Novel tunable CuX(2)-mediated cyclization reaction of cyclopropylideneacetic acids and esters for the facile synthesis of 4-halomethyl-2(5H)-furanones and 4-halo-5,6-dihydro-2H-pyran-2-ones

[reaction: see text] A mixture of cyclopropylideneacetic acids (or esters) and CuBr(2) (or CuI/I(2)) in aqueous acetonitrile afforded 4-substituted 2(5H)-furanones or 3,4-substituted 5,6-dihydro-2H-pyran-2-ones in moderate to good yields. The selectivity of the reaction greatly depended on the reaction temperature.     

A new approach to the facile synthesis of 2-substituted-quinazolin-4(3H)-ones

A new approach to the facile synthesis of 2-substituted-quinazolin-4(3H)-ones and its derivatives using the condensation reaction of substituted 2-aminobenzamide and orthoesters is reported.     

An efficient synthesis of 4-Halo-5-hydroxyfuran-2(5H)-ones via the sequential halolactonization and gamma-hydroxylation of 4-aryl-2,3-alkadienoic acids

4-Halo-5-hydroxyfuran-2(5H)-ones were synthesized via the efficient sequential halolactonization-hydroxylation reaction of 4-aryl-2,3-allenoic acids with I(2) or CuX(2) (X = Br or Cl) in moderate to good yields. The structures of the products were established by the X-ray single-crystal diffraction study of 3-methyl-4-iodo-5-phenyl-5-hydroxyl-2(5H)-furanone (2a). A rationale for this reaction was discussed based on some brief mechanistic study.     

Intermolecular coupling of alkynes, isocyanates, and acyl chlorides: an efficient method for the synthesis of 5-hydroxypyrrol-2(5H)-ones

New insights into the reaction of diethylzirconocene with an alkyne, an isocyanate, and an acyl chloride in this order are reported. The products of 5-hydroxypyrrol-2(5H)-ones are obtained in good yields after hydrolysis. It is an efficient method for the synthesis of 5-hydroxypyrrol-2(5H)-ones.     

A facile synthesis of 3-substituted 2-cyanoquinazolin-4(3H)-ones and 3-alkyl-2-cyanothieno[3,2-d]pyrimidin-4(3H)-ones via 1,2,3-dithiazoles

The reaction of methyl anthranilate with 4,5-dichloro-1,2,3-dithiazolium chloride (Appel's salt) in the presence of pyridine (2 equivalents) in dichloromethane at room temperature gave methyl N-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)anthranilate ( 3a ) (50% yield), which reacted with sterically less hindered primary alkylamines to give directly 3-alkyl-2-cyanoquinazolin-4(3H)-ones 5 in moderate to good yields. With tert-butylamine, N-(2-methoxycarbonylphenyl)iminocyanomethyl N-(tert-butyl) disulfide 7 and methyl 2-(N-cyanothioformamido)anthranilate ( 8 ) were isolated in 33% and 59% yields, respectively. The cyano group of quinazoline 5a (R = CH₃) is readily displaced by various nucleophiles to give 2-substituted quinazolinones 11–19 , which indicates that compounds 5 can be utilized as starting materials for the synthesis of new 2-substituted quinazolines. Similarly 3-alkyl-2-cyanomieno[3,2,-d]pyrimidin-4(3H)-ones 22 were prepared from methyl 3-[N-(4-chloro-5H-1,2,3-dimiazol-5-ylidene)]-2-thiophencarboxylate ( 21 ) in moderate to good yields.     

A facile and efficient approach for the synthesis of 3-arylthiazol-2(3H)-one

A facile and efficient method for synthesis of 3-arylthiazol-2(3H)-one through the reaction of acyl azide and 1,4-dithiane-2,5-diol was reported. This reaction proceeded at 80?°C at first and then in acidic condition at room temperature, to afford products in good yields for a wide range of substrates and a possible mechanism has also been proposed.     

A novel and facile synthesis of 4-arylquinolin-2(1H)-ones under metal-free conditions

A novel and facile synthesis of 4-arylquinolin-2(1H)-ones without metal catalysis has been developed. This reaction involved cyclization/elimination steps and was performed under metal-free conditions using inexpensive reagents such as NaI, selectfluor and KOH.     

Sulfated polyborate catalyzed expeditious and efficient three-component synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones

A rapid and highly efficient methodology for the synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones has been developed using sulfated polyborate as a catalyst. The multicomponent reaction of an aromatic/heterocyclic aldehyde, hydroxylamine hydrochloride, and ethyl acetoacetate under a solvent free condition at 80 °C is described. This protocol has promising features for the reaction response such as shorter reaction time, easy work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure. The products have been obtained in high yields (80–90%) and convenient reaction time (15–30 min). The method is operationally simple and eco-friendly.     

A facile preparation of 4-(1-Acetyl-4(1H)-pyridylidene)-2-oxazohn-5-ones

4-(1-Acetyl-4(1H)-pyridylidene)-2-oxazolin-5-ones were prepared by the reaction of acylglycines with pyridine and acetic anhydride under oxygen. Acidic and alkaline hydrolysis of 2-oxazolin-5-ones provided oxazole derivatives, pyridine derivatives, and carboxylic acids.     

