Pharmaceutical compositions containing di-and trisubstituted xanthines,some new such xanthines and their preparation

'This, .invention relates to. new pharmacological ly . (' ' active d 1-^ a'rid tri- substituted xanthines, ;to processes

י.׳‘.,' ., - . ־ . . , ,.*׳’ ז , * . ׳ ’ . , .- ׳ <־ for their preparation and to a medicament containing them. ;׳.::... French’Patent Specification 2,346,353.is concerned with 7-ca,rbalkoxy-;xanthines/having antia 1 lergy and bronchodilator ־ activity. British'(Patent Specification 1,435,916 is related to lipo'lytic compositions containing.a mixture Of carnitine.

' and a lipolytic factor which may be a xanthine./British : ί/χ׳ Patent Specification 766,7.54 is concerned with 7-carbamoyl- .' xanthines having diuretic act iv. ity., -.'Bri t isir 'Patent Spec if !cation > 982 ,.079 is related to. a process for the preparation of 8- // ’//: ^;subst'itute’d.derivat i ves of theophyl1ihe, xanth ihe and/1 - . '־'־ ־ ' . ' * יי.,־’ > • methylxanthine. :British Patent Specification 759,1 74 is . .’. concerned ,with 7-hydroxyalky 1 -xanthines׳ having diuretic ־; activity,United States Patent. Specificaticn 2,673,848 is .

. related to 1-aIky 1-3-alkenyl-xanthines having diuretic and /c-ardiOvascular properties , C. A. 45 ,' 1.0,401e mentions . ' Ί ,3’-di.ethylxanthine. as having diuretic properties. C.A. 56, 7,935e is concerned .with l,/pdialky-U6^th10-xanthines ' ., .

./׳ ' having'bronchodi lator, coronary di lator, central stimulate

C.A. 94,. 15,773u is. concerned .with /;' .'xanthines unsubstituted in position 1 and. show bronchodilator-/, and chronotropic activities. ׳.East German Specification 3.1,772. is related to a process for the preparation of theophyl 1 ine . or 8-alkyl-, 8-alkylamino-alkyl-, 8-carbal.koxy- or 8^phenyl- y ,./ ' theophy 1l ine . G . A'. 34, 48,034 . i s concerned wi th 1 ,3-d imethy l ל. , 1,3-di'ethyl-, '8-methyl- and '8-ethyl-substituted corresponding . xanthines .as vasodilator's. C.A. 48, 1 ,347d is related to ׳ .alkyl homologs of theophyl1ine'for'the.treatment of cardiac /; diseases and as diuretics. ₁ ׳ ., ‘ ., ' . X 62641/2 ׳ י 2 . י

;. . In some, of the above-7,1 .isted Patent Specifications and articles xanthines similar to the present one's are disclosed as inter- m'ediate.sjbut none of the present compounds are explicitly mentioned therein. Furthermore,.the compounds of the present invention

־ .־ י ׳ . . . ' ־' ' ' ׳' ’ ‘ .י.־” are for an entirely different use. . ./ / Xanthines are /known, for their stimulating effect on the < . central nervous system.Examples of xanthines, are caffeine and theophylline. . .’/.־.' -. ./ . Certain'xanthines have been described for their ' . .י ־^,- ' ׳ . . י' ‘ . '. ’י .W ' spasmolytic activity, for example ־in German Patent Application ,No. 2,713,389 or i n ' European ’Patent Appl ic'at ron Publication //.: No. 773.5. - -.׳. X X .'// .'‘י ' //./X<

,. . It' has now been found that, unlike the therapeutically ׳. . . ./ '.^;־ / /״ . ׳ /.-׳ ־. י. ⁷:1/ /'' 7 ' יל ' X used psychostimulating xanthines, certain new 1,3- and'1,3,8substituted xanthines show sedative. or: anxiolytic activity :at / a remarkable activity level and without any side effects being observed at the effective doses (ED5O) for the neuroleptic activity.

Some' of the new xanthines show additional diuretic, anti'-allergi'c or br.onchodi latory activity, in minimal ׳t effective doses, lie. producing a significant response in base screening, distinctly greater than the effective doses (ED50) .f,or th.^ neuroleptic effect,־ in other words this additional activity does not in any way diminish the value of the neuroleptic activity. . . _; / ־ The compounds according to the invention are xanthines r _; . . .. . , ., ' corresponding to. the genera 1 formula /

<img file="IL62641A_D0001.tif" />

14.4.81 .־ w ith the exception .Of'.¹

R 1 8= ןly1. . R₃=buty1

Rg=niethyl

14.4:81 where . ' under 1 i ned

14.4.81 /

14.4.81 ' where under 1 i ned.

' ' . ' .' 62641/2 &lt;׳..; - 3 /-/ 7,. 7 . . &lt;/.' .X ./ .

׳’.'-' י י ’ % ’־. . זי־’’ י י.^,.׳.'.

and_;phy.siol.igicar1y'acceptable sa.lts thereof in which /.: ־ Ry represents C₂־C₄־a1 ky 1, - i so a-1 kyj , CH״- (C״-C77/ >. ' -״ alkenyl) or CH₂-(C₃-isoa'lkenyl); .. ^; ί :

^R3 Represents Cg-Cg-alky 1, C₃-Cg-isoa 1 ky 1 ,. CH״-(C₂־C₄- '' alkenyl) or CH₂-(C₃-C₄-is021kenyl);

R₈ represents H, methyl or ;ethyl ;׳ .

with the-.prpviso. that .1.) when Rg represents H, R₁ represents i.',. allyl and . .'./77x7.

^: ,. ^R ן־; a nd R₃ ca ח no t bot h rep resent ^,.׳ . - . butyl orally! at the same time; and־ ' . , . : . , 3.) when R^ i.siethyl, R₃ is.other than ' ' . '... . .' 2 .'׳-methy 1 buty 1 '. ־ ־׳ .

