CA1068226A - Aminoglycoside-aminocyclitol derivatives and process for preparing the same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Novel aminoglycoside-aminocyclitol derivatives corresponding to the general formula :
wherein R1 and R2, which are different, represent hydrogen or CH2NH2 and R is selected from the group consisting of :

A = and B =
wherein R3 represents NH2 or OH and R4 represents or wherein R5 represents hydrogen or methyl and the pharmaceutically acceptable acid addition salts thereof.
They are useful as antibiotics.

Description

- ` 1068'~Z6 NOV~ ~MINOG~YCOSIDE - ~MINOC`Y(~LI'~O~ DERIVATIVES AND PROCESS
.
FOR PREPARI~ T~E S~lE~
This invention relates to aminocyclitol derivatives and is concerned with novel aminoglycoside-aminocyclitol derivatives having pharmacological activity and with a process for preparing the same.
~ he aminoglycoside-aminocyclitol derivatives with which the invention i~ concerned can be represented by the ` general formula:
" 10 :: c~l 0~

2 ox .,'., I~ ~
:. ~ I
' ~21 ~~ ~ Z 1ll2 "', ' ~ ' ' Ho OH

wherein Rl and R2, which are different, represent hydrogen or j 20 CH~NH~ and R is sclected f.rom the gro~p consis-ting of:
,~, l~i, ~` 110 --~ ~0 ~ o _ ~ , N112 2 ~ 1~12 ~, H2N o ~~~\ 112N o~~\
\ ~ N112 \ ~ N~12 .,~

A 3 and B = R5 30 wherein R~ represents NH2 or OH, and R4 represent~ CHNH2 or ~, CH3 i~ 1 CHNHCH3 wherein R5 represents hydrogen or methyl.
.~j ' 1 -` ~i ~ - , ~068Z26 The pharmaceutically acceptable acid addition salts of these derivatives are also included within the scope of t;he invention.
~he compounds of formula I can exist in the form of ~pimers and of mixtures of the said epimers.
Such epimers and mixtures thereof are included within the scope of the present invention.
~he compounds of tne present invention have chemical structures which are similar to that of neomycin or paromomycin.
~or this reason~ compounds of formula I will be designated hereinafter as neomycin or paromomycin derivatives as follows:
6-Deoxyneomycin ~ when Rl represents hydrogen, R2 represents CH2~H2 and R represents the group A wherein R3 represents NH2.
; 6-Deoxyneomycin C when Rl represents CH2~H2, R2 represents hydrogen and R represents the group A wherein R3 represents NH2.
The mixture of these two epimer~ as obtained by the process described herein will be referred to hereinafter as -, ~; 20 ~-deoxyneomycin.
6-Deoxyparomomycin 1 when Rl represents hydrogen, R2 represents CH2NH2 and R represents the group A wherein R3 represents OH.
6-Deoxyparomomycin II when Rl represents CH2NH2, R2 represents hydrogen ~nd R represents the group A wherein R3 represents OH.
he mixture of these two epimers as obtained by the ; process described herein will be referred to hereinafter as 6-deoxyparomomycin.
.J
~he mixture of 3~, 4~-dideoxyneomycin and its deri-vatives to designate the unseparated combination of compounds wherein Rl and R2~ which are different, represent hydrogen ~! .

3 ~ --2--!

~ 068Z;~6 or C1~2NH2 and ~ represents the group ~, thé said mixture being obtained by the process described hereinafter.
"Neomycin" will be used herei~after to designate the mixture of neomycin ~ and neomycin C which is obtained when cultivating Streptom~ces fradiae . . .
Similarly, "paromomycin" will be used hereinafter to designate the mixture of paromomycin I and paromomycin II
which is obtalned wnen cultivating StrePtomyce~ rimosu~ forma paromom~cinus.
Another object o~ the invention is to provide a pharmaceutical or veterinary composition containing a~ an -essential active ingredient at least one of the epimers of formula I or a pharmaceutically acceptable acid addition salt thereof or a mixture of the said epimers or of their pharma-ceutically acceptable acid addition salts, in association with , a pharmaceutical carrier or excipient therefor.
Yet another object of the present invention is con-cerned with a process for preparing pharmaceutical or vete-rinary compositions comprising the association of at least one of the epimers of formula I or a pharmaceutlcally accep-table acid addition salt thereof or a mixture of the saidepimers or of their pharmaoeutically accep~able acid addition salts with an appropriate carrier or excipient therefor.
As will be demonstrated further on, the aminogly-co~ide-aminocyclitol derivatives of the invention have been : ~s ~
; found to present raluable antibiotic aotivity which is likely ~-s~ to~ render them useful for -the treatmen-t of disea3cs provoked by~the growth of pathogenic bacteria such a~ for e~ample:
Escherlchia coli, Proteus mira~ , Staph.Yloooccus aureus.
~ ~ Sarcina lutea, Klebsiella edwardsii, Shi~ lla sonnei, S~lmo-` nella ty~ ri;um.

