ChemInform Abstract: THE CRYSTAL STRUCTURE OF OROTIC ACID MONOHYDRATE (VITAMIN B13)

Abstract

The crystal structure of orotic acid monohydrate (Vitamin B13) has been determined by the method of X-ray diffraction. The crystals are triclinic with the space group of P\bar1 and with cell dimensions of a=9.561, b=7.261, c=5.895 A, α=117.6°, β=107.6°, and γ=90.4°. The structure was determined by an inspection of the sharpened Patterson map. The final R value was 5.75% for 1345 observed reflections. The uracil group of orotic acid resembles uracil itself in its molecular dimensions. The molecules are arranged in layers closely parallel to the (\bar2 1 1) plane. The orotic acid molecules are linked through two kinds of N–H···O hydrogen bonds in zig-zag chains extending in the [1 1 1] direction. Each chain is joined, by three kinds of O–H···O hydrogen bonds through the medium of a water molecule, with two neighboring chains, and each forms a sheet parallel to the (\bar2 1 1) plane. The hydrogen bond of the water molecule as an acceptor is of the F type, in which the bisector of lone pairs in the oxygen ato...