.Preferred, compounds corresponding to .general. formula (I): are those in whichR₁ represents allyl, propyl or isobutyl, // R₃ represents propyl , butyl, or isobutyl and R_y represents. ’ methyl., particularly'preferred compounds .being 1-al lyl-3-butyl-8 methyl, xanthine, 1 -propy 1 -3-buty 1 ^8-me’thy 1 xanth ine1 ,׳ - a 11 y 1. - 3 isobutyl-8-methyl xanthine, Ί ,.3-di 1 sobutyN8-met.hy 1 xanthine,1., 3-di prop.y 1-8^.methy 1-xan:t h i,ne , 1-propyl-.3 -i.sobutyl-8-methyl xanthine and 1-ally1-3-propy1-8-methy 1 xanthine־ and cal ly acceptable salts thereof. .. . .

:PpJiiPbunds׳ of f0rmu 1 a ׳(I) in ׳which represents represents, butyl-and Rg represents H also consitute p refer red class. . . .'^;' . . '. ^: ־־’־־ ־.

physiologiallyl, Ro λ

' ?י . .

-,׳ ־ 6

In the context of the invention, .physiologically acceptable salts of the compounds corresponding to general formula (I) are understood to be the salts which these compounds form with pharmaceutically acceptable bases. The salts in question are salts the cations of which are harmless to animal organisms and do not cause any side effects in therapeutic doses. Salts such as these include the salts of alkali metals, such as sodium, potassium, pharmaceutically acceptable salts of ammonium and amines known to the expert. These salts may be prepared by heating the.compound of general formula (I) in the presence of the appropriate base and in the presence or absence of a solvent, preferably followed by recrystallisation.

The compounds according to the invention may be prepared by one of the following processes: a) A uracil corresponding to the formula

<img file="IL62641A_D0002.tif" />

is reacted with an' alkylating agent of the formula I^-X where R^, Rg and Rg have the same meaning as in general formula (I), except that neither nor Rg may be isopropyl, and where X is a halogen atom, preferably bromine, or monosulphate or disulphate or p-toluene sulphonate and the ־5compound obtained is cyclised. The reaction is preferably carried out,in a solvent suitable for all the reactants, such as for example dimethyl formamide (DMF), dimethyl sulphoxide. (DMSO) or hexamethyl phosphorotriamide (HMPT)at a temperature in the range from 20 to 40°C and in the presence of an alkali metal hydroxide, for example sodium hydroxide in solid form. The reaction is preferably carried out in DMF at 20°C in accordance with the following scheme:

<img file="IL62641A_D0003.tif" />

<img file="IL62641A_D0004.tif" />

(III)

The product corresponding to general formula (III) is then cyclised in a boiling solution of alkali metal hydroxide in accordance with the following reaction scheme:

<img file="IL62641A_D0005.tif" />

Although it is possible to isolate the intermediate of general formula (III), it is preferred to carry out cyclisation directly without isolating or purifying the intermediate in question. To this end, the reaction

־6־ medium is neutralised and the solvent evaporated, after which the residue is dissolved in an alkali hydroxide solution and the resulting solution heated to reflux temperature.

The starting uracil of general formula (II) may be prepared by conventional methods, for example Traube's method (Cheg. Ber. 33, 1371 and 3055, 1900) in which a urea R₃־NH־C־NH₂ is reacted with cyanoacetic acid in acetic anhydride, the acetic anhydride is evaporated and 10 the residue treated with sodium hydroxide, leading to a l-alkyl-6-aminouracil which is then converted into the compound of general formula (II) in accordance with the following reaction scheme:

2) Na₂S₂O₄/NH₃

3) R₀COOH, Δ .'NH x _c/^R8 (II) ^NH2

b) In a variant of the above-described process, a compound corresponding to general formula (I), in which at least one of the substituents R, and R_ is alkenyl or

J. 0 isoalkenyl, is hydrogenated to form the corresponding saturated compound in which the same two groups are alkyl or isoalkyl. It has been found that this synthesis route is preferred in cases where it is desired to obtain a compound of general formula (I) in which R_x is propyl, butyl or isobutyl and R₃ is an

14.4.81 alkyl group different from φ, particularly because the

14.4.81 alkylation step leading to the compound of general formula (III) gives better yields with an alkylating

I agent of the formula ^_C=C-CH -x where X is as defined above.

The catalytic hydrogenation of the alkenyl or isoalkenyl group or of the two alkenyl or isoalkenyl groups is carried out in a good solvent for the xanthines, such as methanol, ethanol or ethyl acetate, in the presence of a hydrogenation catalyst, such as Raney nickel, palladium on active carbon (Pd/C) or platinum oxide. It is generally preferred to use ethanol and Pd/C. Although ׳ the reaction can be carried out under excess pressure and under heat, normal conditions, i.e. ambient temperature and atmospheric pressure, are preferred.

c) A compound of formula

<img file="IL62641A_D0006.tif" />

may be reacted with an acid of the formula R־״COOH (where O ^Rl׳ ^R3^{and R}g ^{are as} defined above except that and R₃are other than isopropyl) and the compound obtained cyclised. In this variant, which is preferably used for preparing compounds of general formula (I) in which and R₃ are identical, but other than isopropyl, a urea identically substituted in the one-position and three-position is used

־8־

14.4.81 as the starting material and is treated with cyanoacetic acid in the presence of acetic anhydride and then with sodium hydroxide in accordance with Traube's classical synthesis to form a 1,3-dialkyl־6־aminouracil which is then converted into the compounds of general formula (III) in accordance with the following reaction scheme which enables the alkylation step to be avoided:

1) NaNO₂/CH₃COOH

2) Na₂S₂O₄/NH₃

3) RgCOOH/Δ ^N-c

It 0

N ^NH2

The compound of general formula (III) thus obtained is then cyclised as indicated above in reference to process a to form the corresponding compound of general formula'(I).

d) A final process comprising reacting a compound corresponding to the formula with an alkylating agent of the formula R₃־X, treating the compound obtained with an amine of the formula

14.4.81

R8־CH2־־NH₂ where Rj, Rg , X and Rg are as defined above, to form a compound corresponding to the following formula

־־ד-׳^-ישד^דייךןה»

־9-

<img file="IL62641A_D0007.tif" />

which is converted into a 5-nitroso derivative corresponding to the formula

<img file="IL62641A_D0008.tif" />

.which cyclises spontaneously or which is cyclised by heating.

