Modular Synthesis of 3,6-Disubstituted-1,2,4-triazines via the Cyclodehydration of ß-Keto- N-acylsulfonamides with Hydrazine Salts.

A straightforward method for preparing 3,6-disubstituted-1,2,4-triazines through a redox-efficient cyclodehydration of ß-keto- N-acylsulfonamides with hydrazine salts is described. Two approaches for synthesizing the requisite ß-keto- N-acylsulfonamides are presented, which allow for the late stage incorporation of either the C3 or C6 substituent in a flexible manner from acid chlorides or α-bromoketones, respectively. The scope of this methodology includes primary and secondary sp3-linked substituents at both the C3 and C6 positions, and the mild reaction conditions tolerate a variety of sensitive functionalities.

4-Bromo-2-({4-[(hy-droxy-imino)-meth-yl]phen-yl}imino-meth-yl)phenol.

In the title compound, C(14)H(11)BrN(2)O(2), the mean planes of the two benzene rings are almost parallel to each other, making a dihedral angle of 4.09 (1)°. An intra-molecular O-H⋯N hydrogen bond occurs. In the crystal, inter-molecular O-H⋯N and C-H⋯O hydrogen bonds link the mol-ecules into a chain-like supra-molecular structure.

2,2'-[1,1'-(Octane-1,8-diyldioxy-dinitrilo)diethyl-idyne]diphenol.

The title compound, C(24)H(32)N(2)O(4), has a crystallographic inversion centre at the mid-point of the central C-C bond. At each end of the mol-ecule, intra-molecular O-H⋯N hydrogen bonds generate six-membered S(6) ring motifs. The crystal structure is stabilized by pairs of weak inter-molecular C-H⋯O hydrogen bonds that link neighbouring mol-ecules into R(2) (2)(40) ring motifs, which in turn form infinite one-dimensional supra-molecular ribbon structures.

Bis[(E)-4-bromo-2-(ethoxy-imino-meth-yl)phenolato-κN,O]copper(II).

The title compound, [Cu(C(9)H(9)BrNO(2))(2)], is a centrosymmetric mononuclear copper(II) complex. The Cu atom is four-coordinated in a trans-CuN(2)O(2) square-planar geometry by two phenolate O and two oxime N atoms from two symmetry-related N,O-bidentate (E)-4-bromo-2-(ethoxy-imino-meth-yl)phenolate oxime-type ligands. An inter-esting feature of the crystal structure is the centrosymmetric inter-molecular Cu⋯O inter-action [3.382 (1) Å], which establishes an infinite chain structure along the b axis.

Bis[(E)-4-bromo-2-(methoxy-imino-meth-yl)phenolato-κN,O]copper(II).

In the title centrosymmetric mononuclear copper(II) complex, [Cu(C(8)H(7)BrNO(2))(2)], the Cu(II) atom, lying on an inversion centre, is four-coordinated in a trans-CuN(2)O(2) square-planar geometry by two phenolate O atoms and two oxime N atoms from two symmetry-related N,O-bidentate oxime-type ligands. Inter-molecular C-H⋯O hydrogen bonds link neighbouring mol-ecules into a one-dimensional supra-molecular structure with an R(2) (2)(14) ring motif. This structure is further stabilized by π-π stacking inter-actions between adjacent benzene rings [centroid-centroid distance = 3.862 (1) Å].

4-({4-[1-(Methoxy-imino)eth-yl]anilino}(phen-yl)methyl-ene)-3-methyl-2-phenyl-1H-pyrazol-5(4H)-one.

In the title compound, C(26)H(24)N(4)O(2), the dihedral angles between the central pyrazole ring and the other three benzene rings are 40.02 (3), 77.51 (5) and 55.72 (3)°. A strong intra-molecular N-H⋯O hydrogen bond forms a six-membered ring with an S(6) motif. In the crystal structure, a weak inter-molecular C-H⋯N inter-action with graph-set motif R(2) (2)(8) and C-H⋯O hydrogen bonds link each mol-ecule to three others, forming an infinite two-dimensional supra-molecular structure.