...
~;~ . , , ,, ~

0 ~ 8 ~ ~ ~

~ furt;hcr object of ~he pr~sent inven'ion is therefore concerned with a m~thod for inhibiting the grow.h of pathogenic bacteria in a host in need of such inhibition comprising the administration to said host o~ at least one of the epimers of formula I or a pharmaceu-tically acceptable acid addition salt thereof or a mixture of -the said epimers or of their pharmaceutically acceptable acid addition salts.
It has been observed, for some years, that certain bacterial strains have de~eloped a re~istance to most of the commercialized antibiotics with the result that the therapeutic value of the latter has been reduced by more than half, while certain bacteria are now even strong enough to withstand all the known antibiotics.
It is thus of prime necessity and of general m tere~t to create new antibiotics capable of destroying organisms which ha~e become resistant to antibiotics currently used.
It is kno~m that this inactiv.--tion of antibiotics is dus to the d~struction or alteration of the a~tibiotic mole-;~ cule by enzymes ~hich attack the latter at certain vulnerable polnts.
In particular, the aminogl~coside-aminocyclitol antibiotics which `~ :

` 1068Z26 are being employed on an increasin~ scale are prone to inactivation by resistant bacteria. The resistance developed by some or~anisms normally susceptible to these aminoglycoside-aminocyclitol antibiotics is due to phosphorylating, acylating or adenylylating enzymes which attack the frcc hydro~.yl and amino ~roups of the antibiotic (hnn. Rev. Biochem., ~2, l~7, 1~3~
Removal of the hydroxyl groups will render the antibiotic immune to inactivation at these sites. It is, thus, desirable to produce anti-biotics with less unessential hydroxyl and amino ~roups.
In the course of trials carried out with the compounds of the invention, the mixture of ~'~ 4'-dideoxyneomycin and its derivatives was found to present marked antibiotic activity against organisms which are resistant to other amino~lycoside-aminocyclitol antibiotics and more particularly neomycin and gentamicin.
Thus, it was demonstrated that the mixture of 3~, 4~-dideoxyneomycin and its derivatives i6 active against Escherichia coli strains which are kno~ln to be resistant to eentamicin and neomycin by virtue of the 2"-adenylylating enzyme and the 3'-phosphorylatin~ enzyme respectively For this reason, the mixture of 3~ 4~-dideoxyneomycin and its derivatives, referred to above, is the antibiotic covered by formula I
which is the preferred antibiotic of the invention.
It is known from U S Patent No. 3,669,838 that mutants of micro-or~anisms known to produce antibiotics containin~ an aminocyclitol subunit, such as, for example neomycin or paromomycin, can be formed which lack the capacity to biosynthetize the aminocyclitol subunit because of a defect in the aminocyclitol pathway so that no antibiotic can be produced.
~ owever, such aminocyclitol-negative mutants have the capacity to utilize a suitable aminocyclitol molecule when the latter is added to the nutrient medium so that an antibiotic can be formed.
It is also known that this technique can be utilized by substitutin~
a pseudodisaccharide to the aminocyclitol subunit.
However, from the results disclosed in ex1stin~ publications, it is not possible to predict whether a ~iven diaminocyclitol or a pseudodi-saccharide ~lill be incorporated into an antibiotic by the aforesaid bioconversion technique ". ~

, 1068ZZf~

Therc are, in fact, numerou~ instances described in the literature where this method o~ producing new antibiotics has proved to be ineffective.
The procedure hereabove described cannot, therefore, be generalized for producing new semi-synthetic or totally s~n thetic antibiotics .
This fact is confirmed, for example, in "The Journal of Antibiotics", Vol. XXVI, No~ 10, p. 551-561 (1973) w~ere a description iS given of trials carried out with 29 different aminocyclitols for incorporation into an antibiQtic by the method of the abo~e-cited U.S. Patent.
Amongst the ~9 aminocyclitols so tested it was found that only strepta~ine and 2-epistreptamine were incorporated by means of the 2-deoxystreptamine-negati~e (D ) mutants of Streptomyces fradiae, of strePtomyces rimosus forma Paromo-mycinus and of Streptomyces Xanamyceticus used for this purpose.
i ~ ikewi~3e, the diaminocyclitols cited in ~rench Patent No. 2,203,808 failed to be incorporated into an anti-,~ 20 biotic using the same D mutants o~ S~ fradiae and of S. rimosus for~3a paro~omycinus a9 those utilized in the aforesaid reference. ~ -In "Biochemistry", Vol. 13, No. 25, p. 5073-5078 (1974), it is disclosed that no success was achieved when attempts were made to incorporate the pseudodisaccharides nown as neamine, paromamine or 6-kanosaminido-2-deoxystrep-tamine~using D mutants of S. fradiae, of S rimosus forma L~ Y~ and of S. kanam~ceticus.
Similarly, "~he Journal fo Antibiotics", Vol. XXVIII, ' ~ 3Q ~ ~ No. 8, p. 57~-579 (1975) reports that gentamines, which are r ~ ~ pseudodisaccharides, were not incorporated into antibiotics -1 using a D mutant of Micromonospora inyoensis.

