Vinyl cyanide, C₂H₃CN, aka acrylonitrile or propenenitrile, has been detected first toward Sgr B2:
F. F. Gardner and G. Winnewisser,
The Detection of Interstellar Vinyl Cyanide (Acrylonitrile),
Astrophys. J. 195, L127–L130 (1975).

The molecule was also detected in the dark cloud TMC-1:
H.E. Matthews and T.J. Sears,
The Detection of Vinyl Cyanide in TMC-1,
Astrophys. J. 272, 149–153 (1983).

It was seen also in one of three translucent clouds (CB 17):
B. E. Turner, R. Terzieva, and E. Herbst,
The Physics and Chemistry of Small Translucent Molecular Clouds. XII. More Complex Species Explainable by Gas-Phase Processes
Astrophys. J. 518, 699–732 (1999).

Quite recently, C₂H₃CN was among several molecules detected with the IRAM 30 m telecope in the circumstellar envelope of the carbon-rich AGB star CW Leo, aka IRC +10216:
M. Agúndez, J. P. Fonfría Expósito, J. Cernicharo, J. R. Pardo and M. Guélin,
Detection of Circumstellar CH₂CHCN, CH₂CN, CH₃CCH, and H₂CS
Astron. Astrophys. 479, 493–501 (2008).

Vinyl cyanide in its two lowest vibrational states v₁₁ = 1 (in plane CCN bend; 239 cm^–1) and v₁₅ = 1 (out of plane CCN bend; 340 cm^–1) has been detected toward Sgr B2(N):
A. Nummelin, P. Bergman,
Vibrationally Excited Vinyl Cyanide in Sgr B2(N)
Astron. Astrophys. 341, L59–L62 (1999).
Previously, three and two lines, respectively, detected in an Orion KL survey have been assigned to vinyl cyanide in its v₁₁ = 1 and v₁₅ = 1 states:
P. Schilke, T. D. Groesbeck, G. A. Blake, and T. G. Phillips,
A Line Survey of Orion KL from 325 to 360 GHz,
Astrophys. J. Suppl. Ser. 108, 301–337 (1997).

Observations of ¹³C singly substituted species in Sgr B2(N) have been reported:
H. S. P. Müller, A. Belloche, K. M. Menten, C. Comito, and P. Schilke,
Rotational Spectroscopy of Isotopic Vinyl Cyanide, H₂C=CH–C≡N, in the Laboratory and in Space,
J. Mol. Spectrosc. 250, 319–325 (2008).
The astronomical observations are based on a molecular line survey carried out with the IRAM 30 m telescope at 3 mm with additional measurements at 2 and 1.3 mm.

The molecular line survey, mentioned in the previous paragraph, was described in detail by
A. Belloche, H. S. P. Müller, K. M. Menten, P. Schilke, and C. Comito:
Complex Organic Molecules in the Interstellar Medium: IRAM 30 m Line Survey of Sagittarius B2(N) and (M)
Astron. Astrophys. 559, Art. No. A47 (2013).
A total of six excited vibrational states of vinyl cyanide were observed in this work. They are v₁₁ = 1, v₁₅ = 1, which both were seen before, plus newly v₁₁ = 2, v₁₁ =  v₁₅ = 1, v₁₁ = 3, and v₁₁ = 3. The latter state has a vibrational energy of about 688 cm^–1 or about 990 K.

A. López, B. Tercero, Z. Kisiel, A. M. Daly, C. Bermúdez, H. Calcutt, N. Marcelino, S. Viti, B.J. Drouin, I. R. Medvedev, C. F. Neese, L. Pszczólkowski, J. L. Alonso, and J. Cernicharo
reported on
Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Vinyl Cyanide in Orion-KL
Astron. Astrophys. 572, (2014), Art. No. A44.
The authors detect one further state newly, v₁₀ = 1, which interacts strongly with v₁₁ =  v₁₅ = 1.

Contributor(s): H. S. P. Müller, 12, 2003; 06, 2008; 03, 2012; 11, 2014