English Synonyms
2-Amino-3-(3,4-Dihydroxyphenyl)propanoic Acid;3,4-Dihydroxyphenylalanine(Form2);3,4-Dihydroxyphenyl-L-Alanine;3,4-Dihydroxy-L-Phenylalanine;3,4-L-Dihydroxyphenylalanine;3-(3,4-Dihydroxyphenyl)-L-Alanine;3-Hydroxy-L-Tyrosine;beta-(3,4-Dihydroxyphenyl)-L-Alanine
Levodopa Properties
| Melting point | 276-278 °C (lit.) |
| Specific rotation | -11.7 º (c=5.3, 1N HCl) |
| Boiling Point | 334.28°C (rough estimate) |
| Density | 1.3075 (rough estimate) |
| Refractive Index | -12 ° (C=5, 1mol/L HCl) |
| Storage conditions | 2-8°C |
| Solubility | It is slightly soluble in water and almost insoluble in ethanol (96%). It is freely soluble in 1M hydrochloric acid and slightly soluble in 0.1M hydrochloric acid. |
| Acidity coefficient (pKa) | 2.32(at 25℃) |
| Form | Crystalline powder |
| Color | White to creamy |
| Odor | Odorless |
| Fragrance | odorless |
| Water solubility | Slightly soluble in water, dilute hydrochloric acid and formic acid. Insoluble in ethanol. |
| Merck | 14,5464 |
| BRN | 2215169 |
| Stability | Stable. Incompatible with strong oxidizing agents. Sensitive to light and air. |
| InChIKey | WTDRDQBEARUVNC-LURJTMIESA-N |
| LogP | -1.154 (est) |
Introduction
Levodopa is a precursor of dopamine and is a commonly used drug name internationally. Different manufacturers have different trade names when the drug is launched on the market. Oral levodopa tablets generally disintegrate and dissolve in the stomach, then discharge into the duodenum, and then reach the small intestine, where they are absorbed into the blood at the upper end of the small intestine. A small portion of levodopa can eventually pass through the "blood-brain barrier" and enter the brain, where it is taken up by the substantia nigra nerve cells or other nerve cells. Under the action of dopa decarboxylase, it loses a carboxyl group and becomes dopamine, thereby replenishing dopamine in the brain and alleviating the symptoms of Parkinson's disease.
Appearance
Off-white powder; slight odor, no bitterness.
Applications
Levodopa can treat Parkinson's disease and Parkinson's syndrome; treat hepatic coma, improve central nervous system function, make patients awake, and improve symptoms. It can promote sleep and reduce fat; increase bone density and reverse osteoporosis; increase muscle strength and enhance sexual ability.
Chemical properties
White or off-white crystalline powder. Melting point 285.5℃ (decomposition). Soluble in dilute acid, slightly soluble in water, insoluble in ethanol, ether and chloroform. Odorless, tasteless, turns black in the air.
Uses
1. Levodopa is one of the effective drugs for the treatment of Parkinson's disease. It is one of the precursors of norepinephrine, dopamine, etc. in the body and belongs to catecholamine. Levodopa can pass through the blood-brain barrier and enter the brain, and is converted into dopamine by dopa decarboxylase to exert its effects. However, it takes a long time to show effects and has great side effects. Oral LD50 of rats>4000mg/kg.
2. Uses It is an effective drug for the treatment of Parkinson's disease, mainly used for Parkinson's disease, etc.
3. Uses Hydroxylates of tyrosine
Production method
Dopa is contained in some legumes and can be oxidized and polymerized under the action of oxidase to produce melanin. The pods of some legumes turn black when they mature. Melanin such as human and animal hair, squid ink, and watermelon seed coat also belong to this type of melanin. Amino acids - L-DOPA can be extracted from the seeds of Chenopodium album (Mucunas pervirens Hemsl). The extraction method is as follows: crush the quinoa beans and extract them three times at room temperature with a mixture of 30% ethanol and 0.1% acetic acid, each time for 24 hours. Filter to obtain the extract. Concentrate the extract under reduced pressure (21.3kPa) to precipitate crystals, let it stand at 0-10℃ overnight, filter, and crude L-DOPA. Dissolve the crude product with 1N hydrochloric acid, add activated carbon and filter, add a small amount of vitamin C to the filtrate and neutralize it with 2N ammonia water to pH3.5, and a large number of crystals will precipitate. Let it stand at 0-10℃ for 4 hours and filter. The filter cake is washed twice with distilled water containing a small amount of vitamin C, and dehydrated once with acetone. Dry at 60-70℃ to obtain L-dopa. The yield is about 2% based on soybean powder. L-dopa can also be obtained by oxidation of L-tyrosine. Dissolve tyrosine in formic acid phosphoric acid, heat to 40℃ and keep warm for 12 hours, and dilute with 20 times distilled water. The dilution is passed through a strong acid styrene cation exchange resin to adsorb unreacted tyrosine, and then the finished product is obtained after post-processing.
