  Context. As a building block for amino acids, formamide (NH$_2$CHO) is an
important molecule in astrobiology and astrochemistry, but its formation path
in the interstellar medium is not understood well.
  Aims. We aim to find empirical evidence to support the chemical relationships
of formamide to HNCO and H$_2$CO.
  Methods. We examine high angular resolution (~0.2") Atacama Large
Millimeter/submillimeter Array (ALMA) maps of six sources in three high-mass
star-forming regions and compare the spatial extent, integrated emission peak
position, and velocity structure of HNCO and H$_2$CO line emission with that of
NH$_2$CHO by using moment maps. Through spectral modeling, we compare the
abundances of these three species.
  Results. In these sources, the emission peak separation and velocity
dispersion of formamide emission is most often similar to HNCO emission, while
the velocity structure is generally just as similar to H$_2$CO and HNCO (within
errors). From the spectral modeling, we see that the abundances between all
three of our focus species are correlated, and the relationship between
NH$_2$CHO and HNCO reproduces the previously demonstrated abundance
relationship.
  Conclusions. In this first interferometric study, which compares two
potential parent species to NH$_2$CHO, we find that all moment maps for HNCO
are more similar to NH$_2$CHO than H$_2$CO in one of our six sources (G24 A1).
For the other five sources, the relationship between NH$_2$CHO, HNCO, and
H$_2$CO is unclear as the different moment maps for each source are not
consistently more similar to one species as opposed to the other.
