| 摘要 |
<p>The methods currently known for the preparation of meclocycline are unsatisfactory as secondary products which are difficult and costly to remove form during different stages of the synthesis. One of the critical points for the synthesis is dehalogenation of the molecule at the 11 position. We have discovered that by performing this stage in a suitable manner, different from those described previously, an appreciably purer compound is obtained which can be more readily increased to a level of purity for pharmaceutical use. Meclocycline, i.e. 7-chloro-6-methylene-5-oxytetracycline (I) <IMAGE> is the drug of choice for the treatment of skin infections because its antibacterial activity against both gram-positive and gram-negative strains is truly very high, its toxicity is low, its absorption through the skin is virtually zero, and one reason for this lack of absorption both via the skin and via the gastrointestinal tract may be its very great capacity to bind with macromolecules present on the absorption surface. In addition to the absorption spectrum, chemical- therapeutic activity and stability are not affected by exposure to UV rays.</p> |
