N. Kaifu, M. Morimoto, K. Nagane, K. Akabane, T. Iguchi, and K. Takagi
reported on the
Detection of Interstellar Methylamine
Astrophys. J. 191, L135–L137 (1974).
They used the Mitaka 6 m telescope for the a-symmetry 5₁₅ – 5₀₅ transition near 73.0 GHz and the 11 m Kitt Peak telescope for the s-symmetry, 4₁₄ – 4₀₄ transition near 86.1 GHz to detect molecular emission from Sagittarius B2.

At the same time,
N. Fourikis, K. Takagi, and M. Morimoto
reported on the
Detection of Interstellar Methylamine by its 2₀₂ – 1₁₀ //A_a// State Transition
Astrophys. J. 191, L139–L141 (1974).
They used the Parkes 64 m telecope to detect the transition near 8.8 GHz in emission toward Sagittarius B2.

Both papers mentioned above reported also the detection toward the Orion A molecular cloud, however, these detections are incorrect, see e.g.
L. E. B. Johansson, C. Andersson, J. Elldér, P. Friberg, Å. Hjalmarson, B. Höglund, W. M. Irvine, H. Olofsson, and G. Rydbeck,
Spectral scan of Orion A and IRC+10216 from 72 to 91 GHz
Astron. Astrophys. 191, L139–L141 (1974).

T. Kamiński, K. M. Menten, R. Tylenda, A. Karakas, A. Belloche, and N. A. Patel
investigated the
Organic Molecules, Ions, and Rare Isotopologues in the Remnant of the Stellar-merger Candidate, CK Vulpeculae (Nova 1670)
Astron. Astrophys. 607, Art. No. A78 (2017).
Methylamine was identified through several transitions covered by the IRAM 30 m and APEX 12 m telescopes.

S. Zeng, I. Jiménez-Serra, V. M. Rivilla, S. Martín, J. Martín-Pintado, M. A. Requena-Torres, J. Armijos-Abendaño, D. Riquelme, and R. Aladro
carried out a study on
Complex Organic Molecules in the Galactic Centre: the N-bearing Family
Mon. Not. R. Astron. Soc. 478, 2962–2975 (2018).
They performed an unbiased molecular line survey of the quiescent molecular cloud G+0.693−0.03 using the GBT 100 m dish (12.7–15.5 GHz and sections of 18–27 GHz) and the IRAM 30 m dish (80–116, 128–176, and 240–272 GHz). The detected five lines of methylamine.

E. G. Bøgelund, B. A. McGuire, M. R. Hogerheijde, E. F. van Dishoeck, and N. F. W. Ligterink
reported on
Methylamine and other simple N-bearing species in the hot cores NGC 6334I MM1–3
Astron. Astrophys. 624, Art. No. A82 (2019).
The authors describe the first unambigous detection of methylamine outside of the Galactic center.

P. Gyawali, R. A. Motiyenko, A. Belloche, I. Kleiner, V. V. Ilyushin, E. A. Alekseev, I. Gulaczyk and M. Kreglewski
described the
Rotational Spectrum and Interstellar Detection of the First Torsionally Excited State of Methylamine
Astron. Astrophys. 677, Art. No. A65 (2023).
Five lines in v_t = 1 were reported as blended or only slightly blended in addition to ten in v_t = 0. The observational data are from the ReMoCA survey of Sagittarius B2(N) carried out with ALMA at 3 mm.

Contributor(s): H. S. P. Müller; 03, 2016; 06, 2019; 08, 2020; 03, 2023; 09, 2023.