CA2186847A1 - Adenosine derivatives - Google Patents

Abstract

Compounds of formula (I), wherein R1 is one of a number of significances, including cycloalkyl and hydroxycycloalkyl; R2 is hydrogen, (C1-4)alkyl, amino, (C3-5)cycloalkyl or halogen with an atomic number of 9 to 35, and R3 is (C1-4)alkyl, are useful as analgesic agents. Compounds of formula (I) wherein R1 is hydroxy alkyl are new. The compounds of formula (I) may be produced by alkylation in the 2' position in the presence of tetrabutylammonium hydrogen sulfate and a non-polar solvent.

Description

wo ss/306s3

2~8~8~7 Ar)ENOSINE DERIVATIVES

This invention relates to adenosine derivatives, and in particular, provides a new use of A1 recepl:or agonis~s.
In particular the present invention relates to a new use of compounds of fonmula (I):

,R1 HN
~ N>
/\~~
HO ~<

wherein R1 is Ihydrogen, (C, ,)alkyl, allyl; methallyl; a straight-chain or branched (C3.7)alkinyl, (C3~)cycloalkyl, hydroxy(C~3)cycloalkyl, phenyl being mono-, or i"dep~, Id~ y of each other di-s~ ~hstitl l'^d by halogen with an atomic number of 9 to 35, (Cl8)alkyl, (C,.,)alkoxy or CF3; or phenyl(Cl ,)alkyl wherein the phenyl ring is ur~ hstit~ d or mono- or i"dt:~,ellcle"~ly of each other di-s~ stit~ ~ ' by halogen with an atomic number of 9 to 35, (Cl ,)alkyl, (Cl ,)

3 o a~koxy or CF3; (Cl ,)alkyl having at least one hydroxy group or at least two phenyl groups, a bicycloalkyl such as endo- or exo-bicyclo[2,2,1]heptyl, a naphthyl (Cl.4)alkyl-group, an acenapthylenyl (Cl ,)alkyl-group or a group of formula A or fommula B

wo gs/30683 2I868q 7 . . ~
Z ~ or ~3 Y Q Y
(A) Q (B) wherein Z is hydrogen, a hydroxy group or a (C,.")alkoxy group Q is hydrogen or hydroxy, A is -CH2-, -0-, -S- or a direct bond, Y is -(CH2)n- or a direct bond, n is a whole number from 1 to 3 and the broken line in formula A ~ st"~ts an optional bond, R2 is hydrogen, (Cl.,)alkyl, amino, (C3s)cycloalkyl or halogen with an atomic number of 9 to 35 and R3 is (C1~)alkyl.
Some of these compounds e.g. those wherein Rl is other than hydroxy cycloalkyl are known and disclosed, for example, in published British Patent Application 2 226 027 A and European Patent ~!, " ' ls EP-0-378 518 and EP-0-269 574, and USP 4,843, 066 and 4,985,049.
3 o In the formulae described herein the 2', 3', 4' and 5' substituents of the tetrahydrofuran ring have the configuration as in adenosine.

wo 95/30683 2 1 ~ 6 8 4 7 ln one group of compounds under fommu~a 1 R, is other than hydroxycycloalkyl. Inanother group of compounds under fommula 1, R1 is hydroxy(C~ 3)cycloalkyl.
Preferably the compound of fonnula I is of 6-cy~ xyl 2-0-methyl-adenosine, he,t,i,,drl~l referred to as Compound M.
Typically the A adenosine activlty in the preferred compounds of fomnula I may be dt,l~""i"~d as follows:-Affinity for adenosine receptors Pig striatal " ~IllLld~ ,es are prepared as previously described by H. Bruns et al. in Molecular Pl,al",acoloyy 29 (1986) pages 331-344.
3H-NECA, a non-selective adel~o:.i"e receptor agonist is used to label both A, and A2 receptors. ICso values are derived from the dis~,lact:",~"l curves by weighted non-linear least-square curve fitting to the Langmuir equation and pKD values r::llcl ll~tF~rl T~h~ ffinity of adenosine receptor ligands for A, and A2 receptors A, A2 A,: A2 (KD;nM) (KD;nM) selectivity n CPA 0.74 + 0.08 930 + 110 1260 6 25 CV 1808 2460 + 757 269 + 70 0.1 5 CGS 21680 4360 +1080 18.6 + 4 0.004 4 Compoulnd M 23 + 2 24500 + 5160 1090 5 1.5 H2O
3o CPA = Cyclopentyla~el10s;"e CV 18013 = 2-Phenyld",i"oadel~o:,i"e (Carbohydrates vol. 81 .

WO9!i/30683 218684 7 1974) ref. 91898 K) CGS 21680 = 2-lp-(2-Carboxyethyl)phenethylamino]-5'-N-ethyl ca, i~OXd~ -acll~"osi"e (FASEB J, 1989; 3 (4) Refs. 4770/3) In ay,~a",t",I with the literature CPA proves to be a potent and highly selective displacer of binding to the A1 receptor CV 1808 is a relatively weak but selective A2 receptor ligand and CGS 21680 shows high potency and selectivity for the A2 receptor.
Compound M in the form of its 1.5 hydrate shows good affinity and high selectivity for the A, receptor vis à vis the A2 receptor.
The known compounds of the fommula I are known as antihype,It" .;~ agents and coronary vaso, ni.
Furthermore it is known that the compounds of fommula I protect the vascular endothelium by inhibiting both Illlu~ ocyt~ ayylt:y ~ and activation of leucocytes. They also lower the blood lipid leYels. Further compounds of formulaI have a protective effect against diseases caused by hypeltel~sioll such as congestive heart failure Illy~cdrdidl infarction or sudden cardiac death and renal insufficiency (see Europ. Pat. Appl. EP-0-378 518 and EP-0-269 574).
These compounds are also known for the treatment of neu,.,dey~"t:,dIiol1 disorders, peripheral neuropathies such as diabetic neuropathy and of disorders ~Cso. i ,l.-d with peripheral vascular diseases and/or disorders ~~~ ' with neuronal dey~"~,dIiol~, hypertriglyceridemia/low HDL ~l,olt~ ,ul levels, lipid dysfunction, elevated free fatty acids or type I or type ll diabetes including non-insulin depel-d~"I diabetes arrhythmias in particular paroxysmal supraventricular tachycardia and tachycardiac atrial fibrillation and for protection 3 0 against myocardial infarction.

