Acetamidine hydrochloride
| Names | |
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| IUPAC name
Ethanimidamide; hydrochloride
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| Other names
Acetamidinium chloride
Ethanimidamide monohydrochloride | |
| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | Lua error in Module:Wikidata at line 879: attempt to index field 'wikibase' (a nil value). Lua error in Module:Wikidata at line 879: attempt to index field 'wikibase' (a nil value). |
| E number | Lua error in Module:Wikidata at line 879: attempt to index field 'wikibase' (a nil value). |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C2H7ClN2 | |
| Molar mass | 94.54 g·mol−1 |
| Structure | |
| Monoclinic | |
| C2/c | |
a = 11.673, b = 9.862, c = 9.601 α = 90°, β = 111.71°, γ = 90°[1]
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| Hazards[2] | |
| GHS pictograms | 
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| GHS Signal word | |
| <abbr class="abbr" title="Error in hazard statements">HH315, <abbr class="abbr" title="Error in hazard statements">HH319, <abbr class="abbr" title="Error in hazard statements">HH335 | |
| <abbr class="abbr" title="Error in hazard statements">PP261, <abbr class="abbr" title="Error in hazard statements">PP264, <abbr class="abbr" title="Error in hazard statements">PP271, <abbr class="abbr" title="Error in hazard statements">PP280, <abbr class="abbr" title="Error in hazard statements">PP312, <abbr class="abbr" title="Error in hazard statements">PP302 + P352, <abbr class="abbr" title="Error in hazard statements">PP304 + P340, <abbr class="abbr" title="Error in hazard statements">PP305 + P351+P338, <abbr class="abbr" title="Error in hazard statements">PP362+P364, <abbr class="abbr" title="Error in hazard statements">PP403+P233, <abbr class="abbr" title="Error in hazard statements">PP501 | |
| NFPA 704 (fire diamond) | <imagemap>
File:NFPA 704.svg|80px|alt=NFPA 704 four-colored diamond poly 150 150 300 300 150 450 0 300 Health 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroform poly 300 0 450 150 300 300 150 150 Flammability 0: Will not burn. E.g. water poly 450 150 600 300 450 450 300 300 Instability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogen poly 300 300 450 450 300 600 150 450 Special hazards (white): no code desc none </imagemap> |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Acetamidine hydrochloride is an organic compound with the formula CH
3C(NH)NH
2 · HCl, used in the synthesis of many nitrogen-bearing compounds. It is the hydrochloride of acetamidine, one of the simplest amidines.
Properties
Acetamidine hydrochloride is a hygroscopic solid which forms colourless monoclinic crystals.[1] It is soluble in water and alcohol.
It releases ammonium chloride upon heating. Dry acetamidine hydrochloride releases acetonitrile, while in aqueous solution, it instead undergoes hydrolysis to acetic acid and ammonia.[3]
CH
3C(NH)NH
2 · HCl → CH
3CN + NH
4Cl
CH
3C(NH)NH
2 · HCl + 2 H
2O → CH
3COOH + NH
3 + NH
4Cl
As free base amidines are strong Lewis bases, acetamidine hydrochloride is a weak Lewis acid. Treatment with strong base gives free base acetamidine:
CH
3C(NH)NH
2 · HCl + KOH → CH
3C(NH)NH
2 + KCl + H
2O
Synthesis
Acetamidine hydrochloride is synthesised in a two-step process that begins with a solution of acetonitrile in ethanol at close to 0 °C.[4] First, the mixture is treated with anhydrous hydrogen chloride in a Pinner reaction, producing crystals of acetimido ethyl ether hydrochloride:
H
3C–C≡N + C
2H
5OH + HCl → H
3C–C(=NH · HCl)–OC
2H
5
The imino ether salt is then treated with an excess of ammonia in dry ethanol, converting the ether to the amidine:
H
3C–C(=NH · HCl)–OC
2H
5 + NH
3 → H
3C–C(=NH)–NH
2 · HCl + C
2H
5OH
All reagents must be thoroughly dried using a strong desiccant such as phosphorus pentoxide, as the intermediate imido ether is susceptible to hydrolysis, yielding ammonium chloride and ethyl formate. Layers of ammonium chloride can form on the imido ether salt, limiting the formation of amidine.[4]
Applications
As a source of amidine, acetamidine hydrochloride is a precursor to the industrial and laboratory synthesis of many nitrogen compounds. It reacts with β-dicarbonyls to produce substituted pyrimidines,[5] with acetaldehydes to form substituted imidazoles,[6] and with imidates to form substituted triazines.[7]
In particular, its reaction with a dicarbonyl intermediate is an early step in the synthesis of thiamine (vitamin B1) and many of its derivatives.[8]
References
This article "Acetamidine hydrochloride" is from Wikipedia. The list of its authors can be seen in its historical and/or the page Edithistory:Acetamidine hydrochloride. Articles copied from Draft Namespace on Wikipedia could be seen on the Draft Namespace of Wikipedia and not main one.
- ↑ 1.0 1.1 Cannon, Jack R.; White, Allan H.; Willis, Anthony C. (1976). "Crystal structure of acetamidinium chloride". Journal of the Chemical Society, Perkin Transactions 2 (3): 271. doi:10.1039/P29760000271.
- ↑ Fisher Scientific, acetamidine hydrochloride 98+%
- ↑ Shriner, R. L.; Neumann, Fred W. (1944). "The Chemistry of the Amidines". Chemical Reviews. 35 (3): 351–425. doi:10.1021/cr60112a002.
- ↑ 4.0 4.1 Template:OrgSynth
- ↑ Chu, Xue-Qiang; Cao, Wen-Bin; Xu, Xiao-Ping; Ji, Shun-Jun (2017). "Iron Catalysis for Modular Pyrimidine Synthesis through β-Ammoniation/Cyclization of Saturated Carbonyl Compounds with Amidines". The Journal of Organic Chemistry. 82 (2): 1145–1154. doi:10.1021/acs.joc.6b02767.
- ↑ Wang, Jing; Zhang, Fang-Dong; Tang, Dong; Wu, Ping; Zhang, Xue-Guo; Chen, Bao-Hua (2017). "I2/TBPB mediated oxidative reaction of aryl acetaldehydes with amidines: Synthesis of 1,2,5-triaryl-1H-imidazoles". RSC Advances. 7 (40): 24594–24597. Bibcode:2017RSCAd...724594W. doi:10.1039/C7RA01966A.
- ↑ US patent 3203550A, Frederic Charles Schaefer, "Method for the preparation of substituted s-triazine compounds", issued 1965-08-31, assigned to American Cyanamid Company
- ↑ Tylicki, Adam; Łotowski, Zenon; Siemieniuk, Magdalena; Ratkiewicz, Artur (2018). "Thiamine and selected thiamine antivitamins — biological activity and methods of synthesis". Bioscience Reports. 38. doi:10.1042/BSR20171148. PMID 29208764.
