  We show that in the transitions psi' -> h_c \pi^0 and eta_c' -> chi_{c0} pi^0
the contributions from charmed meson loops are highly suppressed, in contrast
to various other charmonium decays. We calculate the width of the psi' -> h_c
pi^0, which agrees with the recent BES-III data, and predict the width of the
eta_c' -> chi_{c0} pi^0, \Gamma(eta_c' -> chi_{c0} pi^0) = 1.5\pm0.4 keV. A
confirmation of this prediction would also provide additional support for a
recent analysis of psi' -> J/psi pi^0 (eta), where loops are claimed to play a
prominent role.