W0 95/30683~
~ 21868q7 The present Applicants have found that the compounds of fommula I are particularly i"~ "dlyesics for example for the treatment of pai~, e.g. acute or chronic pain.
The analgesic activity of the compounds of the fommula I are indicated by their analgesic activity in standard animal tests, e.g. illlld~llllld~vly and neuropathic models e.g. in reducing persistent i"" Illlldluiy ",eul,a"i..al l,;p~,dl~aly~:~id [(tests a) and b)] and persistent neuropathic themmal hy,o~,alye:.id [test c)] indicative of chronic lleuropathic pain.
ld"", IdlUIy hyp~,dlu~aid Test a~ Freund's adjuvant-induced hy~ ldlyesid Rats are injected i~tra-articularly in one knee joint with Freund's complete adjuvant (100 microlitres). The load that the rat will tolerate on that leg de,;,~ases and remains d~ ssed for up to 5 days. This effect is indicative of ",e~l,a"i~;al hyperalgesia, and is responsive to NSAlD's and opiates. The compounds of the formula I are adl "i"i~ rt:d by injection and preferably orally at doses of from about 3 to 60 Illi~;lUyldll~y animal body weight. The increased load tolerated on the injected side is measured to determine the reversal of hyperalgesia.
Compound M shows particularly illt~.~alillg activity on p.o. a.l~"i"i:.l,d~ioll from about 3 to about 60 ~iu~uyldllllkg with a duration of action of about 1 hour. There is no significant difference in response between the doses of 3 30 and 60 Illi~ luyldll~kg suggesting that the maximum effect had been reached in the range 3 to 30 I l li~;l uyl dl l l/l~y.
Test b) Turpentine-induced ",e~;l,a,~ical hy~61alUe:~id A local intra-plantar injection of h~ ,6/~,ardl~i" in rat paw (left hind) results in 218~847 -6- ~
a local ill~ldlllllldlUIy response and a reduction in the ~ 'Idlcl~vdl threshold (cut-off threshold 340 9) for a ",~uI,d,~ical stimulus (paw pressure). The compounds of fommula I are active at doses from about 1 to 100 Illicluylall~y p.o. or s.c.
adl"i"i~ rt,d three days after the injection, further threshold readings being taken 1 and 3 hours later.
Compound M shows significant activity at doses of 30 and 60 Illiuluyldll~ky orally, with the maximum effect at 30 Illi~lUyldll~y. Morphine has an EDso value of 1.2 mg/kg s.c. in this test.
Neuropathic hy~ldl,U,esid Test c) Neuropathic thermal hy~eldl,u,t:aid (according to the principles of Z. Seltzer et ~I Pain. 1990. 43. 205-218) Unilateral partial ligation of the sciatic nerve eliminates fibres throughout the innervation of a paw of a rat. The rats develop II~ ldlyt:aia to ",eul,anicdl and thermal stimuli and allodynia of the partially denervated paw without the induction of autotomy. The animals are placed in a perspex box on a thin glass plate and aramp-shaped heat stimulus is applied to the planter surface of a paw. Latency topaw ~;.lldlCIvvdl is measured. The compounds of the fommula I are active at doses from about 1 to about 100 ~ uyldllJky injection (s.c. or preferably orally), ad" ,i"i~l~rt:d 12 to 15 days after nerve ligation. Compound M is particularly active against thermal hyp~ldlgesid. Compound M shows significant activity at doses of 30 and 60 Illi.. lugldlll/kg, with the maximum effect at 30 ",iuluyldlll/kg. The EDso is around 60 IlliUlUyldlll /kg p.o. Morphine has an EDso of around 3 mg/kg in this test when a~l"i"ial~,~d subcutaneously.
~ini~l trials _ _ _0 Clinical trials may be effected as follows:-W09~30683 ~ 8~8~7 Subjects suffering from pain, post-operative pain or post herpetic neuralgesia, are a.i",i"ial~,~d with compounds of the fommula 1, especially compound M, i.v. at adose of ~rom 0.02 to 5 mg. The alleviation of pain is noted.
The compounds of the invention are therefore useful as al ,dl~siua, e.g. againstacute or chronic pain, e.g. chronic neuropathic pain.
In one aspect, therefore, the present invention provides a method forthe treatment of pain which comprises a~",i"i~ ri"g a therapeutically effective amount of a compoulld of fommula I as defined above, to a subject in need of such treatment.
In another aspect, this invention provides the use of a compound of formula I asdefined above as an analgesic in the ,UIt:pdldtiOI~ of ",edi-,d",~"l suitable for the treatment of pain.
In anothler aspect, this invention provides a compound of formu~a I as defined above for use in tlle treatment of pain.
In a furtller aspect, this invention provides an analgesic c~,,,,uo:,iliu,, c~",,uri~i"g a compound of fommula I as defined above as an analgesic in A.c5or~ n with a phanmaceutically ;Irc:ul~ carrier or diluent.
Il Idi~dliuns include pain, for example acute pain Accor iAtr~d with tissue damage and dl 1111 IClliUI~ (e.g. post operative pain, bum pain, injuries, etc.) chronic i, I~ldl 111 l IdlUIy pain (e.g. arthritis) and chronic neuropathic pain (e.g. diabetic neuropathy, post-herpetic neuralgia, multiple sclerosis, causalgia, etc.).
The doses of the compound used in the uses of the invention indicated above will, - of course, vary depending with the compound employed, the seriousness of the disorders, the host, the weight of the patient, the mode of ad~"i"i~l,dliol, and the relative efficacy of the compound. However, in general, Sdli:~d~;~UIy results in 21~6~ 8- --animals are indicated to be obtained at 3 daily doses from about 1 to about 100 ;lUyldll~y animal body weight, e.g. 3 to 60, such as 10 to 60, IlliClu"ldllllk~.In iarger mammals, for example humans, an indicated daily dose is from about 0.1to about 10 mg, conveniently a~l"i"i~ d in unit doses from about 0.02 to about 5 mg, and such unit doses may be adl"i"i~ d more than once a day, for example 2, 3, 4, 5 or 6 times a day, but preferably 1 or 2 times per day.
In test a) above, the NSAID ibuprofen has an ED60 of about 4 mg/kg p.o. and i"d~",tltl,a-,i" 13 mg/kg p.o.. Compound M is about 3ûû times more active. For compound M the preferred dose range is from about 0.1 mg/day to about 10 mg/day, e.g. 3 - 30 ~ uy~d~l~kg for a 70 kg adult, cle~ di"g on the severity of the indication(s) and frequency of ad",i"i:,l~ ).
Compound M has been shown to have no serious adverse effects in man after single doses up to 5 mg p.o.
When used herein the term "~JI,ar",~l~el~ y ~cept~ cu"".asses materialssuitable for both human and veterinary use.
The compounds of the invention may be fommulated for a~lllilli:illdli~ll by any suitable route, the preferred route d~uel ,di"9 upon the disorder for which treatment is required, and preferably in unit dosage fomm or in a form that a human patient may a,ll"i"iblel to himself in a single dosage. Advantageously, the cu"",osit;o~ is suitable for oral, rectal, topical, parenteral, intravenous or intramuscular a~ dliu~.
The co" ,yosit;ul la of the invention may be in the fomm of tablets, capsules, sachets, vials, powders, granules, lozenges, s~,u,uosilo, it:5, reconstitutable powders, or liquid p,~parnliol~s such as oral or sterile parenteral solutions or Su:"Jt",:,iol~s. Topical fommulations are also envisaged where a,o,u~u,uli~

WO g5/30683 ~1 868~ 7 -9-ln order to obtain col)s~ cy of adl l lil lia~ liù~) it is preferred that a cul l lpûailion of the invention is in the form of a unit dose.
Unit dose ~ "ldLiùn fonms for oral a.i",i"i~ may be tab~ets and capsules 5 containing 0.02 - 5 mg ûf a compûund of the invention and may containco" ~ tivnal excipients such as binding agents, for example syrup, acacia, gelatin, sorbitol, I,dgacd"tl" or polyvinylpyrrolidone; fillers, for example lactose, sugar, maize-starch, calcium ,ul,o~ullal~, sorbitol, or glycine; tabletting lubricants, for example magnesium stearate; diaill ~ ,.s, for example starch, cross-linked polyvinyll~yrrolidone, sodium starch glycollate or microcrystalline cellulose; or pl)di",ac,~utically A~c~lJ~ wet~ing agents such as sodium lauryl sulphate.
The solid oral cur"p~ )s may be prepared by conventional methods of blending, filling, tabletting or the like. Repeated blending ùperdliu,,s may be used to distribute the active agent throughout those cu,, ,,u~ ~s employing large quantities of fillers.
Such oper~t;J,)s are of course conventional in the art. The tablets may be coated according to methods well known in normal ,ul,al",aceutical practice, in particular 2 o with an enteric coating.
Oral liquid ~,~par 15 may be in the fomm of, for example, emulsions, syrups, or elixirs, or may be presented as a dry product for reconstitution wlth water or other suitable vehicle before use. Such liquid ~ UdldliU~)s may contain conventional 2 5 additives such as suspending agents, for example sorbitol, synup, methyl cellulose, gelatin, llydroxyethylcellulose, caluu~y",~ ,ylcellulose, aluminium stearate gel, h~,~,uy~,,dlt:d edible fats; emulsifying agents, for example lecithin, sorbitan I"u,)o~ledl~:, or acacia; non-aqueous vehicles (which may include edible oils), for example almond oil, i, d~;tiUI~dl~d coconut oil, oily esters such as esters of glycerine, propylen~ glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoate or sorbic acid; and if desired conventional flavouring or WO 95/30683 P~
2186~7 -10-colouring agents.
Examples for solid oral c~ll r- ~s, e.g. tablets and capsules, are as follows:
The tablets are c~," ",r~sed from the capsule granulation of the c~" ~.olldi"g dose strength. Size #3, yellow capsules are used for the er~rs~ of compound M, and the respective fommulation for the 0.1 and 5 mg dose strengths are shown below.
0.1 mQ Tab/Cap 5.0 mg Tab/Cap Compound M 0.1 5.0 Microcrystalline Cellulose 76.92 74.96 Lactose, hydrous 87.63~ 84.69 Polyvinylpyrrolidine 7.4 7.4 Crospovidone 7.4 7.4 Magnesium Stearate 0.925 0.925 Moisture Retained 4.625 4.625 Size Three Capsule 50 50 Theoretical Capsule Fill Weight or Tablet Weight 185 185 Theoretical Capsule Weight 235 235 ~ The amount of lactose is adjusted to CUIII~ ,dl~ for the amount of moisture in the drug substance.
The compounds may also be adl"i"i~ d in the fomm of a sustained release form, in order to provide a prolonged duration of action. Conventional drug delivery systems may be used to provide sustained release, for example, coated pellets or push-pull osmotic systems.

