NZ205390A - Imidazolidine derivatives - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £05390 2 053 o Priority Date(s): , q_»T'6 -S?i Complete Specification Filed: .......

Class; . CP. 7P.Tf..... f-• • • •• ! 3 1 MAY 1Q851 Publication Date: ? O, Journal ftSo: / 2»7«e. \cj !er the provisions of RegU* l^jon 23 (I) the Specification has been ante-dated to £.SZ 19&L Initials Divided out of Application N5-: 197530 Date: 25 June 1981 NEW ZEALAND PATENTS ACT, 1953 COMPLETE SPECIFICATION COMPOUNDS FOR TREAIMENT OF DIARRHOEA XP^We, BEECHAM GROUP p. I.e., a British Company of Beecham House, Great West Road, Brentford, Middlesex, England, hereby declare the invention for whichXK/ we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - 2 0 53 9 0 This invention relates to a class of novel compounds having activity useful in the treatment of diarrhoea in animals including man, and to processes for their production.

Diarrhoea (also referred to as scours in cattle, sheep and pigs) can be a severe disease particularly in young animals and can often result in death. Diarrhoea is also common amongst human travellers and those exposed to low. standards of hygiene. The diarrhoea frequently involves colonisation of the small intestine with enteropathogenic strains of E. coli which produce heat stable and/or heat labile enterotoxins. Related enterotoxins are produced by other enteropathogens, for example, cholera, and also cause diarrhoea. These enterotoxins stimulate fluid secretion in the gut lumen and hence cause diarrhoea. The associated fluid loss may lead to loss of condition, reduced weight gain of livestock and often to death.

It has now been discovered that a certain class of novel compounds have activity useful in treating diarrhoea. In particular, these compounds inhibit small-intestinal secretion whilst having less CNS activity than a-agonists of similar structure.

Accordingly, the present invention provides compounds of formula (II) 2053 90 hydrogen, (^-4) alkyl or acyl; hydrogen, (C alkyl or acyl; hydroxy, halogen, (C^_4> alkyl, (^-4) alkoxy or a group R8; an ortho or para substituent selected from amino, mono- or di-(C^_^) alkyl amino, aminomethyl, mono- or ai-(C^_^) alkylamino-methyl, amidino, guanidinyl or 2-imidazolidimmino optionally substituted on a nitrogen atom with (C^_4) alkyl or acyl; and selected from hydroxy, halogen, (C, J alkoxy, 8 and a group R when in the para position. selected from hydroxy, halogen, (^-4) alkyl, and (C-^_4) alkoxy when in a meta position, selected from hydroxy, halogen, (C, ,) alkyl, 8 — (C^_4) alkoxy and a group R when in the ortho position, or a salt thereof, 9 provided that when R - is in the ortho position and is chloro, 7 5 6 R is chloro, R is hydrogen and R is hydrogen, ethyl or acetyl, O then R is other than para-amino, or a methyl, ethyl or acetyl derivative or salt thereof; 9 and provided that when R is in the meta or para position and 6 7 is halogen, R is hydrogen, R is hydrogen and R is hydrogen, 8 then R is other than para-amino, or an acid addition salt thereof. wherein RJ is R^ is 7 R is R8 is 9 . R is hydrogen 9 or R is 9 or R is c 2 0 53 9? Preferably FT* and are hydrogen. 8 Preferably R is at the 4-position. 7 9 Preferably R and R are the same and are at the 2,6 positions. g Preferably R is amino, substituted amino or guanidinyl, Preferred compounds within formula (II) include: 2 ,6-dimethyl-4-aminophenylamino-2-imidazoline; 2 , 6-dibromo—4-aminophenylamino-2-imidazoline, It will be appreciated that certain compounds of formula (II) will exist in tautomeric forms of the structure shown above. The present invention embraces all such tautomers.

Salts of compounds of formula (II) need not be pharma-ceutically acceptable: if they are not they may be useful in purification of compounds of formula (II). 2 0 53 t According to the present invention there is also provided a process for producing a compound of formula (II) which process comprises (a) reacting a compound of formula (IV) (IV) 7 9 wherein R to R are as defined with respect to formula (II) CI and X is a group - N - CN ; - N R14 CI SR14 I N - C = N- 14 wherein R is an (C1-4) alkyl group, with a compound of formula (III) H2N - CH2 - CH2 - NHR19 (III) 19 wherein R is hydrogen or (C^_^) alkyl.

