Crystal and molecular structure of (3R)-3-(3-methyl-7-phenoxyacetamido-3-cephem-4-yl)-3-hydroxybutanoic acid

Abstract

The R configuration of the side-chain linked to the C(4) atom of the Δ³–cephen derivative (6) was unequivocally established by means of crystal-structure determination. Crystals are monoclinic, space group P2, with Z= 4, unit-cell dimensions a= 11.293(4), b= 20.211(4), c= 8.927(3)Å. In the asymmetric unit of (6) two independent molecules (6a and b) are present. The structure was solved by direct methods and refined by least-squares to R 0.042. The relevant molecular parameters are compared with the corresponding ones of the ketone (1).