blue emission in solution. The reaction is very simple from an experimental point-of-view and allows the creation of a fused benzene ring with concomitant formation of three new C–C bonds in a single operation.     

Mono- und Bis-[(di)alkylamino-dimethylsilyl]-amine

Dialkylaminodimethylchlorosilanes react with sodium amide mainly to dialkylamino-dimethylsilyl-amines, besides to the free dialkylamine and cyclo- and polysilazanes. Bis(alkylamino)-dimethylsilanes can be isolated from the reaction of alkylaminodimethylchlorosilanes with NaNH₂. Dialkylaminodimethylsilanes are formed likewise in the reaction of alkylaminophenoxydimethylsilanes with NaNH₂. The analogous reaction of alkylaminophenoxydimethylsilanes leads on the other hand to 1,3-bis(alkylamino)-tetramethyldisilazanes.     

Catalyst-free synthesis of 3-(alkylamino)-2-arylimidazo[1,2-a]pyridine-8-carboxylic acids via a three-component condensation

The synthesis of a number of 3-(alkylamino)-2-arylimidazo[1,2-a]pyridine-8-carboxylic acids via a facile route involving the reaction between 2-amino-3-pyridinecarboxylic acid, benzaldehyde derivatives, and isonitriles is reported. The structures of the synthesized compounds are proved by X-ray crystallography.     

One-pot three component isocyanide-based reaction: Synthesis of novel tetracyclic fused furo[2′,3′:4,5]pyrimido[2,1-b][1,3]benzothiazole

A rapid, efficient and benign protocol has been developed for the construction of potentially biologically active furo[2′,3′:4,5]pyrimido[2,1-b][1,3]benzothiazole derivatives as major products along with (3E)-3-[(alkylamino)methylene]-2H-pyrimido[2,1-b][1,3]benzothiazole-2,4(3H)-dione derivatives as minor products using a one-pot, multi-component reaction of isocyanides, aromatic aldehydes and 2-hydroxy-4H-pyrimido[2,1-b][1,3]benzothiazol-4-one. The significant features of this protocol are the readily available and low-cost starting materials, short reaction time, mild reaction conditions, high yield of products and avoidance of toxic solvents and catalysts. Structures of compounds 4b and 5a were confirmed from single crystal X-ray studies.     

A convenient synthesis of functionalized pyrazolones bearing a highly twisted 1,3-butadiene moiety with skew geometry

Abstract

The four-component reaction among arylhydrazine, alkyl acetoacetate derivatives, alkyl isocyanides, and dialkyl acetylenedicarboxylates, leading to the formation of dialkyl 2-[(Z)-(alkylamino)(3-alkyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)methyl] fumarates is described. The structure of target compounds was confirmed using X-ray diffraction study. These pyrazolone derivatives contain a highly twisted exocyclic 1,3-butadiene moiety with skew (??=?87°) geometry.     

A facile, KF/Al2O3 mediated method for the preparation of functionalized pyrido[2,3-d]pyrimidin-7(8H)-ones

A series of functionalized pyrido[2,3-d]pyrimidin-7(8H)-ones were prepared by a KF/Al₂O₃ mediated condensation of 4-(alkylamino)-2-(methylthio)pyrimidine-5-carbaldehydes and phenyl acetic acid ester derivatives.     

One-pot synthesis of 4,5-dihydro-1H-pyrrol-3-carboxamide derivatives via a four-component reaction

An effective route to functionalized 4,5-dihydro-1H-pyrrol-3-carboxamide derivatives is described. This involves reaction of N-alkyl-3-oxobutanamides, which result from the addition of an amine to the diketene, and a primary amine in the presence of dibenzoylacetylene. The 1,3-dicarbonyl compounds obtained from the addition of an amine to diketene were trapped with a primary amine to produce (Z)-3-(alkylamino)-N¹-alkyl-2-butenamide, which reacts with dibenzoylacetylene to produce 4,5-dihydro-1H-pyrrol-3-carboxamide derivatives.     