- N or 205390 (b) reacting a compound of formula (V) 6 9 wherein R - R are as defined with respect to formula (II) , with a compound of formula (VI) R20 i XC - R18 (VI) / XR17 wherein R2°is hydrogen, alkyl or, when R"*"7 and R"*"8 are oxo, acyl, R16 and R17 together form a bond and R18 is (C-i_.) alkylthio or benzylthio 16 or R is hydrogen, 17 18 and R and R together form an oxo group; or (c) converting the corresponding compound with a nitro substituent in the ortho or para position to the required compound of formula (II); . and optionally thereafter forming an acyl derivativesj^aad/or a salt thereof. 2 0^ Process (a) may be conducted according to the process described in UK Patent No. 1,229,995 when .CI X is. - N < ; according to the process described in CI U.K. Patent No. 1,034,938 when X is - N Rl4 HH ■ SR 14 ; according to the process described in Chem. Abs. , 8_5, P94364b when X is N - CN , and according to the process described in Chem. Abs. , J55, P5633g when X is 2053 Process (b) may be conducted according to the process described in U.K. Patent No. 1,506,914 or U.K. Patent No. 1,450,250 17 18 when R and R together form an oxo group, and according to the process described in Chem. Abs., 84, 16 17 P59465t when R and R together form a bond.

Process (c) may be conducted according to the process described in Rouot & Leclerc (supra) or in European Patent Application No. 12,822, and U.K. Patents Nos. 1,180,766 and 2,014,983.

The starting materials may be produced by conventional methods, as may the salts and acyl derivatives of compounds of formula (II).

The compounds of the invention may be formulated into pharmaceutical compositions comprising a compound of formula (II) and a pharmaceutically acceptable carrier therefor.

As used herein the term 'pharmaceutical composition1 includes compositions suitable for human and/or animal use and "pharmaceutically acceptable' includes veterinarily acceptable.

Pharmaceutical compositions of compounds of formula (II) will, of course, be adapted for administration to humans or the animals to be treated.

Thus for example the composition may be a shaped composition, such as a bolus, tablet or capsule. In such cases the pharmaceutically acceptable carrier will be chosen from-the usual range of lubricants, dispersants, binders and fillers and the like. When these shaped compositions are for administration to cattle and pigs, often they will weigh at least 1 g, on occasions at least 2 g For administration to humans, especially young ones, the drug may suitably be presented as a syrup including suitable colouring and/or flavouring agents. Such syrups are conveniently - .9 - 2 0 53 - presented in unit or multi-dose containers.

For veterinary use the composition may also be a dispersion or a solution of a compound of formula (II) (hereinafter referred to as 'the drug1) in a suitable vehicle for use with an oral doser (this is a well known item of farm equipment, basically comprising a liquid reservoir, a mouthpiece adapted for insertion into animal mouths, and a pump mechanism whereby unit doses can be ejected from the reservoir through the mouthpiece). Conveniently the vehicle will be an oil or water based cream to ensure homogeneity of the unit doses administered. Alternatively, the drug may be administered as an aqueous solution using an oral doser.

The drugs of the invention may also be added to the animal feed or drinking water. It will be convenient to formulate these animal feed and drinking water compositions with a multi-dose of the drug so that the animal takes in an appropriate quantity of the drug along with its diet. It will also be convenient to present the drugs of the invention as pre-mixes for addition to the feed or drinking water.

With young humans or animals, a particularly useful technique is to blend their milk with the drugs of this invention.

The compounds of the invention may also be formulated for injection. In such cases the drug chosen is suitable dissolved in water for injection.

Often it will be appropriate to include in the compositions a further medicine such as an antibacterial agent, for example an antibiotic such as amoxycillin or neomycin or a sulphonamide such as sulfadoxin.

Clearly the compositions will contain sufficient drug to enable this effective dose to be administered in convenient manner. Thus by way of example useful dosage units of the composition may contain 1 yg to 50 mg of the drug, more suitably 20 yg to 20 mg. Of course, it will be appreciated that many preferred compositions are in multi-dose form, as for the therapy of animals, it is often most desirable to be able rapidly to treat a number of animals. - .10- 2 0 53 Such multi-dose compositions will contain by way of example, at least 1 mg of the drug. Depending on the exact nature of the said multi-dose composition, often it will contain at least 50 mg of the drug, and on occasions as much as 1 g.