2,2'-[Octane-1,8-diyldioxy-bis(nitrilo-methyl-idyne)]diphenol.

The complete mol-ecule of the title compound, C(22)H(28)N(2)O(4), is generated by a crystallographic inversion centre at the mid-point of the central C-C bond. The two benzene rings are parallel to each other with a perpendicular inter-planar spacing of 1.488 (2) Å. Intra-molecular O-H⋯N hydrogen bonds generate two six-membered rings with S(6) motifs. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link neighbouring mol-ecules into an infinite three-dimensional network, which is further stabilized by weak C-H⋯π inter-actions.

{2,2'-[1,1'-(Ethyl-enedioxy-dinitrilo)diethyl-idyne]di-1-naphtholato}copper(II).

The title complex, [Cu(C(26)H(22)N(2)O(4))], is isostructural with its Ni analogue. All intramolecular distances and angles are very similar for the two structures, whereas the packing of the molecules, including C-H⋯O and C-H⋯π interactions, are slightly different.

{2,2'-[1,1'-(Ethyl-enedioxy-dinitrilo)diethyl-idyne]di-1-naphtholato}nickel(II).

In the title complex, [Ni(C(26)H(22)N(2)O(4))], the Ni(II) atom has a slight distortion toward tetra-hedral geometry from a square-planar structure, coordinated by two O and two N atoms of the tetra-dentate salen-type bis-oxime 2,2'-[1,1'-(ethyl-enedioxy-dinitrilo)diethyl-idyne]di-1-naphtholate (L(2-)) unit, with a mean deviation of 0.022 Šfrom the N(2)O(2) plane. The N- and O-donor atoms are mutually cis. The dihedral angle between two naphthalene systems of the L(2-) ligand is 67.59 (4)°. The crystal structure is stabilized by inter-molecular C-H⋯O and C-H⋯π inter-actions, which link neighbouring mol-ecules into extended chains along the b axis.

2,2'-[1,1'-(Ethyl-enedioxy-dinitrilo)diethyl-idyne]di-1-naphthol.

The complete molecule of the title compound, C(26)H(24)N(2)O(4), is generated by a crystallographic centre of inversion. There are two intra-molecular O-H⋯N hydrogen bonds. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds result in zigzag chains.

2,2'-[1,1'-(Heptane-1,7-diyldioxy-dinitrilo)diethyl-idyne]di-1-naphthol.

The mol-ecule of the title compound, C(31)H(34)N(2)O(4), adopts an L-shaped configuration, in which the naphthalene units are approximately perpendicular, making a dihedral angle of 87.89 (3)°. Intramolecular H-bonds are formed between the OH substituents and the N atoms at each end of the molecule. In the crystal structure, each mol-ecule links six other mol-ecules into an infinite three-dimensional network supra-molecular structure, which is built from one-dimensional zigzag chains via weak C-H⋯π stacking and inter-molecular C-H⋯O hydrogen bonds.

2,2'-{1,1'-[Pentane-1,5-diylbis(oxy-nitrilo)]diethylidyne}di-1-naphthol.

The title compound, C(29)H(30)N(2)O(4), adopts a distorted Z configuration with respect to the oxime group, which is almost coplanar with the adjacent naphthalene ring [dihedral angle = 4.11 (2)°]. There is one half-mol-ecule in the asymmetric unit, with a crystallographic twofold rotation axis passing through the central C atom of the -CH=N-O-(CH)(5)-O-N=CH- bridge. Within the mol-ecule, the dihedral angle formed by the two naphthalene rings is 79.08 (3)°, and there are two intra-molecular O-H⋯N hydrogen bonds.

2,2'-[1,1'-(Decane-1,10-diyldioxy-dinitrilo)diethyl-idyne]diphenol.

The salen-type bis-oxime title compound, C(26)H(36)N(2)O(4), lies about a crystallographic inversion centre. Classical intra-molecular O-H⋯N hydrogen bonds generate two S(6) ring motifs. In the crystal structure, pairs of weak inter-molecular C-H⋯O hydrogen bonds link adjacent mol-ecules into an infinite one-dimensional supra-molecular structure.