Crystal structure and Hirshfeld surface analysis of the hydrated 2:1 adduct of piperazine-1,4-diium 3,5-dinitro-2-oxidobenzoate and piperazine

The crystal structure of the adduct piperazine-1,4-diium 3,5-dinitro-2-oxidobenzoate–piperazine–water (2/1/2) shows the existence of a 3,5-dinitrosalicylate dianion (DNSA2−) and a protonated piperazine-1,4-diium cation (PIP2+) along with a piperazine molecule. The formula of the title adduct in the asymmetric unit is 2C4H12N2 2+·2C7H2N2O7 2−·C4H10N2·2H2O with Z = 1. The piperazine ring in the piperazine-1,4-diium cation and in the neutral piperazine molecule adopt chair conformations. All O atoms in the DNSA2− moiety and the water molecule act as hydrogen-bonding acceptors for various intermolecular O—H...O, N—H...O and C—H...O interactions, which stabilize the crystal structure. Various supramolecular architectures formed by the different intermolecular interactions are discussed. The relative contribution of various intermolecular contacts is analysed with the aid of two-dimensional (full and decomposed) fingerprint plots, indicating that H...O/O...H (50.2%) and H...H (36.2%) contacts are the major contributors to the stabilization of the crystal structure.

Molecular and crystal structure of a copper(II) complex of sildenafil

The crystal structure of a copper(II) complex of protonated sildenafil, CuCl3C22H31N6O4S⋅2H2O was studied by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n with the unit cell parameters a = 15.4292(2), b = 9.06735(12), c = 21.1752(2) Å, V = 2945.48(7) Å3, Z = 4. The Cu atom is coordinated by the sildenafil ligand via the N2 atom of the pyrazolopyrimidine ring and by three chloride anions. Sildenafil is protonated at the methylated N6 atom of the piperazine ring and it is cation ligand with a 1+ charge.

Recent Advances in the Synthesis of Piperazines: Focus on C–H Functionalization

Piperazine ranks as the third most common nitrogen heterocycle in drug discovery, and it is the key component of several blockbuster drugs, such as Imatinib (also marketed as Gleevec) or Sildenafil, sold as Viagra. Despite its wide use in medicinal chemistry, the structural diversity of piperazines is limited, with about 80% of piperazine-containing drugs containing substituents only at the nitrogen positions. Recently, major advances have been made in the C–H functionalization of the carbon atoms of the piperazine ring. Herein, we present an overview of the recent synthetic methods to afford functionalized piperazines with a focus on C–H functionalization.

Crystal structure and Hirshfeld surface analysis of trans-2,5-dimethylpiperazine-1,4-diium tetrachloridocobaltate(II)

In the title molecular salt, (C6H16N2)[CoCl4], the complete dication is generated by crystallographic inversion symmetry and the piperazine ring adopts a chair conformation with the pendant methyl groups in equatorial orientations. The complete dianion is generated by crystallographic twofold symmetry. In the crystal, the (C6H16N2)2+ and [CoCl4]2− ions are linked by N—H...Cl and C—H...Cl hydrogen bonds, thereby forming a two-dimensional supramolecular network. The Hirshfeld surface analysis and fingerprint plots reveal that the largest contributions to the crystal stability come from H...Cl/Cl...H (68.4%) and H...H (27.4%) contacts.

Crystal structure of tert-butyl 4-[4-(4-fluorophenyl)-2-methylbut-3-yn-2-yl]piperazine-1-carboxylate

The title sterically congested piperazine derivative, C20H27FN2O2, was prepared using a modified Bruylants approach. A search of the Cambridge Structural Database identified 51 compounds possessing an N-tert-butyl piperazine substructure. Of these only 14 were asymmetrically substituted on the piperazine ring and none with a synthetically useful second nitrogen. Given the novel chemistry generating a pharmacologically useful core, determination of the crystal structure for this compound was necessary. The piperazine ring is present in a chair conformation with di-equatorial substitution. Of the two N atoms, one is sp 3 hybridized while the other is sp 2 hybridized. Intermolecular interactions resulting from the crystal packing patterns were investigated using Hirshfeld surface analysis and fingerprint analysis. Directional weak hydrogen-bond-like interactions (C—H...O) and C—H...π interactions with the dispersion interactions as the major source of attraction are present in the crystal packing.

Recent advances in the synthesis of piperazine based ligands and metal complexes and their applications

The piperazine ring is an indispensable part of many biomolecules and can be easily modified through substitution on the ring nitrogen for desired application in pharmacology as well as metal binding studies.

1-(3,5-Dinitrobenzoyl)-4-(2-methoxyphenyl)piperazine

In the title compound, C18H18N4O6, the piperazine ring adopts a chair conformation, the amidic N atom is planar (sum of angles = 360°) and the non-amidic N atom is pyramidal (343°). There are no hydrogen bonds of any kind in the crystal, but the molecules are linked by two independent π(nitrobenzene)...π(methoxybenzene) stacking interactions to form π-stacked sheets with inter-centroid separations of 3.8444 (12) and 3.9197 (12) Å.

A Single-Step Synthesis of 1,3,4,6-Tetraaryl-5-Aryliminopiperazin-2-One

We report here novel reaction that we found unprecedented, up to our knowledge. In a single step, we obtained unusual result. After magnificent efforts we could deduce the structure. We confirmed the structure of this product by reproducing the reaction using other substrates. The reaction therefore resulted in a piperazine ring that is functionalized on every atom in the ring. This was stage 1. We almost finished making this reaction more utilizable (stage 2) in a future paper. Enjoy it because you won't see a new chemistry everyday.

A Single-Step Synthesis of 1,3,4,6-Tetraaryl-5-Aryliminopiperazin-2-One

We report here novel reaction that we found unprecedented, up to our knowledge. In a single step, we obtained unusual result. After magnificent efforts we could deduce the structure. We confirmed the structure of this product by reproducing the reaction using other substrates. The reaction therefore resulted in a piperazine ring that is functionalized on every atom in the ring. This was stage 1. We almost finished making this reaction more utilizable (stage 2) in a future paper. Enjoy it because you won't see a new chemistry everyday.