Search results
Results from the WOW.Com Content Network
Such reactions (summarized in formula below) involve the removal of two hydrogen atoms from the reactant (R), in the form of a hydride ion (H −), and a proton (H +). The proton is released into solution, while the reductant RH 2 is oxidized and NAD + reduced to NADH by transfer of the hydride to the nicotinamide ring. RH 2 + NAD + → NADH ...
The starting material was an N-substituted pyrrole derivative, which was heated to convert it by a [1,5] sigmatropic shift to the isomer with a carbon bond between the pyrrole and pyridine rings, followed by methylation and selective reduction of the pyrrole ring using tin and hydrochloric acid.
A carbon–nitrogen bond is a covalent bond between carbon and nitrogen and is one of the most abundant bonds in organic chemistry and biochemistry. [ 1 ] Nitrogen has five valence electrons and in simple amines it is trivalent , with the two remaining electrons forming a lone pair .
Bifurcated H-bond systems are common in alpha-helical transmembrane proteins between the backbone amide C=O of residue i as the H-bond acceptor and two H-bond donors from residue i + 4: the backbone amide N−H and a side-chain hydroxyl or thiol H +. The energy preference of the bifurcated H-bond hydroxyl or thiol system is -3.4 kcal/mol or -2. ...
Ammonia, NH 3, is a molecule whose three N−H bonds have only a slight polarity (toward the more electronegative nitrogen atom). The molecule has two lone electrons in an orbital that points towards the fourth apex of an approximately regular tetrahedron, as predicted by the VSEPR theory .
When the N-substituent is an electron-withdrawing group such as a tosyl group, the carbon-nitrogen bond breaks, forming another zwitterion TsN − –CH 2 –CH + 2 –R [23] This reaction type requires a Lewis acid catalyst such as boron trifluoride. In this way 2-phenyl-N-tosylaziridine reacts with alkynes, nitriles, ketones and alkenes.
Pauling estimated that an electronegativity difference of 1.7 (on the Pauling scale) corresponds to 50% ionic character, so that a difference greater than 1.7 corresponds to a bond which is predominantly ionic. [10] Ionic character in covalent bonds can be directly measured for atoms having quadrupolar nuclei (2 H, 14 N, 81,79 Br, 35,37 Cl or ...
A general linear imide functional group. In organic chemistry, an imide is a functional group consisting of two acyl groups bound to nitrogen. [1] The compounds are structurally related to acid anhydrides, although imides are more resistant to hydrolysis.