10~8'~

It has also b~en fo~ that 5-0-~D-ribopyranosyl-2,

4-dideo~ystreptamine is incapable o~ producing a~tibiotics using D mutants of S. fradiae and of S. rimosus forma paro-momycinus in accordance with the a~i~e3aid procedure.
Prior publications have also demon~trated that diaminocyclitols or pseudodisaccharides which are present in already known antibiotics, such as stxeptomycin, bluensomycin and hygromycin, cannot be incorporated into antibiotics using the above-cited mutants.
~or example, it is disclosed in "The Journal o~
~ntibiotics", Vol. XXVI, No. 10, hereabo~e cite~, that bluen-samine, streptidine, bluensidine, :

10~8226 hyosamine and actinamine are not incorporated into antibiotics by the D mutants of S. fradiae, S rimosus forma paromom~cinus and S.
ka~amyceticlls when these mutants are used for this purpose.
Similarly, neamine and paromamine, which are found in neomycin and ~aromomycin rcspcctive~y, werc not incor~orated into antibioticF. u-;inG
a D mutant of S fradiae ("Biochcmistry" : refcrence hereabove-cited).
Furthermore, it has also been observed that a diaminocyclitol or a pseudodisaccharide, which can be incorporated into an antibiotic using a mutant strain in accordance with the process of the above-cited U.S.
Patent, will not necessarily be incorporated into an antibiotic by a different mutant strain. Examples are given in the aforesaid reference from "The Journal of Antibiotics", Vol. XXVI, No. 10, which sho~s that a D mutant of S. rimosus forma paromomycinus with 2-epistreptamine does not produce any antibiotic while a D mutant of S. fradiae and of S kanamyceticus are capable of incorporating this subunit into anti-~ . .
~iotics Furthermore, the same D mutant of S. kanamyceticus with streptaminedoes not provide any antibiotic while the sa~e D mutant of S fradiae and of S. rimosus forma paromomycinus incorporates this diaminocyclitol into antibiotics.
~ Jith respect to neamine, this pseudodisaccharide can provide ribostamycin wllen a D mutant of S. ribosidificus is used as reported in "The Journal of Antibiotics", Vol. XXVI, No. 12~ p. 784-785 (1973) while neamine is incapable of bein~ incorporated into an antibiotic when a D mutant of S. fradiae, for example, is employed.
Finally, prior publications also show that the structure of a hypothetical antibiotic cannot be predicted, in any event,-when a diaminocyclitol or a pseudodisaccharide is used together with a mutant strain. This fact is clearly demonstrated in "The Journal of Antibiotics", Vol. XXVI, No. 12, cited above where it is disclosed that the antibiotics obtained when a D mutant of S. kanamyceticus is used together with 1-N-methyl-deo~ystreptamine or myo-inosa-1,3-diamine, are " not the expected products " but other compounds. Likewise~neamine and a D
mutant of M. inyoensis provide sisomicin but this mutant together with paromamine, a different pseudodisaccharide, a~so produces sisomicin (I'The Journal of Antibiotics"~ Yol. XXVIII, llo. 8, cited above).

. .
.

-~ \

It has also been demonstrated that a D mutant of S. ribosidificus in the presence of neamine only provides ribostamycin but not an analog of neomycin as could be expected ("~he Journal of Antibiotics", Vol.
XXVI, No. 12, nbove-cited).
It ir, clear from the fore~oin~ that no valid prediction can be made re~arding the possible incorporation of a particular diaminocyclito1 or pscudodisaccharide into an antibiotic using a given mutant strain in accordance with the procedure of the above-cited U.S. Patent. In no case, i8 it possible to prcdict whether this method will be valid or what will be the exact structure of the antibiotic which it is hoped to produce.
Therefore, the allegation made in J. Or6. Chem.~ Vol. ~, No. 4, p. 456-lt61 (1975) that 2,4-dideoxystreptamine might be incorporated into neomycins, paromomycins and ribostamycin by a bioconversion tcchnique must be considered as excessively vague, indefinite and devoid of any reasonable and valid foundation.
It has now been quite unexpectedly found, in accordance with the present invention~ that 2~4-dideoxystrep~amine can be incorporated into new antibiotics by D mutants of S. fradiae and of S rimosus forma ~aromo~ycinus and that a mixture of pseudodisaccharides i.e. a mixture of gentamines can also be incorporated into new antibiotics by a D
mutant of S. rimosus forma paromomycinus.
This discovery is rendered still more surprisin~ when it is consi-dered that trials carried out with 2,4-dideoxystreptamine in the presence of a D mutant of S. kanamyceticus did not produce any antibiotic and that a D mutant of S. fradiae was incapable of incorporatin~ the mixture of gentamines in question intoi~ antibiotic.
All thë results obtained with 2,4-dideoxystreptamine and the mixture of gcntamines render the invention completely unexpected with respect to the state of the art.
The compounds of the invention can be prepared by cultivating a deoxystreptamine-negative mutant of S eptomyces in an appropriate medium containing a soluble carbohydrate, a source of assimilable nitrogen, essential mineral salts and : i~