This final process is particularly applicable to compoundsof general formula (I) in which at least one of the groups R^ and R^ is isopropyl. The process is 20 similar to the process described by Goldner, Dietz and Carstens, for example in Justus Liebigs Ann. Chem. 691, 142, 1966.

A monosubstituted urea corresponding to the formula is used as the starting material and is reacted with diethyl malonate in ethanol in the 14.4.81 presence of sodium ethylate to form a !-substituted .4.81 barbituric acid, which is then reacted with a

14.4.81 chlorinating agent, for example phosphorus oxychloride, to form a 6-chlorouracil, the substituent R then being situated in the three-position. The 6-chlorouracil is then treated with an alkylating agent R_g-x to form a !”^3 3 ׳-R^-dialkyl-substituted uracil. In the presence of an amine of the formula R_g-CH₂-NH₂, this uracil gives the 6-amino derivative into which the nitroso group is introduced, for example using isopentyl nitrite in the 5-position, to form the uracil corresponding to general formula (IV) below. This uracil (IV) cyclises either . xanthine corresponding he following reaction

1) r₃־x

2) R_q-CH₀-NH_

Q 2 2

3) i-pent-ONO ׳ or to general formula (I), as shown in scheme:.

<img file="IL62641A_D0009.tif" />

H

POC1

<img file="IL62641A_D0010.tif" />

H

Cl

<img file="IL62641A_D0011.tif" />

'׳ ί י 2/ 1 6264/ ., י־ ^וו '־ . ־. י- 33’ יי יי ׳3 י יj.־.’ .’ I * ^J ‘ י * .׳>. י _f י ’ ; .י . . ־ . . ־.'.8 . ־ י י ..

׳. י . י ׳ ׳ י .'.’ . ' . . ' ־ ‘ . ^J : _L , . *י .־‘ י . ־ ׳ י . . . . . .''ίί' -׳'ί; ^,‘י . י . . י ׳ י י ’ . ’ . י י י' 1 י . י י .יי . . A. ’ . .-.׳-t'-i’.

: ׳: . ׳&lt; . The, present invention. also relates to a pharmaceutical composition containing a . compound ־ of general. formul.a (I) &lt;1.4.81 / -־'.' /¾ ' / ith. th-e_; , / ’ / q .*'/ ./-/-, ׳' 'י’; ' &lt;ception/ i -'./&lt;' : / ' R^, / '.' . 'י'. י. ,.׳־'-. י' ' : ,.»,11:^ Vrγ/./ . .,. //'/

«.; .'׳. .'י^, י ״.י.׳. י' .־ « /methyl .־ I /.,⁸ . .. .

// /' ' י.?. / / ^K3, י ' . / ,/. ? / . ,. , &lt;Ζ////' . ־ .,' י י i '3 . . , . ' י׳.' . י ׳־. ־ '«.'(&lt; ׳ ־ ־ י;.// ?./.׳'.and'ph^;ysioi׳og.ica'.11 y accept'dbie./'aIts thereof,.in which .5;‘- י ' R.j represents 'C^-C^-a 1 ky 1, /־C/i soa 1 ky I , , /: 33 CH^-iC^-C^ralkenyl ) or CH₂׳-(C₃־isoalkenyl); ..׳ / ' ' // 'O '.R₃ represents C^-Cg-alkyl, C^-Cg-is.oa.l ky!, CH?-(G^-C^-alkeny:l) .// . /./.,, or CHp- (Cβ-C׳^- is0a 1 keny 1);// . . ' . ,.. '.. .; . . ־ י ׳./ /. . ί׳/׳' Rg represents H, methyl or ethyl; /,.

/ ' / e-'w 1th the proviso th.at when R^ represents H׳, R^' is allyl / .'/' : ׳ and -2.) vR׳. and Rt'cannot .both represent'-butyl־ or” allyl.

. ' ,-.3' . . ־.־.'- י.* ._fc ־ _?1 .״.. . . .גי. . i . . ',־.׳

1^:'3 - in׳ an .active, quantity f or^? the^ netlro lepti c effect in '.. /.'.־ ל/.,' / י : .'־' combination, with an inert _rpharmac.eu;tica-1 iy' acceptable, support.'

- ׳ The medicament according to the . invention may be made .'־.

up .in/ various pharmaceutical. forms' containing the usual.. ,' '..

' e.xi'p:ierts or vehicle-s, .such'as tablets.',׳ cap.su les׳,'. suppositories?,.־

׳. .: solutions , suspens ions', ‘and may b,e ־administered oral ly , '^y/..

׳.* ' ,, . ; . ' ׳.־..-.‘. ^נ י., ' . , f . -'.־. ξ I ־ ־.,^r'

--.::: . ' subl ingual-ly/ recta lly. subcutaneously,, intra-muscularlyintrf.--.

־. ' venousl-y’ or by׳ inhalation in,doses of from 0.0004 to 0.04 g , '//.' &lt;. . per day. ^;..׳. ' .//, .’’/'. - ,-,/// ׳ .' י ־ _: יי׳, י' ' ':/,/ ‘ The ‘invent i.o.nu's’i 1 lustrated by. the following Examples, .. ־ ׳ ./ _ןי’ : in which the quantities quoted represent quantities by . ־ . - ' weight unless otherwise', indicated: . . . , . ' ,-. ' ^;. .. ־.- . r 1 1.a- ., '..62641/2 ...־

Z ו. י י 'י . ' ' ־. . ' י‘ י. ‘ '. i.- ־״ _ן י -,- , ' ־ ־ ך . ' ,. ' ., . ' .f ,* ־ ־ y ‘ '־ ‘ .&lt; v ' ;. '' ’ . .&lt;

EXAMPLE' 1 ,;.י־ ; ’..',:.' j/ 'י’., י

Synthesis of 1-al lyl'-3-buty 1-8-methy.l 'xanthine . .