WO 95/30683 1 ._ 1 / L ~, C, 218 6 8 ~
For parenteral ad",i"i:,l,dli~l), fluid unit dosage forms are prepared utilizing the compound and a sterile vehicle, and, .It~ "~i"g on the col ~C~"~d~ used, can be either suspended or dissolved in the vehicle. In preparing solutions the compound can be dissolved in polyethyleneglycol or ethanol and diluted with water for injection and filtel sterilized before filling into a suitable vial or ampoule and sealing.
Advanta~eously, adjuvants such as a local m ,a~ t;_, a preservative and buffering agents can be dissolved in the vehicle. Parenteral su:.~e":.iol1s are prepared in S~u~ldll 'Iy the same manner, except that the compound is suspended in the vehicle instead of being dissolved, and ~lt:,ili~d~ion cannot be accu,,,,uli~.,,ed by filtration. The compound can be sterilized by exposure to ethylene oxide before suspending in the sterile vehicle. Advantageously, a surfactant or wetting agent is included in the cu,,,,uo:,iliu,, to facilitate uniform distribution of the compound.
The compositions may contain from about 0.1% to about 99% by weight, preferably from 1û to 6û% by weight of the active material, depending on the method of ad" ~i"iall dliùn.
Compou~1ds M of the invention, or a hydrate or an addition product with other solvents or salts thereof, may also be adl"i"isl~ d as a topical formulation in COIlluilldliul~ with conventional topical excipients.
Topical formulations may be presented as, for instance, ointments, creams or lotions, illl,ultlylldlt:d dressings, gels, gel sticks, spray and aerosols, and may contain ~.,u, up, idl~ conventional additives such as preservatives, solvents to assist drug pt~ ldliOI1 and emollients in ointments and creams. The formulations may contain c~""~dlil,le conventional carriers, such as cream of ointment bases and ethanol or oleyl alcohol for lotions.
Suitable cream, lotion, gel, ointment, spray or aerosol fommulations that may be 3 o used for compounds of formula I or a hydrate or an addition product with other solvents or salts thereof, are conventional fommulations well known in the art, for example, as described in standard text books of pl,al",aceutics and cosmetics, such as Harry's Co:""~lk"~luy,r published by Leonard Hill Books, P~ l,u,~ull's Pl,d""aceutical Sciences, and the British and US rlldlll.~:OI)OF~;~C
In another aspect, the present invention provides adenosine~t"i:. ".rcc, of fomnula la /R~' HN
R 1`~ N~
H 0/~~ ~1 H O = =
wherein R1~ is (C~3)cycloalkyl ~llh'~ ' by a hydroxy group, R2 iS as defined above or preferably hydrogen, (Cl.,,)alkyl or halogen with an atomic number of 9 to 35, and R3 is as defined above.

Compounds of formula la can exist in fomn of el~d,,liu,,,e,a or ~lid~ u~eli~
mixtures.
In formula la, halogen with an atomic number of 9 to 35 is fluorine, chlorine orbromine; (C,,,)alkyl is methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert.-butyl, especially methyl; and (C~ 8)cycloalkyl is cyclobutyl, cyclopentyl, cy~luhex~l, WO ~5/30683 2 1 8 6 8 4 7 cycloheptyl or cycloctyl, especially cyclohexyl or cy~,lu~t:"tyl.
The compounds of formula la may be prepared by a process .,I,d,c.~,Lt~ ,ed in that comp~unds of fomnula lla x 1~ >
~o¦ ~a ~1 .

wherein R2 and R3 possess the :,iyll ' ,ces given above and X is chlorine or bromine, are reacted with a compound of fomnula Illa Rl'-NH2 Illa wherein Rl' poss~s~s the siy"iri~;d"ces given above.
3 o The above process is conveniently effected by heating a compound of formula lla together ~Nith a compound of formula Illa in the presence of a solvent such as W09~/30683 ~ , I~l/~i,, ' 218fi8~7 -14-dioxane to a temperature of between about 80C to and 1 20C, preferably to boiling temperature.
In the compounds of fommula lla, which are used as starting compounds in this process, X is especially chlorine. The compounds of fommula lla, as well as a process for the production thereof, are described in published European Patent Application 269 ~74.
A further process for p,e:ualdliùn of compounds of fommula la comprises treatingcompounds of fommula IVa ,Rl ~ ' ` IVa Si OR3 ~ ~
wherein R,' , R2 and R3 possess the ~iyl," )ces given above with tetrabutylammonium fluoride trihydrate.

The above reaction may be performed in an organic solvent e.g. tetrahydrofuran at room temperature under stirring. Compounds of fommula IVa can be obtained by treatment of compounds of formula lla with 1,3-dichloro-1,1,3,3-Le~ uulu,u;l disiloxane in an alkaline solvent e.g. pyridine, and reacting the so obtained compounds of formula Va WO 95130683 1 ~, 11 J.. '. ~
2~868~7 -15- -RJ~ N
~ / \~~/ Va 1' \o o~
\ / OR3 wherein X, R2 and R3 have ths ~iy~ ical1ces given above with compounds of formula Illa.
In the following Examples 1 to 8, all temperatures are in degrees Celsius and are 2 o uncorrected.
Exampl~2 1: 6-[(trans~-4-Hydrox~/cyclohexyl]-2'-0-methyl adenosine 19 of 6-[(trans)-4-hydroxycyclohexyl]-9-purinyl-2'-0-methyl-3',5'-0-(1,1,3,3-tetraiso-2 5 propyldisilox-1 ,3-diyl)-D-ribose is stirred during 15 minutes at room temperature with 2 9 of tetrabutyl ammonium fluoride trihydrate in 20 ml of tetrahydrofuran. The mixture is subsequently evaporated to dryness and the residue is eluted on siiica gel witll a mixture of ethyl 2C~Idl~ IlldllOI 85:15. The purified product is crystallised from methanol/ethyl acetate. The title compound crystallises with one equivalent of methanol and has a melting point of 121-124C.
[a]D2~ = -50.2 (c = 1 in dimethyl~,,,,d,,,ide) WO 95130683 . ~I/ I
q 7 -16- ~ --The compound may aiso be IC~ y " 3r' from ethanol and crystallises with one equiYalent of water after standing in moist air. Melting point:114-117.
[a]D20 = -46.9 (c = 1 dimethy:~,,,,c.,,,ide).
The 6-[(trans)-4-hydroxycyclohexyl]-9-purinyl-2'-o-methyl-3',5'-0-(1,1,3,3-tetraiso-propyl- disilox-1 ,3-diyl-)-D- ribose used in the above process as starting material may be produced as follows:
2gof6-chioro-9-purinyl-2'-0-methyl-3',5'-0-(1,1,3~3-~ ;C~UIU~JY ' ' -1,3-diyl)-D-ribose are stirred together with 1.32 g of trans-4-hydroxycyclohexylamine and 1,4 ml of N-ethyl-diisopropylamine in 80 ml of dioxane during 6 hours in an oil bath of 105C. The mixture is .sllhseq~lently cooled to room l~"".e, ~re, filtered and the filtrate col ,c~ ldl~d to dryness. For purification the so obtained mixture is eluted on silica gel, first with a mixture of hexane/ethyl acetate 7:3 and then with a mixture of ethyl act:ldt~,,'~, le:ll ,al~ol 95:5. The so purified oily compound has a R, value of 0,3 (from ethyl acetate / methanol 95:5).
Exarnple 2: 6-[(cis)-4-Hydroxycyclohexyl]-2'-0-methyl adenosine 2 0 The compound named in the title is obtained analogously to example 1 when cis~
hydroxyc~,.,lol ,~,~ylnmine is used instead of trans-4-hydroxycyclohexylamine.
The so obtained compound named in the title crystallises with a half of an equivalent of ethyl acetate and has a melting point of 110-111C. []D20 = -48,6 2 5 (c = 1 in dimethyl~", Idl "i.le).
EYSIIT~31P 3 6-[(1S,trans)-2-Hydroxycy11u~Jt"~yl] 2'-0-methyl adenosine The compound named in the title is obtained analogously to example 1 when 1 S, trans-2-hydroxycyclopentylamine is used instead of trans-4-hydrox~",y.iloh~,~ylnmine. The so obtained compound named in the title has the w0 95/30683 r~ oC
21868~7-17' following ~ dld~.luli~ . Foam, R, in ethyl~retr'-l~,t',a,~ol 75:25 = 0,44, []D20 =
25,5 ~c = 1 in dimethyl~v,,,,d,,,idt,) Example 4: 6-[(1R,trans)-2-Hydroxy~.y~,lop~"~1]-2'-0-methyl adenosine The compound named in the title is obtained analogously to example 1 when 1 R, trans-2-hydroxycyclopentylamine is used instead of trans-4-hydroxycy~;lùi ,~Aylnmine. The so obtained compound has the following 1 0 ~.1 Idl dl,lC~ s.
Melting p~oint: 164-166, R, in ethylacetate/ethanol, 75:25 = 0,44, [a]D20 = -80,2 (c =1 in dimethyl~ul",a",id~).
FY-~PIP 5: 6-[(1S,trans)-2-Hyd,uAy.,y~ilul,t,Ayl]-2'-0-methyl adenosine The compound named in the title is obtained analogously to example 1 when 1 S, trans-2-hydroxycyclohexylamine is used instead of trans~-hydroxycyclohexylamine.The so obtained compound named in the title has the following .,I,d,d.,leri~l;.,s.
Foam, R, in ethylacetate / Ethanol 75:25 = 0,42; [a]D20 = -26.2 (c = 1 in dimeth~,llv""d",ide).
EY~-rple 6: 6-[(trans)-4-hydroxycyclohexyl]-2'-0-ethyl adenosine Prepared analogously to Example 5. Obtained as 0.4 hydrate M.pt. 98C
(liquefies). [a]DZ = - 58 (c = 1 in dimethyl ~VIIIIdllli(le).
EY_~PIP 7: 6-[lS,(trans)-2-hydroxycyclohexyl]-2'-0-ethyl avel~osi"e Prepared analogously to that described in Example 5.
FY~mple 8: 6-[(1R,trans)-2-Hydroxycyclohexyl]-2'-0-methyl avel,osi"e W0 95130683 j l 218681t7 -18-The compound named in the title is obtained analogously to examp~e 1 when 1 R
trans-2-~ Jd UAy~ :~u~ 2m~ne ~s used ~nstead of trans~-hydroxycyc~ohexylam~ne.
The so obtained compound named ~n the t~t~e has the fol~owing :I a a k i~ti~s:
Foam; R in ethyl~At~ t. a~ol 75:25 = û.42; [a]D20 = -69.5 (c = 1 in dimethy;~u Idl ici~).
The compounds according to the invention have i t li g ~ dl~ lC..J;. .Ipropert~es. They are therefore usefu~ as ~ di-idlllt:llts. For this compounds according to the invention can be used as such as hydrates or addition products with organic so~vents e.g. methano~ ethano~ or ethy~ acetate. The most i L~ . g compound of fommu~a ~a is the compound of Examp~e 1 above wh~ch ~s in the fo~owing named compound No. 1.
The compounds of fommu~a la are of interest as ana~gesic as described above. They are a~so of interest for other activities. Among other activities the compounds according to the invention have anti-hypertensive activ~ty as indicated from theresu~ts of the fo~owing inve~liydliùl: .
Measurement of the b~nding to adenos~ne A1 and A2 receptors in t~ d~es from 2 0 the rat s cortex or from the cortex or striatum of the pig s brain using the method of R.F. BRUNS G.H. LU and T. A. PUGSLEY wh~ch is described in MOLEC.
PHARMACOL. 29 331-346 (1986) . Further testing of the activity of the compounds is effected in the iso~ated perfused rats k~dney for the fo~lowing pdldlll~l~la.
- renin secretion - rena~ haemodynam~cs - ~nh~b~t~on of the re~ease of noradrena~ne from the nerve endings fo~owing 3 o e~ectro-stimulation of the rena~ nerves according to the method of P. M.
VANHOUTTE D. BROWNING E. COEN T. J. VERBEUREN L. ZONNEKEYEN

