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Pyrazole

January 01, 1970

Pyrazole is an organic compound of azole group with the formula C3H3N2H. It is a heterocycle characterized by a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in ortho-substitution. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugate acid 2.49 at 25 °C).[3] Pyrazoles are also a class of compounds that have the ring C3N2 with adjacent nitrogen atoms.[4] Notable drugs containing a pyrazole ring are celecoxib (celebrex) and the anabolic steroid stanozolol.

Pyrazole
Names
Preferred IUPAC name
1H-Pyrazole[1]
Systematic IUPAC name
1,2-Diazacyclopenta-2,4-diene
Other names
1,2-Diazole
Identifiers
  • 288-13-1 Y
3D model (JSmol)
  • Interactive image
103775
ChEBI
  • CHEBI:17241 Y
ChEMBL
  • ChEMBL15967 Y
ChemSpider
  • 1019 Y
DrugBank
  • DB02757 Y
ECHA InfoCard 100.005.471
EC Number
  • 206-017-1
1360
KEGG
  • C00481 Y
  • 1048
UNII
  • 3QD5KJZ7ZJ Y
  • DTXSID2059774
  • InChI=1S/C3H4N2/c1-2-4-5-3-1/h1-3H,(H,4,5) Y
    Key: WTKZEGDFNFYCGP-UHFFFAOYSA-N Y
  • InChI=1/C3H4N2/c1-2-4-5-3-1/h1-3H,(H,4,5)
    Key: WTKZEGDFNFYCGP-UHFFFAOYAW
  • c1cn[nH]c1
Properties
C3H4N2
Molar mass 68.079 g·mol−1
Melting point 66 to 70 °C (151 to 158 °F; 339 to 343 K)
Boiling point 186 to 188 °C (367 to 370 °F; 459 to 461 K)
Basicity (pKb) 11.5
Hazards
GHS labelling:[2]
Danger
H302, H311, H315, H318, H319, H335, H372, H412
P260, P261, P262, P264, P264+P265, P270, P271, P273, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P305+P354+P338, P316, P317, P319, P321, P330, P332+P317, P337+P317, P361+P364, P362+P364, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)

Preparation and reactions edit

Pyrazoles are synthesized by the reaction of α,β-unsaturated aldehydes with hydrazine and subsequent dehydrogenation:[5]

 

Substituted pyrazoles are prepared by condensation of 1,3-diketones with hydrazine (Knorr-type reactions).[6] For example, acetylacetone and hydrazine gives 3,5-dimethylpyrazole:[7]

CH3C(O)CH2C(O)CH3   +   N2H4   →   (CH3)2C3HN2H   +   2 H2O
 
Novel pyrazole ligands

History edit

The term pyrazole was given to this class of compounds by German Chemist Ludwig Knorr in 1883.[8] In a classical method developed by German chemist Hans von Pechmann in 1898, pyrazole was synthesized from acetylene and diazomethane.[9]

Conversion to scorpionates edit

Pyrazoles react with potassium borohydride to form a class of ligands known as scorpionate. Pyrazole itself reacts with potassium borohydride at high temperatures (~200 °C) to form a tridentate ligand known as Tp ligand:

 

3,5-Diphenyl-1H-pyrazole edit

3,5-Diphenyl-1H-pyrazole is produced when (E)-1,3-diphenylprop-2-en-1-one is reacted with hydrazine hydrate in the presence of elemental sulfur[10] or sodium persulfate,[11] or by using a hydrazone in which case an azine is produced as a by-product.[12]

 

Occurrence and uses edit

 
Celecoxib, a pyrazole derivative used as an analgesic

In 1959, the first natural pyrazole, 1-pyrazolyl-alanine, was isolated from seeds of watermelons.[13][14]

In medicine, derivatives of pyrazole are widely used,[15] including celecoxib and similar COX-2 inhibitors, zaleplon, betazole, and CDPPB.[16]

The pyrazole ring is found within a variety of pesticides as fungicides, insecticides and herbicides,[15] including fenpyroximate, fipronil, tebufenpyrad and tolfenpyrad.[17] Pyrazole moieties are listed among the highly used ring systems for small molecule drugs by the US FDA[18]