Γ) ' 1 -butyl-6-aminourac i 1 ,..,

115 g (1 mole) of butyl, urea and 9.4 g .(1.1 mole) of cyanoacetic acid are heated for.2 hours at 75 to,80 C 'in 200 mf. of acetic anhydride. The mixture is cooled and 500 ml. of ether are added. The, precipitate is collected,. washed with ether and dried. . . ' ׳ ..

The product thus obtained is suspended in a mixture Of 300 ml of water , and 150 ml. of .'ethano l'. Af ter the ,.־ resulting suspension h-as been heated to: 85 C, 75 ׳ ml of a. 10% aqueous' NaOH solution are' s lowly added. The .;־ ־/ . :. .' ' ,.. \ ־ ' . . * . .. ' “12r.

solid solubilises and shortly afterwards the uracil begins to precipitate. On completion of the addition, the mixture is left to react for another 30 minutes.

The reaction product is acidified to pH 5 with HC1, ר r,. off left to cool and the precipitate is filtered. After washing with ice water, 100 g of colourless powderform crystals are obtained.

2) l-butyl-5־nitroso-6-aminouracil

91.5 g (0.5 mole) of l-butyl-6-aminouracil are suspended in 1 litre of water in a reactor equipped with a magnetic stirrer. A solution of 38 g of sodium nitrite in 250 ml of water is added to the suspension. 65 ml of acetic acid are then run in dropwise with stirring, after which the.mixture is stirred for 18 hours at ambient temperature. After cooling in an ice bath, the precipitate is filtered, giving 90 g of violet-coloured crystals.

3) 1-butyl6 , 5־-diaminouracil

84.8 g (0.4 mole) of l-butyl-5-nitroso-6aminouracil are suspended in 440 ml of a concentrated 50% aqueous solution of ammonium hydroxide. The resulting suspension is heated to 80°C. 88 g (0.48 mole) of sodium dithionite are added in portions with stirring over a period of 30 minutes. Stirring is then continued for 30 minutes at 80°C and then overnight at room temperature. The product is cooled in ice, the precipitate is Off .

filtered/and then washed with a little ice water, giving .־1362 g crystals in the form of a very fine powder.

4) l-butyl~5-acetylamino-6~aminouraci1

59.4 g (0.3 mole) of l-butyl5,6־-diaminouracil are refluxed for 2 hours with stirring in 240 ml of acetic acid in a reactor equipped with a condenser. The acetic acid is evaporated and the residue is taken up in a little ethanol which is then evaporated. This operation is repeated until a semi-crystalline residue is obtained. The semi-crystalline residue thus obtained is then triturated until solidification is complete.

off

The solid is filtered/and washed with ether, giving 72 g of fine, faintly yellow crystals.

5) l~allyl-3~butyl-8-methyl xanthine

13.2 g (0.055 mole) of l־butyl-5-amino6־acetylamino uracil are dissolved in 110 ml of dimethyl formamide. 2.4 g (0.06 mole) of NaOH and 7.3 g (0.06 mole) of allyl bromide are added to the resulting solution with stirring. The reaction takes place at ambient temperature over a period of from 30 to 60 minutes.

After the reaction mixture has been neutralised to pH 5 with a concentrated solution of HC1, the dimethyl formamide is evaporated. The oily residue is dissolved in 40 ml of a 10% NaOH solution and the resulting solution is refluxed for 2 hours. The product is then cooled to ambient temperature, washed with dichloromethane (2 x 10 ml) and adjusted to pH 5 with a concentrated IIC1 solution.

The precipitate is extracted with dichloromethane (3 x 20 ml),

-.

after which the solution is dried and evaporated, giving

6.5 g. of coloured crystals.

is .

The crystals are decoloui/ed by treatment with activl ¹*carbon for 1 hour in boiling ethanol. Recrystallisation from a 1:1 mixture of ethanol and water gives colourless woolly crystals. Melting point (Mp): 170-171°C. Nuclear magnetic resonance spectrum of the carbon (C-NMR): see Table 2 below.

¹⁴⁸¹ ־ ⁴ ־ EXAMPLES 2 to 10

Following the procedure described in Example 1, the compounds are prepared using the appropriate reactants containing the groups R,, R_ and R_o, i.e. respectively: the monosubstituted urea in step 1, the carboxylic acid in step 4 and the alkylating agent in step 5, as shown in Table 1 below. Table 2 below shows the recrystallisation solvent, the melting points and

14.4.81 the NMR values of the carbon.

Example No, Compound Urea (step 1) Acid (step 4) Alkylating agent (step 5)

Table 1

<td> 2</td><td> l-allyl-3־butyl xanthine</td><td> butyl urea</td><td> formic</td><td> allyl bromide</td>

<td> 3</td><td> l־allyl3־-isobutyl xanthine</td><td> isobutyl urea</td><td> formic</td><td> allyl bromide</td>

<td> 4</td><td> l“allyl־3־isobutyl-8-methyl xanthine</td><td> isobutyl urea</td><td> acetic</td><td> allyl bromide</td>

<td> 5 '</td><td> l-allyl-3־butyl-8-ethyl'xanthine</td><td> butyl urea</td><td> propionic</td><td> allyl bromide</td>

<td> 6</td><td> l־allyl-3-propyl-8־methyl xanthine .</td><td> propyl urea</td><td> acetic</td><td> allyl bromide</td>

<td> 7</td><td colspan="3"> l-allyl-3-isopentyl־8־methyl xanthine isopentyl urea acetic</td><td> allyl bromide</td>

<td> 8</td><td> l-ethyl־3״butyl-8״methyl xanthine</td><td> butyl urea ,</td><td> acetic</td><td> diethyl sulphate</td>

<td> 9</td><td> l,8-diethyl-3-butyl xanthine</td><td> butyl.urea</td><td> propionic</td><td> diethyl sulphate</td>

<td>¹⁰.</td><td> l-butyl-3-allyl8־-methyl xanthine</td><td> allyl urea</td><td> acetic</td><td> butyl p-toluene</td>

<td></td><td></td><td></td><td></td><td> sulphonate</td>

co

-.

