ÐKnoevenagel condensation between 3-nitro-2-pyridinecarbaldehyde and diethyl malonate catalyzed by titanium(IV) chloride gave diethyl 3-nitro-2-pyridylidenemalonate which was oxidized with peracetic acid to give corresponding 1-oxide. Reaction of the latter with diethylamine in the presence of primary and secondary alcohols resulted in the reduction of the nitro group and the oxidation of the v...

In the title pyrazole compound, C(22)H(17)N(3)O(4), an intra-molecular C-H⋯O contact generates a seven-membered ring, producing an S(7) ring motif. The furan and pyrazole rings are essentially planar [maximum deviations = 0.004 (1) and 0.004 (2) Å, respectively] and are almost coplanar, making a dihedral angle of 3.75 (10)°. One of the methyl-phenyl groups is inclined to the pyrazole ring, as i...

In the title compound, C(12)H(10)N(2)O(3), the oxygen atom bridging the two aromatic rings is in a synperiplanar (+sp) conformation. The dihedral angle between the aromatic rings is 71.40 (12)°. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O hydrogen bonds.

In the title compound, C(21)H(14)ClN(3)O(5), an intra-molecular C-H⋯O hydrogen bond generates an S(7) ring motif and the furan and pyrazole rings are almost coplanar, making a dihedral angle of 1.98 (5)°. The pyrazole ring is inclined at dihedral angles of 47.59 (4) and 7.27 (4)° to the chloro-phenyl and methoxy-phenyl groups, respectively. The nitro group is almost coplanar to its attached fur...

In the title compound, C(12)H(10)N(2)O(4)S, the dihedral angle between the aromatic rings is 36.19 (18)°. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into C(4) chains running along the a axis.

a series of 2-(4-nitro-1-imidazolylmethyl)-1,3,4-oxadiazole, 1,3,4-triazole and 3-(4-nitro-1-imidazolylmethyl)-1,2,4-triazole derivatives were synthesized and tested for their antimicrobial activity. some of the tested compounds were active against staphylococcus aureus, staphylococcus epidermidis, bacillus subtilis, clostridium difficile, aspergillus niger and cryptococcus neoformans.

Simple systems are considered in which the binding of a ligand at a single site exhibits a doubly sigmoid curve when saturation is plotted against the logarithm of ligand concentration, i.e. where a fraction of the site exhibits one dissociation constant and the rest exhibits another. The condition for this to occur is that the ligand should also combine at another site on the binding molecule ...