  We present new ALMA observations aimed at mapping molecular gas reservoirs
through the CO(3-2) transition in three quasars at $z\simeq2.4$, LBQS
0109+0213, 2QZ J002830.4-281706, and [HB89] 0329-385. Previous [OIII]5007
observations of these quasars showed evidence for ionised outflows quenching
star formation in their host galaxies. Systemic CO(3-2) emission has been
detected only in one quasar, LBQS 0109+0213, where the CO(3-2) emission is
spatially anti-correlated with the ionised outflow, suggesting that most of the
molecular gas may have been dispersed or heated in the region swept by the
outflow. In all three sources, including the one detected in CO, our
constraints on the molecular gas mass indicate a significantly reduced
reservoir compared to main-sequence galaxies at the same redshift, supporting a
negative feedback scenario. In the quasar 2QZ J002830.4-281706, we tentatively
detect an emission line blob blue-shifted by $v\sim-2000$ km/s with respect to
the galaxy systemic velocity and spatially offset by 0.2 arcsec (1.7 kpc) with
respect to the ALMA continuum peak. Interestingly, such emission feature is
coincident in both velocity and space with the ionised outflow as seen in
[OIII]5007. This tentative detection must be confirmed with deeper observations
but, if real, it could represent the molecular counterpart of the ionised gas
outflow driven by the AGN. Finally, in all ALMA maps we detect the presence of
serendipitous line emitters within a projected distance $\sim 160$ kpc from the
quasars. By identifying these features with the CO(3-2) transition, the
serendipitous line emitters would be located within |$\Delta v$|$<$500 km/s
from the quasars, hence suggesting an overdensity of galaxies in two out of
three quasars.