 

3-(Difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid is used in the manufacture of six commercial fungicides which are inhibitors of succinate dehydrogenase.[19][20]

See also edit

References edit

  1. ^ "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 141. doi:10.1039/9781849733069-FP001 (inactive 12 April 2024). ISBN 978-0-85404-182-4.{{cite book}}: CS1 maint: DOI inactive as of April 2024 (link)
  2. ^ "Pyrazole". pubchem.ncbi.nlm.nih.gov. Retrieved 17 February 2024.
  3. ^ "Dissociation constants of organic acids and bases" (PDF). (PDF) from the original on 12 July 2017.
  4. ^ Eicher, T.; Hauptmann, S. (2003). The Chemistry of Heterocycles: Structure, Reactions, Syntheses, and Applications (2nd ed.). Wiley-VCH. ISBN 3-527-30720-6.
  5. ^ Schmidt, Andreas; Dreger, Andrij (2011). "Recent Advances in the Chemistry of Pyrazoles. Properties, Biological Activities, and Syntheses". Curr. Org. Chem. 15 (9): 1423–1463. doi:10.2174/138527211795378263.
  6. ^ Nozari, M., Addison, A., Reeves, G.T, Zeller, M., Jasinski, J.P., Kaur, M., Gilbert, J. G., Hamilton, C. R., Popovitch, J. M., Wolf, L. M., Crist, L. E., Bastida, N., (2018) Journal of heterocyclic Chemistry 55, 6, 1291-1307. https://doi.org/10.1002/jhet.3155.
  7. ^ Johnson, William S.; Highet, Robert J. (1963). "3,5-Dimethylpyrazole". Organic Syntheses; Collected Volumes, vol. 4, p. 351.
  8. ^ Knorr, L. (1883). "Action of ethyl acetoacetate on phenylhydrazine. I". Chemische Berichte. 16: 2597–2599. doi:10.1002/cber.188301602194.
  9. ^ von Pechmann, Hans (1898). "Pyrazol aus Acetylen und Diazomethan". Berichte der deutschen chemischen Gesellschaft (in German). 31 (3): 2950–2951. doi:10.1002/cber.18980310363.
  10. ^ Outirite, Moha; Lebrini, Mounim; Lagrenée, Michel; Bentiss, Fouad (2008). "New one step synthesis of 3,5-disubstituted pyrazoles under microwave irradiation and classical heating". Journal of Heterocyclic Chemistry. 45 (2): 503–505. doi:10.1002/jhet.5570450231.
  11. ^ Zhang, Ze; Tan, Ya-Jun; Wang, Chun-Shan; Wu, Hao-Hao (2014). "One-pot synthesis of 3,5-diphenyl-1H-pyrazoles from chalcones and hydrazine under mechanochemical ball milling". Heterocycles. 89 (1): 103–112. doi:10.3987/COM-13-12867 (inactive 17 February 2024).{{cite journal}}: CS1 maint: DOI inactive as of February 2024 (link)
  12. ^ Lasri, Jamal; Ismail, Ali I. (2018). "Metal-free and FeCl3-catalyzed synthesis of azines and 3,5-diphenyl-1H-pyrazole from hydrazones and/or ketones monitored by high resolution ESI+-MS". Indian Journal of Chemistry, Section B. 57B (3): 362–373.
  13. ^ Fowden; Noe; Ridd; White (1959). Proc. Chem. Soc.: 131. {{cite journal}}: Missing or empty |title= (help)
  14. ^ Noe, F. F.; Fowden, L.; Richmond, P. T. (1959). "alpha-Amino-beta-(pyrazolyl-N) propionic acid: a new amino-acid from Citrullus vulgaris (water melon)". Nature. 184 (4688): 69–70. Bibcode:1959Natur.184...69B. doi:10.1038/184069a0. PMID 13804343. S2CID 37499048.
  15. ^ a b Kabi, Arup K.; Sravani, Sattu; Gujjarappa, Raghuram; et al. (2022). "Overview on Biological Activities of Pyrazole Derivatives". Nanostructured Biomaterials. Materials Horizons: From Nature to Nanomaterials. pp. 229–306. doi:10.1007/978-981-16-8399-2_7. ISBN 978-981-16-8398-5.
  16. ^ Faria, Jéssica Venância; Vegi, Percilene Fazolin; Miguita, Ana Gabriella Carvalho; dos Santos, Maurício Silva; Boechat, Nubia; Bernardino, Alice Maria Rolim (1 November 2017). "Recently reported biological activities of pyrazole compounds". Bioorganic & Medicinal Chemistry. 25 (21): 5891–5903. doi:10.1016/j.bmc.2017.09.035. ISSN 0968-0896. PMID 28988624.
  17. ^ FAO
  18. ^ Taylor, R. D.; MacCoss, M.; Lawson, A. D. G. J Med Chem 2014, 57, 5845.
  19. ^ Walter, Harald (2016). "Fungicidal Succinate-Dehydrogenase-Inhibiting Carboxamides". In Lamberth, Clemens; Dinges, Jürgen (eds.). Bioactive Carboxylic Compound Classes: Pharmaceuticals and Agrochemicals. Wiley. pp. 405–425. doi:10.1002/9783527693931.ch31. ISBN 9783527339471.
  20. ^ Jeschke, Peter (2021). "Current Trends in the Design of Fluorine-Containing Agrochemicals". In Szabó, Kálmán; Selander, Nicklas (eds.). Organofluorine Chemistry. Wiley. pp. 363–395. doi:10.1002/9783527825158.ch11. ISBN 9783527347117. S2CID 234149806.

