Methyl 2-[(ferrocenylcarbonyl)amino]thio­phene-3-carboxyl­ate

The title compound, [Fe(C₅H₅)(C₁₂H₁₀NO₃S)], was synthesized from ferrocenecarboxylic acid and methyl 2-amino­thio­phene-3-carboxyl­ate in modest yield. The substituted ring system is essentially planar through the amido­thienylcarboxyl­ate moiety, η⁵-(C₅H₄)CONH(C₄H₂S)CO₂Me, with the amido unit at an angle of 3.60 (7)° to the five-atom thienyl group, which is oriented at an angle of 3.17 (7)° to the ester moiety. The primary hydrogen bond is an intramolecular N—H...O=C_{carboxyl­ate} interaction [N...O 2.727 (2) Å], and the main intermolecular hydrogen bond involves a thienyl carboxyl­ate and the carboxyl­ate of a symmetry-related molecule [C...O 3.443 (3) Å].

Redetermination of para-amino­pyridine (fampridine, EL-970) at 150 K

The structure of fampridine (EL-970) or 4-amino­pyridine, C₅H₆N₂, has been redetermined at 150 K. The room-temperature structure has been reported previously [Chao & Schempp (1977). Acta Cryst. B33, 1557–1564]. Pyramidalization at the amine N atom occurs in fampridine, with the N atom 0.133 (11) Å from the plane of the three C/H/H atoms to which it is bonded; the inter­planar angle between the pyrid­yl ring and NH₂ group is 21 (2)°. Aggregation in the solid state occurs by N—H...N and N—H...π(pyridine) inter­actions with N...N and N...π(centroid) distances of 2.9829 (18) and 3.3954 (15) Å, respectively; a C—H...π(pyridine) contact completes the inter­molecular inter­actions [C...π(centroid) = 3.6360 (16) Å].