CN1147815A

CN1147815A - Adenosine derivatives

Info

Publication number: CN1147815A
Application number: CN95192979A
Authority: CN
Inventors: F·加迪恩; B·L·K·曼戈; J·R·福扎德; M·法拉沙德; P·K·卡帕
Original assignee: Sandoz AG
Current assignee: Sandoz AG
Priority date: 1994-05-10
Filing date: 1995-05-09
Publication date: 1997-04-16
Also published as: FI964468A0; NO964735L; BR9507683A; EP0759925A1; PL316985A1; WO1995030683A1; SK146096A3; HU9603105D0; FI964468A; JPH09512823A; CA2186847A1; CZ327896A3; AU2546195A; NO964735D0; HUT75338A

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

Adenosine derivatives

The invention relates to adenosine derivatives, more specifically A₁Novel uses of receptor agonists.

The invention relates in particular to novel uses of compounds of formula (I).

I

In the formula, R₁Is hydrogen, (C)_1～4) Alkyl, allyl; a methallyl group; straight-chain or branched (C)_3-7) Alkynyl (C)_3～8) Cycloalkyl, hydroxy (C)_4～8) Cycloalkyl, by halogen of atomic number 9-35, (C)_1～4) Alkyl, (C)_1～4) Alkoxy or CF₃Phenyl which is monosubstituted or disubstituted independently of one another; or phenyl (C)_1～4) Alkyl, wherein the benzene ring is unsubstituted or substituted by halogen of atomic number 9-35, (C)_1～4) Alkyl, (C)_1～4) Alkoxy or CF₃Monosubstituted or disubstituted independently of each other; (C) having at least one hydroxyl group or at least two phenyl groups_1～4) Alkyl, bicycloalkyl such as inner or outer bicyclo [ 2,2, 1 ] heptyl, naphthyl (C)_1～4) Alkyl, acenaphthenyl (C)_1～4) Alkyl or a radical of the formula A or B

Or

Wherein,

z is hydrogen, hydroxy or (C)_1～4) An alkoxy group,

q is hydrogen or a hydroxyl group,

a is-CH₂-, -O-, -S-or a direct bond,

y is- (CH)₂)_nOr a key that is directly connected to it,

n is an integer of 1 to 3,

the dotted line in formula A represents an optional bond, R₂Is hydrogen, (C)_1～4) Alkyl, amino, (C)_3～5) Cycloalkyl or halogen of atomic number 9 to 35, and R₃Is (C)_1～4) An alkyl group.

Certain of these compounds, e.g. as in formula R₁Compounds which are not hydroxycycloalkyl groups are known and are disclosed, for example, in published British patent application 2,226,027A and European patent applications EP-O-378,518 and EP-0-269,574 and USP4,843,066 and 4,985,049.

In the formulas described therein, the 2 ', 3', 4 'and 5' substituents of the tetrahydrofuran ring have the same configuration as in adenosine.

In a group of compounds of formula 1, R₁Is not hydroxycycloalkyl. In another group of compounds of formula 1, R₁Is hydroxy (C)_4～8) A cycloalkyl group.

A preferred compound of formula 1 is 6-cyclohexyl-2' -O-methyl-adenosine, hereinafter referred to as compound M.

A of the preferred compounds of formula 1 can generally be determined as follows₁Adenosine activity:

affinity for adenosine receptor

Porcine striatum membranes were prepared as described in H.Bruns et al Molecular Pharmacology 29(1986) p 331-344.

