Basicity of 1-nitroaryl-4,5-dihydropyrazoles: pKa �measurements and theoretical calculations

X-ray Molecular Structures of 23 N1-4-Nitrophenyl, 2,4-Dinitrophenyl, and 2,4,6-Trinitrophenyl-2-pyrazolines

“…Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. 11,12,15,19,82,83 In the present paper, we report the determination of the crystal structures of 23 2-pyrazolines N-substituted by 4nitrophenyl, 2,4-dinitrophenyl, and 2,4,6-trinitrophenyl groups which will be discussed together with the three structures determined in the literature (see above). All structures were determined at room temperature, about 298 K, save in the case of compound 2l, which was determined at 100 K. We will use a double code system: a number, from 1 to 3, to characterize the nitrophenyl substituent, and a letter, from a to r, to characterize the 2-pyrazoline (Figures 3 and 4).…”

“…Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. 11−18 A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, 19 whose pK a values we have previously determined. 20−22 In what concerns the determination of the structure of nitrophenyl-2-pyrazolines by X-ray crystallography there are only two previous studies reporting three structures.…”

“…At the beginning, our own research , consisted of extending the reaction discovered by Mousseron et al to other pyrazolines and other halonitrobenzenes. Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. − A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, whose p K a values we have previously determined. − …”

“…A search for these compounds shows that the great majority of the described compounds belong to the p -nitrophenyl series. − The reason is that these compounds can be obtained by cyclization of the p -nitrophenylhydrazones of α,β-unsaturated carbonyl compounds and by 1,3-dipolar cycloaddition of p -nitrophenylnitrilimines on olefins (including fullerenes). , The 1-(2,4-dinitrophenyl) derivatives are much less frequent because the cyclization of the 2,4-dinitrophenylhydrazones of α,β-unsaturated carbonyl compounds was rarely successful. Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. ,,,,, …”

X-ray Molecular Structures of 23 N1-4-Nitrophenyl, 2,4-Dinitrophenyl, and 2,4,6-Trinitrophenyl-2-pyrazolines

“…Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. 11,12,15,19,82,83 In the present paper, we report the determination of the crystal structures of 23 2-pyrazolines N-substituted by 4nitrophenyl, 2,4-dinitrophenyl, and 2,4,6-trinitrophenyl groups which will be discussed together with the three structures determined in the literature (see above). All structures were determined at room temperature, about 298 K, save in the case of compound 2l, which was determined at 100 K. We will use a double code system: a number, from 1 to 3, to characterize the nitrophenyl substituent, and a letter, from a to r, to characterize the 2-pyrazoline (Figures 3 and 4).…”

“…Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. 11−18 A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, 19 whose pK a values we have previously determined. 20−22 In what concerns the determination of the structure of nitrophenyl-2-pyrazolines by X-ray crystallography there are only two previous studies reporting three structures.…”

“…At the beginning, our own research , consisted of extending the reaction discovered by Mousseron et al to other pyrazolines and other halonitrobenzenes. Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. − A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, whose p K a values we have previously determined. − …”

“…A search for these compounds shows that the great majority of the described compounds belong to the p -nitrophenyl series. − The reason is that these compounds can be obtained by cyclization of the p -nitrophenylhydrazones of α,β-unsaturated carbonyl compounds and by 1,3-dipolar cycloaddition of p -nitrophenylnitrilimines on olefins (including fullerenes). , The 1-(2,4-dinitrophenyl) derivatives are much less frequent because the cyclization of the 2,4-dinitrophenylhydrazones of α,β-unsaturated carbonyl compounds was rarely successful. Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. ,,,,, …”

X-ray Molecular Structures of 23 N1-4-Nitrophenyl, 2,4-Dinitrophenyl, and 2,4,6-Trinitrophenyl-2-pyrazolines

“…Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. 11,12,15,19,82,83 In the present paper, we report the determination of the crystal structures of 23 2-pyrazolines N-substituted by 4nitrophenyl, 2,4-dinitrophenyl, and 2,4,6-trinitrophenyl groups which will be discussed together with the three structures determined in the literature (see above). All structures were determined at room temperature, about 298 K, save in the case of compound 2l, which was determined at 100 K. We will use a double code system: a number, from 1 to 3, to characterize the nitrophenyl substituent, and a letter, from a to r, to characterize the 2-pyrazoline (Figures 3 and 4).…”

“…Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. 11−18 A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, 19 whose pK a values we have previously determined. 20−22 In what concerns the determination of the structure of nitrophenyl-2-pyrazolines by X-ray crystallography there are only two previous studies reporting three structures.…”

“…At the beginning, our own research , consisted of extending the reaction discovered by Mousseron et al to other pyrazolines and other halonitrobenzenes. Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. − A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, whose p K a values we have previously determined. − …”

“…A search for these compounds shows that the great majority of the described compounds belong to the p -nitrophenyl series. − The reason is that these compounds can be obtained by cyclization of the p -nitrophenylhydrazones of α,β-unsaturated carbonyl compounds and by 1,3-dipolar cycloaddition of p -nitrophenylnitrilimines on olefins (including fullerenes). , The 1-(2,4-dinitrophenyl) derivatives are much less frequent because the cyclization of the 2,4-dinitrophenylhydrazones of α,β-unsaturated carbonyl compounds was rarely successful. Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. ,,,,, …”

X-ray Molecular Structures of 23 N1-4-Nitrophenyl, 2,4-Dinitrophenyl, and 2,4,6-Trinitrophenyl-2-pyrazolines

“…Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. 11,12,15,19,82,83 In the present paper, we report the determination of the crystal structures of 23 2-pyrazolines N-substituted by 4nitrophenyl, 2,4-dinitrophenyl, and 2,4,6-trinitrophenyl groups which will be discussed together with the three structures determined in the literature (see above). All structures were determined at room temperature, about 298 K, save in the case of compound 2l, which was determined at 100 K. We will use a double code system: a number, from 1 to 3, to characterize the nitrophenyl substituent, and a letter, from a to r, to characterize the 2-pyrazoline (Figures 3 and 4).…”

“…Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. 11−18 A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, 19 whose pK a values we have previously determined. 20−22 In what concerns the determination of the structure of nitrophenyl-2-pyrazolines by X-ray crystallography there are only two previous studies reporting three structures.…”

“…At the beginning, our own research , consisted of extending the reaction discovered by Mousseron et al to other pyrazolines and other halonitrobenzenes. Subsequently, when 1 H, 13 C, 15 N NMR was available, a series of papers were devoted to the use of these techniques to structural studies of nitrophenylpyrazolines. − A less explored approach to the structure of 1-nitrophenyl-2-pyrazolines was the use of mass spectrometry to determine the gas-phase basicities of these compounds, whose p K a values we have previously determined. − …”

“…A search for these compounds shows that the great majority of the described compounds belong to the p -nitrophenyl series. − The reason is that these compounds can be obtained by cyclization of the p -nitrophenylhydrazones of α,β-unsaturated carbonyl compounds and by 1,3-dipolar cycloaddition of p -nitrophenylnitrilimines on olefins (including fullerenes). , The 1-(2,4-dinitrophenyl) derivatives are much less frequent because the cyclization of the 2,4-dinitrophenylhydrazones of α,β-unsaturated carbonyl compounds was rarely successful. Finally, the 1-(2,4,6-trinitrophenyl) derivatives have only been prepared by our group. ,,,,, …”