wos~/306s3 21 8fi8~ 7 r~

and Ml. G. COLLIS described in HYPERTENSION 4, 251-256 (1982).
- Measurement of blood pressure, heart rate, urine production and renin activityin plasma of wake, NaCI-depleted and repleted, n~", lUt~ C or :"u~ dl ,eously I,ype~tel,:,ive rats with catheters implanted in the clLdu~ al aorta and in the vena cava, following i.v. a.ll"i"i~ , or a.l",i,~ l,d~iul1 of the compounds according to the invention as an infusion or bolus according to the method of J.F.M. SMITS and J. M. BRODY described in Am. J. Physiol. 247, R1003-R1008 (1984).
It is deduced from the results of the t:AdlllilldliUils that both the inhibition of renin secretionl and of release of noradrenaline from nerve endings, and the direct VnSOI "' " I, take part in the anti-hypertensive activity of the compounds of fommula la. In contrast to the lowering of the blood pressure, urine production and electrolyte excretion remain u~ l Idl ,ged. It results from this that the compounds of formuia la can not only be used as a"lil,j~.e,lti,sive agents, but also effect coronary \~dsouildliull. Furthermore, they protect the vascular endothelium by inhibiting both thrombocyte agy,~d~ and activation of leucocytes. They also lower blood lipid levels.

For the above illdk.dli~l1s, of the compounds of formula la, the compound of Example 1 is preferred. The ca,~io~-,ult:~.live and analgesic ill~iudliolls are preferred.
Furthermore the compounds of formula la are also active in the treatment of arrhythmias as indicated by their adenosine A1 receptor agonist activity, which is selective via-a-vis their activity against the A2 receptor, as stated e.g. in test a) described ht:l ~i"dtler and for example their capability to prolong conduction through the atrio-ventricular (A-V)node of the heart as indicated in test b) described he,~i,,drl~l. Thus, they restore sinus rhythm in supraventricular tachycardias, in particular paroxysrnal supraventricular tachycardia, reduce cardiac rate in WO 95/30683 ~ s 21~6847 -20-tachycardic atrial fibrilation and retum ventricular tachycardias induced by ~-a ilt"~yiu stimulation to nommal rhythm.
The compounds of formula la mimic the effect of "~ col, iilivl ,i"y", the procedure wherein a brief period of ischaemia renders the heart resistant to infaretion from sllhse~ nt ischaemia. They are, therefore, useful to protect the heart during unstable angina, against myocardial infaretion with or without adjunctive thrombolytic therapy, or ischaemic injury in patients Ull i~lyuilly (e.g.) coronary artery bypass graft surgery, d~lyiu~-ld~ly, eardiac ~Idllb,uldllldliun or non-cardiac surgery.
The compounds of fommula la are especiaily useful for a il"i"i~ ,i"g to subjectsprone to myocardial i"~drutivlls, e.g. as result of diagnosis or those who have already suffered from a myocardial infaretion.
The compounds of fommula la lower further plasma insulin without influencing glucose tolerance. They potentiate the insulin effect to increase glucose uptake and decrease lipolysis in adipose tissue leading to lower plasma free fatty acid collcelllldlivlls (see test d) described ll~,~i,,d~l~l). Lower piasma free fatty acids in tum lead to lower triglycerides, which leads to increased HDL .. I,~le~ ,ul.
The insulin sparing effect and/or action to lower free fatty acids makes the compounds of formula la useful for the treatment of Type I diabetes and Type ll diabetes i.e. non-insulin d~pellde"l diabetes.
The compounds of formula la lower plasma triglycerides and free fatty acids (seetest e) lle,~i, Id~ l) and raise HDL ~:I lol~:,t~, ul and hence, are useful in treating lipid dysfunction, and conditions AccO~ ;..l.-d with elevated free fatty acids and triglycerides and where an increase in HDL .I,~leal~,ul is desirable.
The compounds of fommula la show good metabolic stability.