Using a non-selective adenosine receptor agonist³H-NECA to mark A₁And A₂A receptor. Obtaining IC from a surrogate curve by weighted nonlinear least squares curve fitting of the Langmuir equation₅₀Value and calculate pK_DThe value is obtained. Table: adenosine receptor ligand pair A₁And A₂Affinity of the receptor A₁ A₂ A₁∶A₂(K_D；nM) (K_D(ii) a nM) selective nCPA 0.74 + -0.08930 + 11012606 CV 18082460 + -757269 + -700.15 CGS 216804360 + -108018.6 + -40.0044 Compound M23 + -224500 + -5160109051.5H₂OCPA-cyclopentyladenosine CV 1808-2-phenylaminoadenosine (carbohydrate, vol. 81, 1974) ref91898

K) CGS21680 ═ 2- [ p- (2-carboxyethyl) phenethylamino ] -5' -N-ethylformyl

Aminoadenosine (FASEBJ, 1989, 3(4) Refs.4770/3)

According to this document, it is confirmed that CPA is the pair A₁An effective and highly selective binding alternative for the receptor, CV1808, a weaker but selective A₂Receptor ligands, CGS21680 for A₂The receptor exhibits high efficiency and selectivity.

1.5 hydrate form of Compound M for A₁Receptor ratio for A₂The receptor exhibits better affinity and high selectivity.

Known compounds of formula I are known as antihypertensive agents and coronary vasodilators.

It is also known that compounds of formula I protect the vascular intima by inhibiting platelet aggregation and activating leukocytes. They also lower blood lipid concentrations. Furthermore, the compounds of the formula I are preventable for diseases which are caused by hypertension, such as congestive heart failure, myocardial infarction or sudden myocardial necrosis, and renal insufficiency (see European patent applications EP-0-378518 and EP-0-269574).

Such compounds are also known for the treatment of neurodegenerative disorders, peripheral neurological disorders such as diabetic neuropathy and for the treatment of diseases associated with peripheral vascular disease and/or diseases associated with neuronal degeneration, high triglyceride/low HDL cholesterol levels, lipid dysfunction, high free fatty acids or type I and type II diabetes, including non-insulin dependent diabetes mellitus, cardiac arrhythmias, in particular paroxysmal supraventricular tachycardia and tachycardia atrial fibrillation, and for the prevention of myocardial infarction.

The applicants have found that the compounds of formula I are particularly interesting analgesics, e.g. for the treatment of e.g. acute or chronic pain.

The analgesic activity of chronic neuropathic pain, as expressed in standard animal tests, such as models of inflammatory and neurological diseases, e.g., reduction of persistent inflammatory mechanical hyperalgesia (tests a) and b) and persistent neurological thermal hyperalgesia (test c), indicates that the compound of formula I has analgesic activity.

Inflammatory hyperalgesia

Test a) Floeider's adjuvant induces hyperalgesia

One knee joint of the mice was injected intra-articularly with complete Freund's adjuvant (100 microliters). The tolerable load of the rats decreased in the leg until day 5. This effect is indicative of mechanical hyperalgesia and is responsive to NSAID's and opiates. The compound of formula I is administered by injection, preferably orally, at about 3-60 μ g/kg animal body weight. The increase in load that can be tolerated on the injection side was measured and the reversal point of hyperalgesia was determined.

Compound M shows particularly interesting activity when administered orally at a dose of 3-60. mu.g/kg during about 1 hour of action. No significant differences were reflected between the 3, 30 and 60. mu.g/kg doses, indicating that the maximum effect was achieved at the 3-30. mu.g/kg dose.

Test b) turpentine induces mechanical hyperalgesia

Intraplantar local injection of turpentine/liquid paraffin on the rat paw (left hind leg) resulted in a local inflammatory response that reduced the withdrawal threshold (340 g reduction) to mechanical stimulation (paw pressure). The compound of formula I is active when administered orally or subcutaneously at a dose of about 1-100 μ g/kg 3 days after injection and the threshold reading is taken 1-3 hours later.

Compound M showed significant activity at doses of 30 and 60 μ g/kg orally and showed the greatest effect at 30 μ g/kg. In this test, the ED of morphine₅₀The value was 1.2mg/kg (subcutaneous injection).

