Crystal structure of 4-chloro-2-[(5-eth-oxy-1,3,4-thia-diazol-2-yl)meth-yl]-5-(piperidin-1-yl)pyridazin-3(2H)-one.

In the title mol-ecule, C14H18ClN5O2S, the six atoms of the 1,6-di-hydro-pyridazine ring are essentially coplanar (r.m.s. deviation = 0.008†à ), and the dihedral angle between this and the 1,3,4-thia-diazole ring is 62.06†(10)°. In the crystal, centrosymmetrically related mol-ecules are linked by inter-molecular C-H-O hydrogen bonding to form a supra-molecular dimer. The terminal ethyl group is statistically disordered over two positions.