6-Deoxyneamines

#Aminoglycoside antibacterials containing neamine are well known to those skilled in the art. Two reviews are K. E. Price, et al. Adv. in Appl. Microbiol. 17, 191 (1974) and S. Umezawa, Adv. in Carbohydrates 30, 111 (1974).

#More particularly various deoxyneamines are known. S. Umezawa et al., J. Antibiotics 24, 711 (1971) reported the synthesis of 3',4'-dideoxyneamine derivatives. S. Ogawa, et al., Bull. Chem. Soc. Jap. 49, 1975 (1976) reported the synthesis and biological activity of 5-deoxyneamines. U.S. Pat. No. 3,963,695 claims 3',4',5,6-tetradeoxyneamines. J. Cleophax et al., J. Am. Chem. Soc. 98, 7110 (1976) described the synthesis of 6-deoxyneamine. T. Suami et al., Carbohydrate Research, 53, 239 (1977) describe the synthesis of 5- and 6-deoxyneamine and 5,6-dideoxyneamine.

#Refer to Charts A thru D.

#The invention may be more fully understood from the following examples which are illustrative of the process and compounds of the present invention but are not to be construed as limiting.

#5,6o-Isopropylidene-1,2',3,6'-tetrakis-N-(trifluoroacetyl)-neamine (U.S. Pat. No. 3,984,393, Example 2, 5.0 g.) in acetic anhydride (15 ml.) and pyridine (15 ml.) are stirred at about 22.degree. for 17 hours. After work-up there is obtained 3',4'-di-O-acetyl-5,6-O-isopropylidene-1,2',3,6'-tetrakis-N-(trifluoroacet yl)-neamine. IR (neat) 3400, 1760, 1725, 1560 and 1160-1240 cm.sup.-1 ; NMR (acetone-d.sub.6) 1.34, 1.91, 1.97, 3.1-4.5 and 5.42.delta..

#3',4'-Di-O-acetyl-5,6-O-isopropylidene-1,2',3,6'-tetrakis-N-(trifluoroacety l)-neamine (8.3 g.), acetic acid (56 ml.) and water (30 ml.) are heated at 80.degree. for 1 hour and cooled. The diluent is evaporated under reduced pressure. The residue is dissolved in ethyl acetate-methylene chloride. After washing with water and bicarbonate solution the filtrate is concentrated under reduced pressure. The residue is column chromatographed on silica gel (500 g.) using chloroform-methanol (10:1) for elution. Homogeneous one-spot TLC fractions corresponding to the desired product are pooled and concentrated to give the tilte compound. IR (neat) 3250-3700, 1720, 1760, 1560, 1220, 1580 and 1560 cm.sup.-1 ; NMR (acetone-d.sub.6) 1.90, 1.98, 3.4-4.5, and 5.5.delta..