Example 1 2-(4-amino-2,6-dibromophenylimino)imidazolidine A solution of concentrated hydrochloric acid (2.8 ml, 0.028 £4) in aqueous ethanol (50%, 15 ml) was added dropwise to a stirred heated mixture of 2-(2,6-dibromo-4-nitro phenylimino)imidazolidine (4 g, 0.011 M) and iron powder (1.9 g, 0.034 £5) in aqueous ethanol (50%). The mixture was heated under reflux for 3 hours after which time it was filtered hot and evaporated to a low volume. This residual solution was acidified with dilute hydrochloric acid and the resulting solid was removed. The solution was then basified with dilute aqueous sodium hydroxide yielding a solid which was collected. This solid was triturated with hot methanol which was then evaporated to leave a brown solid (3.2 g). This solid was chromatographed on alumina and eluted with a methanol in methylene chloride gradient. The fractions containing the required compound were combined and evaporated affording 2-(4-amino-2,6-dibromophenylimino) imidazoline dihydrochloride, mp~7 320°C (1.6 g) .

Analysis calculated for CgH^2Br2C12N4 Theory: C 26.56; H 2.97; N 13.77 Found : C 27.07; H 3.02; N 13.79 2053 "ii ~ J Example 2 2-(4-amino-2,6-dimethylphenylimino)imidazolidine The. 2- (2,6-dimethyl-4-nitrophenylimino)imidazolidine (8.75 g) was reduced with iron and hydrochloric acid in aqueous ethanol according to the process of Example 1. The product was chromatographed on a silica column and eluted with a methanol in methylene chloride gradient. The fractions containing the required compound were evaporated and the residue was treated with ethanolic hydrochloric acid to give 2-(4-amino-2,6-dimethylphenylimino)imidazolidine dihydrochloride. An analytical sample was recrystallised as the mono-hydro-iodide salt, mp 252-253°C.

Example 3 2-(4-amino methyl-2,6-dichlorophenylimino)imidazolidine Borane methyl sulphide complex (10.7 ml, 0.107 ^) was added slowly to 2-(4-carboxamido-2,6-dichlorophenylimino) imidazolidine (8.0 g, 0.029 M) in dry tetrahydrofuran (160 ml) under nitrogen with stirring. The reaction mixture was heated under reflux for 3 hours and cooled to room temperature Methanol was added until the mixture became clear and stirring was continued for 12 hours. Hydrogen chloride gas was bubbled into the mixture for 15 min and then the mixture was heated under reflux for 1 hour. It was then evaporated and the residue was taken up in water. The solution was basified with sodium hydroxide solution and the resulting oily solid was collected and crystallised from acetone. This solid was dissolved in dilute hydrochloric acid, filtered and basified with sodium hydroxide solution yielding the 2-(4-aminomethyl-2 6-dichlorophenylimino)imidazolidine. An analytical sample was recrystallised as the mono hydro-iodide salt, mp 205-206.5°C. 205390 12 Example 4 2- (2 ,6-dichloro-4-diethylaminomethylphenylimino)imidazolidine Lithium aluminium hydride (3.4 g, 0.08 M) was added portionwise to 2-(4-diethylcarboxamido-2,6-dichlorophenyl imino)imidazolidine (3.4 g, 0.01 M) in ether (350 ml) with stirring. After 2.5 hours ethyl acetate was added followed by methanol. The mixture was then evaporated and dilute sodium hydroxide was added to the residue. The residue was extracted with methylene chloride and the extract was evaporated to give the required compound as an oil (3.3 g) which was recrystallised as 2-(2 , 6-dichloro-4-diethylamino-methylphenylimino)imidazolidine dihydrochloride, MP 272-274°C.

Example 5 2- (2 , 6-dichloro-4- ( 2-iroidazolidin imino) phenylimino) imidazolidine A mixture of 2-(4-amino-2,6-dichlorophenylimino) imidazolidine (3.7 g, 0.015 ^) and l-acetyl-2-imidazolidone (2.2 g, 0.02 in phosphoryl chloride (25 ml) was heated under reflux for 3 days. After cooling to room temperature the phosphoryl chloride was evaporated to give an oily residue. The residue was basified with sodium hydroxide (50%) and the insoluble solid was filtered off. This solid was hydrolysed with dilute sodium hydroxide in methanol.

After evaporation of the mixture the product was extracted into methylene chloride. Evaporation of the extract gave a gum which crystallised giving 2-(2 , 6-dichloro-4- (2-imidazolidin-imino) phenylimino)imidazolidine dihydroiodide, MP 298-300°C.

