SYNTHESIS 2011, No. 20, pp 3209–3219xx.xx.2011 Advanced online publication: 07.09.2011 DOI: 10.1055/s-0030-1260212; Art ID: E69311SS © Georg Thieme Verlag Stuttgart · New York Abstract: The direct functionalization of pyridine and related azine derivatives through carbon–carbon bond-forming reactions is reviewed. Various transformations that use a variety of transitionmetal catalysts are covere...

The title compound, C(22)H(30)N(4)O(2), has a crystallographic inversion center located at the mid-point of the N-N single bond. Apart from the four ethyl C atoms, the non-H atoms are nearly coplanar with a mean deviation of 0.0596 (2) Å. An intra-molecular O-H⋯N hydrogen bond occurs. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into layers parallel to (100).

The molecule of the title compound, C(18)H(14)N(4), lies on a center of inversion such that there is one half-mol-ecule in the asymmetric unit. The N-N single bond adopts a trans configuration and the indole fused-ring system is nearly coplanar with the -CH=N-N=CH- fragment [dihedral angle = 9.8 (2)°]. Adjacent mol-ecules are linked by indole-azine N-H⋯N hydrogen bonds into a layer motif.

The crystal structures of N'-amino-pyridine-2-carboximidamide (C6H8N4), 1, and N'-{[1-(pyridin-2-yl)ethyl-idene]amino}-pyridine-2-carboximidamide (C13H13N5), 2, are described. The non-H atoms in compound 1 are nearly planar (r.m.s. deviation from planarity = 0.0108 Å), while 2 is twisted about the central N-N bond by 17.8 (2)°. Both mol-ecules are linked by inter-molecular N-H⋯N hydrogen-bondin...

The complete mol-ecule of the title compound, C(26)H(20)N(2), is generated by crystallographic inversion symmetry. The terminal phenyl ring is twisted by 19.2 (1)° with respect to the adjacent phenyl-ene ring.