wo 95/30683 2 1 8 68 4 7 In another aspect, the invention provides the use of compounds of fommula la for thetreatmentof~orinthepl~:iJaldliunof~lledi~dlll~l~tasuitableforthetreatmentof~
pain.
In another aspect, this invention provides a compound of formula la as defined above for use in the treatment of pain.
In a further aspect this invention provides an analgesic cull,uuailiul) c~,,,,uriaillg a compound of fommula la as defined above in ~C50; ~ .., with a i l~a""ac~utically~C~ carrier or diluent. The present applicants cu"l~",~ the use of compounds of formula la in the ii ~di. .~t;o,~s as described above for compounds of formula 1.
The following i l,a""~ lo.J;~I tests illustrate the above ",~"~;~",ed activity of the compounds of formula la.
a) ~lfini~y for a~ aill~ reoeptors Pig striatal Illc:lllLldiles are prepared as previously described by H. Bruns et al. in Molecular Pl,a""acolùgy 29 (1986) pages 331-344. 3H-NECA a non-selective d~el1oai"e receptor agonist is used to label both A, and A2 receptors. ICso values arederiv~dfromthedia~ula- ~",_"~curvesbyweightednon-linearleast-squarecurve fitting to the Langmuir equation and pKD values ~ tPrl The compounds of fommula la show affinity for the A, receptor e.g. at a range offrom 1 to 500 nM.
b) A~ ;a~
3 o Adenosine A, receptor activation reduces the incidence of, e.g. paroxysmal supraventricular tachycardia, Id :l "/_~l diL atrial fibrillation and other arrhythmias by WO 95/306U , I ~
21868~7 -22- 1--slowing conduction through the atrio-ventricular (AV) node of the heart detected by increases in the P-R interval. The test method involves recording of ECG changesin conscious adult Rhesus monkeys. The compounds of formula la are a~i~"i"i~ d at dosage ranges from about 0.1 mg/kg to about 1000 mg/kg p.o. or 0.03 to 30 mg/kg i.v. in the test referred to by C. Clarke et. al. in The Pl,d""ac~utical Joumal 244, 595-597 (1990). For example in this test compound No. 1 prolongs P-R interval of the surface ele~.l,u- d, iiuy,d,,, (ECG), indicating siowing of conduction through the AV node at doses~ 'of 0.1, 0.3 and 0.6 mg/kg p.o. As noted above such an action leads to ltlllllilldli~o of AV nodal reentrant tachycardia and reduction in heart rate in tachycardic atrial fibrillation.
c) Protec~Yon against infar~Yon by r ~ Y( ~ 9 P,~con ,il,g (5 minutes of ischaemia followed by 10 minutes of recovery) renders the heart very resistant to infarction from s~ ~hsequent ischaemia (30 min) and reperfusion (3h). The test method is disclosed in the article of G. S. Liu et. al.
1991 - Circulation (~4) 1 350 - 356 and J. D. Thomton et al. in 1992 - Circulation (85), 659-665. The compounds of fommula la are a~i~"i"i~l~,t,d i.v~ at a dose of from about 0.01 to 10 mg/kg to rabbits. In this test rabbits given 100 ug/kg of compound No. 1 were protected to neariy the same extent as elldo~e~ous plc:co,.~ g from infarction induced by a 30 min. period of coronary occlusion.
d) Glucose Tmnsi~ort and Lipoiysis Ll Rst A i;~
2 5 i) Adipocytes are isolated f rom the epididymal fat pads of normal chow-fed rats by digestion with c~lldg~l~ase. Cells (final cul lu~ dtiùl~ 2% v/v) are pre-incubated with ad~"o~i"e cied",i"as~ (1 U/ml) and with test compounds e.g. compound No. 1 and other additions as indicated to measure glucose transport at 37C.
[3-3H]Glucose (final c~l~c~ ldliol~ 50 uM 0.5 uCi/ml) is then added after 30 W095/30683: r~
- -23- 21868~ 7 minutes, and incubation is continued for a further 60 min. lllcOl~Olaliui~ of radioactivity from [3-3H]glucose into cell lipids (a measure of glucose transport) is evaluated by extraction of the cell suspension (0.5 ml) with 5 ml of toluene-based scintillant, followed by liquid 5..i~ counting; water-soluble " ~ i and residual [3-3H] glucose remain in the aqueous phase and are not detected.
Lipolysis is measured in a conventional manner. In one method cells are incubated with and ~Nithout 1 uM isop,v~ ol and then the incubation continued for 60 min.
The supsmatant is separated from the cells after b~ll' '' l~ptinn through dinonylphthalate and lipolysis estimated by enzymatic d~l~llllilld~iuil of giycerol released into the supematant.
The compounds of formula la are active at col~ct:lllldlio~ls from 0.1 to 10ûO nM.
Compound No. 1 suppressed lipolysis in rat adipocytes at col~c~"I,dliu11s from 0.1 to 100 niM.
In the presence of adenosine ded",i"ase (1 U/ml), compound No. 1 has no significan~: effect on the il)co~uordl;v,, of rddiua-;.iJity from [3-3H]glucose into cell lipids in tlle absence of insulin and only a marginal effect in the presence of a maximally stimulating insulin cullc~ dliol~ (8 nM), but siy"iri-;d,.:!y increases the stimulatiol~ of i"~,uOrdli~l1 of ~ddiua~ ;.y in a cu"~ ~"l~dliol~-dep~"dt",~ manner, at cu,1ce,,l,dliul,s from 0.1-50 nM insulin. These observations indicate that the compound increases the sensitivity of glucose transport to insulin. In the presence of anear-l~aximallyeflectivecc,,~c,:,,lldliu,, of compoundNo.1,theECsOforinsulinstimulatioll of [3-3H]glucose illC~lUOIdliUII into lipids is d~ ased between 2 and 3 fold. In the presence of ad~l,osi"e dea",i"ase and 1 uM isuj r- ~"ol, 10-50 nM
of compound No. 1 increases both the sensitivity and the magnitude of the response to insulin; the EC50 for insulin is reduced up to 5- fold and the stimulation by a maximal insulin CullC~Itldtiull is ~iy" Illy increased.

2186,8 ~ 24-ii) Lipid and G~ucose in Nommal 18 hr Fasted Piats The rats, 2 to 3 months of age,~weighing ca. 250 grams are kept in a room at a controlled ambient temperature of 22 C and a 12/12 hour lighVdark cycle for seven days.
Purina rat chow and water are available ad libitum. Following an 18 hour fast, rats (5/group) are given test compounds by gavage in 0.5% CMC. The animals receive 1.0 mU100 9 body wt. Three hours after a~ d~i~o~ the rats are a~,e~l,t,li~t,d with CO2 and blood collected via cardiac puncture.
Sera are collected and used for glucose, free fatty acid and ~-hydroxybutyrate d~ ,;"at;o,~. Free fatty acids are measured by acyl-COA peruA;ddse cdlulilll_~ic enzyme assay, glucose is measured by the glucose oxidase method (YSI Model 27, Yellow Spring, Oh) and ~-hydroxybutyrate is assayed with a ~-hydroxybutyrate dehy.l,ugellase-linked en_yme assay (Sigma Kit 310-A - St. Louis, Mo.).
The compounds of fommula la are active at a dose of from about 1 to about 5û00 ,ug/kg.
The doses for lowering free fatty acids (the primary result of the effect on adipocytes) for the compound No. 1 are between 5 and 100 ug/kg at 2 hr post dose. This results in dose d~pt:llltlt:lll decrease in ,I~-hydroxybutyrate and blood glucose levels.
iii) Effects in non-insulin Dependent Diabetic (NIDD) Rats In the NIDD screen test, the rats (200-220 9) are fed a high fat diet ad Ji~ihlm. At fed state, 40 mg of a~ 71~t~ /kg of body weight are injected via the tail vein. One week later, those rats are cull~idt,rt,d to be diabetic 3 o which have fed blood glucose of greater than 200 mg/dl and, following an ovemight fast, when given an oral glucose tolerance test, have blood WO 95/306~3 -25- 1 868~ 7 glucose of 40 to 80 mg/dl three hours after the test. Four days later, animals are used in the screen, if fed blood glucose levels are greater than 180 mg/dl. Blood glucose is ~ d with a YSI Glucose Analyzer. The cllronic screen test is carried out as follows:

