摘要:
As new compounds are now provided 5-deoxy-5-fluorokanamycin B, 5,3'-dideoxy-5-fluorokanamycin B, 5,4'- dideoxy-5-fluorokanamycin B and 5,3',4'-trideoxy-5-fluorokanamycin B as well as 1-N-(3-amino-2-hydrox- ypropionyl)-or 1-N-(4-amino-2-hydroxybutyryl)-derivatives thereof which are all useful as antibacterial agents and exhibit improved antibacterial activities. These new compounds may be produced by synthetic processes starting from an appropriately N,O-protected 5-epi-kanamycin B, 3'-deoxy-5-epi-kanamycin B, 4'-deoxy-5-epi-kanamycin B or 3',4'-dideoxy-5-epi-kanamycin B derivative which is now prepared by a combination of reaction steps.
摘要:
As new compounds N-methyl-3-(3,4-dihydroxyphenyl)serine alkyl esters. These are effective as a-adrenergic and β-adrenergic agenta to stimulate the a-adrenergic and β-adrenergic functions of the central nervous system of mammalian animals. Such compounds can be useful for therapeutic treatment of disorders as invoked by reduced biological activities or functions of the a-and/or β-adrenergic neurons. N-methyl-L-threo-3-(3,4-dihydroxyphenyl)serine (C 1 - Cs) alkyl esters are preferred amongst the new compounds of this invention.
摘要:
N-acyl-DL-3-(3,4-dihydroxyphenyl)serine or a catecholic hydroxyl-protected derivative thereof is stereospecifically de-acylated by reaction with a microorganism of Streptomyces or Streptoverticillium having an acylase or with an extract of said microorganism containing said acylase, to produce L-3-(3,4-dihydroxyphenyl)serine or the hydroxyl-protected derivative thereof, with the N-acyl-D-3-(3,4-dihydroxyphenyl)serine compound remaining unaltered. The L-3-(3,4-dihydroxyphenyl)-serine compound so produced can be separated from the N-acyl-D-3-(3,4-dihydroxyphenyl)serine compound owing to its different properties.
摘要:
A tylosin derivative represented by the general formula wherein R. represents a hydrogen atom or a hydroxyl group and R. represents (wherein R 9 and R 10 may be the same or different and selected from a hydrogen atom and C, to C. alkyl groups or which may together form an alkylene group having 3-7 carbon atoms) or -S-R 11 (wherein R " represents a furanyl group or a pyridyl group).
摘要:
As new semi-synthetic antibiotic derivatives are provided N-methanesulfonic acid derivatives of 3-demethoxyistamycin B which are less toxic than the parent 3-demethoxyistamycin B but retain usefully high antibacterial activity of the parent antibiotic. The new derivatives are produced by a method of N-sulfomethylation where 3-demethoxyistamycin B is reacted with an aldehyde such as paraformaldehyde and sulfurous acid or sulfite reagent.
摘要:
3-Amino-2-hydroxy-4-phenylbutanoyl-leucyl-asparagines which are related to bestatin in their chemical structure and which are active to enhance the immune response in living animals are now provided.
摘要:
Caprazol-1"'-amide derivatives of the formula (V) and caprazol-1"'- amide-3"'-ester derivatives from caprazol. The novel caprazol derivatives now synthesized exhibit excellent antibacterial activities against a variety of bacteria including acid-fast bacteria.
摘要:
An antibiotic SF2487 substance having the formula (I) or a salt thereof possesses an antimalarial activity against the proliferation of malarial parasites and is therefore useful as an antimalarial drug.