1-Methylimidazole

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1-Methylimidazole
Names
Preferred IUPAC name
1-Methyl-1H-imidazole
Other names
1-Methylimidazole
N-Methylimidazole
NMI
Identifiers
3D model (
JSmol
)
105197
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.009.532 Edit this at Wikidata
EC Number
  • 210-484-7
2403
UNII
  • InChI=1S/C4H6N2/c1-6-3-2-5-4-6/h2-4H,1H3 checkY
    Key: MCTWTZJPVLRJOU-UHFFFAOYSA-N checkY
  • InChI=1/C4H6N2/c1-6-3-2-5-4-6/h2-4H,1H3
    Key: MCTWTZJPVLRJOU-UHFFFAOYAU
  • n1ccn(c1)C
  • Cn1ccnc1
Properties
C4H6N2
Molar mass 82.10 g/mol
Density 1.03 g/cm3
Melting point −6 °C (21 °F; 267 K)
Boiling point 198 °C (388 °F; 471 K)
Hazards
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H302, H312, H314
P260, P264, P270, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P363, P405, P501
Safety data sheet (SDS) Oxford MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

1-Methylimidazole or N-methylimidazole is an

heterocyclic
organic compound with the formula CH3C3H3N2. It is a colourless liquid that is used as a specialty solvent, a base, and as a precursor to some ionic liquids. It is a fundamental nitrogen heterocycle and as such mimics for various nucleoside bases as well as histidine and histamine.

Basicity

With the N-methyl group, this particular derivative of imidazole cannot tautomerize. It is slightly more basic than imidazole, as indicated by the pKa's of the conjugate acids of 7.0 and 7.4.[1] Methylation also provides a significantly lower melting point, which makes 1-methylimidazole a useful solvent.

Synthesis

1-Methylimidazole is prepared mainly by two routes industrially. The main one is

Radziszewski reaction from glyoxal, formaldehyde, and a mixture of ammonia and methylamine.[2][3]

(CHO)2 + CH2O + CH3NH2 + NH3 → H2C2N(NCH3)CH + 3 H2O

The compound can be synthesized on a laboratory scale by methylation of imidazole at the pyridine-like nitrogen and subsequent deprotonation.[4] Similarly, 1-methylimidazole may be synthesized by first deprotonating imidazole to form a sodium salt followed by methylation.[5][6]

H2C2N(NH)CH + CH3I → [H2C2(NH)(NCH3)CH]I
[H2C2(NH)(NCH3)CH]I + NaOH → H2C2N(NCH3)CH + H2O + NaI

Applications

In the research laboratory, 1-methylimidazole and related derivatives have been used as mimic aspects of diverse imidazole-based biomolecules.

1-Methylimidazole is also the precursor for the synthesis of the methylimidazole monomer of pyrrole-imidazole polyamides. These polymers can selectively bind specific sequences of double-stranded DNA by intercalating in a sequence dependent manner.[7]

Ionic liquid precursor

1-Methylimidazole alkylates to form dialkyl imidazolium salts. Depending on the

1-butyl-3-methylimidazolium hexafluorophosphate ("BMIMPF6"):[8][9]

BASF has used 1-methylimidazole as a means to remove acid during their industrial-scale production of diethoxyphenylphosphine. In this biphasic acid scavenging using ionic liquids (BASIL) process, 1-methylimidazole reacts with HCl to produce 1-methylimidazolium hydrochloride, which spontaneously separates as a separate liquid phase under the reaction conditions.[8][10]

2 MeC3N2H3 + C6H5PCl2 + 2 C2H5OH → 2 [MeC3N2H4]Cl + C6H5P(OC2H5)2

Donor properties

1-methylimidazole (NMIz) as a ligand forms octahedral ions M(NMIz)62+with M = Fe, Co, Ni, and a square-planar ion Cu(NMIz)42+. [11] 1-methylimidazole forms adducts with Lewis acids such as molybdenum perfluorobutyrate and [Rh(CO)2Cl]2. The donor properties of 1-methylimidazole have been analyzed by the ECW model yielding EB= 1.16 and CB= 4.92.

See also

References

  1. ISBN 0-485-11092-X
  2. ISBN 978-3527306732
    .
  3. doi:10.1002/cber.18820150207
    .
  4. ISBN 0-582-06420-1
  5. ISBN 0-12-303190-7
  6. ISBN 3-540-65252-3
  7. doi:10.1021/ja960720z
    .
  8. ^
    ISBN 978-3-527-30673-2
    .
  9. doi:10.15227/orgsyn.079.023
    .
  10. PMID 26730217.Open access icon
  11. doi:10.1016/S0020-1693(00)92544-1
    .
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