|Company Name:||J & K SCIENTIFIC LTD. |
|Norfloxacin Chemical Properties|
|Norfloxacin Usage And Synthesis|
|Anti-infection drug||Norfloxacin is a quinolone-class anti-infective drug with high degree of antibacterial activity against Escherichia coli, Shigella, Salmonella, Proteus, Pseudomonas aeruginosa and other gram-negative bacteria as well as excellent antibacterial effect against Staphylococcus aureus, pneumococcus bacteria and other Gram-positive bacteria. Its major site of action is in the bacterial DNA gyrase, causing the rapid cracking of the bacteria DNA helix and rapidly inhibiting the bacterial growth and reproduction, finally killing the bacteria. Moreover, it has a strong penetration capability into the cell walls so that it has a stronger bactericidal effect with a small stimulation on the gastric mucosa. |
It is clinically used for treating the susceptible strains caused infection diseases in urinary tract, intestinal, ENT, gynecology, surgery and dermatology with the major indications as follows:
1, genitourinary infections: simple and complicated urinary tract infections, bacterial prostatitis, gonococcal urinary tract infections and reproductive tract infections.
2, gastrointestinal tract infections.
3, typhoid and other Salmonella infections.
Norfloxacin is a concentration-dependent drug which means that the in vivo concentration of the drug is directly proportional to the in vivo efficacy of the drug. The higher the concentration is, the better effect is. As the food will slow down the absorption rate of norfloxacin in the human body, the plasma concentration in the case of taking it before meals (with empty stomach) is 2-3 fold of that in the case of taking it after a meal; therefore, taking it after the meal will greatly reduce the efficacy and may also lead to the drug resistance issue of the susceptible bacteria to the norfloxacin and other similar antimicrobial drugs.
The above information is edited by the Chemicalbook of Dai Xiongfeng.
|Chemical Properties||It is white to light yellow crystalline powder. It is odorless with slightly bitter taste. Upon exposure to the air, it can easily absorb moisture to form a hemihydrate. Its color will be deepened upon light. Solubility (mg / m1) in 25 ℃: 0.28 in water, 0.98 in methanol, 1.9 in ethanol, 5.1 in acetone, 5.5 in chloroform, 0.01 in diethyl ether, 0.15 in benzene, 0.94 in ethyl acetate, 5.1 in octanol, and 340 in glacial acetic acid. It is easily soluble in acidic or alkaline solution and slightly soluble in dimethylformamide. Its solubility in the water depends on the pH value and increases rapidly within the range of at pH <5 or pH> 10. It has a melting point of 218-224 ℃. It has also been reported of a melting point of 220-221 ℃. The maximum UV absorption (0.1mol / L sodium hydroxide solution): about 274,325.336nm (A has a height of about 1109, 437, 425). pKal 6.34; pKa2 8.75. Acute toxicity LD50 in mice, rats (mg / kg): All> 4000 oral administration; all hypodermic 1500; 470,> 500 intramuscular injection; 220,270 intravenous injection.
|Uses||Norfloxacin belongs to third-generation quinolone antibacterial agent developed by Japanese Kyorin Company in 1978. It has features of broad antibacterial spectrum and strong antibacterial activity. It has a strong antibacterial effect against Escherichia coli, pneumobacillus, Aerobacter aerogenes, and Aerobacter cloacae, Proteus, Salmonella, Shigella, Citrobacter and Serratia. It is clinically used for treating the susceptible strain’s causing infections of urinary system, intestinal, respiratory system, surgery, gynecology, ENT and dermatology. It can also be used for the treatment of gonorrhea.
|Production method||Nitration of o-dichlorobenzene or the chlorination of nitro chlorobenzene can both generate 3, 4-dichloro-nitrobenzene. It then undergoes reflux with potassium fluoride in dimethyl sulfoxide for being fluorinated to give 3-chloro-4-fluoro-nitrobenzene. In the presence of hydrochloric acid or aqueous acetic acid, it is further reduced by iron to 3-chloro-4-fluoro-aniline. 3-chloro-4-fluoro-aniline was then subject to reflux together with triethyl orthoformate and diethyl malonate (generate diethyl ethoxymethylenemalonate) in the presence of ammonium nitrate to give the condensation product with heating and cyclization in diphenyl ether or liquid paraffin to form the 7-chloro-6-fluoro-4-hydroxyquinoline-3-carboxylate with ethylation and further hydrolyzation to obtain the ethylated product. Finally, the ethylated product is condensed with piperazine to obtain norfloxacin. Its technology is relatively mature with a relative high yield being generally 40% to 65%. However, when introducing the piperazinyl group to the 7 position, the byproduct with the fluorine atom in 6 position can account for about 25%. It is hard for separation that can affect the yield. The overall yield calculated based on nitro chlorobenzene is above 8%. |
Before the introduction of the pyrazine ring, 1-ethyl-6-fluoro-7-chloro-1,4-dihydro-4-oxo-quinoline-8-carboxylic acid ethyl ester should first react with fluoroboric acid or a boron trifluoride-diethyl ether or boron acetate to have the carbonyl group in 4 position form boron chelate. Further re-introduction of pyrazinyl can reduce the side reactions of the displacement of the position 7’s fluorine and can increase the yield by 15%, as well as improve the quality of the product.
There are many studies regarding the synthesis of norfloxacin at home and abroad. But there have not been too many way for being used in industrial production. The improvement of its synthesis route can be mainly reflected in two aspects. First, improve the process of forming a ring; the second is doing sth on the introduction of piperazine group.
|Acute toxicity||intravenous - rat LD50: 245 mg / kg; Oral - Mouse LD50: 4000 mg / kg
|Flammability and hazardous characteristics||it is combustible with combustion produces toxic fumes of nitrogen oxides and fluorides; Side effect when patients take it: musculoskeletal functional changes
|Storage Characteristics||ventilation low-temperature and dry
|Extinguishing agent||Dry powder, foam, sand, carbon dioxide, water spray
|Chemical Properties||Off-white to light yellow cryst powder|
|Usage||An antibacterial. Fluorinated quinolone antibacterial|
|Usage||Pefloxacin derivative as antibacterial. Fluorinated quinolone antibacterial.|
|Norfloxacin Preparation Products And Raw materials|