' EXAMPLE 11

Synthesis of l-propyl-3-butyl8־~methyl xanthine g of l-al,lyl-3-butyl-8-methyl xanthine (Example 1) are dissolved in 100 ml of ethanol in a hydrogenation apparatus, followed by the addition of

500 mg of Pd (10¾)/C. Hydrogenation is carried out at . ambient temperature until the consumption of hydrogen is over (approximately 1 hour). The mixture is filtered under heat, the precipitate is washed with ethanol and the solvent is evaporated from the filtrate, leaving 5 g of colourless crystals which are recrystallised from methanol. Mp: 174-175°C. C-NMR (Table 2). EXAMPLES 12 and 13 ¹⁵. . Following the procedure described.in Example 11, l-propyl-3-isobutyl-8־methyl xanthine is prepared from l-allyl-3-isobutyl“8-methyl xanthine (Example 4) and l־butyl-3-propyl-8-methyl xanthine is prepared from 1butyl-3-allyl-8־methyl xanthine (Example 10).

The melting point, the recrystallisation solvent and the NMR values of the carbon of these compounds are shown in Table 2 below.

EXAMPLE

Preparation of 1,3-dipropyl8־-methyl xanthine

1) 1,3־dipropyl-6-aminouracil

37.5 g (0.26 mole) of 1,3-dipropyl urea and l

14.4.81 22.5 g (0.26 mole) of cyano acetic acid are heated for .4.81 2 hours to 70°C in 125 ml of acetic anhydride. The acetic anhydride is then evaporated, leaving approximately 90 g of an oily residue.

290 ml of a 10% aqueous NaOH solution are slowly 5 added with stirring to this residue. The mixture undergoes a spontaneous increase in temperature and the oil dissolves. Soon afterwards, a precipitate is 1 formed. It is left to cool to ambient temperature,

Off precipitated/, washed with water and dried, giving 55 g of a faintly yellow crystalline powder.

2) 1,3-dipropyl-5-nitroso-6-aminouracil

This compound is prepared in the same way as in Example 1, step 2.

3) 1,3־dipropyl-5,6-diaminouracil ¹⁵ . This compound is prepared in the same way as in

Example 1.3.

4) 1,3־-dipropyl-5-acetylamino-6־a1ninouracil

This compound is prepared in the same way as in Example 1.4.

5) 1,3~dipropyl־8־methyl xanthine g of 1,3-dipropyl-5-acetylamino-6-aminouracil (4) are refluxed for 1 hour in 150 ml of a 10% aqueous NaOH solution. The solution is cooled and acidified to pH 2 with concentrated HC1. The precipitate formed is off . 25 filtered/, washed with water and dried, leaving 13 g of colourless crystals.

14.4.81 The crystals thus obtained are decolored by ־18a ted

4.4.81 treatment with activ^ carbon for 1 hour in a 1:1 mixture of ethanol and water. Recrystallisation from a mixture of the same composition gives colourless woolly crystals melting at 202 to 203°C. C-NMR (Table 2) ⁵ EXAMPLE 15

1,3-diisobutyl-8-methyl xanthine is preapred from 1,3-diisobutyl urea by the process described in Example 14. The Mp, recrystallisation solvent and C-NMR values are shown in Table 2 below.

EXAMPLE 16

Preparation of l-isoprppyl3־-butyl8־-methyl xanthine 1) !־isopropyl barbituric acid

1.3.8 g (0.6 mole) of sodium are dissolved in 250 ml of anhydrous ethanol. 61.2 g (0.46 mole) of diethyl malonate and 47.3 g of isopropyl urea (0.46 mole) are added to the resulting solution. The mixture thus formed is heated for 7.5 hours to 120°C (temperature of the bath). After cooling, a solution of concentrated HC1 and water (1:4) is slowly added until the precipitate formed during the reaction has dissolved. The resulting solution is evaporated until a precipitate appears and is then left standing at 0°C. The precipitate is then off filtered/, washed with cold water and dried, giving 75 g of colourless crystals.

2) 3־isopropy1-6-chlorouracil

350 ml of phosphorus oxychloride containing

4.4.81 15 ml of water are slowly run into 75 g (0.44 mole) of .4.81 1-isopropyl barbituric acid. After the violent exothermic reaction has abated, the reaction mixture is refluxed for 1 hour. The excess POC1₃ is removed by evaporation in vacuo and the oily residue is poured off כ onto ice, giving a precipitate which is filtered/, washed with ice water and dried. 55 g of yellowish crystals are thus obtained.

.3) l-butyl-3-isopropy16־-chlorouracil

16.6 g (0.12 mole) of potassium carbonate and ¹⁰ 24 g (0.105 mole) of butyl p-toluene^sulphonate are added to a solution of 19 g (0.10 mole) of 3-isopropyl6-chlorouracil in 200 ml of dimethyl formamide. The mixture is heated, for 1 hour to 80°C. After evaporation of the solvent, the residue is taken up in water, ¹⁵ followed -by extraction with CH₂C1₂. The extract is dried over Na₂SO₄ and the solvent is evaporated, leaving 24 g of a pale yellow oily product.

4) l-butyl-3-isopropyl-6-ethylaminouracil

100 ml of ethanol and 100 ml of a 70% ethylamine ²θ solution in water are added to the above oil (0.1 mole).

The whole is then refluxed for 2 hours and evaporated to dryness, giving’25 g of a yellow oily product which is further f-ur-ther-used without/purification.

