164 research outputs found
Polymorphic form II of 4,4′-methylenebis(benzenesulfonamide)
In the title compound, C13H14N2O4S2 (alternative names: diphenylmethane-4,4′-disulfonamide, nirexon, CRN: 535–66-0), the two benzene rings form a dihedral angle of 70.8 (1)°. There are two sets of shorter (H⋯O < 2.1 Å) and longer (H⋯O > 2.4 Å) N—H⋯O hydrogen bonds per sulfonamide NH2 group, which together result in hydrogen-bonded sheets parallel (102). Adjacent sheets are connected to one another by an additional N—H⋯N interaction so that a three-dimensional network of hydrogen-bonded molecules is formed. The investigated polymorph is identical with the form II previously described by Kuhnert-Brandstätter & Moser [(1981). Mikrochim. Acta, 75, 421–440]
Aminophobanes:hydrolytic stability, tautomerism and application in Cr-catalysed ethene oligomerisation
The bicyclic aminophobanes have significantly different chemistry from their acyclic analogues Cy2PNHR′.</p
Gliquidone
The title compound {systematic name: N-cyclohexylcarbamoyl-4-[2-(7-methoxy-4,4-dimethyl-1,3-dioxo-1,2,3,4-tetrahydroisoquinolin-2-yl)ethyl]benzenesulfonamide}, C27H33N3O6S, displays an intramolecular N—H⋯O=S interaction, as well as intermolecular N—H⋯O=C hydrogen bonds. The latter interactions lead to the formation of hydrogen-bonded chains parallel to the c axis. The conformation of the sulfonylurea fragment is in agreement with a recent theoretical study [Kasetti et al. (2010 ▶). J. Phys. Chem. B, 114, 11603–11610]
Benzylsulfamide
The crystal of the title compound [systematic name: 4-(benzylamino)benzenesulfonamide], C13H14N2O2S, displays a hydrogen-bonded framework structure. Molecules are doubly N—H⋯O hydrogen bonded to one another via their NH2 groups and sulfonyl O atoms. These interactions generate a hydrogen-bonded ladder structure parallel to the a axis, which contains fused R
2
2(8) rings. The NH group serves as the hydrogen-bond donor for a second set of intermolecular N—H⋯O=S interactions
Polythiazide
The crystal structure of the title compound, C11H13ClF3N3O4S3 (systematic name: 6-chloro-2-methyl-3-{[(2,2,2-trifluoroethyl)sulfanyl]methyl}-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide; CRN: 346–18–9), exhibits a two-dimensional network of hydrogen-bonded molecules parallel to (01). The NH and NH2 groups act as donor sites and the sulfonyl O atoms as acceptor sites in N—H⋯O hydrogen bonds, and a C—H⋯O interaction also occurs. The thiadiazine ring adopts an envelope conformation with the N atom bonded to sulfur at the tip of the flap, and the methyl substituent is in an axial position
B-Methylated Amine-Boranes:Substituent Redistribution, Catalytic Dehydrogenation, and Facile Metal-Free Hydrogen Transfer Reactions
Although
the dehydrogenation chemistry of amine-boranes substituted at nitrogen
has attracted considerable attention, much less is known about the
reactivity of their B-substituted analogues. When the B-methylated
amine-borane adducts, RR′NH·BH<sub>2</sub>Me (<b>1a</b>: R = R′ = H; <b>1b</b>: R = Me, R′ = H; <b>1c</b>: R = R′ = Me; <b>1d</b>: R = R′ = <i>i</i>Pr), were heated to 70 °C in solution (THF or toluene),
redistribution reactions were observed involving the apparent scrambling
of the methyl and hydrogen substituents on boron to afford a mixture
of the species RR′NH·BH<sub>3–<i>x</i></sub>Me<sub><i>x</i></sub> (<i>x</i> = 0–3).
These reactions were postulated to arise via amine-borane dissociation
followed by the reversible formation of diborane intermediates and
adduct reformation. Dehydrocoupling of <b>1a</b>–<b>1d</b> with Rh(I), Ir(III), and Ni(0) precatalysts in THF at 20
°C resulted in an array of products, including aminoborane RR′NBHMe,
cyclic diborazane [RR′N–BHMe]<sub>2</sub>, and borazine
[RN–BMe]<sub>3</sub> based on analysis by in situ <sup>11</sup>B NMR spectroscopy, with peak assignments further supported by density
functional theory (DFT) calculations. Significantly, very rapid, metal-free
hydrogen transfer between <b>1a</b> and the monomeric aminoborane, <i>i</i>Pr<sub>2</sub>NBH<sub>2</sub>, to yield <i>i</i>Pr<sub>2</sub>NH·BH<sub>3</sub> (together with dehydrogenation
products derived from <b>1a</b>) was complete within only 10
min at 20 °C in THF, substantially faster than for the N-substituted
analogue MeNH<sub>2</sub>·BH<sub>3</sub>. DFT calculations revealed
that the hydrogen transfer proceeded via a concerted mechanism through
a cyclic six-membered transition state analogous to that previously
reported for the reaction of the <i>N</i>-dimethyl species
Me<sub>2</sub>NH·BH<sub>3</sub> and <i>i</i>Pr<sub>2</sub>NBH<sub>2</sub>. However, as a result of the presence
of an electron donating methyl substituent on boron rather than on
nitrogen, the process was more thermodynamically favorable and the
activation energy barrier was reduced
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