  We aim to detect methylamine, CH$_{3}$NH$_{2}$, in a variety of hot cores and
use it as a test for the importance of photon-induced chemistry in ice mantles
and mobility of radicals. Specifically, CH$_3$NH$_2$ cannot be formed from atom
addition to CO whereas other NH$_2$-containing molecules such as formamide,
NH$_2$CHO, can. Submillimeter spectra of several massive hot core regions were
taken with the James Clerk Maxwell Telescope. Abundances are determined with
the rotational diagram method where possible. Methylamine is not detected,
giving upper limit column densities between 1.9 $-$ 6.4 $\times$ 10$^{16}$
cm$^{-2}$ for source sizes corresponding to the 100 K envelope radius. Combined
with previously obtained JCMT data analyzed in the same way, abundance ratios
of CH$_{3}$NH$_{2}$, NH$_{2}$CHO and CH$_{3}$CN with respect to each other and
to CH$_{3}$OH are determined. These ratios are compared with Sagittarius B2
observations, where all species are detected, and to hot core models. The
observed ratios suggest that both methylamine and formamide are overproduced by
up to an order of magnitude in hot core models. Acetonitrile is however
underproduced. The proposed chemical schemes leading to these molecules are
discussed and reactions that need further laboratory studies are identified.
The upper limits obtained in this paper can be used to guide future
observations, especially with ALMA.