On Day 1, food is removed from rats at 9:00 a.m.; and after an initial blood glucose reading is taken via the tip of the tail, vehicle (control) or compound (9 Idla/tl~dLIllt:l ll) is a~",i"ia~ d orally. Six hours later blood glucose level is measured; and illllll~didl~ly thereafter the rats are refed.
The same rats are given either vehicle or drug once a day for 11 consecutive days. Blood glucose is d~ l lil ,ed at 0 hour and after a 6-hour fast post dosing on days 4, 8, and 11. 100 Illi~;luyldll~kg of a compound oF fommula la e.g. compound No. 1 for 11 days results in a significant : reduction in plasma free fatty acids that produces a significant decrease in b ood glucose.
e) Dy 'i~ ~,i~dbyelevateda-erumbi,~ .i.l~s Several studies have shown a positive co"~' l between serum triglyceride levels (and an ~.so,,; U~d cl~ ased HDL l,l ,uleal~,ul level) and the risk for coronary heart disease (CHD) (Grundy, in Cholesterol and Alllelusc~leluais~DiagnosisandTreatment~Lippincott~pll;ldd~l~Jllid(199o))~
The value of reducing elevated triglyceride levels as an approach to reducing the risk of CHD emerged from the Helsinki Heart Study where, following treatment with y~lll"' u,;l, the greatest reduction in serious coronary events occured in Type IIB hyp~,li,u;d~,,,;c patients in whom both LDL-~I loleal~, ul and total serum triglycerides are elevated and HDL
- cholesterol levels are generally reduced. The compounds of formula la are 3 o a~tive in the Rhesus monkey at doses from about 0.03 to 30 (e.g. 0.1 to 30)mg/kg i.v. and 0.1 to 100 (e.g. 0.1 to 10) rng/kg p.o. Compound No. 1 WO 95/30683 . . J ~ -1~)'''~ ' 2i~8~ -26-produces doc,0..~,1.2~d and long-lasting falls in plasma free fatty acids and triglycerides in the Rhesus monkey at doses from 0.03-0.6 mg/kg i.v. and 0.1-1.2 mg/kg p.o.. Re,,u, ~s~"tdlive results for Compound No. 1 at 0.6 mg/kg p.o. show a lowering of free fatty acids by ca. 60 % compared to a control after 300 minutes and of l~i~u,~ycelid~s by 40%.
The compounds of fommula la are also active in tests for mean arterial blood pressure, ~,d~y~ar,lid and peripheral v~ in d"a~ d rats.
ThQ ~ ue, i" ,~"ts are carried out on male Wistar rats, body weight 300-350 g under Pentothal anaesthesia (120 mg/kg i.p.), according to the method of Salzmann et al. (J. Cardiovasc. rl,d""acol. 12, 451-460, 1988). Catheters are placed in the right jugular and right femoral veins, in the left ventricle (inserted via the right carotid artery), left femoral artery, and aorta ~inserted through the right femoral artery). The following variables are measured or calculated: systolic, diastolic, and mean arterial blood pressure (mm Hg; left femoral artery, Statham pressure transducer P 23 Gb), pulse pressure (mm Hg), heart rate (bedt~~ l, triggered from the blood pressure curve), rate of rise of left ventricular pressure (dP/dtmaX, mm Hg/s; Statham pressure transducer P 23 Gb), cardiac output (mUmin/100 g body weight, " ""- lllti~,n method, right jugular vein and aorta), total peripheral resistance (dynes s.cm ~/100 9 body weight), superficial ECG. Arterial blood pressure, left ventricular pressure, dP/dt m~X~ heart rate, and ele.:~,u..a,diug,d,,, are continuously recorded with a Schwarzer polygraph.
The pdldlll~t~l~ are measured 30, 20, 10 and 2 min before ad,,,i,,ial,dliùn of the test substance and 1, 5, 10 and 15 min after injection of the drug into the right femoral vein. The compounds of formula la are injected at dosage ranges from about 0.001 to about 1 û mg/kg animal body weight. Compound No. 1 was tested in cumulative doses of 0.003, 0.010 and 0.03 mg/kg, three animals per dose being used. Compound No. 1 induced falls in blood pressure [EDso = 49 Illi.;lUyldll~ u, iv] and heart rate and an increase in WO 9~il30683 1' ~, I I 1~... _ .
2l8684 7 -2~-systemic vascular conductance.
The doses of the compound of fommula la used in the above illdk.dliulls will vary in the usual way with the seriousness of the disorders, the weight of the sufferer, and the relative efficacy of the compound. Hûwever, as a general guide suitable unit doses may be 0.1 to 1 ûOO mg, such as 0.1 to 10, 0.5 to 200, 0.5 to 100 or 0.5 to 10 mg, for example 0.1, 0.5, 1, 2, 3, 4 or 5 mg; and such unit doses may be adl"i"iale,~d more than once a day, for examp!e 2, 3, 4, 5 or 6 times a day, butpreferabl~l~ 1 or 2 times per day, so that the total daily dosage for a 70 kg mammal including humans is in the range of about 0.1 to 1000 mg e.g. per os or 0.0û3 to300 mg i.~., that is in the range of about 0.001 to 20 mg/kg/day, such as 0.007 to 3, 0.007 to 1.4, 0.007 to 0.14 or 0.01 to 0.5 mglkg/day, for example 0.01, 0.02,0.04, 0.05, 0.06, 0.08, 0.1 or 0.2 mg/kg/day; and such therapy may extend for a number of weeks or months. For compound No. 1 the preferred dose range for all the illli~;d~iUlls of the invention is from 0.1 mg/day to 10 mg/day for a 70 kg adult.
For the preferred indication non-insulin depe~ "l diabetes and for hypertrigl~/ceridemia the indicated dose for humans is 0.2 to 2 mg per day per os and for treating heart failure and other cardiac disorders 0.2 to 10 mg per day in particular 0.5 to 5 mg/day per os or 0.25 to 5 mg i.v. for arrhythmias e.g.
tachycardic atrial fibrillation.
The compounds of formula la may be fommulated for adl "i, liall dliUO by any suitable route, the preferred route ~ept:"-li"g upon the disorder fûr which treatment is required, and preferably in unit dosage fomm or in a form that a human patient may administer to himself in a single dosage. Advantageously, the compositiûn is suitable for oral, rectal, topical, parenteral, intravenous or intramuscular a.llllill;a~ldLiol~ as described above with respect to the analgesic use.
- Unit dose ,ul~a~ dliull forms for oral adlllillialldliui~ may be tablets and capsules co"ldi"i"g 0.05-20 mg of a compound of formula la.

W0 95/30683 ,~
- 218~8~7 -28~
Suitabiy, the compounds according to this invention, or a hydrate or an additionproduct with organic solvents, will comprise from about 0.5 to about 20% by weight of the fommulation, preferab~y from about 1 to about 10%, for example 2 to 5%.
Compounds of forrnula la wherein Rl' is hydroxy (C4.8)cycloalkyl and R3 is alkyl, are detected as ,,, ~c~L " - on a~"i"ibl, , of com~pounds of forrnula I wherein R, is (C4.")cycloalkyl and R3 is alkyl to warm blood~3d animals, e.g. rats, dogs and humans.
Thus a-l~"i, lialldliU~ of Compound M leads to the production of hydrox~ ,lul,~Ayl 2'-O-methyl adenosine.
In a further aspect, the present invention provides a method of ad~llillibIt~lillg N6-cyclohexyl-2'-O-methyladt31~0~i"e to a warm blooded animal in order to produce N6-hydroxycyclohexyl-2'-O-methyl adenosine.
The present invention provides in another aspect N6-hydroxycycloalkyl-2'-O-alkyladel10si"e in pure form, e.g. greater than 95% pure. The eAt:",, ' ' 3~ compounds described herein meet this criterion.

The present invention provides in a further aspect N6-hydroxycyclohexyl-2'-O-alkyl adenosine free from cyclohexyl-2'-O-methyl adenosine.
In another aspect, the present invention provides a process for the production of 2'-0-alkyldd~:llObille5 which comprises treating adenosine with an a,u,uluplidIc: alkyl sulphate in the presence of a phase transfer catalyst.
Preferably the 2'0-alkyl adenosine is any compound defined above.
3 o In a further aspect, the present invention provides a process for the production of compounds of formula I as defined above, which comprises reacting a compound WO 95/30683 1~ Jr ~, ' 29 2186847 of fommula Vl R2 ~\ $N
N ,~
H O--~/
HO O H

Vl with a basic solution of a compound of formula (R3)2SO4 in the pre~ence of tetrabutylammonium hydrogen sulfate and a non-polar solvent and purifying the product by recry: ' " ' ~.
If necessary reactive groups may be It~ Ial;ly protected.
Preferably the alkyl sulphate is di(C1 4)alkyl sulphate.
3 o Preferably the phase transfer catalyst is tetrabutyl ammonium hydrogen sulphate.

~ .3~ ~
Preferably the reaction is effected in a non-polar solvent, e.g. as described he~ ~i, la~lar.
A group of compounds of the formula l is defined wherein R1 is (C3 s )cycloalkyl, R2 iS hydrogen or (Cl ,)alkyl, and R3 is (Cl, )alkyl.
Hitherto, the pl~,udldlioO of compounds of formula i typically involved six steps, which includethe pl~:pdl " .1 of 2',3',5'~ tyli"~si"e; cl~ illdlioll and hydrolysis to 6-chloro-9-13-D-ribofu,d, l~all ~1 I purine; protection of the 3'-0- and 5'-0-positions with ItslldiSoplupy; ' ' ,e (TIPDS-CLz); 2'-0-alkylation and purification by silica gel ~ l ul l ldluyla~ul ly; d~ul ut~ ivl~ of the 3l-o- and 5l-o-positions; and reaction with R1NH2 and ,~."y~ " ~Atinn to obtain the compound of fommula 1.
The present applicants have found that the compounds of forrnula I can be prepared in good yields and purity without the need for 3'-0- and 5'-0-disiloxane protection and dt:,ulul~ul;ol~ or for silica gel ~IIlullldluyld~lly~ The applicants have found that the inosine-2',3,'5'-triacetate starting material of the prior art process may be advantageously replaced with the lipophilic inosine-2',3',5'-l,i,u,u,uiul~dl~, which pemmits the doubling of throughput and the ~i.llilldliul~ of u"d~si,dule pyridine 2 0 solvent.
In the present invention the compounds of fomnula I are prepared under phase transfer catalysis conditions in accoldal~ce with the following reaction scheme:

