ChemicalBook CAS DataBase List 2-Methylimidazole

2-Methylimidazole synthesis

9synthesis methods

Product Name:2-Methylimidazole
CAS Number:693-98-1
Molecular formula:C4H6N2
Molecular Weight:82.1

2-Methylimidazole is prepared by condensation of glyoxal, ammonia and acetaldehyde, a Radziszewski reaction. It is widely used as a polymeriza tion cross-linking accelerator and a hardener for epoxy resin systems for semiconductor potting compounds and soldering masks.
It is obtained by eliminating dehydrogenation of 2-methylimidazoline. 2-methylimidazoline heated to melt (melting point 107 ℃), carefully add active nickel, raise the temperature to 200-210 ℃ reaction 2h. cool down to below 150 ℃, add water to dissolve, while hot pressure filtration, separation of active nickel, the filter Chemicalbook liquid concentrated to a temperature of 140 ℃ or more, put the material cooling that 2-methylimidazole. Use the method to produce purity of ≥ 98% of the product, 1t product consumption of ethylenediamine (95%) 1095kg, acetonitrile 975kg. better method is to use glyoxal and aldehyde as raw materials.

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693-98-1
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Yield:693-98-1 97%

Reaction Conditions:

with triethylsilane;palladium 10% on activated carbon in tetrahydrofuran at 20; for 24 h;Inert atmosphere;

Steps:

General Procedure:

General procedure: A 16 mL vial with a PTFE/silicone septum and a nitrogen-bubbler line was charged with N-benzylbenzimidazole (208.1 mg, 1.0 mmol), Pd/C (10 wt %, dry powder, reduced) (20 mg) and THF (5 mL). The mixture was treated at rt with triethylsilane (320 μL, 2.0 mmol) and then stirred under nitrogen for 14 h at rt. The mixture was filtered through a 0.45 μM PTFE syringe filter and the filtrate was concentrated in vacuo. The residue was purified by column chromatography (0 to 10% MeOH/ dichloromethane) to afford benzimidazole as a colorless solid (117.6 mg, 0.996 mmol 99%). The reactions generally exhibit an induction period of 5 to 30 min as indicated by the initiation of gas release (i.e., bubbling) from the reaction mixture. The use of Pd/C on a dry matrix is imperative as wet Pd/C results in decreased yield or no reaction.

References:

Graham, Thomas H. [Tetrahedron Letters,2015,vol. 56,# 21,p. 2688 - 2690] Location in patent:supporting information

534-26-9 Synthesis