Reaction of 4-arylidene-3-methyl-1-phenyl-5-pyrazolones with amines

The reaction of primary and secondary amines with 4-arylidenepyrazolones gives the corresponding ammonium salts of 4,4-benzylidenebis-5-pyrazolone derivatives but not adducts on the exocyclic C=C bond as was previously believed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 905–908, July, 1988.     

1,3-Dipolar cycloaddition reactions of 4-arylidene-2-phenyl-1,4-dihydroimidazol-5-ones with nitrile oxides

Stable nitrile oxides add regioselectively to the carbon-carbon double bond of 4-arylidene-2-phenyl-1,4-dihydroimidazol-5-ones to afford spiro isoxazolines 3 . Compounds 3 are further hydrolysed to isoxazole derivatives.     

Formylation of 2-phenyl- and 3-phenyl-5-hydroxybenzofuran derivatives

The Vilsmeier formylation of 2-phenyl- and 3-phenyl-5-hydroxybenzofuran derivatives was studied. It is shown that 2-phenyl-5-methoxybenzofuran is formylated in the 4 position, whereas 3-phenyl-5-methoxybenzofuran is formylated in the 2 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1023–1024, August, 1976.     

5-Hydroxy-3-phenyl-5-vinyl-2-isoxazoline and 3-phenyl-5-vinylisoxazole: synthesis and reactivity

5-Hydroxy-3-phenyl-5-vinyl-2-isoxazoline has been synthesized by reacting benzonitrile oxide with the enolate ion of methyl vinyl ketone. From 5-hydroxy-5-vinyl-2-isoxazoline, 5-vinylisoxazole was then quantitatively obtained by dehydration-aromatization under acidic conditions. Similar results, though not quantitative, were also found by treatment in 2-propanol under basic conditions (i-PrOH/H₂O, Na₂CO₃, reflux). In contrast to 2-propanol, reactions performed in methanol (and, in part, those carried out in ethanol) revealed a more complex behaviour, the nucleophilic addition of ROH onto the vinyl group being mainly observed. Nucleophilic addition was also found with alkyllithiums. The mechanism of the nucleophilic addition is discussed. Epoxidation and further reaction with benzonitrile oxide of both 3-hydroxy-5-phenyl-5-vinyl-2-isoxazoline and 3-phenyl-5-vinylisoxazole are also described.     

1,3-Dipolar cycloaddition reactions of 2-phenyl-4-arylidene-5(4H)-oxazolones with nitrile oxides

Stable nitrile oxides are added stereospecifically and regioselectively to the carbon carbon double bond of 2-phenyl-4-arylidene-5(4H)-oxazolones resulting spiro-derivatives 3, 5 . The spectral properties of the reaction products are discussed. The cycloadducts give several substituted isoxazolines via an opening of the oxazolone ring with nucleophilic reagents.     

Michael condensation of 3-arylidene-3H-pyrrol-2-ones and 3-arylidene-3H-furan-2-ones with cyclohexanone

The Michael condensation in the series of 5-aryl-3-arylidene-3H-pyrrol-2-ones and 5-aryl-3-arylidene-3H-furan-2-ones, containing an activated C=C bond, with cyclohexanone was investigated. It was shown that the condensation products were 1,5-dicarbonyl compounds containing a heterocyclic fragment. The enolization of one of the oxo groups, leading to the formation of hydroxypyrrole or hydroxyfuran structures, was demonstrated by the spectral data. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 823–827, June, 2007.     

2-芳基-5-(5-苯基-2H-四唑-2-亚甲基)-1,3,4-噁二唑类化合物的研究

作者曾研究2-芳基-5-(2-苯基-4-喹啉基)-1,3,4-噁二唑类衍生物,并发现它们具有促进小麦发芽生长的功效。Juby和Shan等报道某些四唑类化合物具有消炎性     

Reactions of 3-hydrazino-5,6-diphenyl-1,2,4-triazine with 4-arylidene-2-phenyl-5(4H)-oxazolones and 4-benzylidene-3-methyl-5(4H)-isoxazolone

3-Hydrazino-5,6-diphenyl-1,2,4-triazine reacts with 4-arylidene-2-phenyl-5(4H)-oxazolones in toluene to give substituted acrylic acid hydrazides, and in glacial acetic acid to give substituted imidazolones. On the other hand the hydrazinotriazine reacts with 4-benzylidene-3-methyl-5(4H)-isoxazolone, probably via a 1,4 addition reaction followed by an elimination reaction, to give benzaldehyde 5,6-diphenyl-1,2,4-triazin-3-ylhydrazone and 3-methyl-5(4H)-isoxazolone.     

Copper-catalyzed multicomponent reaction: facile access to functionalized 5-arylidene-2-imino-3-pyrrolines

The synthesis of a novel class of 2-imino-5-arylidene-3-pyrrolines via a copper-catalyzed multicomponent reaction of sulfonyl azides with alkynes and aziridines is described. The protocol is efficient and general.     

Calcium acetate catalyzed synthesis of 4-arylidene-2-phenyl-5(4H)-oxazolones under solvent-free conditions

Eight 4-arylidene-2-phenyl-5(4H)-oxazolones (azlactones) have been prepared via Erlenmeyer synthesis from aromatic aldehydes and hippuric acid using calcium acetate under solvent-free conditions with microwave irradiation.     

Ultraviolet spectra of 2-phenyl-4- and 2-phenyl-5-azaindan-1, 3-diones

The UV spectra of 2-phenyl-4-azaindan-1, 3-dione (I), 2-phenyl-5-azaindan-1, 3-dione (II), and their N-methylbetaines are investigated. 2×10^–5 M aqueous alcoholic solutions of 2-phenyl-4-azaindan-1, 3-dione (I) contain the anionic form (IA), and in solutions of 2-phenyl-5-azaindan-1, 3-dione (II) the betaine form (IIB) is also in equilibrium with the anion (IIA). Solutions of I and II in 0.1 M sulfuric acid are characterized by a wide and rather intense absorption band at about 500 m, indicating the presence of a betaine form (IB and IIB). In 2M hydrochloric acid solution 2-phenylazaindan-1, 3-diones and their N-methylbetaines (III and IV) are protonated at the oxygen atom, giving the enol forms of the N-protonated or corresponding N-methylated 2-phenylazaindandiones.     

Preparation of 3(5)-phenyl-1-hydroxypyrazole 2-oxide and 4-methyl-3(5)-phenyl-1-hydroxypyrazole 2-oxide

Nitrosation of acrylophenone oxime or of methacrylophenone oxime with n-butyl nitrite in the presence of pyridine and copper(II) sulfate gives the copper complexes of the title compounds. The free 1-hydroxypyrazole 2 -oxides are isolated by treating the copper complexes with dilute sodium hydroxide, filtration, and acidification of the basic filtrates. The title compounds are the first examples of 1-hydroxypyrazole 2 -oxides in which the C3(5) ring position is unsubstituted.     

Studies on the photochromic mechanism of 1,2-dimethyl-5-phenyl-3-pyrryl succinic anhydride

Photochromism of 1,2-dimethyl-5-phenyl-3-pyrryl fulgide (compound I) has been investigated in various solvents. The photocyclization process of I has been examined by means of nanosecond time resolved absorption spectroscopy; a new transient species was found on the nanosecond time scale. Oxygen can severely quench the new transient species. The photocyclization process is shown to be complicated. Both the excited singlet state and the excited triplet state are involved in the photochromic process.