Further reading edit

A. Schmidt; A. Dreger (2011). "Recent Advances in the Chemistry of Pyrazoles. Part 2. Reactions and N-Heterocyclic Carbenes of Pyrazole". Curr. Org. Chem. 15 (16): 2897–2970. doi:10.2174/138527211796378497.

January 01, 1970
pyrazole, organic, compound, azole, group, with, formula, c3h3n2h, heterocycle, characterized, membered, ring, three, carbon, atoms, adjacent, nitrogen, atoms, which, ortho, substitution, weak, base, with, conjugate, acid, also, class, compounds, that, have, r. Pyrazole is an organic compound of azole group with the formula C3H3N2H It is a heterocycle characterized by a 5 membered ring of three carbon atoms and two adjacent nitrogen atoms which are in ortho substitution Pyrazole is a weak base with pKb 11 5 pKa of the conjugate acid 2 49 at 25 C 3 Pyrazoles are also a class of compounds that have the ring C3N2 with adjacent nitrogen atoms 4 Notable drugs containing a pyrazole ring are celecoxib celebrex and the anabolic steroid stanozolol Pyrazole Names Preferred IUPAC name 1H Pyrazole 1 Systematic IUPAC name 1 2 Diazacyclopenta 2 4 diene Other names 1 2 Diazole Identifiers CAS Number 288 13 1 Y 3D model JSmol Interactive image Beilstein Reference 103775 ChEBI CHEBI 17241 Y ChEMBL ChEMBL15967 Y ChemSpider 1019 Y DrugBank DB02757 Y ECHA InfoCard 100 005 471 EC Number 206 017 1 Gmelin Reference 1360 KEGG C00481 Y PubChem CID 1048 UNII 3QD5KJZ7ZJ Y CompTox Dashboard EPA DTXSID2059774 InChI InChI 1S C3H4N2 c1 2 4 5 3 1 h1 3H H 4 5 YKey WTKZEGDFNFYCGP UHFFFAOYSA N YInChI 1 C3H4N2 c1 2 4 5 3 1 h1 3H H 4 5 Key WTKZEGDFNFYCGP UHFFFAOYAW SMILES c1cn nH c1 Properties Chemical formula C 3H 4N 2 Molar mass 68 079 g mol 1 Melting point 66 to 70 C 151 to 158 F 339 to 343 K Boiling point 186 to 188 C 367 to 370 F 459 to 461 K Basicity pKb 11 5 Hazards GHS labelling 2 Pictograms Signal word Danger Hazard statements H302 H311 H315 H318 H319 H335 H372 H412 Precautionary statements P260 P261 P262 P264 P264 P265 P270 P271 P273 P280 P301 P317 P302 P352 P304 P340 P305 P351 P338 P305 P354 P338 P316 P317 P319 P321 P330 P332 P317 P337 P317 P361 P364 P362 P364 P403 P233 P405 P501 Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Y verify what is Y N Infobox references Contents 1 Preparation and reactions 1 1 History 1 2 Conversion to scorpionates 1 3 3 5 Diphenyl 1H pyrazole 2 Occurrence and uses 3 See also 4 References 5 Further readingPreparation and reactions editPyrazoles are synthesized by the reaction of a b unsaturated aldehydes with hydrazine and subsequent dehydrogenation 5 nbsp Substituted pyrazoles are prepared by condensation of 1 3 diketones with hydrazine Knorr type reactions 6 For example acetylacetone and hydrazine gives 3 5 dimethylpyrazole 7 CH3C O CH2C O CH3 N2H4 CH3 2C3HN2H 2 H2O nbsp Novel pyrazole ligands History edit The term pyrazole was given to this class of compounds by German Chemist Ludwig Knorr in 1883 8 In a