~ --7--.. .. .
,~

,. ~ . ~ , . . . .. . ~ . . ... .

a) either 1D-(1, 3, 5/2)-1,5-diamino-2,3-cyclohexanediol or 2,4-dideoxystreptamine of the formula :

2 :
~10 ~\ "' \ . \ II ~`

or an acid addition salt thereof, for example the dihydrochloride.

b) or a mixture of gentaminès represented by the general formula :

~ 0 III

NH2 ¦ NH2 ~ HO ~ ~ NH2 i ~ .
: -8 , , .

or an acid addition salt thereof, wherein R4 has the same meanings as in group B of formula I.
When u~ing the process described herein the antibiotic obtained is in free base form, regardless of whether the dia-minocyclitol of formula II or the mixture of gentamine~ of formula III is in ~ree base form or in the form of a salt. `~
If it is desired to utilize the resulting antibiotic as a salt, it is sufficient to react it with a suitable organic or inorganic acid such as, for example, sulphuric acid, to obtain a pharmaceutically acceptable acid addition salt.
The microorganisms which are used in the present invention are D StrePtomyces fradiae ~CC21401 and D
Streptom~ces rimosus forma paromom.ycinus ATCC21484 both des-cribed in U.S. Patent No 3,669,838: D strePtomyces fradiae A~CC21401 is utilized to produce 6-deoxyneomyoin of the invention and D Streptomyce~ rimo~us forma ~aromomycinus ATCC21484 is employed for the preparation of the 6-deoxy-paromomycin and the mixture of 3',4'-dideoxyneomycin and its ~-derivative~ of the invention. -i ~ 20 In accordance with known techniquest the mioroorganism ~; :
is grown in a nutrient medium having the appropriate pH value and containing for example gluoose, casein hydrolysate, (NH4)2 HP04, NgS04 .7H20, FeS04 .7H20, CuS04 .5H20, CaC03 and then ~ adae~ to another growth medium containing the diaminocyclitol d'', ~ o~formuIa II or the mixture of gentamines of Yormula III both in the; form of~a~free base or of an acid addition salt and, or example~oyabean meal, yea~t extract, NaCl, CaC03 and glucose, again at~ ~he appropriate pH value The culture medium ~is~incubated~at~a temperature of about 28 to ~0C with shaking dj,~ and~ good aeration during at least 5 days to achieve the optimal production of the required 6-deoxyneomycin, 6-deoxyparomomycin ~d ~ 9 _ ~068ZZ6 or the mixture of 3',4~-dideoxyneomycin and its derivatives.
~-Deoxyne`omycin B and ~-deoxyneomycin C as well as 6-dcoxyparomomycin I and 6-deoxyparomomycin II will be obtained from 6-deoxyneomycin and 6-deoxyparomomycin respectively, by conventional procedures, for example by separating them by means of paper chromatography.
~he isomers constituting the mixture of 3',4~-dideoxyneomycin and it~ derivative~ can also be 3eparated by conventional procedures. -The diaminocyclitol of formula II is a known compound having been described in British Patent No 1,445,675. It can be obtained tollowing the method described in the aforesaid British Patent namely by hydrogenating in the presence of a catalyst, for example Raney's nickel, lD-tl, 3, 5/2)-1,5-diazido-2,3-cyclohexanediol obtained from 1~-1,5-di-0-tosyl-1, ~-2, 5/~-cyclohexa~tetrol and sodium azid~.
With regard to the mixture of gentamines of formula III, this can be obtained from commercial gentamicin sulphate by the method of COOPER et al. desoribed in J.Chem. Soc. (c) , 20 1971, 960.
As mentioned hereabove the amino~lycoside-aminocyclitol derivatives of the invention ha~e been found to present v~lu-able antibiotic activity.
his antlbacterial activity against various test organisms is lllustrated by the following data:
a) ~ tibacter]al activit~ of 6-deox~neom~cin and 6-deox~aromom~cin he~e aminoglyco~ide-aminocyclitol derivatives of the invéntion were tcsted for antibiotic activity by adding 3~ ~
measured quantitles o~ the compound under study in sterile water to nutrient agar.

