Rearrangement of N-(3-pyridyl)nitramine

Abstract

Contrary to other N-(pyridyl)nitramines, the title compound cannot be rearranged to 3-amino-2-nitropyridine or other isomers. Hypothetical products of its transformation under influence of concentrated sulphuric acid, viz. 3-hydroxypyridine, 3,3′-azoxypyridine and 3,3′-azopyridine, were obtained from 3-nitro- and 3-aminopyridine in oxidation and reduction reactions. N-(3-Pyridyl)nitramine was prepared and rearranged in concentrated sulphuric acid. 3-Hydroxypyridine and 3,3′-azoxypyridine were isolated from the reaction mixture, other products were identified by the HPLC and GCMS methods. The results indicate that N-(3-pyridyl)hydroxylamine is an intermediate formed from N-(3-pyridyl)nitramine under the influence of concentrated sulphuric acid. The reaction path, leading to the final products, is discussed in context of the mechanism of nitramine rearrangement.

Interdependence of structure and physical properties in co-crystals of azopyridines

“…The melting points of the pure diacids also decrease upon moving from shorter to longer chain acids. 15 The same trend is also maintained in their co-crystals with 4,4'-azopyridine. Despite the fact that 4,4'-azpy:SeA exhibits motif 2, instead of motif 1 (observed in all other cases), its melting behaviour does not show significant difference from this pattern.…”

“…We have postulated four different motifs that could be prepared 15 by combining 3,3'-azpy and 4,4'-azpy with even-chain aliphatic diacids. The basic assumption is that chains will form in all cases, and they could then be arranged either out-of-phase (motifs 1 and 3) or in-phase (motif 2 and 4) within a 2-D architecture constructed via inter-chain interactions, (Scheme 3).…”

“…Scan speeds and scan widths were chosen based on scattering power and peak rocking curves. 15 Unit cell constants and orientation matrices were improved by least-squares refinement of reflections threshold from the entire dataset. Integrations were performed with SAINT, using these improved unit cells as a starting point.…”

“…Finally, the relative positions of binding sites on related compounds can also be used to prepare new solid-forms that display physical properties that can be fine-tuned with respect to those of the individual components. 15 …”

1D iron(ii) spin crossover coordination polymers with 3,3′-azopyridine – kinetic trapping effects and spin transition above room temperature

“…The octahedral ironIJII) 1D coordination polymers were obtained in a one-pot reaction using the related mononuclear methanol complexes as starting materials. 12,13 A ligand substitution reaction with the bridging ligand 3,3′-azopyridine 14,15 gave complexes {[FeL1IJazpy)]•0.5IJazpy)} n (1) and {[FeL2IJazpy)]} n (2) in good yields. Scheme 1 displays the general synthesis of the ironIJII) coordination polymers 1 and 2.…”