2018ApJ...862...84F

As one of the simplest molecules containing a peptide bond, N-methyl formamide (HCONHCH₃) represents a potential key molecule involved in the peptide bond polymerization in extraterrestrial ices. Detected tentatively toward the star-forming region Sgr B2(N2), the synthetic pathways have previously been elusive. By exploiting isomer-selective detection of the reaction products via photoionization, coupled with reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), we present compelling evidence for the formation of N-methyl formamide (HCONHCH₃) in astrochemically relevant ice mixtures of methylamine (CH₃NH₂) and carbon monoxide (CO), upon irradiation with energetic electrons as generated in the track of galactic cosmic ray particles (GCRs) penetrating interstellar ices. As one of the simplest molecules containing a peptide bond (-CO-NH-), N-methyl formamide could represent a benchmark involved in radiation-induced peptide bond polymerization in extraterrestrial ices, and thus bring us closer to revealing where in the Universe the molecular precursors linked to the origins of life might have been synthesized.