Isocrotonic acid

Isocrotonic acid
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name
(2Z)-But-2-enoic acid
Other names
(Z)-But-2-enoic acid
(Z)-2-Butenoic acid
cis-2-Butenoic acid
cis-β-Methylacrylic acid
(Z)-β-Methylacrylic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.007.249 Edit this at Wikidata
EC Number
  • 207-973-2
UNII
  • InChI=1S/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/b3-2- ☒N
    Key: LDHQCZJRKDOVOX-IHWYPQMZSA-N ☒N
  • InChI=1/C4H6O2/c1-2-3-4(5)6/h2-3H,1H3,(H,5,6)/b3-2-
    Key: LDHQCZJRKDOVOX-IHWYPQMZBE
  • C/C=C\C(=O)O
Properties
C4H6O2
Molar mass 86.090 g·mol−1
Density 1.03 g·cm−3 [1]
Melting point 12.5–14 °C (54.5–57.2 °F; 285.6–287.1 K)[2]
Boiling point 168 to 169 °C (334 to 336 °F; 441 to 442 K)[1]
Related compounds
Crotonic acid (trans isomer)
Angelic acid
Senecioic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Isocrotonic acid (also known as quartenylic acid; formally named (Z)-2-butenoic acid) is the cis isomer of crotonic acid. It is an oil, possessing an odor similar to that of brown sugar. At its boiling point of 171.9 °C, it converts into crotonic acid. The compound can be prepared from 1,3‑dibromo-2‑butanone via the Favorskii rearrangement.[2]

Ethyl isocrotonate can be prepared by semihydrogenation of ethyl tetrolate.[3]

Rudolph Fittig and Hugo Erdmann showed that the γ-phenyl structural analog of isocrotonic acid forms α-naphthol when dehydrated, an observation that provided useful evidence in understanding the nature of naphthalene.[4]

(Z)-(C6H5)CH=CHCH2COOH   →   α-naphthol   +   H2O

References

  1. ^ a b The Merck Index. An Encyclopaedia of Chemicals, Drugs and Biologicals. 14. Auflage, 2006, S. 894, ISBN 978-0-911910-00-1.
  2. ^ a b C. Rappe (1973). "cis-a,b-Unsaturated Acids: Isocrotonic Acid". Organic Syntheses. 53: 123. doi:10.15227/orgsyn.053.0123.
  3. ^ Michael J. Taschner, Terry Rosen, Clayton H. Heathcock (1986). "Ethyl Isocrotonate". Organic Syntheses. 64: 108. doi:10.15227/orgsyn.064.0108.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Fittig, Rudolph; Erdmann, Hugo (1883). "Synthese des α-Naphtols" [Synthesis of α-Naphtol]. Ber. Dtsch. Chem. Ges. (in German). 16 (1): 43–44. doi:10.1002/cber.18830160115.