Comparison of various synthesis methods and synthesis parameters of pyrazoline derivates

Explaining the selectivities and the mechanism of [3+2] cycloloaddition reaction between isoalantolactone and diazocyclopropane

CONTEXT

[3+2] cycloaddition processes between isoalantolactone (ISALL) and diazocyclopropane (DCYP), have been surveyed exercising the MEDT, reactivity indices, reactions, and activation energies, are computed. In an investigation of conceptual DFT indices, DCYP behaves as a nucleophile in this reaction, whereas ISALL acts as an electrophile. This cyclization is stereo-, chemo-, and regiospecific, as demonstrated by the activation and reaction energies, in clear agreement with the experiment's results. The mechanism for this [3+2] cycloaddition is occurring in two steps, according to ELF analysis.

METHODS

For the purposes of this investigation, all computations were performed using the Gaussian 09 program. The optimization was completed using Berny's computational gradient optimization approach with the basis set 6-311G(d,p) and wB97XD functional. Frequency computations were utilized to characterize and locate stationary points where the transition phases have just one imaginary frequency and all frequencies for the reactants and products are positive. After evaluating the effect of dichloromethane (DCM) as a reaction solvent, the stationary point optimization was updated using the polarizable continuum model (PCM) developed by the Tomasi team. The electron localization function (ELF) has been examined within the context of topological investigations using Multiwfn software with a 0.05 grid step.

2-[5-(2,3-Di-meth-oxy-naphthalen-1-yl)-4,5-di-hydro-1H-pyrazol-3-yl]-3-meth-oxy-phenol

In the title compound, C22H22N2O4, the central pyrazoline ring exhibits a nearly planar structure (r.m.s. deviation = 0.025 Å) despite having two sp 3 carbon atoms. The pyrazoline ring subtends dihedral angles of 4.61 (1) and 87.31 (1)° with the pendant benzene ring and naphthalene ring system, respectively. The dihedral angle between the planes of the benzene ring and the naphthalene ring system is 89.76 (2)°. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. In the crystal, inversion dimers formed by pairwise weak N-H⋯N hydrogen bonds generate R 2 2(4) loops and the dimers are linked by pairwise C-H⋯O hydrogen bonds [which generate R 2 2(8) loops] into [100] chains.