.~ , .

lQ~8'~

Thc agar cont~.irling increasing concentrations of the compound to be tested was thcn poured into ~etri dishes to e~ch of which se~er~l different or~nisms, prevlously gro-~n in an appropriate medium and stored a-t - 20C in a 1 ~o 1 mi.-~ture of growth medium and glycerol were applied mechani-cally with a multiinoculator. The dishes were i~cubated at 37C .for 1~ hours and then inspected for growtn.
The concentration of antibiotic whi~h just i.nhibited growth oE the bacteria was then recorded and was r~ferred to as "min~mum inhibitory concentration`' or M.I.C.
The results regi~tered in this test are listed in ~able I in comparison with neomycin and paro~omycin both in sulphate form.

``` lQ68ZZ6 The figures shown in Tables I and II correspond to the quantity of ~ree base.
TABLE I

:
Organism (a) : ~g/ml required to prevent growth neomycin 6-deoxy- paromomycin 6-deoxy-paro-: : : neomycin: : momycin :
Escherichia coli W 3110 i.e. ATCC 27325 2 ~ 5 1.25 5.0 40 Proteus mirabilis i.e.
: NCIB 11355 : 5~ : 5 1.25 : 20 : Staphylococcus aureus i.e. ATCC 9144 2.5 3.75 1.25 20 Sarcina lutea i.e.
NCIB 11356 2.5 2.5 5.0 40 Klebsiella edwardsii 7.5 10 2.5 4 : Shigella sonnei C63 1978 i.e. NCIB 11357 2 - 5 3.75 2.5 40 Salmonella typhimurium ' LT2 i.e. ATCC 19585 5.0 5.0 2.5 40 , . .
(a) ATCC, American Type Culture Collection ; NCIB, National Collection of Industrial Bacteria (Great Britain) These results show that the removal of the hydroxyl group àt the 6th position of the aminocyclitol moiety of neomycin, which corresponds to 6-deoxyneomycin does not significantly alter the overall antibacterial activity of neomycin. Attention may be drawn to the antibacterial acti-vity of 6-deoxyneomycin against Escherichia coli W 3110 i.e. ATCC 27325 which is superior to that of neomycin.
b)~Acti~ity of 6-deoxyneomycin B and 6-deoxyneomycin C.
The~an~t~ibacterial activity of 6-deoxyneomycin B and 6-deoxyneomycin C
`~ wa~tested~by the same method as that described above using D.S.T. agar a&-~nutrlent edlum and tho~M.I.C. wa~ regiotered in comparison with neomycin~and 6-deoxyneomycin :

`~

.' ,: .
l ~:
~ . . ... .. ..

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h .~f .. .. .. .. . . .. .. . . .. .. .. .. . . .. . . .. .. .. . . ..

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h ~ f C~ f~ ~ f :` .

s~ `d .........................................
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~ h v .. .. .. . .. .. .. .. .; .. .. .. .. .. .. .. .. .. .. ..

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a~ ~ff ,~ ff Frl ~ h ~ ~ ~ O ~
: ,` ~ f~f ~ ;~ f ~; O ~`f ~ O,f :, ~ ~ C) ~ ~ f~ - ` O '~I rl ~f 7.:, ~ : : f~ - ~rl ff--l rl fl~f a~ ff~ ) ~ ~ ~ :hff :af ~ a) ~ fl~ ,~ ~ O ~ f~
~ o ~ h Qh ~qff ~f ~
~ m ~; ~f ~I ff~l ftf~f f~ ff J~ U~ El f~l :~7~ 12- ` ~
f: :~

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~ rom th~se results i~ c~n b~ concluded that 6-deoxy-neumycin B is somewha~ s po-tent th<~n neomycin B but that 6-deoxyneomycin C is more potent t~lan neomycin ~.
c) ~ctivity of the mixture of ~,4'-~id~ox~neom~cin and its _______ _____________________ _________ ____ ___________ derivati~es ___________ The antibacterial activity oY the mixture of 3~,4'-dideoxyneomycin and its derivatives was determined in accor-d~lce with the procedure described hereunder.
D Streptomyc~s rimosus forma paromomycinus ATCC
21484 was incubated at 30C on a nutrient agar plate containing 50 ~g/ml of a mixture of gcntamines of formula ~II. After three days, the plate was overlaid with agar seeded with a test organism ~d the production of antibiotic was shwon by a zone of inhibition around tne StrePtomyc~s. This zone of inhibition was measured an~ compared with that of a control conætituted ~y nutrient agar alone.
As a comparlson, a similar ~est was also carried out wit~ g/ml of ne~nine as a supplement to nutrient agar, in place of the mixture ol g~ntamines o~ formula III and also using D StrePtomyces rimosus ~orma ~aromomyclnus ATCC 21484.
. 'rhe antibiotlc so produc~d ~as found to be neomycin~

~ iO~8Z26 The results obtained are given in the following Table :
Table III
.
Zone of inhibition (in mm) when nutrient : : agar is supplemented with Organism Nothing Neamine Mixture of genta-: : : : mines of formula :
III
:
Eschérichia coli PT2 0 O 21 Escherichia coli ML
: 1629 i.e. NCIB11354 : O : : 25 : Escherichia coli ML
1410 i.e. NCIB11353 O O 20 Escherichia coli JR
66 i.e. NCIB 11352 0 0 25 '' :
The6e figures show that the mixture of 3~,4'-dideoxyneomycin and its derivatives of the invention i8 active against orgar.isms which are -`-re~i6tant to neomycin. It may be added that the orga~ism E. coli PT2 i8 also resistant to gentamicin.
