  Using a chiral unitary approach for meson-baryon scattering in the
strangeness zero sector, where the $N^*(1535)$ and $\Delta^*(1700)$ resonances
are dynamically generated, we study the reactions $\gamma p \to \pi^0 \eta p$
and $\gamma p \to \pi^0 K^0 \Sigma^+$ at photon energies at which the final
states are produced close to threshold. Among several reaction mechanisms, we
find the most important is the excitation of the $\Delta^*(1700)$ state which
subsequently decays into a pseudoscalar meson and the $N^*(1535)$. Hence, the
reaction provides useful information with which to test current theories of the
dynamical generation of the low-lying $1/2^-$ and $3/2^-$ states. Predictions
are made for cross sections and invariant mass distributions which can be
compared with forthcoming experiments at ELSA.