W0 95/30683 21 ~ 68~ 7 -31- , .
\ / (R3)2SO~ N
5 R~ $~ N
H O/~ N Bu~N~HSo4- HO /~N~
HO OH HO Ol~
Vll ' ' where R1 R2 and R3 are as defined above.
The compounds of formula I may be prepared by reacting a basic aqueous solution of a~compound of fommula (V~) with a di-(C1 1)alkyl sulfate in the presence of tetrabutylammonium hydrogen sulfate and an organic water-i"""is.i~le solvent.
The base used to prepare the basic aqueous solution is preferably an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The solvent can be any water i"""i:,.;il,le or esst",~i..lly i"""is~i~le solvent in which the compound of formula I is soluble such as ",t,tl,yl~.~e dichloride or t-amyl alcohol. It is also preferred that the reaction be run at temperatures between about -20C to about 50C in particular, room temperature. The time of the reaction is not critical but it is pref~rably carried out over a period of from about 5 to 10 hours especially about 7 to 8 hours. The crude compound of formula I is isolated by evaporation 2 5 followed by stinring with a 1:1 mixture of water and inert solvent, preferably toluene, at room temperature for 5 to 7 hours, then filtering and drying. Pure compound may be obtail1ed by fractional cry~ldlli~dliv,), preferably by:
1) recry~t~ ti~n from an inert solvent, such as toluene, by dissolving the crudecompound in the solvent at 80C, heating at about 55C for d~J~lU~ y 1 hour cooling to room temperature, seeding with pure compound and filtering;
2) repeating the recr~,: 1 procedure of step 1) but heating at about 65C

WO 9S/30683 218 6 8 4 i F~

before cooling to room temperaturQ; and 3) recrystallizing from 100% ethyl alcohol by dissolving at reflux, diluting with water, seeding, then filtering and drying.
Many of the compounds of fommula Vl are known and may be prepared by methods described in the literature such as the rcvrt~ tio~led USP 4,843,066 and USP

4,985,409. The compound formula Vl may also be prepared advantageously, as indicated above, in acc-,,dd,~ce with the following preferred reaction scheme:

N$ (C~HsCO)20 )~ G~/N
H O O H H5C C2Hs 2~
O O
Vll Vlll WO 9~/30683 21 ~8 g 7 Cl 2 --<\ $ N

5 ,, ~ HsC2 )~ ~ N~ Vl H5C2 ~ O ~C2H5 O O
IX
where R1 and R2 are as defined above.
The compounds of fommula Vl may be prepared by acylating inosine of formula Vll with propionic anhydride to form the 2-O-, 3-O- 5-O-protected compound of formula \1111; llalogel,dli"y the compound of fonnula Vlll with thionyl chloride to form the i~ lll of formula IX; and simultaneously aminating and hydrolyzing the compound of formula IX. Acylation of inosine is preferably carried out in a mixture oi toluene tributylamine and 4-dimethylaminopyridine at a temperature offrom 100 to 110C over a period of 4 to 5 hours. The compound of formula Vlll is isolated by prt~ dliOI~ with heptane. HdlOg~lld~iOIl of the compound of formula Vlll is preferably carried out in a mixture of toluene and N N-dimethy;'u, ",a",i~e at a temper~ture of from about 60 to 70C over a period of 3 to 4 hours, and the solution of the compound of formula IX may be used after washing with water and brine. Arnination a~d simultaneous hydrolysis of the illl~lllledidlt: of formula IX is preferably effected by adding the amine R1NH2 and reacting at a temperature of from 100 to 11 0C over a period of 15 to 20 hours. The compound of formula Vl is isolated by filtration at room temperature and purified by recr~
The proc~ss of this invention is illustrated by the following examples.
Process IExample 1:

,, A ~ ~:
WO 9~i/30683 2186847 _34-N -cy,,l~ Ayl 2 -O-meth~,ld~t" ,o~i"~
Step A. Inosine-2',3',5'-l,i,u,u,uiu,,dl~
A miAture of 271.2 9 of inosine, 966 ml of tributylamine, 3.30 9 of 4-dimethylaminopyridine and 600 ml of toluene is heated to an intemal temperature of 104-105C; and oYer a period of 35 minutes, 453 ml of propionic anhydrida areadded at a rate which maintains the intemal temperatùre between 104-1 05C. After stirring the mixture at this temperature for an additional 4 hours, the miAture is cooled to 5-10C with an ice bath; and 1000: ml of heptane are added. The resulting suspension is stirred at room temperature (20-22C) for 30 minutes andthen filtered e.g. on a Buchner funnel. The solids are washed with a total of 450 ml of heptane in three equal portions of 150 ml each and dried at 45-50C (25 mmHg) ovemight (14 hours) to yield 425.9 9 of inosine-2',3',5'-l,i~ ,u,ùio~,dlt: as a white solid. (MP 171-172C; yield 96.5%).

Ste~ B. N6-cyclohexylafiello~i"e A mixture of 270.6 9 of inosine-2~,3~,5~-l,i,u,uyioll , 240 ml of N,N-dimeth~l~u""a",i~t, and 600 ml of toluene is heated to 65C; and over a period of 1 hour, 67.84 ml of thionyl chloride are added at a rate which maintains the intemal temp~rature between 62-65C. The mixture is stirred at this temperature for an additional 2.5 hours and then cooled to 1 0C with an ice bath. After addition of 60û ml of water precooled to 10-15C in an ice bath at a rate which maintainsthe temperature below 20C, the organic layer is separated and washed with a total of 800 ml of 10% aqueous sodium chloride in four equal portions of 200 mi each. The organic layer containing crude 6-chloro-9-(2,3,5-tri-O-,ulupiu~yl B-ribofuranosyl)-9H-purine is added with stirring to 620 ml of cyclohexylamine heated to 105C over a period of 2 hours at a rate which maintains the intemal temperature at 105C. After this mixture is stirred at this 3 o temperature for an additional 17 hours, it is cooled to room temperature (25C) over d,u,uluAi,lldl~ly 2 hours with efficient stirring and then filtered e.g. in a Buchner WO 95130683 1 ~_l~.l.. ~' _35, ~`~8~ 7 funnel with suction. The solid containing N6-cyclohexyladt" ,o~i"e and cyclohexylamine hydlu~ uricl~ is washed with a total of 46û ml of toluene in four equal po:~tions of 115 ml. each and ~, m la~ d damp to a 5-liter flask equipped with a ~ ulldllicdl stirrer. After addition of 2 liters of aqueous saturated sodium bi-,dl bUIl~dlt~ solution and 2.5 liters of ~thyl acetate, the mixture is stirred until all the solid dissolve (d~ ll U)~il l ' ~y 1 û-15 min.). The oryanic layer is s~ and theaqueous layer is extracted with 1.5 iiters of ethyl acetate in two portions of 1 liter and 500 ml-, ~ -r ~ ~'IY
The organic layers are combined and evaporated until about 3 liters of ethyl acetate (at 40C, 1 00-2ûO mbar) is removed. To the residue, 500 ml. of heptane is added;
and the Iresulting mixture is stirred for 30 minutes. The solids are separated on a Buchner funnel, and washed with a total of 300 mi of heptane in three equal portions of 100 ml each. The solids are then dried at 45-50C (30-35 mbar) for a~J,ulu.~illlut~ly 3 hours to yield 148 9 of crude N6-cyclohexylad_noai"e as a white solid. This is lldt~F~ d to a 1 liter round-bottomed flask equipped with a ",e~,l,a"iual stirrer, and 175 ml. of 95% ethanol are added. The suspension is stirred for 15-20 min and 175 ml of tert-butyl ethyl ether are added. After stirring for 5 min, tlle suspension is cooied in an ice bath and stirred for an additional 152 0 minutes. This suspension is filtered in a Buchner funnel and washed with a total of 50 ml. oF tert-butyl methyl ether in two equal portions of 25 ml. each.
The filtered solid is dried at 45-50C (30-35 mbar) for 14 hours to yield 130 9 of N5-cyclohex~,ldd~"osi"e as a white solid (m.p. 185-187C; yield 60.0%).