Hyperalgesia in neurological diseases

Test c) neuropathic thermal hyperalgesia (according to the principle described in Z.Seltzer et al, pain, 1990, 43, 205-

Unilateral ligation of the sciatic nerve abolished nerve fibers to the rat paw nervous system. The mouse developed hyperalgesia to mechanical and thermal stimuli and had a partially denervated paresthesia (allodynia) without causing limb separation. The animal was placed in a plexiglas box placed on a thin glass plate and a crocodile-clip-shaped thermal stimulator was placed on the plantar surface of the paw. The lag time for retracting the jaws was measured. Subcutaneous injection, preferably oral administration, at a dose of about 1 to about 100 μ g/kg 12 to 15 days after nerve ligation indicates that the compound of formula I is active. Compound M is particularly active against heat-induced pain hypersensitivity. At doses of 30 and 60. mu.g/kg, Compound M showed significant activity with the best effect at 30. mu.g/kg. ED (electronic device)₅₀About 60. mu.g/kg (oral). When administered subcutaneously, the ED of morphine in this test₅₀About 3 mg/kg.

Clinical trial

The clinical trial may be performed as follows:

for animals suffering from pain, post-operative pain or postherpetic neuralgia, a compound of formula I, in particular compound M, is administered by intravenous injection at a dose of 0.02-5 mg. A reduction in pain was observed.

Thus, the compounds of the invention are useful as analgesics, for example against acute or chronic pain, such as chronic neuropathic pain.

In one aspect, therefore, the present invention provides a method of treatment of pain, which comprises administering to a subject in need of such treatment a therapeutically effective amount of a compound of formula I as hereinbefore defined.

In a further aspect, the present invention provides the use of a compound of formula I as defined hereinbefore as an analgesic in the manufacture of a medicament suitable for the treatment of pain.

In a further aspect, the present invention provides a compound of formula I as defined hereinbefore for use in the treatment of pain.

In a further aspect, the present invention provides an analgesic composition comprising a compound of formula I as hereinbefore defined as an analgesic, together with a pharmaceutically acceptable carrier or diluent.

Indications include pain, such as acute pain associated with tissue damage and inflammation (e.g., post-operative pain, burn pain, trauma pain, etc.), chronic inflammatory pain (e.g., arthritis), and chronic neuropathic pain (e.g., diabetic neuropathy, post-herpetic neuralgia, multiple sclerosis, causalgia, etc.).

In the use of the invention as indicated above, the dosage of the compound employed will, of course, vary with the type of compound employed, the severity of the disease, the condition of the host, the weight of the patient, the mode of administration and the relative effect of the compound. In general, however, a 3 day dose of from about 1 to about 100. mu.g/kg animal body weight will show satisfactory results in animals, e.g., 3 to 60, such as 10 to 60. mu.g/kg. For large animals, such as humans, a daily dosage of from about 0.1 to about 10mg is required, typically in a unit dose of from about 0.02 to about 5mg, and more than 1 such unit dose may be administered within a day, such as 2, 3, 4, 5 or 6 times daily, but preferably 1 or 2 times daily.

In the above test a), the ED of NSAID ibuprofen₅₀About 4mg/kg (oral) and indomethacin 13mg/kg (oral). While the activity of compound M is about 300 times higher. For compound M, the preferred dosage is about 0.1mg daily to about 10 mg/day, e.g., 3-30 μ g/kg for a 70kg adult, depending on the severity of the indication and the frequency of dosing.

For humans, compound M showed no serious side effects after a single dose of up to 5mg (oral).

The term "pharmaceutically acceptable" as used herein includes materials which are suitable for use by both humans and animals.

The compounds of the invention may be administered by any suitable route, the preferred route depending on the condition to be treated, preferably in a single dosage form or the patient may administer the compounds in a single dosage form on their own. The composition is preferably suitable for oral, rectal, topical, parenteral, intravenous or intramuscular administration.

The compositions of the present invention may be in the form of tablets, capsules, sachets (sachets), vials, powders, granules, lozenges, suppositories, reconstitutable powders, or liquid preparations, such as oral or sterile injectable solutions or suspensions. If appropriate, also to be designed as a topical preparation.

