Context : The dynamical survival of intermediate-age/old open clusters in the inner Galaxy .

Aims : To establish the nature and derive fundamental and structural parameters of the recently catalogued objects FSR 1744 , FSR 89 and FSR 31 .
This work intends to provide clues to constrain the Galactic tidal disruption efficiency , improve statistics of the open cluster parameter space , and better define their age-distribution function inside the Solar circle .
The current status of the issue dealing with the small number of detected open clusters in the inner Galaxy is discussed .

Methods : Properties of the objects are investigated by means of 2MASS colour-magnitude diagrams and stellar radial density profiles built with field star decontaminated photometry .
Diagnostic-diagrams for structural parameters are used to help disentangle dynamical from high-background effects affecting such centrally projected open clusters .

Results : FSR 1744 , FSR 89 and FSR 31 are Gyr-class open clusters located at Galactocentric distances 4.0 - 5.6 kpc .
Compared to nearby open clusters , they have small core and limiting radii .

Conclusions : With respect to the small number of open clusters observed in the inner Galaxy , the emerging scenario in the near-infrared favours disruption driven by dynamical evolution rather than observational limitations associated with absorption and/or high background levels .
Internally , the main processes associated with the dynamical evolution are , e.g .
mass loss by stellar evolution , mass segregation and evaporation .
Externally they are , e.g .
tidal stress from the disk and bulge , and interactions with giant molecular clouds .
FSR 1744 , FSR 89 and FSR 31 have structural parameters consistent with their Galactocentric distances , in the sense that tidally induced effects may have accelerated the dynamical evolution .