Reactions of 9-chloro-1,10-anthraquinone 1-dichlorophosphorylimine with N- and C-nucleophiles

9-Chloro-1,10-anthraquinone 1-dichlorophosphorylimine formed in the reaction of 1-amino-9,10-anthraquinone with PCl₅ followed by dehydrochlorination reacts with primary amines with substitution of chlorine atoms. In the case of aliphatic amines, the reaction occurs further concurrently in two directions: the addition of the amine molecule with the formation of 9,9-di(alkylamino) derivatives of the anthrone and the substitution of hydrogen atom at position 4 with the formation of 4,9-di(alkylamino) derivatives of 1,10-anthraquinone 1-imine. In the case of aromatic amines, 1-amino-9,10-anthraquinone 9-arylimines are the end products. Reactions with the anions of CH-acids containing an alkoxycarbonyl or cyano group occur with substitution in position 9 followed by intramolecular cyclization with the formation of 2-alkoxy- or 2-amino-7H-dibenzo[f,ij]isoquinolin-7-one derivatives, respectively. For preliminary communication, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1179–1184, June, 1998.     

Synthesis of S-(2-thioxo-1,3-dithiolan-4-yl)methyl dialkylcarbamothioate and S-thiiran-2-ylmethyl dialkylcarbamothioate via intermolecular O-S rearrangement in water

A facile synthesis of S-(2-thioxo-1,3-dithiolan-4-yl)methyl dialkylcarbamothioates (3) and S-thiiran-2-ylmethyl dialkylcarbamothioate (5) has been reported by the reaction of 5-(chloromethyl)-1,3-oxathiolane-2-thione (1) with sodium dialkylcarbamodithioate (2) and dialkylamine (4), respectively, through intermolecular O-S rearrangement in water. A plausible mechanism of formation of the title compounds has also been proposed.     

Synthesis of 2-amino(alkylamino)-3-nitro-1,4-naphthoquinones

The reaction of 2-amino(alkylamino)-1,4-naphthoquinones with nitrating mixture in concentrated sulfuric acid leads to the formation of 2-amino(alkylamino)-3-nitro-1,4-naphthoquinones.     

Reaction between isocyanides and dialkyl acetylenedicarboxylates in the presence of strong CH-acids: one-pot synthesis of highly functionalized annulated 4H-pyrans

The highly reactive 1:1 adduct, produced from the reaction between dialkyl acetylenedicarboxylates and alkyl isocyanides, was trapped by strong cyclic CH-acids such as 4-hydroxy-6-methyl-2H-pyran-2-one or 4-hydroxycoumarin to yield dialkyl 2-(alkylamino)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3,4-dicarboxylates or dialkyl 7-methyl-2-(alkylamino)-5-oxo-4H,5H-pyrano[4,3-b]pyran-3,4-dicarboxylates in good yields at room temperature.     

Synthesis of 4H-benzo[a]phenoselenazin-4-ones as near-ir dyes

The condensation of 2-bromo- or 2, 6-dibromo-4, 8-bis(alkylamino)-1, 5-naphthoquinones with zinc 2-amino-benzeneselenolates gave 1, 5-bis(alkylamino)-4H-benzo[a]phenoselenazin-4-one and the 3- and/or 10-substituted compounds. These phenoselenazone derivatives absorb nearly infrared light and can be used as optical recording media for a laser beam.     

1,2-fused pyrimidines. V. Synthesis of 1-alkyl or phenyl-2H-dipyrido-[1,2-a:2′,3′-d]pyrimidine-2,5(1H)-diones

The reaction of 2-[(N-acyl, N-alkyl or phenyl)amino]-4H-pyrido[1,2-a]pyrimidin-4-ones 8a-g with the N,N-dimethylformamide/phosphorus oxychloride Vilsmeier reagent 1 (95°, 90 minutes) afforded 1-alkyl or phenyl-2H-dipyrido[1,2-a:2′,3′-d]pyrimidine-2,5(1H)^?diones, 3-alkyl substituted or not, 10a-g . The starting compounds 8 were prepared by treating 2-amino-4H-pyrido[1,2-a]pyrimidin-4-ones N-alkyl substituted 7a,b or N-phenyl substituted 4 with excess anhydrides (130°, 7 hours) when the 2-(alkylamino) derivatives 7 were used in the reaction, compounds 8 were obtained along with very small amounts of 3-acyl-2-(alkylamino)-4H-pyrido[1,2-a]pyrimidin-4-ones 9 .     

Reaction of alkyl- and arylamines with 2-(hydroxyimino)-3-oxobutanal

The condensation of 2-(hydroxyimino)-3-oxobutanal with primary aliphatic amines, cyclohexanamine, and amines containing an adamantane fragment afforded 4-(alkylamino)- and 4-(cyclohexylamino)-3- nitrosobut-3-en-2-ones. Analogous reaction with substituted anilines RC₆H₄NH₂ (R = H, 4-Me, 4-OMe, 4-NH₂, 4-Br, 4-I, 3-NO₂) led to the formation of 4-aryl-3-hydroxyiminobutan-2-ones.     