5) 1-isopropyl-3-butyl-8-methyl xanthine

2⁵ י The above oil is dissolved in 100 ml of ethanol.

drops of an ethanolic HC1 solution are then added,

14.4.81 . followed by the introduction with stirring of 25 ml of .4.81 isopentyl nitrite (slow addition, 15 minutes). The mixture is then left reacting for another hour, the solution obtained being deep violet in colour. The ‘ solution is evaporated to dryness, the residue is dissolved in dilute NaOH and the resulting solution is acidified to pH 2 with concentrated HCl. After standing at 0°C, the precipitate formed is filtered.off, dissolved in chloroform and the resulting solution filtered through a column containing 50 g of silica gel (eluent: chloroform). 10 g of faintly coloured crystals are thus obtained. The product is recrystallised twice from a 1:1 mixture of ethanol and water, giving fine colourless crystals melting at 172 to 173°C. C-NMR

14.4.81 15 (Table 2).

TABLE 2

<td></td><td> Example No.</td><td> M.p. (°C),</td><td> Recrystallisation solvent .</td><td> C־NMR־values (CDCL; Sppm) . Reference: TMS (tetramethyl silane)</td>

<td></td><td> 1</td><td> 170-171</td><td> EtOH/H,O 1:1 L</td><td> 13,8; 14.8; 20.0; 30.2; 43.8; 43.8; 106.7; 117.3; 132.4; 149.7; 150.7; 152.4; 155.6;</td>

<td> 14.4.81</td><td> 2</td><td> 149-150</td><td> MeOH</td><td> 13.8; 20.0; 30.2; 43.7; 43.9; 107.0; 117.5; 132.2; 140.6 149.0; 157.7; 155.9;</td>

<td></td><td> 3</td><td> 194-195</td><td> EtOH/H.O 1:1</td><td> 20.0; 20.0; 27.4; 43.8; 51.0; 106.9; 117.5; 132.2; 140.5; 149.4; 151.0; 156.1;</td>

<td> . 1' Η (N</td><td> 4</td><td> 226-227</td><td> EtOH/HjO 1:1</td><td> 14.8; 19.9; 19.9; 27.2; 43.7; 50.8; 106.5; 117.2; 132.4; 150,1; 151.0; 152.3; 155.6,.</td>

<td> 1</td><td> 5</td><td> 154־153</td><td> EtOH/H₂O 1:1</td><td> 12.6; 13.8; 20.0; 22.7; 30.2; 43.7; 43.3; 106.7; 117.2; 132.5; 149.6; 150.8; 155.5;. 157.4;</td>

<td></td><td> 6</td><td> 187־186</td><td> MeOH</td><td> 11.1; 14.8; 21.4; 43.7; 45.4; 106.6; 117.3; 132.4; 149.7; 150.7; 152.3; 155.6;</td>

<td></td><td> 7</td><td> 171-172</td><td> MeOH</td><td> 14.8; 22.5; 22.5; 26.1; 36.8; 42.6; 43.7; 106.7; 117.3; . 132.4; 149.7; 150.6; 152.4; 165.6;</td>

<td> 14.4.81</td><td> . 8</td><td> 214-215</td><td> EtOH/H״O 1:1 M</td><td> 13.3; 13.8; 14.7; 20.0; 30.2; 36.9; 43.7; 106.8; 149.5; 150.7; 152.1; 155.7;</td>

TABLE 2 (Continued

<td></td><td> Example 'No.</td><td> M.p. (°C)</td><td> Recrystallisation solvent .</td><td> C-NMR־values (CDCk; J ppm) Reference: TMS (tetramethyl silane)</td>

<td> 14.4.81</td><td> 9</td><td> 154־153</td><td> EtOH/H^O 1:1</td><td> 12.5; 13.3; 1318; 20.0; 22.7; 30.3; 36.9; 43.7; 106.9; 149.4; 150.9; 155.7; 157.1;</td>

<td></td><td> 10</td><td> 197־196</td><td> MeOH</td><td> 13.8; 14.7; 20.3; 30.2; 41.7; 45.7; 106.8; 117.8; 131.6; 149.2; 150.7; 152.2; 155.8;</td>

<td></td><td> 11</td><td> 175־174</td><td> MeOH</td><td> 11.4; 13.8; 14.7; 20.0; 21.5; 30.2; 43.3; 43.8; 106.8; 149.5; 151.0; 152.1; 155.9; . ..; .. /</td>

<td> ’ 1 N</td><td> 12</td><td> 231־230</td><td> MeOH</td><td> 11.4; 14.7; 19.9; 19.9; 21.4; 27.3; 43.3; 50.8; 106.7; 149.9; 151.2; 152.0; 155.9;</td>

<td> (N 1</td><td> 13</td><td> 190־189</td><td> EtOH/HJ 1:1 4 \</td><td> 11.1; 13.8; 14.7; 20.3; 21.4; 30.2; 41.6; 45.4; 106.8; 149.6; 150.9; 152.1; 155.9;</td>

<td></td><td> 14</td><td> 202-203</td><td> EtOH/H,O 1:1</td><td> 11.1; 11.5; 14.7; 21.4; 21.4; 43.3; 45.4; 106.8; 149.5; 151.0; ,152.1; 155.8;.</td>

<td></td><td> 15</td><td> 242־241</td><td> EtOH/H,0 1:1 Lt</td><td> 14.7; 19.9; 19.9; 20.3; 20.3; 27.2; 27.4; 48,6; 50.8; 106.7; 149.9; 151.5; 152.0; 156.1;</td>

<td> 14.4.81</td><td> .16</td><td> 172-173</td><td> EtOH/H,O 1:1 4</td><td> 13.8; 14.8; 19.7; 19.7; 20.1; 30.2; 43.7; 46.4; 107.1; 149.4; 150.9; 152.0; 156.5;</td>

־23EXAMPLE 17

The xanthines obtained in accordance with the preceding Examples were the subject of a behavioural study in rats as a function of the anxiety induced by a new environment. In rats, anxiety is manifested rearing by rearing the animal/on its two hind paws, whilst locomotive activity is expressed by their movements. Method

A state of anxiety is induced by confronting naive male Sprague-Dawley (Iffa-Credo, France) rats weighing from 260 to 300 g with a new environment in the form of cages of MacroIon (30 x 25 cm) which are situated in a sound-proofed air-conditioned room (22°C/50% relative humidity).

