3,5-Dimethylpyrazole
Names
Preferred IUPAC name
3,5-Dimethyl-1H-pyrazole
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.000.597
EC Number
  • 200-657-5
UNII
  • InChI=1S/C5H8N2/c1-4-3-5(2)7-6-4/h3H,1-2H3,(H,6,7)
    Key: SDXAWLJRERMRKF-UHFFFAOYSA-N
  • CC1=CC(=NN1)C
Properties
C5H8N2
Molar mass 96.133 g·mol−1
Appearance white solid
Density 1.027 g/cm3
Melting point 107.5 °C (225.5 °F; 380.6 K)
Boiling point 218 °C (424 °F; 491 K)
Hazards
GHS labelling:
GHS07: Exclamation markGHS08: Health hazard
Warning
H302, H315, H319, H335, H361, H373
P201, P202, P260, P261, P264, P270, P271, P280, P281, P301+P312, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P314, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

3,5-Dimethylpyrazole is an organic compound with the formula (CH3C)2CHN2H. It is one of several isomeric derivatives of pyrazole that contain two methyl substituents. The compound is unsymmetrical but the corresponding conjugate acid (pyrazolium) and conjugate base (pyrazolide) have C2v symmetry. It is a white solid that dissolves well in polar organic solvents.

It is a precursor to a variety of ligands that are widely studied in coordination chemistry including trispyrazolylborate, a trispyrazolylmethane, and a pyrazolyldiphosphine.[1][2]

Condensation of acetylacetone and hydrazine gives 3,5-dimethylpyrazole:[3]

CH3C(O)CH2C(O)CH3   +   N2H4   →   (CH3C)2CHN2H   +   2 H2O

It has found use as a blocking agent for isocyanates.[4]

References

  1. ↑ Reger, Daniel L.; Grattan, T.Christian; Brown, Kenneth J.; Little, Christine A.; Lamba, Jaydeep J.S.; Rheingold, Arnold L.; Sommer, Roger D. (2000). "Syntheses of tris(pyrazolyl)methane ligands and {[tris(pyrazolyl)methane]Mn(CO)3}SO3CF3 complexes: Comparison of ligand donor properties". Journal of Organometallic Chemistry. 607 (1–2): 120–128. doi:10.1016/S0022-328X(00)00290-4.
  2. ↑ Schenck, Terry G.; Downes, J. M.; Milne, C. R. C.; MacKenzie, Peter B.; Boucher, Terry G.; Whelan, John; Bosnich, B. (1985). "Bimetallic reactivity. Synthesis of bimetallic complexes containing a bis(phosphino)pyrazole ligand". Inorganic Chemistry. 24 (15): 2334–2337. doi:10.1021/ic00209a003.
  3. ↑ Johnson, William S.; Highet, Robert J. (1951). "3,5-Dimethylpyrazole". Organic Syntheses. 31: 43. doi:10.15227/orgsyn.031.0043.
  4. ↑ "Blocked Isocyanates" (PDF). Lanxess. June 2020. Archived (PDF) from the original on 2020-09-27.
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