Piero Sarti-Fantoni

The reactivity of 3-methyl-4-nitro-5-styrylisoxazole with some bis-enolisable ketones

The expected Michael adducts and spiroisoxazolines are obtained from the reaction between 3-methyl-4-nitro-5-styrylisoxazole and bis-enolisable ketones. Contrary to reported data, Michael adducts are obtained in good yields only when a substoichiometric amount of base is used, whereas spiroisoxazolines were obtained as the major product when the base is present in a large excess.

Thermal Behaviour and Monomerization Kinetics of 9-CN Anthracene and 9-CN, 10-Acetoxy Anthracene Dimers in the Solid State

Abstract The thermal stability of 9-CN-anthracene dimer (9-CNAD) and 9-CN, 10-Acetoxy anthracene dimer (9-CN, 10-Ac AD) was studied by differential scanning calorimetry and by direct microscopic examination. Both compounds monomerize below the melting point of the corresponding monomer. From thermograms, first order kinetics are found for both. 9-CN, 10-Ac AD monomerizes, even at room temperature, to an amorphous phase which then crystallizes. Thermal data and activation energies are reported.

Calorimetric Study on Some Anthracene Photodimers

Abstract Calorimetric data referring to dimers of anthracene, 9-CN-anthracene, 9-Cl-anthracene, 1-Cl-anthracene and 9-anthraldehyde are reported. Values for heat of melting for monomers are listed.

Photoreactions and Fluorescence Ageing in Crystalline Anthracene

Abstract Fluorescence changing of anthracene crystals in air, O2, N2, recorded at room temperature is reported. Two different products formed under irradiation of anthracene were isolated and recognized as anthracene dimer and anthraquinone. A correlation between the above fluorescence change and the photochemical behaviour of anthracene was found.

On the Fluorescence of 9-Cyanoanthracene

Abstract The polarized green fluorescence of 9-cyancanthracene crystals is reanalysed and found to be structured. The green emission is progressively weakened by irradiation, and becomes replaced by a blue fluorescence.

Solid State Photodimerization Reaction of Some 3-Sytrylisoxazolo[3,4-d]pyridazin-7(6H)-ones

Photodimerisation des composes du titre en diphenyl-1,3- (ou bis-[chloro-4 phenyl]-1,3) bis-[dihydro-6,7 dimethyl-4,6 oxo-7 isoxazolo [3,4-d] pyridazinyl-3]-24 cyclobutanes (identifies par donnees spectrales et oxydation en les acides diaryl-2,4 cyclobutanedicarboxyliques-1,3)

Evaluation of the Enthalpic Change During the Monomerization Reaction of Crystalline Anthracene Photodimer (AD)

Abstract The isothermal determination of the heat change during the monomerization reaction of crystalline anthracene photodimer (AD) was performed by quantitative differential enthalpic analysis at temperatures lower than the melting point of the formed monomer.

Defects and Fluorescence of 9-Cyanoanthracene

Abstract The fluorescence of 9-cyanoanthracene (9-CNA) crystals analysed in polarized light was found to change under irradiation with the light of mercury lamp. Intensity changes of fluorescence maxima for crystals and powders (microcrystals) are reported. Crystals of 9-CNA examined on the stage of a microscope were found to re-emit light from defects at beginning of irradiation whereas additional emitting centres were created as the irradiation proceeded. The green fluorescence (beginning of irradiation) is now correlated with defects and the blue one (after ≈ 60 min. of irradiation) is thought to be due to monomer in dimer matrix formed under irradiation with a mercury light.

The Effect of Long Irradiation on the Fluorescence Emission of Anthracene Crystals at Room Temperature

Abstract Microphotographs showing the effect of increasing irradiation time of anthracene single crystals are reported and the surface effect correlated to the fluorescence emission changing.

A new spiro annellation reaction in the isoxazole series: applications and limits. Part 2. Reactivity of ethyl 4-nitro-3-phenylisoxazole-5-carboxylate with nitrogen binucleophiles

Treatment of the title compound (5) with benzamidine and 1,3-diphenylguanidine afforded in good yields the spiro nitronate (6) and a mixture of the regioisomeric salts (12) and (13), respectively; these products were easily converted into the corresponding nitro derivatives (7), (14), and (15), respectively, with hydrochloric acid. The same nitro ester (5) reacted smoothly with o-phenylenediamine and NaH to give, after acidification, the heterospiran (16). Some limits of this spiro annellation process are emphasized. The structures of the new compounds have been established on the basis of spectral data.