1-cloro-3-metil-2-buteno - 1-cloro-3-metil-2-buteno

IUPAC name
Other names Prenyl
chloride 3,3-dimethylallyl
chloride 3-methyl-2-butenyl
chloride 3-methylcrotyl chloride
Semi-developed formula Cl CH 2 -CH = C (CH 3 ) -CH 3
Molecular formula C 5 H 9 Cl
CAS number 503-60-6[1]
RTECS number EM4298500
ChemSpider 10000
PubChem 10429
Physical properties
Appearance liquid colorless
Density 928 kg/; 0,928 g/cm³
Molar mass 104.58 g / mol
Melting point −82 °C (191 K)
Boiling point 109 °C (382 K)
Vapor pressure 29,6 mmHg
Refractive index (n D ) 1,4488
Chemical properties
Solubility in water 1 g/L
log P 2,72
Family Haloalkene
Flash point 286 K (13 °C)
Related compounds
dichloroalkenes 1,4-dichloro-2-butene
3-chloro-2- (chloromethyl) -1-propene
cloroalcanos 1-chloro-3-methylbutane
Values ​​in the SI and under standard conditions
(25 and 1 atm ), unless otherwise indicated.

The 1-chloro-3-methyl-2-butene is an organic compound of molecular formula C 5 H 9 Cl . It is a haloalkane nonlinear five carbons in which one atom of chlorine is attached to one of the terminal carbons. Also receives the names of prenyl chloride , chloride 3,3-dimethylallyl , butenyl-3-methyl-2 chloride and 3-metilcrotilo chloride . [ 2 ] [ 3 ] [ 4 ]

Physical and chemical properties

At room temperature , 1-chloro-3-methyl-2-butene is a colorless liquid with a density lower than that of water , ρ = 0.928 g / cm³ . It has its boiling point at 109 ° C and its melting point at -82 ° C, although the latter value is estimated. [ 3 ] [ 5 ]

The value of the logarithm of the partition coefficient , log P ≃ 2.72, it indicates that it is soluble in solvents apolar to polar solvents. Very slightly soluble in water, it is miscible with chloroform , acetone , diethyl ether and ethanol . [ 4 ]


1-Chloro-3-methyl-2-butene can be synthesized by reacting isoprene with thionyl chloride in the presence of silica gel at -10 ° C. The reaction time is less than 30 minutes and a yield of 82% is obtained . [ 6 ]

Another synthesis route is through the halogenation of prenol 2 · 8H 2 O / MX mediated by ZrOCl 2 · 8H 2 O / MX in water, X being chloride , bromide or iodide . In this case the yield reaches 93%. [ 7 ] Similarly, the reaction between 2-methyl-3-buten-2-ol and 32% hydrochloric acid provides 1-chloro-3-methyl-2-butene as the major product (84%), while the product secondary (16%) is its 3-chloro-3-methyl-1-butene isomer . [ 8 ]


1-Chloro-3-methyl-2-butene is very useful in organic synthesis . For example, the interaction between acetoacetic ester and 1-chloro-3-methyl-2-butene in the presence of solid potassium carbonate and catalytic amounts of benzyltriethylammonium chloride leads to the selective formation of the monoalkylated product (prenylacetoacetic ester) in high yield. . To obtain the dialkylated product, it is necessary to use a stronger deprotonating agent such as cesium carbonate . [ 9 ]

This chloroalkene has been used in the transformation of ubiquinone-9 to ubiquinone-10 using copper salts as a catalyst . The key stage of this transformation, of the ten that it has, is a Wurtz reaction . [ 10 ] Similarly, 3-hydroxyisoesqualene tosylate has been used in the stereospecific synthesis of a squalene monoisoprenologue by cross-combining according to the Wurtz reaction. [ 11 ] It has also been used in the complete synthesis of geraniol . [ 12 ]

Another use of 1-chloro-3-methyl-2-butene is in the preparation of 2-fluoro-6- (3-methyl-2-butenyl) phenol (FMBP), through its reaction with 2-fluorophenol in the presence of sodium metal. Subsequently the FMBP is oxidatively polymerized to produce poly [oxy-2-fluoro-6- (3-methyl-2-butenyl) -1,4-phenylene] or copolymerized with 2,6-dimethylphenol (DMP). [ 13 ]


1-Chloro-3-methyl-2-butene is a highly flammable compound , with a flash point of 13ºC . Its vapors can form explosive mixtures with air. Contact with this product causes skin and eye irritation. [ 5 ]

See also

The following compounds are isomers of 1-chloro-3-methyl-2-butene:


  1. CAS number
  2. 1-Chloro-3-methyl-2-butene (PubChem)
  3. a b 1-Chloro-3-methyl-2-butene (ChemSpider)
  4. a b 1-Chloro-3-methyl-2-butene (Chemical Book)
  5. a b 1-Chloro-3-methyl-2-butene. Safety data sheet (ThermoFisher)
  6. De Mattos, M.C. .S.; Sanseverino, A.M. (2003). «Surface-Mediated Hydrohalogenation of Isoprene: A Facile Preparation of Prenyl Halides». Synthetic Communications 33 (13): 2181-2186. Consultado el 30 de enero de 2020.
  7. Jafarpour, M.; Rezaeifard, A.; Heidari, M. (2011). «Efficient Organic Transformations Mediated by ZrOCl2·8H2O in Water». Phosphorus, Sulfur, and Silicon and the Related Elements 186 (7): 1470-1482. Consultado el 30 de enero de 2020.
  8. Schneider P.; Cloux, R.; Foti, K.; Kovats, E. sz. (1990). «Tailor-Made Silylating Agents for Efficient Surface Modification». Synthesis 11: 1027-1031. Consultado el 26 de febrero de 2020.
  9. Yufit, S.S.; Esikova, I.A. (1983). «Reactions of carbonyl compounds in the presence of phase transfer catalysts». Bulletin of the Academy of Sciences of the USSR, Division of chemical science 32 (1): 36-41. Consultado el 30 de enero de 2020.
  10. Moiseenkov, A.M.; Veselovskii, A.B.; Filippova, T.M.; Kharchevnikov, A.P.; Obol'nikova, E.A.; Samokhvalov, G.I. (1989). «Transformation of ubiquinone-9 into ubiquinone-10 by the cuprate version of the Wurtz reaction at the key stage». Bulletin of the Academy of Sciences of the USSR, Division of chemical science 38 (7): 1476-1479. Consultado el 30 de enero de 2020.
  11. Veselovskii, A.B.; Filippova, T.M.; Moiseenkov, A.M. (1989). Synthesis of E-C5-homolog of squalene 38 (10). pp. 2107-2110. Consultado el 30 de enero de 2020.
  12. Kwart, H.; Mille, R.K. (1954). «Allylic Rearrangement in the Reactions of 1-Chloro-3-methyl-2-butene; an Attempt at Total Synthesis of Geraniol». J. Am. Chem. Soc. 76 (21): 5403-5405. Consultado el 30 de enero de 2020.
  13. Hyun, S.J.; Nishide, H.; Tsuchida, N.; Yamada, S. (1988). «Preparation and oxidative polymerization of 2-fluoro-6(3-methyl-2-butenyl)phenol». Polymer Bulletin 19 (6): 527-532. Consultado el 30 de enero de 2020.