Propynal (HC2CHO) was detected in 1988 by
Irvine and co-workers toward
Taurus Molecular Cloud 1 (TMC-1),
where many complex organic molecules have been detected.
The observations were collected with the 43m telescope at
NRAO and also with the
45m telescope at
Nobeyama Radio Observatory. In 1991,
Turner reported a very tentative detection of
propynal toward Sgr B2 (and its absence toward Orion-KL).
Cernicharo and co-workers solidly confirmed
the detection of propynal in 2012 toward the b1 core in
In 2016, Loison and co-workers reported
multiple observations of propynal toward seven starless cores and clouds.