Preparation and some microbiological properties of novel kanamycin-glucoside derivatives.

Some years ago, glycosyl derivatives of kanatnycin A (KMA) were obtained enzymatically by ENDo et al.') and chemically by PERLMAN et al.'" Although their chemical and biological properties were partially described, their precise chemical properties and antibacterial activities against drug-resistant bacteria producing specific aminoglucosides-inactivating enzymes were not mentioned. In this study, we have prepared new reduced types of KMAglucosides and their chemical and microbiological properties have been investigated. At first, we tried to prepare the enzymatically-derived compounds by the method of ENDO et a1.". Utilizing the identical method, we prepared the glucosyl derivative of KMA by transglucosylase activity of ClaraseR. We detected a glucosyl derivative possessing the same properties as described by them. However, this compound could not be regarded as the O-glucoside, reported in the case of neamine", because analysis in high-voltage paper electrophoresis (pH 1.8, 220 volts/cm, about 40 mA/cm, for 30 minutes, with Model HV 5000-3 of Savant Instruments, Inc.) and in silica gel thin-layer chromatography (using CHC13 MeOH NH4OH, 1:3:2), showed unchanged mobility and failed to detect reducing sugar after hydrolysis of this derivative with purified a-glucosidase from Aspergillus niger or Rhizopus delemar. An additional reason against the existence of an O-glucoside is that boiling the derivative in phenylhydrazine hydrochloride solution has liberated free KMA with the precipitation of phenylglucosazone. All our attempts to synthesize the O-glucosides of KMA using maltose as a glucosyl donor have been unsuccessful by enzymes such as purified a-glucosidase from Aspergillus niger or Aspergillus oryzae or Rhizopus delemar which are found to associate with partial transglucosylase activity and by crude cyclodextrin glycosyltransferase produced by Bacillus macerans. We have tried to prepare different type of glucosides of KMA by the following method: 1.0 g KMA (free base) and 4.0 g glucose were dissolved in 10 ml of 0.02 N NH4OH and after gradual addition of 1.0 g NaBH4 with stirring, the reaction mixture was permitted to stand for 5 hours at 45°C. In order to degrade excess