Crystal and molecular structure of 1,4‐bis(chloroacetyl)‐trans‐2,5‐dimethylpiperazine, a model compound of poly(trans‐2,5‐dimethyl‐1,4‐piperazinediylfumaroyl)

Abstract

AbstractThe molecular and crystal structure of 1,4‐bis(chloroacetyl)‐trans‐2,5‐dimethylpiperazine synthesized by us, was determined from X‐ray diffractometer data. The structure was solved by Patterson and Fourier methods and refined by least‐squares techniques to R 0,065 for 1081 independent reflections. The crystals are monoclinic, space group P21/n, with Z = 2 in a unit cell of dimensions: a = 9,486 (6), b = 9,139 (6), c = 7,036 (5) Å, β = 95,73 (10)°, the numbers in parentheses being the estimated standard deviations refering to the last significant digit. The trans‐2,5‐dimethylpiperazine ring is in a flattened‐chair conformation with the side methyl groups in axial position. The atoms of the amide are nearly coplanar. It seems to be proved that the structure of the trans‐2,5‐dimethylpiperazine ring in poly(trans‐2,5‐dimethyl‐1,4‐piperazinediylfumaroyl) is similar to that found for 1,4‐bis(chloroacetyl)‐trans‐2,5‐dimethylpiperazine.