CA1050975A - 2-HYDROXY-.omega.-AMINOALKYL-DERIVATIVES OF AMINOGLYCOSIDE ANTIBIOTICS - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Compounds of the general formula:

where R1 represents a hydrogen atom or a lower alkyl group;
R2 represents an amino or hydroxyl group;
one of R3 and R4 represents a hydrogen atom, while the other represents a glycosyl group as herein defined; and n is 4, 5 or 6;
and their pharmaceutically acceptable acid addition salts.

Description

7~
This invention relates to antibacterial agents and is particularly concerned with novel antibacterial

2-deoxy-streptamine aminoglycosides and with methods for the preparation of such compounds.
According to our Co-pending Application Number 238246, there are provided novel compounds having the general formula~
CH2NHRl NH2 N~lcEl2cH(c~l2)n 2 HO R2 R30 oR4 .~.(I) ; .
where R1 represents a hydrogen atom or a lower alkyl group;
R2 represents an amino or hydroxyl group;
~, one of R3 and R4 represents a hydrogen atom, ; while the other represents a glycosyl group as hereinafter defined; and n is 1, 2 or 3;
wherein R3, when it is a glycosyl group, is of ~he formula:

O~
HO-CH ~ ~
2 l l or ~'1 HO OH

~' H N-CH~ : ~ O ~
.~0 0~0 0~

HO ~ -2- b~

:.~' ' ' ' ," .'. :,': :, ", ", " ' " . :' ',', '. " ' :' :"". .' ' .,, . ''. '. " . "' "'' . ' . ' '. ,. ' ',' " ' , '.: , ' . ,."' ' ' , i ~ ~
75;, -and R9, when it is a glycosyl group, is o the formula:
~0 , ' `. HO~CH2-OH
~ 2N b}~
and their pharmaceutically-acceptable acid addition salts.
When R4 represents a glycosyl gro~p such group may be a ~ingle hexopyranosyl group, prefera~bly containing an amino group, for example, a 3-amino-3-deoxy--D-glycopyranosyl gr~up as found in kanamycin A and B. When R3 represents a glycosyl group such group is generally a pentofuranosyl group, optionally iinked to a further hexopyranosyl group by a further glycosidic linkage. For example, R may be a ~-D-ribofuranosyl group as found in ribostamycin. The term lower alkyl group means a group containing from 1 to 4 carbon atoms which may be straight or branched chain.
-~acording to the present invention, which is an improvement or modification. of the invention the subject of the above-mentioned Application Number 238,246, there are ~ow provided a process ~or the production of~novel compounds of the general formula:
'' C~12NEIR

il~O ~i~gCH2CH(CH2)nilH

HO R OR ...~
where R represents a hydrogen atom or a lower alkyl group;
R2 represents an amino or hydroxyl group; ~
one of R and R represents a hydrogen atom, while ~;the other represents a glycosyl gsoup as herein definèdj and n is 4, 5 or 6; ~
wherein R , when it is a glycosyl group, is of the formula: HO-C~2 il2ilCI~

HOCH~ ~ ~ ; or ~ ~ ~ ~ ' :

2~
ana R4, when it is a glycosyl group, is o~ the formul2l~-r -2a-~5C39~5 ~o HO ~ ~ CH2-OH

and their pharmaceutically acceptable acid addition salts, which comprises reducing a compound of the formula:

CH2NHRl \2 H ~ _ O ~ _ NHC-~H~CH2)n_lxNH2 HO 2 oR4 ...(II) where Rl to R4 and n are as previously defined and X is CH2 or CO, and isolating the compound of E`ormula (I).
Pharmaceutically-acceptable acid addit:ion salts ' of the compounds of the invention are those formed from acids which form non-toxic acid addition salts containing pharmaceutically-acceptable anions, such as the hydrochloride, hydrobromide, sulphate, or bisulphate, phosphate or acid phosphate, acetate, maleate, fumarate, lactate, tartrate, citrate, gluconate, succinate, p-toluene sulphonate and carbonate salts.
The compounds of the invention may be prepared by the methods described in the complete Specification of the above-mentioned Application Number 238246, for example, by ` reduction o a compound of the formula:

