Description
Methylamine Hydrochloride is a colorless organic solid that has an odor similar to that of fish and is used as an essential part for the synthesis of a wide variety of commercial compounds such as ephedrine, theophylline and other intermediates for a wide range of agricultural chemicals, including herbicides, fungicides, insecticides, biocides, and miticides. Methylamine hydrochloride is also a key ingredient in the synthesis of methamphetamine
Chemical Properties
white to light tan solid
Uses
Methylamine is used as a building block for the synthesis of other organic compounds. It is on the DEA watchlist for chemical precursors because of clandestine use in manufacture of the drug MDMA (ecstasy) and methamphetamine.
The HCl salt is in the form of white deliquescent crystals, and is frequently substitutable for the aq. soln. in many synthesis preparations. Methylamines are used directly as catalysts or as raw materials to produce other compounds with catalytic activity. Fuel additives are used to improve engine performance in a variety of ways. Trimethylamine is used to make paper chemicals. The manufacture of intermediates to make pharmaceuticals is one of the most diverse uses of methylamines.
Preparation
Methylamine hydrochloride is prepared by heating a mixture of aqueous formaldehyde and ammonium chloride; the residual water and the formic acid produced in the reaction are removed via vacuum distillation. This leaves behind solid methylamine hydrochloride. The solid is then purified by organic extractions and additional vacuum distillations. Methylamine gas for the reaction with P2P is generated in situ by heating the hydrochloride salt with sodium hydroxide. Alternatively, methylamine can be liberated from the hydrochloride with base and collected in a cold finger or flask immersed in a dry ice bath.
Application
Methylamine hydrochloride can be used as a reactant to synthesize:
Betahistine via aza-Michael reaction with 2-vinylpyridine in water.
Azatripyrrolic and azatetrapyrrolic macrocycles by reacting with pyrrole and formaldehyde via base-catalyzed Mannich reaction.
Tetrahydropyridines via Aza-Diels–Alder reaction with dienes and aldehydes.
N-methylsecondary arylamines from aryl chlorides via nickel-catalyzed amination reaction.
Definition
ChEBI: The hydrochloride formed from methylamine.
Pharmacology
Methylamine hydrochloride reduces blood pressure in both normotensive and hypertensive individuals. It has a gradual onset of action (1/2 to 2 hours) and a long-lasting effect (usually 6 to 12 hours or more). A small oral dosage often produces a smooth and predictable reduction of blood pressure. Although this antihypertensive effect is predominantly orthostatic, the supine blood pressure is also significantly reduced.
Solubility in organics
Very soluble in N,N-Dimethylformamide,Soluble in methanol,Sparingly soluble inglacial acetic acid, Very slightly soluble inchloroform.
Solubility in water
The experimental water solubility of Methylamine hydrochloride at 20 ℃ was 1080mg/L. Methylamine hydrochloride is highly soluble in water.
storage
Keep in a dry, cool and well-ventilated place. Keep container tightly close
Purification Methods
Crystallise the salt from n-butanol, absolute EtOH or MeOH/CHCl3. Wash it with CHCl3 to remove traces of dimethylamine hydrochloride. Dry it under vacuum first with H2SO4 then P2O5. It is deliquescent; store it in a desiccator over P2O5. [Beilstein 4 IV 122.]
Toxics Screening Level
The initial threshold screening level (ITSL) for methylamine hydrochloride is 140 μg/m3 with an 8-hr averaging time.