The number.Of rearings and movements is automatically determined by means of infrared photoelectric cells which only emit electrical pulses for the active movements of the animal and not for its static movements, such as those of its head and tail, for reasons of reproducibility. These photoelectric cells scan the cages at two different levels so as to distinguish the standingup movements from the other movements. The number of rearings and movements is counted by the two rows of photoelectric cells, memorised and read out using a printer in accordance with a pre-established program.

The tested compound in solution in the form of its sodium salt is orally administered by oesophagus

־24־ probe (the reference administration being formed by ml/kg of distilled water) 30 minutes before the animals are placed in the cages. The number of rearings and movements is determined during the 15 minutes after they have been put into the cages in relation to the effect generated by the reference administration.

Evaluation of the results

The ED 50 dose (expressed in mg/kg) , i.e. the quantity of substance required to bring about a 50% .

variation in the motive activity in relation to the reference administration, is determined from the development of the effects of the tested substances on the number of movements and rearings as a function of the progressive doses administered expressed as a percentage of the movements and rearings counted for the reference administration.

The regression curves for the displacements and

*.

rearings are established from the preceding data by the method described by Saubrie, P.J. Pharmacol, (Paris) 2 (1971) 457472־, the equation of these regression 1 curves corresponding to the mean expressed in percent of the performances of the references as a function of the product by 10 of the logarithm of the doses (only the doses which do not reduce the motive activity by more than 75% are considered).

The gradients of the regression curves corresponding ־25to the movements and to the rearings are compared by recording the. value of the gradient of the movement curve on the abscissa (d) and the value of the gradient of the rearing curve on the ordinant (r) of a system of rectangular axes. These values demonstrate the effect-dose relation for a given substance.

The ratio of the gradient׳of the movements to that of the rearings is also determined, enabling the specificity of effect of a given substance on the anxiety state to be assessed.

The results obtained are shown in Table 3 below:

Table 3

<td rowspan="2"> 15</td><td> Compound of Ex.No.</td><td> 1 ED 50 (mg/kg)</td><td> Gradient of the movements ? 0 (d)</td><td> * Gradient of the rearings / 0 (r)</td><td> Ratio of the gradients d/r</td><td> Effect</td>

<td> 1</td><td> 0.14</td><td> p&lt;0.001</td><td> p&lt;0.01</td><td> n. s.</td><td> S.N.</td>

<td> 14.4.81</td><td> 2</td><td> 1.60</td><td> p&lt;0.001</td><td> p&lt;0.001</td><td> /1; p&lt;0.001</td><td> S.A.</td>

<td></td><td> 3</td><td> 0.98</td><td> p&lt;0.001</td><td> p&lt;0.001</td><td> &lt;1; ρςθ.001</td><td> S.A.</td>

<td></td><td> 4</td><td> 0.25</td><td> PvO.001</td><td> p&lt;0.01</td><td> n.s.</td><td> S.N</td>

<td> 20</td><td> 5</td><td> 6.24</td><td> pco.oi</td><td> p^O.001</td><td> &lt;1; p\0.001</td><td> S.A.</td>

<td></td><td> 6</td><td> 0.27</td><td> p&lt;0.001</td><td> p&lt;0.001</td><td> &lt;1; p&lt;«0.01</td><td> S.A.</td>

<td></td><td> 7</td><td> 1.03</td><td> p&lt;0.001</td><td> pcO.Ol</td><td> &lt;1; ρςθ.01</td><td> S.A.</td>

<td></td><td> 8</td><td> 1.02</td><td> p&lt;0.05</td><td> p&lt;0.01</td><td> &lt;1; pco.05</td><td> S.A.</td>

<td></td><td> 9</td><td> 2.38</td><td> p&lt;0.001</td><td> p&lt;0.001</td><td> &lt;1; p&lt;0.001</td><td> S.A.</td>

<td> 25</td><td> 10</td><td> 3.95</td><td> p&lt;0.01</td><td> pcO.Ol</td><td> n.s.</td><td> S.N.</td>

<td></td><td> 11</td><td> 0.35</td><td> p&lt;0.001</td><td> p&lt;0.001</td><td> &lt;1; p&lt; 0.001</td><td> S.A.</td>

<td> 14.4.81</td><td> 12</td><td> 0.25</td><td> ρςΟ.ΟΙ</td><td> p 4,0.01</td><td> &lt;1; ρςθ.001'</td><td> S.A.</td>

Table (Continued)

<td></td><td> Compound of Ex.No.</td><td> ED 50 (mg/kg)</td><td> Gradient of the movements + 0 (d)</td><td> Gradient of the rearings A 0 (r)</td><td> Ratio of the gradients d/r</td><td> Effect</td>

<td> 14.4.01</td><td> 13</td><td> 1.05</td><td> p&lt;0.01</td><td> .p&lt;0.01</td><td> &lt;1; p&lt;0.05</td><td> S.A.</td>

<td></td><td> 14</td><td> 0.37</td><td> p&lt;0.01</td><td> p&lt;0.001</td><td> &lt;1; p&lt;0.01</td><td> S.A.</td>

<td></td><td> 15</td><td> 0.42</td><td> p&lt;0.01</td><td> ρςΟ. 01</td><td> n.s.</td><td> S.N.</td>

<td> 14.4.81</td><td>¹⁶</td><td> 1.76</td><td> p&lt;0.05</td><td> p&lt;0.01</td><td> .n.s.</td><td> S.N.</td>

<td> 10</td><td> chlorproma- zine</td><td> 21</td><td> p&lt;0.05</td><td> p&lt;0.05</td><td> n.s.</td><td> S.N.</td>

<td></td><td> haloperidol</td><td> 1</td><td> p&lt;0.01</td><td> p&lt;0.01</td><td> n.s.</td><td> S.N.</td>

<td></td><td> chlordiazepoxide</td><td> 12</td><td> p&lt;0.01</td><td> p&lt;0.01</td><td> &lt;1; p&lt;0.01</td><td> S.A.</td>

<td></td><td> theophylline</td><td> -</td><td> p&lt;0.001</td><td> n.s.</td><td> 71; p&lt;0.001</td><td> P</td>

Legend:

- The gradients are compared by the t test at the probabilities p&lt;0.05, p&lt;0.01 and p&lt;0.001

- n.s. means that the gradient is not significantly different from 0 or that the ratio between the gradients of the movements and the rearings is not significantly different from 1.