CH2N ~ NH2~ O OH
HO ~ O _ ~ NH -CH(CH2)nNH2 , HO R oR4 ................................. (II) where Rl to R4 are as previously defined and n is 4 to 6, by , ~ 3- ::
.'' ~,~i. ~
' :' ~5~975 reacting with a reducing agent in a suitable solvent in order to effect reduction o the amide link at N~l.
Many of the compounds of Formula (II) are known compound~ previously disclosed, for example, l-N-(6-amino-2-hydroxy~hexanoyl)-kanamycin A is described in J Anti-biotics, 1974, 27, 851. Other compounds may be prepared by analogous methods to those disclosed therein.
; Generally, the rings are each in the "chair"
form, and each of the substituent groups is disposed equa-torially with respect to khe ring. Furthermore, the glyco-sidic linkage between the hexopyranosyl ring and the 2-de-oxystreptamine ring is more usually an -linkage with respect to the former, particularly when the compounds of Formula ~II) are derived ~rom naturally-occurring 2-deoxy-streptamine aminoglycosides. Additionally, the ~-hydroxy-~aminoalkyl group at N-l may exist in the S- or R-form or may be present as a mixture of both optical isomers.
The in vitro evaluation of compounds of the in-.
vention as antibacterial agents is performed by determining the minimum inhibitory concentration (M~I~Co) of the testcompound in a suitable medium at which growth of the parti cular microorganism fails to occur. In practice, agar plates, each having incorporated therein the test compound at a particular concentration are inoculated with a standard number of cells of the test microorganism and each plate is then incubated for 24 hours at 37~C. The plates are then observed for the presence or absence of the growth of bacteria and the appropriate M.I.C. value noted Micro- -organisms used in such tests have included strains of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, .~ .

9~7~

; Pseudomonas ~ , ~ us aureus ~nd ' coccus faecalisO
_ vivo evaluation is carried out by administering the compounds subcutaneously to mice which are exposed to a strain of Escherichia coliO Each compound is administered at a series of dosage levels to groups of mice and its activity is determined as the level at which it gives 50 protection, against the lethal effect of the Escherichia coli organism over a period of 72 hours.
For human use, the antibacterial compounds of the invention can be administered alone, but w:ill generally be administered in admixture with a pharmaceut:ical carrier selected with regard to the intended route of administration and standard pharmaceutical practice. For example, they may ; 15 be administered orally in the form of tablets containing /
such excipients as starch or lactose, or in capsules either alone or in admixture with excipients, or in the form of elixirs or suspensions containing flavoring or coloring "
agents. They may be injected parenterally, for example, intravenously, intramuscularly or subcutaneously. For parenteral administration, they are best used in the form of a sterile aqueous solution which may contain other solutes, ~ for example, enough salts or glucose to make the solution ;~ isotonic.
` 25 For administration to human patients, it is expected that the daily dosage level of the antibacterial compounds of the invention will be comparable with that of aminoglycoside antibacterial agents currently in use, e.g., ~rom 0.1 to 50 mg/kg (in divided doses) when administered i, by the parenteral routes, or from 10 to 100 mg/kg (in ; :
' ~ ' . .

~5~75 divided doses) when administered by the oral route. Thus tablets or cap~ules of the compounds can be expected to con-tain from 0.1 to 1 g of active compound for administration orally up to 4 times a day, while dosage units for parenteral administration will contain from 10 l:o 500 mg of active ~ compound. The physician in any event will determi.ne the -~ actual dosage which will be most suitable for an individual patient and it will vary with age, the weight and response ; of the particular patient. The above dosages are exemplary of the average host. ThPre can, of course, be individual cases where higher or lower dosage ranges are merited, and such are within the scope of this invention.
; The ~ollowing Example describes the preparation of one particular compound according to the invention.
Temperatures are given in C; "Sephadex" is a registered trade mark.
E X A M P L E
l-N~(S)-2-hydroxy-6-amino-hexanoyl]-kanamycin A
dicarbonate ~1.0 g, 1.36 mmole) was dissolved in anhydrous trifluoroacetic acid ~10 ml) and the solution evaporatod to dryness under vacuum to yield a viscou~ gum. The residue was treated with a 1 molax solution of diborane in tetra-hydrofuran (75 ml) under an atmosphere of dry nltrogen, and the resulting ~olution heated at 50-55 for five hours.
Evaporation of the organic solvent under reduced pre$~ure yielded a gum which was taken up in 2N hydrochloric acid ~10 ml). After 10 minutes the solukion was basified to p~
with 5N sodium hydroxide solution and finally taken to p~ 6 with 2N hydrochloric acid. The solution was then chromatographed on a column of Sephadex CM-25 in the ` ammonium-ion form (3.5 x 90 cm) eluting with water and a gradient of ammonium hydroxide of inc:reasing concentration from 0 to 0.6N. Fractions containing the product, as monitored by thin layer chromatography were combined and - 5 evaporated under vacuum to yield l_N~ e~L~_ amino-hexyl]-kanamycin A (0.64 g, 63~)o Thin layer electrophoresis. Rf = 0.85 - (The electrolyte was an equipart mixture of acetic and formic acids, giving a pH value o 2, and a ~- 10 potential difference of 900 volts was applied across the ends of the 20 cm silica coated plate for 45 minutes.
Detection was performed by drying the plate, spraying with a cyclohexane solution of tertiary butyl hypochlorite and then drying, cooling and developing the plate with starch-potassium iodide solution. Under these conditions the . .
starting material gave an Rf value of 1.0)~
Mass s~ectrometry . .
~i, A sample was converted to the volatile penta-N-acetyl-octa-O-trimethyl~ilyl derivative by treatment with , acetic anhydride in methanol at room temperature for 24 hours followed by reaction with a 2:1 mixture of hexamethyl-di~ilazane and trimethylchlorosilane at room temperature for , 24 hours. /e found 1385.C58H123N5O17Si8 requires m/e 1385.
Results of the testing of the compound of the .l 25 Example for antibacterial activity in vitro by the methods ;,Z previously described are given in the folIowing Table.
-¦ TABLE: In vitro activ ty ,, .
1 M.I.C.'s (~ug/ml) } Klebsiella Proteus Pseudomonas Sta~ylococcus E. Coli pneumoniae mirabilis aeru~inosa aureus ~ -6.2 6.2 3.1 3.1 1.6 , . , , ; : . . . ~ . . ::: .. : :

