  In this note we study the applicability of the color-kinematics duality to
the scattering of two distinguishable scalar matter particles with gluon
emission in QCD, or graviton emission in Einstein gravity. Previous analysis
suggested that direct use of the Bern-Carrasco-Johansson double-copy
prescription to matter amplitudes does not reproduce the gravitational
amplitude in multi-Regge kinematics. This situation, however, can be avoided by
extensions to the gauge theory, while maintaning the same Regge limit. Here we
present two examples of these extensions: the introduction of a scalar contact
interaction and the relaxation of the distinguishability of the scalars. In
both cases new diagrams allow for a full reconstruction of the correct Regge
limit on the gravitational side. Both modifications correspond to theories
obtained by dimensional reduction from higher-dimensional gauge theories.