Step C. N6-cyclohexyl-2'-O-meth),ldd~"osi"e A suspension of 94.33 9 of N6-cyuloll~ ,lu~t"~:,i"e and 720 9 of 5% aqueous sodium hydroxide is stirred at room lt:"",~, ~re (24-25C) until all of the solids are dissolved (d,UIJlU~ lldl~ly 5 min.). Using an addition funnel, 850 ml. of di~ rul"_;1,al~e and 5.5 9 of tetrabutylammonium hydrogen sulfate are added ~ ~ . ,t '~ i '' 21~8~7 -36- ~
followed by 61.3 g of dimethyl sulfate over 5-10 minutes while l"ai"lai"i"g the intemal temperature between 24-25C. The addition funnel is washed with an additional 50 ml of di.;l,luru",_ll,a"e which is added to the reaction vessel. After stirring the biphasic mixture at 24-25C (intemal temperature) for 7.5 hours theorganic layer is separated and evaporated àt 40C,(270-290 mbar) until no further solvent distills. The residue is dissolvrid in 200 ml of toluene and evaporated at 45-50C (30 mm Hg) until again no further solvent distills.
A mixture of the above-",~, ,li~l ,ed crude material and 2470 ml of toluene is stirred at room temperature for 10 minutes and then 2470 ml of water are added over a period of 22 min. The resulting suspension is stirred at room temperature for anadditional 6 hours and solids are collected by filtration e.g. on a Buchner funnel with suction. After washing the solids with 114 ml of toluene and a total of 285 ml.
of water in three equal portions of 95 ml each the solids are dried at 48-50C (25 mm Hg) ovemight (14 hours) to yield 53.0 9 of a white solid. A suspension of this solid in 397 ml. of toluene is heated to 80C with stirring to form a clear solution which is cooled to 56C over 45 min and seeded with 10 mg of pure product. The mixture is stirred at 55-56C for 45 minutes and then cooled to room temperatureover l hour. After stirring at this temperature for an additional 1 hour the solid are 2 0 collected by filtration e.g. on a Buchner funnel with suction. The solids are washed with a total of 75 ml. of toluene in three equal portions of 25 ml. each to yield 60 g of a white solid. A suspension of this solid in 159 ml of toluene is again heated to 80C and the above seeding procedure is carried out at 65 to 66C.
2 5 After cooling to room temperature over 1 hour and stirring at the same temperature for an additional 1 hour, the solids are filtered and washed with 42 ml. of toluene in three equal portions of 14 ml. each and dried at 48-50C (25 mm Hg) ovemight (14 hours) to yield 57.7 9 of a white solid. The solid and 122 ml. of 100% ethanol are heated to reflux with stirring to obtain a clear solution, and 288 ml. of water 3 o pre-wamned to 55C are added over 25 minutes. The mixture is cooled to 55Cand seeded with 20 mg of pure product. This mixture is cooled to room wo 95/30683 _ I ~ . I .~... .
21888~7 37 temperature over 1 hour and stirred at this temperature ovemight (16 hours). Thesolids are collected by filtration on a Buchner funnel with suction and washed with a total of 57 ml. of 1:2.36 mixture (Y/Y) of 100% ethanol and water in three equal portions of 19 ml each. The solids are dried at room temperature (29 mm Hg) to yield 62.2 9 of product as a white solid in 1.5 hydrate form (m.p. 88-91C; yield 42.5%).
Process Exam~le 2:
Following the aboYe procedure but using an equiYalent amount of N6-cy~;lope"tylade"osi"e there is obtained N6-cyHui,t "~yl 2'-O- methyl adenosine.
Process FY~rn~le 3 The steps of process Example 1 are followed except that the di~-l,lc,,u,,,~tl,a~le in step C) is replaced by tert-amyl alcohol, and subsequent to the initial t:~l ,c" Inll~dl~l cryst~'- " the product is recrystallised from ethanol and water. 32.19 (yield approx. 30%) N6-cyclohexYI-2-O-methylddt:llosi"e are obtained in excess of 98%
purity.

The process of this inYention is more economic in time and cost than hitherto known p,ucesses. The process provides a convenient method for selective 2-O-methylation of N6-cyclohex~,lddel~o~ e under phase-transfer conditions, and a method of purification of the 2'-O-methyl derivative. Expensive protecting groups and the use of ~.lllollldL~yld,ully are aYoided.

Claims (20)

-38-

1. Use of a compound of formula I
I
wherein R1 is hydrogen, (C1-4)alkyl, allyl; methallyl; a straight-chain or branched (C3-7)alkinyl, (C3-8)cycloalkyl, hydroxy (C4-8)cycloalkyl, phenyl being mono-, or independently each other di-, substituted by halogen with an atomic number of 9 to 35, (C1-4)alkyl, (C1-4)alkoxy or CF3; or phenyl(C1-4)alkyl wherein the phenyl ring is unsubstituted or mono- or independently of each other di-, substituted by halogen with an atomic number of 9 to 35, (C1-4)alkyl, (C1-4) alkoxy or CF3;
(C1-4)alkyl having at least one hydroxy group or at least two phenyl groups, a bicycloalkyl such as endo- or exo-bicyclo[2,2,1]heptyl, a naphthyl (C1-4)alkyl-group, an acenapthylenyl (C1-4)alkyl-group or a group of formula A or B
or (A) (B) Z is hydrogen, a hydroxy group or a (C1-4)alkoxy group Q is hydrogen or hydroxy, A is -CH2-, -O-, -S- or a direct bond, Y is -(CH2)n- or a direct bond, n is a whole number from 1 to 3 and the broken line in (A) represents an optional bond, R2 is hydrogen, (C1-4)alkyl, amino, (C3-5)cycloalkyl or halogen with an atomic number of 9 to 35 and R3 is (C1-4)alkyl as all analgesic in the production of a medicament suitable for the treatment of pain.

2. Use as claimed in claim 1 wherein the compound of formula I is selected from 6'-hydroxy(C4-8)cycloalkyl-2'-O-methyladenosines.

3. Use as claimed in claim 1 wherein R1 is other than hydroxycycloalkyl .

4. Use as claimed in claim 3 wherein the compound of formula I is 6-cyclohexyl-2'-O-methyl-adenosine.

5. Use as claimed in any preceding claim for acute pain.

6. Use as claimed in any preceding claim for chronic neuropathic pain.

7. Use of a compound as defined in any preceding claim in the treatment of pain as defined in any preceding claim, or a method of treating pain as defined in any preceding claim which comprises administering a compound as defined in any preceding claim to a subject in need of such treatment, or an analgesic composition comprising a compound as defined in any preceding claim as an analgesic in association with a pharmaceutical carrier or diluent.

8. A compound of formula Ia Ia wherein R1' signifies (C4-8)cycloalkyl substituted by a hydroxy group and R2 is as defined in claim 1 R3 is as defined in claim 1.

9. A compound as claimed in claim 8 wherein R2 is hydrogen, (C1-4)alkyl or halogen of an atomic number from 9 to 35.

10. A compound selected from:
6-[(trans)-4-hydroxycyclohexyl]-2'-O-methyl adenosine 6-[(cis)-4-hydroxycyclohexyl]-2'-O-methyl adenosine 6-[(1S,trans)-2-hydroxycyclopentyl]-2'-O-methyl adenosine 6-[(1R,trans)-2-hydroxycyclopentyl]-2'-O-methyl adenosine 6-[(1S,trans)-2-hydroxycyclohexyl]-2'-O-methyl adenosine 6-[(1R,trans)-2-hydroxycyclohexyl]-2'-O-methyl adenosine 6-[(trans)-4-hydroxycyclohexyl]-2'-O-ethyl adenosine, and 6-[1S,(trans)-2-hydroxycyclohexyl]-2'-O-ethyl adenosine.

11. A compound as claimed in claim 8, claim 9 or claim 10 which is 95% pure.

12. A compound as claimed in claim 8, claim 9 or claim 10 free from N6-cycloalkyl-2'-O-methyl-adenosine.

13. Use of compounds of formula Ia as defined in any one of claims 8 to 12 for the preparation of medicaments suitable for the treatment of pain, for use against high blood pressure, as coronary vasodilators, for inhibition of both thrombocyte aggregation or activation of leucocytes, for lowering blood lipid levels, against congestive heart failure, myocardial infarction, sudden cardiac death, renal insufficiency further for the treatment of hypertriglyceridemia/lowHDL cholesterol levels, lipid dysfunction, elevated free fatty acids and/or typeI and type II diabetes, arrhythmias or for protection against myocardial infarction.

14. A pharmaceutical composition comprising a therapeutically effective amount of compounds of formula Ia as defined in any one of claims 8 to 12 in association with a pharmaceutically acceptable carrier or diluent.

15. A compound as claimed in any one of claims 8 to 12 for use in the treatment of pain, of high blood pressure, coronary vasoconstriction, thrombocyte aggregation, high blood lipid levels, congestive heart failure, sudden cardiac death, renal insufficiency, hypertriglyceridemia/low HDL cholesterol levels, lipid dysfunction, elevated fatty acids or type I or type II diabetes, arrhythmias andfor protection against myocardial infarction, or a method for using such a compound which comprises administering a compound of formula Ia to a subject in need of such treatment.

16. A process for the production of 2'-O-alkyladenosines which comprises treating adenosine with an appropriate alkyl sulphate in the presence of a phase transfer catalyst.

17. A process as claimed in claim 16 for the production of a compound of formula ? as defined in claim 1.

18. A process as claimed in claim 16 or claim 17 in which the compound produced is N-cyclohexyl-2'-O-methyladenosine.

19. A compound produced by the process of claim 16, claim 17 or claim 18.

20. A method of administering N6-cyclohexyl-2'-O-methyl adenosine to a warm-blooded animal in order to produce N6-hydroxycyclohexyl-2-O'-methyl adenosine.