It will be appreciated that for therapeutic use the compounds of the invention will normaly be administered in the form of a pharmaceutical or veterinary composition in a dosage unit form appropriate to the requi-red mode of administration, the composition comprising as active ingre-dient at least one compound of the invention in association with a phar-maceutical carrier or excipient therefor. For oral administration, the n ~ composition may take the form of, for example, a coated or uncoated tablet, à hard- or soft gelatin capsule, a suspension or a syrup. The composition may alternatively take the form of a suppository for rectal, or~vàginal administration, a solutîon or suspension for parenteral àdministration, or a cream or ointment for topioal administration.
The fol`Iowing Examples illustrate the preparation of the compounds of~t~e~invention~

paration of~6-deoxyneomycin baFie and its ~ulphate à)~6_deoxyneomycin in ~free base form In~a~flask, D Streptomyces fradiae ATCC 21401 was grown for 48 hours on~the~following medium previouæly adjusted to pH 7.2-7.3 :

Glucose Casein~hydrolysate ( 4 2 4 ` -13-~0~8ZZ6 so4.7ll2 05 Fe S04,7H20 0.005 -~
Cu S04.5H20 0.005 CaC03 1 ~- ' ' Wnt;er to 00 ml This culture was shaken and maintened at 280C during the indicated period of time, A 10% inoculum of the culture was then added to the fol-lowing growth medium previously adjusted to pH 7,2 to 7,3 :
':
Glucose Soyabean meal 2,5 Yeast extract 0.5 NaCl '5 CaC0~ 0,2 2,4-Dideoxy-streptamine dihydrochlQride 0,025 Water to 100 ml.
Cultures were incubated in Erlenmeyer flasks at 280C to 30C on a rotary shaker and with good aeration, The production of 6-deoxyneomycin started after 2 days and was optimal after 5 days.
Control cultures containin~ no 2,4-dideoxystreptamine dihydrochloride did not produce any 6-deoxyneomycin.
~ ~ The culturè medium was then centrifuged and the supernatant liquid ! ~ poured through a column containing a weakly acidic~ carboxylic (polymetha-~
~ crylic) type cation exchanGe resin of medium porosity (Amberlite IRC-50, ,~ .
, Amberlite is a registered Trade Mark) in the ammonium form.
This operation was undertaken twice to extract the 6-deoxyneomycin and unchanged 2,4-dideoxystreptamine dihydrochloride, The column was washed with~water~and the 6-deoxyneomycin was eluted with a 2N ammonium hydroxide solut~on in water. The~eluate was concentrated under vacuum on a rotary evaporator~and then~ applied~to a Sephadex G-10 column. Elution with a 0~ U-ammonium hydroxide solution gave 6-deoxyneomycin in the first frac-tions snd~2,l~-dideoxystreptamine dihydrochloride in the subsequent fractions By~this method a quantity of 6-deoxyneomycin in free base form was ;produc~d wh1ch repre6ented o3 units (1 unit = 1~g/ml neomycin) of activity.
Thls~oorresponds to~the incorporatlon in the 6-deoxyneomycin ~` ' ;~ : :

thu~ obtained of approximately 22% of the 2,4-dideoxystreptamine dihydro-chloride initially employed.

This repre6ents the maximum activity obtained and further incubation did not result in any increase in 6-deoxyneomycin.

As an alternative process, the crude 6-deoxyneomycin was purified by paper chromatography on Whatman No 3 MM paper developed with a 4/1 methanol/ammonium hydroxide solution. The location of the 6-deoxyneomycin wa6 visualized using 0.25% sodium hypochlorite in water, then absolute ethanol followed by lX soluble starch and 1% pota6sium iodide in water with air-drying between each application. -In this assay, the Rf of the 6-deoxyneomycin was found to be 0.30, For comparison purposes, it may be mentioned that the Rf of neomycin~
of Z-deoxyotreptamine and of 2,4-dideoxystreptamine with the ~ame 6y~tem of ~ol~ents are :

Rf Neomycin 0.26 2-Deoxystrèptamine o.58 2,4-Dideoxystreptamine 0.62 b) 6-Deoxyneomycin ~ul~hate The 6-deoxyneomycin obtained as described above was converted to its 6ulphate salt by reaction with the equivalent quantity of dilute sulphuric `acid.
t~a3~ ~of 6-deoxyneomycin sulphate ~ +430(c = 1.0)water) c) Structure of 6-deoxyneomycin The structure of the antibiotic compound of formula I in free base form obtain~ed hereabove, wa~ determined by comparison with the natural antlbiotio, neomycin, formed when 2-deoxystreptamine i~ incubated in the appropri~ate medium.

10~82Z6 Thc presumed 6-deoxyneomycin is rcferred to hereinafter as Compound X.
}lethanolysis of both neomycin and Compound X with a 10~ methanolic hydrogen chloride solution for two hours under reflux, gave two major prodllct , one of which corIcsponds to methylncobiosamini~c and was pro-duced from both compounds.
