The mol-ecule of the title compound, C(10)H(6)N(2)O, is nearly planar [maximum deviation = 0.030 (1) Å]. The CN(2) moiety is almost linear, with a C-N-N angle of 175.50 (14)°. A single inter-molecular C-H⋯O hydrogen bond is observed in the crystal structure. A π-π inter-action is also observed with the shortest distance being 3.6832 (12) Å between the the centroids of the six-membered rings.

The crystal structure determination of the title compound, C(15)H(14)N(2)O, confirms the cis relationship between the phenyl groups at the 4- and 5-positions on the imidazolidine ring. The dihedral angle between the two phenyl rings is 48.14 (6)°. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link mol-ecules into centrosymmetric dimers. These dimers are, in turn, linked into a ...

In an asymmetric unit of the title compound, C(8)H(12)N(2)S(4), there are two crystallographically independent half mol-ecules lying on inversion centers. One of the mol-ecules is disordered over two positions with relative occupancies of 82.0 (2) and 18.0 (2) for the major and minor components. In the crystal structure, mol-ecules are linked into a three-dimensional framework via inter-molecul...

In the title compound, C(8)H(5)ClN(2)O, the quinazoline system is approximately planar with a maximum deviation from the least-squares plane of 0.034 (2) Å. In the crystal, classical N-H⋯O and weak non-classical C-H⋯N hydrogen bonds link the mol-ecules.

Paramagnetic NMR is a useful technique to study proteins and protein complexes and the use of paramagnetic relaxation enhancement (PRE) for this purpose has become wide-spread. PREs are commonly generated using paramagnetic spin labels (SLs) that contain an unpaired electron in the form of a nitroxide radical, with 1-oxyl-2,2,5,5-tetramethyl-2,5-dihydropyrrol-3-ylmethyl methane thiosulfonate (M...