  The posibility of quantizing the anomalous $SU(N)$ Yang--Mills model
preserving the symmetry under the orthogonal subgroup is indicated. The
corresponding Wess--Zumino action (1-cocycle) possesses the additional $SO(N)$
symmetry and can be expressed in terms of chiral fields taking values in the
homogeneous space $SU(N)/SO(N)$. The modified anomaly and the constraints
commutator (2-cocycle) are calculated.