The other product referred to hereinafter as Z was different in the two antibiotics, the Z compound from neomycin migratin~ less than the Z
product from Compound X in the chromatographic assay usin~ a 4/1 methanol/
ammonium hydroxide solution as elution solvent.
Confirmation of the structure of each Z wus obtained by mass spectro-metry of the per-trimethyl-silyl derivatives.
Although the molecular ions were not obtained~ the spectra of the/v~r Z compound from neomycin and that of the Z compound from Compound X t~ere/
similar except that two peaks from the spectrum of the former (m/e 343 and It60) were shifted 88 mass units lower in the latter (m/e 255 and 372).
This corresponds to a loss of OSi(C~13)3 and replacement by hydrogen The structure of Z from neomycin thus corresponds to neamine and the structure of Z from Compound X corresponds to 6-deoxyneamine.
~ Acetylation of both Z compounds in methanol followed by acid hydro-i lysis with a 3N hydrochloric acid solution under reflux for 10 hours~ ~ave in each case two maJor products ~- On paper chromatography~ one of these products appeared to be the same in both cases whether obtained from Z issued from neomycin or Z issued from Compound X and must be presumed to be 2,6-diamino-2,6-dideoxy-~-glucose. The other two compounds w~re shown to ~e chromatographically identical to 2-deoxystreptamine from neamine and to 214-dideoxystreptamine f~rom~deoxyneamine.

hc6e results lead to the conclusion that Compound X corresponds bo 6-d~eoxyneomycin.

.,:
, . . ,.. , . - ` .-. - ~ ~ . .. , . ; .. , . `

~0~82Z6 Separation of 6-deoxyneomycin into 6-deoxyneomycin B and 6-deoxy-neomycin C

The 6-deoxyneomycin obtained following the method described in Example 1 was separated into 6-deoxyneomycin B and 6-deoxyneomycin C
by paper chromatography usine a 3/16/6/1 mixture of tert~utanol/buta-none/ 6.5N ammonium hydroxide solution/methanol as 60lvent.

6-Deoxyneomycin B and 6-deoxyneomycin C were detected on the paper using the same method ~s that dc6cribed hereabove.

U6ing aR ~olvent system, methanol and ammonium hydroxide in the proportion of 4 to 1 on 3MM Whatman chromato~raphy paper the ~f values of 6-deoxyneomycin~ B and C were deter~ined in comparison with the correspondin~ epimers of neomycin and the following re~ult6 were obtained 6-Deoxyneomycin B 0.29 `
6-Deoxyneomycin C 0.21 Neomycin B 0,25 Neomycin C 0.165 ~ .

;~ Preparation of 6-deoxyparomomycin and its I and II epimers In a fla~k, D- Streptomyces rimosus forma paromomycinus ATCC 21484 was grown for two to three days on the following medium previously adjusted to pH 7~5 :
F
Soyabean meal Ca~ein hydrolysate 0,25 CaCO, 0 5 G;luco~e NaCl ~ ~ ~-5 NH4Cl 0.167 Water to 100 ml ,.
~, 1 y-. .
.

This culture was shaken and maintained at 28OC during the indicated period of time. A 10X inoculum of this culture was then added to a medium identical to that given hereabove but containing in addition 0.025g of 2,4-dideoxystreptamine dihydrochloride.

Culturcs were incubated in Erlenmeyer flasks at 280 to 30C on a rotary shaker and with good aeration.

The subsequent operations of preparation and purification of the 6-deoxyparomomycin were exactly the same as those described in Example la hereabove.

Purification by paper chromatography under the fiame conditions as those described in the foregoing Example 1 showed that the Rf of 6-deoxyparomomycin was 0,30.

For comparison purpo6es it may be mentioned that the Rf of paromo-~ mycin in an identical chromatographic assay is 0.27.
.j :
Using as solvent sy6tem, methanol nnd ammoniu~ hydroxide in the proportion of 4 to 1 on 3~1M Whatman chromatography paper the Rf values of 6-deoxyparomomycin8 I and II were determined in comparison with the --correspondine epimers of paromomycin and the followin~ results wer~
obtained :
, :
6-Deoxyparomomycin I 0.34 6-Deoxyparomomycin II 0.275 Paromomycin I 0 3 Paromomycin II 0.22 Preparatlon_of the mixture-of 3',4'-dideoxyneomycin and its derivntives a) Mixture of gentamines of formula III
, ~
;A mixture~of gentamineæ of formula III was first prepared from commercially available genta~icin sulphate; This ~alt was first convertel-to its;free ~base and evaporated to obtain an oil. A solution of hydro-ch]orlc acid in methanol, prepared by addin~ hydrochloric acid to dry m~etha~nol, was adde~d to this oil and the solution so obtained wa~ refluxed , ~
'il ~

` : :

for two hours. The methanolic hydrochloric acid was removed under vacuum and the resultant oil wa6 taken up in a little water and pas6ed through a column of ~mberlite I.R.A. 400 to ~rovide the free bafic of tho dcsired Gentaminc~. The difrcrerlt fraction~ 60 collectcd were evaporated to dryness and separated into methyl garo~aminide and mixed gentamines by chromatography on silica gel using a 1~1/1 methanol/
