The title compound, C3H6N4O2, exhibits partial disorder with the refined occupancy ratios of the two components being 0.582 (5):0.418 (5). In the major component, the nitroso groups have a relative syn spatial arrangement [O=N⋯N=O pseudo-torsion angle = 1.1 (4)°], whereas the other component has an anti disposition [177.6 (1)°]. The N—N=O moieties are almost coplanar with a dihedral angle of 5.3 (3)°, while in the minor occupied set of atoms, this angle is 8 (1)°. In both components, the imidazolidine ring adopts a twisted conformation on the C—C bond and the crystal structure shows the strain of this ring according to the N—CH2—CH2—N torsion angles [25.9 (5) and −23.8 (7)°]. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds.

No abstract

From the ethanolic extract of Lentinus edodes (Shiitake) eight known sterols were isolated and identified: ergosterol, ergosterol peroxide, (22E)-ergosta-5,7,9(11), 22-tetraen-3beta-ol, (22E)-ergosta-7,9(11),22-trien-3beta-ol, (22E)-ergosta-6,8,22-trien-3beta-ol, (22E)-norergosta-5,7,9,22-tetraen-3beta-ol, 3beta,5alpha-dihydroxy-(22E)-ergosta-7,22-dien-6-one, (22E)-ergosta-4,6,8(14),22-tetraen-3-one and, for the first time in mushrooms, (22E)-ergosta-6,22-diene-3beta,5alpha,8alpha-triol.

The asymmetric unit of the title compound, C20H24N2O2, contains one half-mol­ecule, which is completed by inversion symmetry. In the crystal, mol­ecular chains are formed through non-classical C—H⋯O hydrogen bonds, formed between axial H atoms of the oxazine ring and a O atom of a neighboring mol­ecule.

The asymmetric unit of the title compound, C18H18Cl2N2O2, contains one half of an independent mol­ecule, the other half being generated via a centre of inversion at the mol­ecular centroid. In the crystal structure, mol­ecular chains are formed through non-classical C—H⋯ O hydrogen bonds between an axial H atom of the oxazine ring and the O atom of a neighbouring mol­ecule.