classical method developed by German chemist Hans von Pechmann in 1898 pyrazole was synthesized from acetylene and diazomethane 9 Conversion to scorpionates edit Pyrazoles react with potassium borohydride to form a class of ligands known as scorpionate Pyrazole itself reacts with potassium borohydride at high temperatures 200 C to form a tridentate ligand known as Tp ligand nbsp 3 5 Diphenyl 1H pyrazole edit 3 5 Diphenyl 1H pyrazole is produced when E 1 3 diphenylprop 2 en 1 one is reacted with hydrazine hydrate in the presence of elemental sulfur 10 or sodium persulfate 11 or by using a hydrazone in which case an azine is produced as a by product 12 nbsp Occurrence and uses edit nbsp Celecoxib a pyrazole derivative used as an analgesic In 1959 the first natural pyrazole 1 pyrazolyl alanine was isolated from seeds of watermelons 13 14 In medicine derivatives of pyrazole are widely used 15 including celecoxib and similar COX 2 inhibitors zaleplon betazole and CDPPB 16 The pyrazole ring is found within a variety of pesticides as fungicides insecticides and herbicides 15 including fenpyroximate fipronil tebufenpyrad and tolfenpyrad 17 Pyrazole moieties are listed among the highly used ring systems for small molecule drugs by the US FDA 18 nbsp 3 Difluoromethyl 1 methyl 1H pyrazole 4 carboxylic acid is used in the manufacture of six commercial fungicides which are inhibitors of succinate dehydrogenase 19 20 See also edit3 5 dimethylpyrazole Pyrazolidine fully saturated analogue imidazole structural analogue of pyrazole with two non adjacent nitrogen atoms isoxazole another analogue the nitrogen atom in position 1 replaced by oxygen References edit Front Matter Nomenclature of Organic Chemistry IUPAC Recommendations and Preferred Names 2013 Blue Book Cambridge The Royal Society of Chemistry 2014 p 141 doi 10 1039 9781849733069 FP001 inactive 12 April 2024 ISBN 978 0 85404 182 4 a href Template Cite book html title Template Cite book cite book a CS1 maint DOI inactive as of April 2024 link Pyrazole pubchem ncbi nlm nih gov Retrieved 17 February 2024 Dissociation constants of organic acids and bases PDF Archived PDF from the original on 12 July 2017 Eicher T Hauptmann S 2003 The Chemistry of Heterocycles Structure Reactions Syntheses and Applications 2nd ed Wiley VCH ISBN 3 527 30720 6 Schmidt Andreas Dreger Andrij 2011 Recent Advances in the Chemistry of Pyrazoles Properties Biological Activities and Syntheses Curr Org Chem 15 9 1423 1463 doi 10 2174 138527211795378263 Nozari M Addison A Reeves G T Zeller M Jasinski J P Kaur M Gilbert J G Hamilton C R Popovitch J M Wolf L M Crist L E Bastida N 2018 Journal of heterocyclic Chemistry 55 6 1291 1307 https doi org 10 1002 jhet 3155 Johnson William S Highet Robert J 1963 3 5 Dimethylpyrazole Organic Syntheses Collected Volumes vol 4 p 351 Knorr L 1883 Action of ethyl acetoacetate on phenylhydrazine I Chemische Berichte 16 2597 