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The nitration of 1-(triisopropyl­silyl)-1H-pyrrole leads to a mixture of products following partial acid cleavage of the triisopropyl­silyl protecting group. Structural determination showed the isolated products to be the title compound, C13H24N22O2Si, and 2,4-dinitro­pyrrole. In the solid state, the title compound exists as discrete mol­ecules with only weak C—H⋯nitro hydrogen bonds between them.

Both the molecular and the crystal structures of the title compound, C9H14N2O2S, are similar to those of its 4-phenyl analogue. The supramolecular network is based upon N—H⋯N hydrogen-bonded centrosymmetric dimers linked by N—H⋯O contacts.

In the crystal structure of the title compound, [Mg(C4H8O)2(C9H7)2], the two indenyl ligands are bound to the Mg atom in a manner intermediate between η1- and η3-coordination; the latter is untypical, as it includes one of the ring-sharing C atoms. The O-Mg-O angle [101.01°] is larger than for any other magnesocene-(THF)2 adduct (THF is tetra­hydro­furan). A crystallographic C2 axis bisects the O-Mg-O angle.

The isoxazole proton is sufficiently acidic to give the title salt, hydroxylammonium 4-(ethyloxycarbonyl)-5-oxo-2,5-dihydroisoxazolide, NH3OH+.C6H6NO4-, in the presence of hydroxylamine. The deprotonation of the heterocyclic ring has a profound effect on its geometry, notably increasing the N-O distance by 0.05 A to 1.433 (2) A.

An important precursor to biologically active compounds, 2,8-dimethylphenoxathiin 10-oxide (C14H12-028), is found to adopt a folded geometry. The dihedral angles between the aromatic rings are 11.8 (2) and 15.4 (2) ° for the two independent molecules, with the S atoms lying out of the ring planes.

The diacetylamino moiety of the title compound, C12H14N2O4, is shown to adopt a syn–anti conformation and is twisted away from the perpendicular to the aryl ring.

An unusual de-alkyl­ation reaction between 2-chloro­benzo­thia­zole and N-ethyl­piperidine gave 2-(1-piperidinyl)-1,3-benzo­thia­zole, C12H14N2S, as pale-yellow orthorhombic crystals. Discrete mol­ecules consist of a planar benzo­thia­zole fragment with a piperidine ring in a chair conformation.

The crystal structure of ethyl 2-amino­oxazole-5-carboxyl­ate, C6H8N2O3, consists of planar sheets internally connected by intermolecular hydrogen bonding running parallel to the (120) plane. Interactions between the sheets are limited to dipole–dipole interactions between antiparallel carbonyl groups.

The synthesis and structure of 2-amino-4-(methoxymethyl)-thiazole-5-carboxylic acid Me ester (C7H10N2O3S) are reported. Crystallog. data and at. coordinates are given. The two crystallog. independent conformations found differ only by the rotational positions adopted by their methoxymethyl substituents. Intermol. contacts are dominated by H bonding involving the amine H atoms.