chloroform/ammonium hydroxide mixture as 601vent. In this chromatographic separation methyl garosaminide showed a Rf of o.8 and the mixture of gentamine6 a Rf of 0.2.
-.
b) Mixture of 3',4'-d'ideoxyneomycin and its derivatives In a flafik~ D- Streptom~e~ rimo~us forma paromomycinus ATCC 21484 was grown for two to three days on the following medium previously adjusted to pH 7.5 :
.,: .

Soyabean meal Casein hydroly~ate 0.25 CaC03 .5 ',~ Glucose NaCl .5 NH4Cl 0.167 This culture was shaken and maintained at 280C durin~ the indicated period of time. A 10% inoculum of this culture was then added -' to a medium identical to that given hereabove adjusted to pH 7.2 but ,~ containing in addition 50 ~g of the mixture of gentamines previously -` -~ obtained.

`~ Cul~ure6 were incubated in Erlenmeyer fla~s at ~0C on a rotary baker~and with good aeration during 5 days.
The crude mixture~of 3~4~-dideoxyneomycin and its derivative6 so obtained was purified by paper chromatography on Whatman No 3l:~ paper developed ~ -with~a 4/1 met~hanol/ammonium hydroxide solution. The location of the mixture of 3';4'-dideoxynecmycin and its derivatives was visualized using ~ , ~ ~ , 0,25% sodium hypochlorite in water, then absolute ethanol followed by 1% 601uble 6tarch and 1% potassium iodide in water with air-drying between each application.

In this assay, the Rf of the mixture of 3',4'-dideoxyneomycin and its dcrivatives was found to be 0.25.

For comparison purposes, it may be mentioned that the Rf of the `~
mixture of gentamines of formula III in an identical chromatographic assay is from 0.5 to .?.

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. Process for preparing novel aminoglycoside-amino-cyclitol derivatives corresponding to the general formula :

I
wherein R1 and R2 which are different, represent hydrogen or CH2NH2 and R is selected from the group consisting of :

A = and B =

wherein R3 represents NH2 or OH and R4 represents or wherein R5 represents hydrogen or methyl and pharmaceu-tically acceptable acid addition salts thereof whereby a deoxy-streptamine-negative mutant of Streptomyces is cultivated in an appropriate medium containing a soluble carbohydrate, a source of assimilable nitrogen, essential mineral salts and :
a) either 2,4-dideoxystreptamine of the formula :

or an acid addition salt thereof, to obtain in free base form the compounds of formula I wherein R represents the group A
b) or a mixture of gentamines represented by the general formula :

or an acid addition salt thereof, wherein R4 represents or wherein R5 represents hydrogen or methyl, to obtain in free base form the compounds of formula I wherein R
represents the group B, the said deoxystreptamine-negative mutant of Streptomyces being D? Streptomyces fradiae ATCC21401 or D? Streptomyces rimosus forma paromomaycinus ATCC21484 in the case of 2,4-dideoxystreptamine or salts thereof and D? Streptomyces rimosus forma paromomycinus ATCC21484 in the case of the mixture of gentamines, the free base so obtained being further treated, if desired, with a suitable organic or inorganic acid to give a pharmaceutically acceptable acid addition salt.

2. A process according to Claim 1 wherein R represents the group A in which R3 represents NH2 and R1 and R2 are different and represent hydrogen or CH2NH2.

3. A process according to Claim 2 wherein R represents the group A in which R3 represents NH2, R1 represents hydrogen and R2 represents CH2NH2.

4. A process according to Claim 2 wherein R represents the group A in which R3 represents NH2, R1 represents CH2NH2 and R2 represents hydrogen.

5. A process according to Claim 2, wherein the free base obtained is further treated with sulfuric acid to be in the form of a sulphate salt.

6. A process according to Claim 1 wherein R represents the groupe B and R1 and R2, which are different, represent hydrogen or CH2NH2.

7. Process according to Claim 1 whereby D? Strepto-myces fradiae ATCC21401 is cultivated in the presence of 2,4-dideoxystreptamine or an acid addition salt thereof to obtain 6-deoxyneomycin in free base form.

8. Process according to Claim 1 whereby D? Streptomyces fradiae ATCC21401 is cultivated in the presence of 2,4-dideoxy-streptamine dihydrochloride to obtain 6-deoxyneomycin in free base form.

9. Process according to Claim 1 whereby D Streptomyces rimosus forma paromomycinus ATCC21484 is cultivated in the presence of the mixture of gentamines to obtain the mixture of 3', 4'-dideoxyneomycin and its derivatives in free base form.

10. Process according to Claim 1 wherein the inorganic acid is sulfuric acid