/ I . 2 0 52 Example 6 2-/2,6-dichloro-4-(1,3-dimethylguanidino)phenylimino/ imidazolidine Phosphoryl chloride (4.4 ml, 0.047 M) was added with cooling to dimethylurea (4 g, 0.045 M) in tetrahydrofuran (60 ml). After stirring at room temperature for 5 hours the mixture was added to 2-(4-amino-2,6-dichlorophenylimino) imidazolidine (3.0 g, 0.012 M) in tetrahydrofuran (60 ml). The mixture was refluxed for 18 hours and then evaporated to give an oily solid. The residue was extracted into 2M HC1, washed with methylene chloride and then basified. Extraction of the alkaline mixture with methyl chloride yielded a gum on evaporation of the extract. The gum was taken up in ethanol and the required guanidino compound (300 mg) crystallised. The product was recrystallised as 2-/2,6-dichloro-4-(1,3-dimethylguanidino) phenylimino/imidazolidine dihydroidide (MP 320°C).

Analysis calculated for C^2H18N6C^2I2 Theory: C 25.24; H 3.18; N 14.72 Found : C 24.91; H 3.47; N 14.92 Example .7 2 (2,6-dichloro-4-guanidino phenylimino)imidazolidine dihydrochloride A solution of cyanamide (0.44, 0.10 M) in water (1 ml)'was added to 2-(4-amino-2,6-dichlorophenylimino)imidazolidine monohydro-chloride (2 g, 0.007 M) in hydrochloric acid (2 M, 3.5 ml) and ethanol (5 ml). This mixture was heated under reflux for 24 hours and then evaporated to give an oily solid. This solid was taken up in the minimum amount of hot ethanol and left standing. The resulting solid was recrystallised from ethanol to give 0.35 g, MP 283-285°C • 2 0 53 Example 8 2-/2,6-dichloro-4-(1,3-diethylguanidino)phenylimino/ imidazolidine 2-(4-amino-2,6-dichlorophenylimino) imidazolidine'was reacted with diethyl urea as described for the dimethyl urea in Example 6, affording the free base MP 216-218°C. This compound was treated with.ethanolic hydrochloric acid to give the dihydrochloride, MP 274-276°C.

\ Example 9 2-/T-(1,3-diallylguanidino)-2,6-dichlorophenylimino7 imidazolidine 2-(4-amiro-2,6-dichlorophenylimino)imidazolidine was reacted with diallyl urea as described for the dimethyl urea in Example 6, affording the free base MP, 185-187°C. This compound was treated with ethanolic hydrochloric acid to give the dihydrochloride MP 264-265°C.

Example 10 The activity of various compounds of formula (n) was assessed in mice by the following method.

Infant mice are separated from their mothers shortly before use. Animals up to 15 days of age are suitable for use but normally animals 7 - 9 days of age are used. Groups of animals are dosed with the compound 45 mins prior to oral challenge with 0.05 -0.10 ml of culture filtrate prepared from an entero-pathogenic strain of E_;_ coli. Control animals receive' drug vehicle 45 mins prior to challenge with a similar administered orally. Animals are killed two hours later and the entire intestine removed.. The ratio of gut weight to remaining bodyweight (GW/BW) is determined from each animal and the increase in this ratio is determined by subtracting 0.06 (GW/BW for untreated mice) from the GW/BW of the animal. Drug treated animals are compared with untreated controls. If the compound has had an effect in inhibiting the fluid secretion caused by the enterotoxin(s) present in the culture filtrate then the gut weight/bodyweight ratio should be reduced in the treated animals. The percentage fluid inhibition is determined from the formula: 100 - Mean increase in GW/BW ratio in treated animals X 100 Mean increase in GW/BW ratio in control animals «- amount of culture filtrate. The compounds are Results are given in the table below.

X OS^o 20539 Oorrpound of Example No.

R5 R6 R a *b *11 . dose mg/Kg • % inhibition H <=3 o-Cl CI 200 72 50 62 37 H H p-NHEt o-Cl CI 200 97 50 79 59 — H H p-NHOAc o-Cl CI 200 57 50 48 42 — H H p-nh2 o-Cl CI 50 78 59 - H H p-nh2 H CI 4 H H p-CH^NEt, o-Cl CI 500 42 200 37 50 28 2 H H p-nh2 OCH3 1 ch3 200 69 ! 50 54 66 i 2 0 5390 i Results continued Compound of Example No.

