4-Dimethylaminopyridine hydrochloride dihydrate

Unusual temperature-sensitive protonation behaviour of 4-(dimethylamino)pyridine

An unusually strong impact of temperature on the protonation degree of DMAP in strong acid solutions has been found.

Influence of Anion-Binding Schreiner's Thiourea on DMAP Salts: Synergistic Catalysis toward the Stereoselective Dehydrative Glycosylation from 2-Deoxyhemiacetals

Amines are used as additives to facilitate or increase the host-guest chemistry between the thiourea and the anions of Bronsted acids. However, we here demonstrate, for the first time, the synergistic effect of the combination of DMAP/HCl/Schreiner's thiourea in catalyzing dehydrative glycosylation. The variations in the electronic effects of the cationic Bronsted acid part (the protonated DMAP) in the presence of chloride binding Schreiner's thiourea have been discussed using NMR and X-ray crystallographic techniques.

Crystal structure, Hirshfeld surface analysis and physicochemical characterization of bis-[4-(di-methyl-amino)-pyridinium] di-μ-chlorido-bis[di-chlorido-mercurate(II)]

The title mol-ecular salt, (C7H11N2)2[Hg2Cl6], crystallizes with two 4-(di-methyl-amino)-pyridinium cations (A and B) and two half hexa-chlorido-dimercurate(II) anions in the asymmetric unit. The organic cations exhibit essentially the same features with an almost planar pyridyl ring (r.m.s. deviations of 0.0028 and 0.0109 Å), which forms an inclined dihedral angle with the dimethyamino group [3.06 (1) and 1.61 (1)°, respectively]. The di-methyl-amino groups in the two cations are planar, and the C-N bond lengths are shorter than that in 4-(di-methyl-amino)-pyridine. In the crystal, mixed cation-anion layers lying parallel to the (010) plane are formed through N-H⋯Cl hydrogen bonds and adjacent layers are linked by C-H⋯Cl hydrogen bonds, forming a three-dimensional network. The analyses of the calculated Hirshfeld surfaces confirm the relevance of the above inter-molecular inter-actions, but also serve to further differentiate the weaker inter-molecular inter-actions formed by the organic cations and inorganic anions, such as π-π and Cl⋯Cl inter-actions. The powder XRD data confirms the phase purity of the crystalline sample. Furthermore, the vibrational absorption bands were identified by IR spectroscopy and the optical properties were studied by using optical UV-visible absorption spectroscopy.

Die Kristall- und Molekülstruktur von 4-Dimethylaminopyridin C7H10N2

4-Dimethylaminopyridine, C7H10N2, crystallizes in the monoclinic space group P21/n with a = 14.813(3), b = 7.604(2), c = 6.103(2) Å, β = 93.2(2)° and Z = 4. The structure was solved from automated diffractometer data by direct methods and refined by least-squares techniques to R = 0.072 (RFw = 0.092) for 1137 observed reflections. Only small deviations from the aromatic pyridine system are found in this molecule. Between the dimethylamino group and the plane of the pyridine ring the torsion angle is 7(1)°. The results are compared with those obtained for other derivatives.

4-(Dimethyl-amino)pyridinium tribromide: whole mol-ecule disorder of cation and anion

In the title salt, C(7)H(11)N(2) (+)·Br(3) (-), the cation and the near-linear anion [Br-Br-Br = 179.41 (8)°] both show whole-mol-ecule disorder about crystallographic twofold rotation axes. The cation is weakly hydrogen-bonded to the anion by an N-H⋯Br inter-action. The crystal studied was found to be a racemic twin, with a twin component of nearly 50%.

4-(Dimethyl-amino)pyridinium 4-toluene-sulfonate

In the title compound, C(7)H(11)N(2) (+)·C(7)H(7)O(3)S(-), the cation is protonated at the N atom of the heterocyclic ring. The dimethyl-amino group lies close to the pyridinium ring plane with a dihedral angle between the pyridinium and the dimethyl-amine CNC planes of 3.82 (17)°. The N-C bond linking the dimethyl-amino substituent to the pyridinium ring is characteristically short [1.3360 (19) Å], suggesting some delocalization in the cation. In the crystal structure, N-H⋯O hydrogen bonds link individual pairs of cations and anions. The structure is further stabilized by an extensive series of C-H⋯O hydrogen bonds, augmented by π-π [centroid-centroid distance between adjacent pyridinium rings = 3.5807 (10) Å] and C-H⋯π inter-actions, giving a network structure.

Synthesis, structural characterization and in vitro antitumor activity of novel 6-chloro-1,1-dioxo-1,4,2-benzodithiazie derivatives

A series of nonconventional aminium N-(6-chloro-7-R-1,1-dioxo-1,4,2-benzodithiazin-3-yl)arylsulfonamidates 7-15 have been synthesized by the reactions of 6-chloro-7-R-3-methylthio-1,4,2-benzodithiazine 1,1-dioxides with 4-dimethylaminopyridine or Et(3)N and some arylsulfonamides. The free N-(6-chloro-7-methyl-1,1-dioxo-1,4,2-benzodithiazin-3-yl)benzenesulfonamides 16-18 were obtained by treatment of their aminium salts with H(2)SO(4) in boiling acetic acid. The in vitro antitumor activity of the compounds 9, 11-14 and 16-18 has been tested in the antitumor screening of the National Cancer Institute (NCI), and relationships between structure and antitumor activity are discussed. 4-Dimethylaminopyridinium 4-chloro-N-(6-chloro-7-methyl-1,1-dioxo-1,4,2-benzodithiazin-3-yl)benzenesulfonamidate 9 is the prominent of the compounds due to its remarkable activity (log GI(50)<-8.00, log TGI=-5.50) and selectivity for the leukemia SR cell line. For that reason experimental and theoretical analysis of the geometric and electronic properties of 9 was carried out.