2599 doi 10 1002 cber 188301602194 von Pechmann Hans 1898 Pyrazol aus Acetylen und Diazomethan Berichte der deutschen chemischen Gesellschaft in German 31 3 2950 2951 doi 10 1002 cber 18980310363 Outirite Moha Lebrini Mounim Lagrenee Michel Bentiss Fouad 2008 New one step synthesis of 3 5 disubstituted pyrazoles under microwave irradiation and classical heating Journal of Heterocyclic Chemistry 45 2 503 505 doi 10 1002 jhet 5570450231 Zhang Ze Tan Ya Jun Wang Chun Shan Wu Hao Hao 2014 One pot synthesis of 3 5 diphenyl 1H pyrazoles from chalcones and hydrazine under mechanochemical ball milling Heterocycles 89 1 103 112 doi 10 3987 COM 13 12867 inactive 17 February 2024 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint DOI inactive as of February 2024 link Lasri Jamal Ismail Ali I 2018 Metal free and FeCl3 catalyzed synthesis of azines and 3 5 diphenyl 1H pyrazole from hydrazones and or ketones monitored by high resolution ESI MS Indian Journal of Chemistry Section B 57B 3 362 373 Fowden Noe Ridd White 1959 Proc Chem Soc 131 a href Template Cite journal html title Template Cite journal cite journal a Missing or empty title help Noe F F Fowden L Richmond P T 1959 alpha Amino beta pyrazolyl N propionic acid a new amino acid from Citrullus vulgaris water melon Nature 184 4688 69 70 Bibcode 1959Natur 184 69B doi 10 1038 184069a0 PMID 13804343 S2CID 37499048 a b Kabi Arup K Sravani Sattu Gujjarappa Raghuram et al 2022 Overview on Biological Activities of Pyrazole Derivatives Nanostructured Biomaterials Materials Horizons From Nature to Nanomaterials pp 229 306 doi 10 1007 978 981 16 8399 2 7 ISBN 978 981 16 8398 5 Faria Jessica Venancia Vegi Percilene Fazolin Miguita Ana Gabriella Carvalho dos Santos Mauricio Silva Boechat Nubia Bernardino Alice Maria Rolim 1 November 2017 Recently reported biological activities of pyrazole compounds Bioorganic amp Medicinal Chemistry 25 21 5891 5903 doi 10 1016 j bmc 2017 09 035 ISSN 0968 0896 PMID 28988624 FAO Taylor R D MacCoss M Lawson A D G J Med Chem 2014 57 5845 Walter Harald 2016 Fungicidal Succinate Dehydrogenase Inhibiting Carboxamides In Lamberth Clemens Dinges Jurgen eds Bioactive Carboxylic Compound Classes Pharmaceuticals and Agrochemicals Wiley pp 405 425 doi 10 1002 9783527693931 ch31 ISBN 9783527339471 Jeschke Peter 2021 Current Trends in the Design of Fluorine Containing Agrochemicals In Szabo Kalman Selander Nicklas eds Organofluorine Chemistry Wiley pp 363 395 doi 10 1002 9783527825158 ch11 ISBN 9783527347117 S2CID 234149806 Further reading editA Schmidt A Dreger 2011 Recent Advances in the Chemistry of Pyrazoles Part 2 Reactions and N Heterocyclic Carbenes of Pyrazole Curr Org Chem 15 16 2897 2970 doi 10 2174 138527211796378497 Retrieved from https en wikipedia org w index php title Pyrazole amp oldid 1218615718, wikipedia, wiki, book, books, library,

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