R5 R6 R a *b R11 Dose mg/Kg % inhibition 1 H H p-nh2 o-Br Br 200 85 50 65 48 6 H H NHMe / p-N=C \lHMe o-Cl CI 200 50 53 37 33 3 H H p-CH NH o-Cl CI 200 39 50 38 H H p-N=/ NH'' o-Cl CI 400 100 41 29 7 H H /H2 p-N=C \H_ o-Cl CI 200 50 33 34 27 8 H H /nhch2ch3 p-N=C \HCH2CH3 o-Cl CI /hch2ch3 p-N=C \thch2ch 8 -2HC1 H H o-Cl CI 200 50 42 34 36 nhch2ch=ch2 9.2HC1 H H p-N=C 1 NHCH 2ch=ch2 o-Cl CI 200 50 10 41 38 20 r 2.oS"V30 205390 Example 11 Rat Jejunal Perfusion Jejunal absorption or secretion of fluid was measured in anaesthetised rats by perfusion of an isotonic solution containing 14C labelled - polyethylene glycol essentially as described by Klipstein, Lee and Engert (Infect. Immun. 1976, 14, 1004-1010). The effect of ST toxin alone or in the presence of drug was established by incorporating these substances in the perfusion solution averaging 14C counts over 2 hours perfusion in six rats and calculating absorption per g of perfused jejum.

Perfusate Absorption yg/min/g No. of rats p * * * (students t) Control (no toxin) + 1.3 0.001 Toxin (60 mouse units/ml) - 8.0 14 " Toxin + compound of Example 2 40 pg/ ml - 2.3 7 0. 05 *** Absorption compared to absorption by jejunum perfused with toxin. ' - 19 -

Claims (5)

WHAT WE CLAIM IS:
1. A compound of formula (II): 205590 (II) 10 wherein R is selected from hydrogen, (C,.) alkyl and acyl; fi R is selected from hydrogen, (C, .) alkyl and acyl; 7 R is selected from hydrogen, halogen, (C, Jalkyl, g 1 **• 4 (C, .) alkoxy and a group R t 8 R is an ortho or para substituent selected from amino, mono- or di-(C^_^) alkyl amino, aminomethyl, mono- or di-(C^_^) alkylamino-methy 1, amidino, guanidinyl or 2-imidazolidinimino optionally substituted on a nitrogen atom with 15 (C^_^) alkyl or acyl; and R is selected from hydroxy, halogen, (C1_.) alkoxy, 8 hydrogen and a group R when in the para position 9 or R is selected from hydroxy, halogen, alkyl, and (C, ,) alkoxy when in a meta position, 9 0 or R is selected from hydroxy, halogen, (C, .) alkyl, i 8 (C^_^) alkoxy and a group R when in the ortho position, or a salt thereof, g provided that when R is in the ortho position and is chloro, 7 5 6 R is chloro, R is hydrogen and R is hydrogen, ethyl or acetyl, Q then R is other than para-amino, or a methyl, ethyl or acetyl derivative or salt thereof; 9 and provided that when R is in the meta or para position and is 5 6 7 halogen, R is hydrogen, R is hydrogen and R is hydrogen, then 8 R is other than para-amino, or an acid addition salt thereof. 2 0 5 3 S 0 20
2. 2. a compound as claimed in claim 1 and selected from 2-(4-amino-2,6-dibromophenylimino) imidazolidine; 2-(4-amino- 2, 6-dimethylphenylimino) imidazolidine; 2-(4-aminomethyl-2, 6-dichlorophenylimino) imidazolidine; 2-(2, 6-dichloro-4-diethylaminomethylphenylimino) imidazolidine; 2-(2, 6-dichloro-4-(2-imidazolidinimino)phenylimino) imidazolidine and 2-[2,6 dichloro-4-(1,3-dimethylguanidino) phenylimino] imidazolidine.
3. 3. A process for producing a compound of formula (II) as defined in claim 1 which process comprises (a) reacting a compound of formula (IV) R (IV) wherein R7 to R9 are as defined with respect to formula (II) Cl and X is a group N - CN ; Cl - 21 - 205390 - N R SR NH, 14 14 or SR - N - C = N il4 14 wherein R is an alkyl group, v/ith a compound of formula (III) H2N - CH2 - CH2 - NHR 19 (III) .19 . wherein R is hydrogen or alkylj (b) reacting a compound of formula (V) wherein R6 - R9 are as defined with respect to formula (II), with a compound of formula (VI) R20 I N ^ „ t,18 C - R / \ 17 N R 16 (VI) f (rt - . - 22 - 2053 90 wherein R 20 17 18 is hydrogen, alkyl or, when R and R are oxo R 16 acyl, 17 18 and R together form a bond and R is or R 16 (C1_^) alkylthio or benzylthio is hydrogen, 17 18 and R and R together form an oxo group; or (c) converting the corresponding compound with a nitro substituent in the ortho or para position to the required compound of formula (II); and optionally thereafter forming an acyl derivative and/or a salt thereof.
4. 4. A compound of formula (II) according to claim 1 and substantially as hereinbefore described.
5. 5. A process for producing a compound of formula (II) according to claim 3 and substantially as hereinbefore described with reference to any one of Examples 1 to 9. DATEB TH