Conformational analysis of functionalized sultines by nuclear magnetic resonance and x-ray crystallography. Application of a generalized Karplus equation (original) (raw)
Helvetica Chimica Acta, 2002
The new six-membered-ring (2R)-10a-homobornane-10a,2-sultam (À)-3a was synthesized and its X-ray structural analysis was compared with that of the novel structure of the five-membered-ring (2R)-bornane-10,2sultam analogues (À)-1a,b as well as with that already published for the six-membered-ring trans-decalin-like sultam 4a. Based on DN** density-function calculations and X-ray crystallographic studies of the N-methylated analogues (À)-1e and 4b and by comparing with the conformation of the N-fluoro derivatives (À)-1c and ()-1d, the anomeric stabilization was estimated to be smaller than the 2.0 ± 2.5 kcal/mol earlier suggested. The direction of pyramidalization is rationalized in terms of H-bond and steric and electronic interactions and extended to the known toluenesultam derivatives 10a ± c. 2 ) For N lp through-bond and through-space directing interactions, initially suggested by M¸ller and Eschenmoser, see [10a]. For nonexhaustive more recent examples, see [10b ± g]. Cieplak also proposed a hyperconjugative influence of the N lp on the incipient bond-formation through the intermediacy of a sp 2 atom, see Schemes 85 and 86 as well as reference 105 in [11]. More recently, King et al. also suggested an anomeric stabilization [12a]
Journal of Organometallic Chemistry, 2001
The crystal structures of orthorhombic and monoclinic diethyltin bis(1,3-dithiole-2-thione-4,5-dithiolate), [Et 2 Sn(dmit)], ortho-3 and mono-3, and dimethyltin bis(1,3-dithiole-2-thione-4,5-dithiolate) (4) have been determined. Transformation of solid ortho-3 to mono-3 occurs at 139-140°C. Molecules of ortho-3, obtained by recrystallisation from aqueous acetone, and 4, are linked into chains as a result of intermolecular Sn thione S(5) interactions: the tin centres are penta-coordinate with distorted trigonal bipyramidal geometries. The intermolecular, Sn S(5) thione bonds {3.0083(15) A , in ortho-3 at 150 K [3.037(4) at 298 K], and 3.001(2) and 2.960(2) A , in the two independent molecules of 4 at 150 K}, are considerably longer than the primary intramolecular Sn bonds to the dithiolato S atoms [between 2.440(3) and 2.5235(15) A , ]. The two independent molecules of mono-3, obtained from aqueous methanol, have quite different arrangements: tin atoms in molecule A form two relatively weak intermolecular Sn thione S bonds, 3.567(2) and 3.620(3) A , , with the formation of sheets, while those in molecule B form one similar bond, Sn S= 3.555(2) A , to give chains, with a much longer contact, Sn•••S =3.927(2) A , to another chain. The latter is only ca. 0.12 A , less than the van der Waals radii sum for Sn and S. Sulfur-sulfur contacts, within the sum of the van der Waals radii of two S atoms, 3.60 A , , in 3 and 4, not only reinforce the chains but also help to establish 3D networks.
Acta crystallographica. Section E, Crystallographic communications, 2015
The title compounds, (N-methyl-N-phenyl-amino)(N-methyl-N-phenyl-car-bam-oyl)sulfide, C15H16N2OS, (I), and (N-methyl-N-phenyl-amino)-(N-methyl-N-phenyl-carbamo-yl)disulfane, C15H16N2OS2, (II), are stable derivatives of (chloro-carbon-yl)sulfenyl chloride and (chloro-carbon-yl)disulfanyl chloride, respectively. The torsion angle about the S-S bond in (II) is -92.62 (6)°, which is close to the theoretical value of 90°. In the crystal of (II), non-classical inter-molecular C-H⋯O hydrogen bonds form centrosymmetric cyclic dimers [graph set R 2 (2)(10)], while inter-dimer C-H⋯S inter-actions generate chains extending along the b axis.
An Adventitious Synthesis of 2,2′-Dipyrryl Disulfides
Australian Journal of Chemistry, 1999
Condensation of 1,2-diketones and a cyanothioacetamide gave hydroxy thiolactams which failed to give the expected 3-cyano methylene thiolactams on dehydration. Disulfides and a thiosulfonate were obtained from the dehydrations. A possible mechanism for their formation is proposed. The crystal structure of the disulfide 4,4′,5,5′-tetramethyl-1,1′-diphenyl-2,2′-disulfanediyldi-1H-pyrrole-3-carbonitrile (9) has been determined by X-ray diffraction.
Journal of Molecular Structure, 2019
Facile conversion of a thiol-Schiff base (obtained from the condensation of 2hydroxynaphthaldehyde and 2-aminothiophenol) to the corresponding homodisulfide derivative is described. The molecular structure and stoichiometry of the thiol (1) and disulfide (2) compounds were characterized by analytical and spectroscopic techniques. The structure of the disulfide derivative was also confirmed by single crystal X-ray analysis. Theoretical calculations based on density functional theory (DFT) were established to verify the structures of the thiol in both solid and solution forms as well the structure of the disulfide. The global chemical reactivity descriptors were estimated from the energy of the HOMO and LUMO orbitals.
Arkivoc
Here we report synthetic methodology affording in the most efficient way the rapid preparation of new dithiolethiones (DTTs) and methanethiosulfonates (MTSs). These were evaluated as STAT3 inhibitors since these electrophilic systems could react with thiol groups of STAT3-SH2 domain. The results showed that MTSs strongly interacted with the SH2 domain, whereas the corresponding DTTs possessed lower affinity, independently from the nature of the linked heterocyclic scaffold.