־.S.N, means that the compound has a non-specific sedative ef feet .

- S.A. indicates a sedative effect of anxiolytic character

- P means psychostimulating

Conclusions

The effect of a.substance is determined by its position relative to the curve d = r of gradient = 1.

The substances situated on this curve have a similar effect on the rearings and movements, being sedatives with a non-specific effect (S.N.). For these compounds, the ED 50 value quoted corresponds to the mean taken from the two regression curves.

The substances for which the absolute value of the gradient of the rearings is significantly greater than that of the gradient of the movements have a specific effect on the anxiety state. These compounds are sedatives of anxiolytic character (S.A.). In this case, the ED 50 value is calculated from the regression curve of the rearings.

Tabl־e 3 above shows

14.4.81 “ that the compounds of Examples 1, 4, 10, 15 and 16 where

- that the compounds of Examples 2, 3, 5 to 9 and 11 to have a similar action profile to chlordiazepoxide,

- that theophylline is psychostimulating and does not 20 have any effect on the anxiety state.

EXAMPLE 18

14.4.81 The compounds of Examples 1, 2, 4, 11 and 12 were subjected to toxicological tests:

a) Determination of the acute toxicity LD 50 in male and female mice in solution in DMSO, the reference being DMSO alone, in accordance with J.T. Litchfield and F.

14.4.81 Wilcoxon Simplified method of evaluating dose-effect

־28־

14.4.81 experiments , Journal of pharmacology and experimental therapy. Vol. 96, pages 99 to 113, 1949.

b) Determination of the acute toxicity LD 50 in male and female rats in solution in DMSO (reference DMSO alone) in accordance with C.S. Veil and G.J. Wright Intraand inter laboratory comparative evaluation of single oral test, Toxicology and applied pharmacology, Vol. 11, pages 3781967 ,388־.

The conpounds of Examples 1, 2, 3, 4, 5, 9 and

11 showed the following activities in a base screening:

c) diuretic in male rats, as determined in accordance with W.L. Lipschitz, Z Hadidian and A. Kerpcsar, JPET, Vol. 79, pages 97-110, 1943.

d) anti-allergic in male and female rats, as determined in accordance with J. Goose and A.M.J.N., Blair, Immunol., Vol. 16, pages 749-760, 1969

e) bronchodilatory in vitro as determined in accordance with F.P. Luduena et al., Arch. int. Pharmacodyn, Vol. Ill, pages 392-400, 1957

f) anti-histamine in vitro as determined in accordance with R. Magnus, Arch f.d., ges. physiol., Vol. 102, pages 123-151, 1904.

The results of these tests are set out in

14.4.81 Table 4 below:

Table 4

<td rowspan="4"> Compound of Example No.</td><td colspan="2" rowspan="3"> a LD 50 in mg/kg p.o., mice</td><td colspan="2" rowspan="3"> b LD 50 in mg/kg p.o., rats</td><td> c</td><td> d</td><td rowspan="2"> e minimal e</td><td rowspan="2"> f fective</td>

<td colspan="2" rowspan="3"> minimal effective dose in mg/kg producing a significant response</td>

<td colspan="2" rowspan="2"> concentration in pg/ml producing a significant response</td>

<td> male</td><td> female</td><td> male</td><td> female</td>

<td> 1</td><td> 72</td><td> 62</td><td> 35</td><td> 24</td><td> .r</td><td> 2.5</td><td> 100</td><td> 100</td>

<td> 2</td><td></td><td> M</td><td> &gt;200</td><td> &gt; 200</td><td> 10</td><td> 10</td><td> 25</td><td> 100’</td>

<td> 3</td><td></td><td> w</td><td></td><td></td><td> 5</td><td> no effect</td><td> no effect</td><td> 200</td>

<td> 4</td><td> 79</td><td> 49</td><td> 23</td><td> 17</td><td> 20</td><td> 50</td><td> no effect</td><td> no effect</td>

<td> 5</td><td> to</td><td> w</td><td></td><td> w</td><td> 2.5</td><td> no effect</td><td> 5</td><td> 100</td>

<td> 1 &lt;31 Q 1</td><td> M</td><td> .</td><td></td><td></td><td> 5</td><td> no effect</td><td> 25</td><td> 50</td>

<td> 1 11</td><td> 91</td><td> 151</td><td> 25</td><td> 15</td><td> 0.25</td><td> no effect</td><td> 10</td><td> 50</td>

<td> 12</td><td></td><td></td><td> 28</td><td> 19</td><td> «</td><td> Mt</td><td> «</td><td></td>

Legend: - means not.tested .4.81 The compounds of Examples 1, 4, 11 and 12 were subjected to behavioural tests in accordance with predictability and specificity of behaviour screening tests for neuroleptics, P. Worms and .

• 5 k.G. Lloyd, Pharmacology, Teratology, Vol. 5, pages 445-450, 1979, comprising:

- catalepsy induced by haloperiodol in rats: potentialisation at 1 mg/kg p.o.

- analgesia induced by pentobarbital in mice: potentialisation at 0.5 mg/kg p.o.

climbing behaviour induced by apomorphine in mice: inhibition at 1 mg/kg p.o.

--stereotype behaviour induced by apomorphine in rats: no antagonism up to 8 mg/kg p.o.

¹⁵ - rectal temperature in mice: hypothermal effect at mg/kg p.o.

- hypomotility induced by amphetamine in rats:, antagonism at 0.5 mg/kg p.o.

These effects are typical of neuroleptics except that, unlike such neuroleptics as haloperidol or chlorpromazine, the above compounds have no effect upon stereotype behaviour in rats as induced by

14.4.81 apomorphine.