~5l9~75 It will be appreciated from the foregoing that .. what we wlll claim may comprise any novel feature described herein, for e~ample:
(1) Novel 2 deoxystreptamine am.inoglycosides of Formula ~I) as previously defined;
~ 2) Pharmaceutical compositions comprising a novel aminoglycoside of the Formula (I) as a pharmaceutically acceptable acid addition salt;

(3) A method of treating gram-positive and gram-nega-tive antibacterial infections in animals, includinq humansby administration of novel aminoglycosides of Formula (I) .in therapeutic dosages;

(4) Processes for the preparation of novel aminoglyco-sides of Formula ~I) as previously described. :

i, .
. ~'.

. .

Claims (8)

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

1. A process for preparing novel 2-deoxystreptamine-amino-glycosides of the general formula:
...(I) where R1 represents a hydrogen atom or a lower alkyl group;
R2 represents an amino or hydroxyl group;
one of R3 and R4 represents a hydrogen atom, while the other represents a glycosyl group as herein defined; and n is 4, 5 or 6;
wherein R3, when it is a glycosyl group, is of the formula:

or and R4, when it is a glycosyl group, is of the formula:

and their pharmaceutically acceptable acid addition salts, which comprises reducing a compound of the formula:
...(II) where R1 to R4 and n are as previously defined and X is CH2 or CO, and isolating the compound of Formula (I).

2. A process as claimed in claim 1, in which the compound of Formula (II) is reduced with diborane to give the compound of Formula (I).

3. A process as claimed in claim 1 or 2, in which R3 is a hydrogen atom and R4 is a 3-amino-3-deoxy-.alpha.-D-glucopyranosyl group.

4. A process as claimed in claim 1 or 2, in which R4 is a hydrogen atom and R3 is a .beta.-D-ribofuranosyl group.

5. A process according to either of claims 1 and 2, in which R1 is a hydrogen atom or a methyl group.

6. A process according to claim 1, in which the com-pound of Formula (I) is l-N-[(S)-2-hydroxy-4-aminohexyl]-kanamycin A is prepared by reduction of l-N[(S)-2-hydroxy-6-amino-hexanoyl]-kanamycin A.

7. A compound of the formula . . .(I) and their pharmaceutically-acceptable salts;
wherein R1 represents a hydrogen atom or a lower alkyl group having from 1 to 4 carbon atoms;
R2 represents an amino or hydroxyl group;
one of R3 and R4 represents a hydrogen atom, while the other represents a glycosyl group; and n is 4, 5 or 6;
wherein R3, when it is a glycosyl group, is of the formula:

or and R4, when it is a glycosyl group, is of the formula:

whenever obtained by the process of claim 1 or an obvious equiv-alent thereof.

8. 1-N-[(S)-2-Hydroxy-4-aminohexyl]-kanamycin A whenever prepared by the process of claim 6 or an obvious equivalent thereof.