ZnO nanoparticle-catalyzed efficient one-pot three-component synthesis of 3,4,5-trisubstituted furan-2(5H)-ones

An efficient and high-yielding protocol using nano-ZnO (50–100 nm) as an efficient heterogeneous catalyst for one-pot three-component synthesis of pharmacologically significant furanone derivatives by the condensation of aromatic aldehyde, amine and dimethylacetylenedicarboxylate has been developed. Since the catalyst is heterogeneous, it can be easily separated and recycled several times without much loss of its catalytic activity. Use of aqueous medium, recyclable nanocatalyst, operational simplicity, non-chromatographic purification technique, excellent yield and short reaction time makes this approach an attractive protocol for the synthesis of 3,4,5-trisubstituted furan-2(5H)-ones.     

A facile and novel synthesis of 1,6-naphthyridin-2(1H)-ones

A new and convenient procedure for the synthesis of 1,6-naphthyridin-2(1H)-ones and their derivatives is described. In the first scheme 5-acetyl-6-[2-(dimethylamino)ethenyl]-1,2-dihydro-2-oxo-3-pyridinecarbonitrile ( 4 ) obtained by the reaction of N,N-dimethylformamide dimethyl acetal with 5-acetyl-1,2-dihydro-6-methyl-2-oxo-3-pyridinecarbonitrile ( 3 ) was cyclized to 1,2-dihydro-5-methyl-2-oxo-1,6-naphthyridine-3-carbonitrile ( 5 ) by the action of ammonium acetate. Thermal decarboxylation of acid 7 obtained from the hydrolysis of nitrile 5 led to a mixture of 5-methyl-1,6-naphthyridin-2(1H)-one ( 8 ) and its dimer 9 . Hydrazide 11 obtained from nitrile 5 in two steps was converted to 3-amino-5-methyl-1,6-naphthyridin-2(1H)-one ( 12 ) by the Curtius rearrangement. The amino group of 12 was readily replaced by treatment with aqueous sodium hydroxide to yield 3-hydroxy-5-methyl-1,6-naphthyridin-2(1H)-one ( 13 ). In the second scheme, Michael reaction of enamines of type 20 with methyl propiolate, followed by ring closure gave 5-acyl(aroyl)-6-methyl-2(1H)-pyridinones ( 21 ) which in turn were treated with Bredereck's reagent to produce 5-acyl(aroyl)-6-[2-(dimethylamino)ethenyl]-2(1H)-pyridinones ( 22 ). Treatment of 22 with ammonium acetate led to the formation of 1,6-naphthyridin-2(1H)-ones 23 .     

The synthesis of isoindolin-3-ones,Phthalazin-4(3H)-ones and related systems

The reaction between methyl 2-cyanobenzoate and its pyridine analogues gave isoindolin-3-ones, phthalazin-4(3H)-ones and their corresponding aza analogues. Some reactions of 1-benzylaminoiminoisoindolin-3-one 5b were investigated.     

Green chemistry approach to the synthesis of 3-substituted-quinazolin-4(3H)-ones and 2-methyl-3-substituted-quinazolin-4(3H)-ones and biological evaluation

ABSTRACT

A synthesis of two series of 3-substituted quinazolinones was performed utilizing a green chemistry approach, deep eutectic solvents and microwaves, namely. 2-Methyl-3-substituted-quinazolin-4(3H)-one derivatives were synthesized in a two-step reaction, using choline chloride:urea deep eutectic solvent (DES). 3-Substituted-quinazolin-4(3H)-ones were synthesized in one-pot one-step reaction of anthranilic acid, amines and orthoester in a microwave reactor. For the synthesis of 2-methyl-3-substituted-quinazolin-4(3H)-ones, first conventional synthesis of benzoxazinone, as an intermediate, was performed. Further, benzoxazinone in reaction with corresponding amines, in choline choline:urea deep eutectic solvent, furnished desired compounds. These procedures are based on green principles with the aim of developing synthetic routes for the potential antitumor agents. All compounds were characterized by LC/MS, ¹H NMR and ¹³C NMR spectral techniques. Compound 1 bearing trifluoromethoxyphenyl group showed promising activity against HuT-78 cell line with IC₅₀ of 51.4?±?5.1?µM.     

An efficient solvent-free synthesis of 3,4-disubstituted isoxazole-5(4H)-ones using microwave irradiation

I have reported one-pot and three-component synthesis of 3-mehyl-4-arylmethyleneisoxazol-5(4H)-ones using microwave radiation under the solvent-free conditions, in the presence of potassium bromide as the catalyst. The method has given the products in high yields and short reaction times with an easy work-up process. The present method provides an easy and efficient approach for the synthesis of this class of compounds, because of its clean reaction profile and operational simplicity.     

Pd(CH3CN)2Cl2-catalyzed oxidative heterodimerization reaction of 2,3-allenamides and 1,2-allenyl ketones: an efficient synthesis of 4-(furan-3'-yl)-2(5H)-furanimines

The Pd(II)-catalyzed oxidative heterodimerization reaction of 2,3-allenamides and 1,2-allenyl ketones was studied. It provides an efficient route for the synthesis of the polysubstituted 4-(furan-3'-yl)-2(5H)-furanimines, which are not readily available from the known methods. Due to the application of benzoquinone, the loadings of both the palladium catalyst and ketone have been greatly reduced for the oxidative heterodimerization of 2,3-allenamides and 1,2-allenyl ketones in acetic acid.     

A facile and environmental friendly strategy for the synthesis of N-methoxyquinolin-2(1H)-ones

A facile and environmental friendly protocol for the construction of N-methoxyquinolin-2(1H)-ones was developed using a stable and easily available N-methoxyquinoline-1-ium tetrafluoroborate as starting material. Due to the mild reaction conditions, a broad range of N-methoxyquinolin-2(1H)-ones with different functional groups have been prepared in reasonable yields.