Nef-isocyanide-Perkow access to novel pyrazolone derivations containing a cyclic ketene dithioacetal moiety

Alkyl (E)-2-(3-Alkyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)-5-(alkylamino)-1,3-dithiole-4-carboxylates have been obtained by condensation of 2-pyrazolin-5-ones with carbon disulfide followed by ring formation with phosphorylated hydroxyketenimines [generated in situ from Nef-isocyanide-Perkow reaction] in the presence of Et₃N. The structure of target compounds was confirmed by X-ray diffraction study. The good yields of the products, diastereoselectivity, and lack of activators or metal promoters are the main advantages of this method.     

Five-membered 2,3-dioxo heterocycles: LXXII. Recyclization of isopropyl 2-(1-aryl-4,5-dioxo-2-phenyl-4,5-dihydro-1H-pyrrol-3-yl)-2-oxoacetates by the action of aliphatic amines

Reactions of isopropyl 2-(1-aryl-4,5-dioxo-2-phenyl-4,5-dihydro-1H-pyrrol-3-yl)-2-oxoacetates with alkylamines involve pyrroledione-pyrroledione recyclization with formation of isopropyl 1-aryl-2-hydroxy-4,5-dioxo-3-[phenyl(alkylamino)methylidene]pyrrolidine-2-carboxylates.     

An organocatalytic rearrangement of 2-(N-alkyl-/aryl-)amino-4-oxo-4H-1-benzopyran-3-carbaldehyde

2-(Arylamino)-4-oxo-4H-1-benzopyran-3-carbaldehyde rearranges to 4-oxo-4H-1-benzopyran-3-carbanilide when treated with glycine in the presence of formalin, but under similar conditions 2-(alkylamino)-4-oxo-4H-1-benzopyran-3-carbaldehyde rearranges to 3-alkylaminomethylenechroman-2,4-dione.     

Heterocyclic N-glycosyl derivatives—XI: Synthesis and NMR conformational study of N-glycosyl benzotriazoles from acetylated glycals

Acid-catalyzed reaction of benzotriazole, 5,6-dimethylbenzotriazole and 5,6-dichlorobenzotriazole with di-O-acetyl-d-xylal in ethyl acetate afforded 1-(4′-O-acetyl-2′,3′-dideoxy-d-glycero-pent-2′-enopyranosyl)benzotriazole derivatives and small amounts of 1,2,3-trideoxy-4-O-acetyl-3-(benzotriazolyl)-d-threo-pent-1-enopyranose derivatives. The reactions using di-O-acetyl-l-arabinal led to the formation of the corresponding 1- and 2-(3′,4′-di-O-acetyl-2′-deoxy-l-erythro-pentopyranosyl)benzotriazole derivatives. In addition the enantiomers of the above 2′, 3′-unsaturated N-glycosyl compounds were also obtained. The configurations and conformations of the products obtained were determined by NMR spectroscopy.     

A comparative study of conventional conditions versus microwave irradiation for the preparation of novel 1,2‐dihydro‐2‐imino‐7‐methyl‐1,6(6H)‐naphthyridin‐5‐ones

The synthesis of novel 1,6‐naphthyridines 6 with potential activity against tuberculosis is described using the reaction sequence 2←4←6. Depending on the ring N‐substitution of the 4‐alkylamino‐6‐methyl‐2(1H)‐pyridones 1 and 2 the electrophilic attack of the Vilsmeier reagent gives rise to the formation of the exocyclic N‐formyl derivatives 3 from 1 and the corresponding 3‐carbaldehydes 4 from 2. 1,2‐Dihydro‐2‐imino‐7‐methyl‐1,6(6H)‐naphthyridin‐5‐ones 6a‐j are prepared by the Knoevenagel reaction of 4 with CH‐acidic nitriles 5. These reactions are carried out using a comparative study of conventional conditions (room temperature or reflux) versus microwave irradiation.     

Reaction of Isatoic Anhydride,Amine, and N,N′-Dialkyl Carbodiimides Under Solvent-Free Conditions: New and Efficient Synthesis of 3-Alkyl-2-(alkylamino)quinazolin-4(3H)-ones

Heating a mixture of isatoic anhydride, amines, and N,N′-dialkyl carbodiimides under solvent-free conditions provided novel 3-alkyl-2-(alkylamino)quinazolin-4(3H)-one derivatives for the first time. The products were obtained in moderate to good yields without formation of any by-products.

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