Melting point: 66-69℃
Boiling point: bp4 180-182°; bp2 159-160°
Density: 0.9944 (rough estimate)
Refractive index: 1.5110 (estimate)
Flash point: 9℃
Lidocaine is a local anesthetic and antiarrhythmic drug. It is a derivative of cocaine, but it has no hallucinations and addictive ingredients. Lidocaine hydrochloride is a white crystalline powder, very slightly soluble in water, its toxicity is equivalent to that of procaine, but the local anesthetic effect is strong and lasting, and it has good surface penetration. It can be injected or used as an injection. Surface anesthesia. Lidocaine is a very good local anesthetic. It usually takes effect one to three minutes after administration, and the effect lasts for one to three hours. Used to treat oral ulcers. As a heart rhythm disorder medicine, it has not been used very often, because some people are worried that it will have long-term side effects.
Lidocaine is a first-line drug for the treatment of ventricular arrhythmias caused by acute and severe hemodynamic abnormalities. For some supraventricular arrhythmias, such as bypass-mediated supraventricular tachycardia and acute-onset or parasympathetic nerve-mediated cardioversion of atrial fibrillation is also effective. It is widely used for mucosal surface anesthesia (such as before tracheal intubation). EMLA cream is used for skin surface anesthesia before intravenous intubation. In order to ensure the anesthesia effect, it needs to be applied to the skin for 45-60 minutes, and wrapped with an airtight dressing to promote absorption. EMLA is very useful for rabbit ear vein cannulation and for young dogs and cats.
1. The synthesis of α-chloro-2,6-dimethylacetanilide, add lmI to a dry Erlenmeyer flask. 2,6-dimethylaniline and 0.4ml. Glacial acetic acid, then add 0.6 mL of chloroacetyl chloride [1一] dropwise, while constantly shaking the mixture in the reaction flask. The mixture was heated to 45. C, add 20 mL of 5% sodium acetate solution. The reactant was cooled to below 10℃ and filtered with suction. Wash the precipitate with water several times to remove the acetic acid in the filtrate until the filtrate is neutral, collect the precipitate, and dry it in an oven at 80-125℃ for 20 minutes. The product is about 1g.
2. Synthesis of Lidocaine Add a-chloro-2,6-dimethylacetanilide to a dry round-bottomed flask and use 10ml. After the toluene was dissolved, 2 mL of diethylamine was added. Heat to reflux for about 1 hour, and use thin-layer chromatography to monitor the progress of the reaction until the starting point almost disappears. The mixture was placed in an ice-water bath and cooled to 5℃, and the crystals were removed by suction filtration. The cold filtrate was placed in a separatory funnel, and the filtrate was extracted twice with 3 mol/L hydrochloric acid, each with 6 mL. Cool the acidic aqueous solution of lidocaine to 10℃, slowly add 6mol/L sodium hydroxide solution while stirring until precipitation is formed, then add 2mL of 6mol/L sodium hydroxide solution, and cool the mixture to 20℃. The mixture was extracted twice with 5 mL of petroleum ether, and the organic layer was washed with water and dried with anhydrous potassium carbonate. The petroleum is distilled off to obtain lidocaine crystals, about 0.3 g.