In order to obtain a stable effect of administration, the composition of the present invention is preferably administered in the form of a unit dose.

For oral unit dosage forms, tablets and capsules containing 0.02 to 5mg of a compound of the invention may be employed, which may contain conventional excipients such as binding agents, for example syrup, acacia, gelatin, sorbitol, tragacanth or polyvinylpyrrolidone; fillers such as lactose, sucrose, corn starch, calcium phosphate, sorbitol or glycine; tableting lubricants, such as magnesium stearate; disintegrants, such as starch, crospovidone, sodium starch glycolate or microcrystalline cellulose; or a pharmaceutically acceptable lubricant such as sodium lauryl sulfate.

Solid oral compositions can be prepared by conventional methods of blending, filling, tabletting and the like. The use of repeated blending allows the active to be distributed throughout the composition when a large amount of filler is used.

These operations are of course common in the prior art. Tablets may be coated according to methods known in normal pharmaceutical practice, in particular with an enteric coating.

Oral liquid preparations may be in the form of emulsions, syrups or elixirs, or as a dry powder for reconstitution with water or other vehicle before administration. Such liquid preparations may contain conventional additives such as suspending agents, for example, sorbitol, syrup, methyl cellulose, gelatin, hydroxyethyl cellulose, carboxymethyl cellulose, aluminium stearate gel, hydrogenated edible fats and oils; emulsifiers, like lecithin, sorbitol monooleate or acacia; non-aqueous carriers (which may include edible oils) such as almond oil, fractionated coconut oil, oily esters such as esters of glycerol, propylene glycol or ethyl alcohol; preservatives, such as methyl or propyl p-hydroxybenzoate or sorbic acid; and may contain conventional flavoring or coloring agents as desired.

Examples of solid oral compositions such as tablets and capsules are as follows:

tablets were compressed from capsule granules with the corresponding dose. Use 3^*Yellow encapsulation compound M, for formulations at 0.1 and 5mg doses, respectively, is shown below.

0.1mg tablet capsule 5.0mg tablet/capsule compound M0.15.0 microcrystalline cellulose 76.9274.96 lactose hydrate 87.63^* 84.69^*Polyvinylpyrrolidone 7.47.4 crospovidone 7.47.4 magnesium stearate 0.9250.925 humectant 4.6254.6253^#Capsule 5050 theoretical capsule fill weight or tablet weight 185185 theoretical capsule weight 235235

^*Adjusting the amount of lactose to compensate for the water content of the drug

The compounds may also be administered in sustained release dosage forms to provide a long lasting effect. Conventional drug delivery systems may be employed to provide sustained release dosage forms, such as sugar coated pills or push-pull osmotic systems.

For parenteral administration, fluid single dosage forms are prepared using the compound and a sterile carrier, and depending on the concentration employed, may be formulated as suspensions or may be dissolved in the carrier. In preparing solutions, the compounds may be dissolved in polyethylene glycol or ethanol and diluted with water for injection, and the contents filtered sterilized before filling into a suitable glass vial or ampoule and sealed after filling. Adjuvants, such as local anesthetics, preservatives, and buffering agents are preferably dissolved in the vehicle. Parenteral suspensions are prepared in substantially the same manner except that the compound is suspended rather than dissolved in the carrier and cannot be sterilized by filtration. The compound may be sterilized by exposure to ethylene oxide prior to sterilization of the suspension formulation in the vehicle. Preferably, a surfactant or wetting agent is included in the composition to provide a uniform distribution of the compound.

Depending on the method of application, the composition may contain from about 0.1 to about 99% (wt), preferably 10 to 60% (wt), of active substance.

The compound M of the present invention, or a hydrate thereof or an adduct with other solvents, or a salt thereof, may also be administered as a topical preparation together with usual topical excipients.

Topical preparations may be, for example, ointments, creams or lotions, impregnated dressings, gels, plasters, aerosols and aerosols, which may contain suitable conventional additives such as preservatives, solvents to aid drug penetration, and emollients in ointments and creams. The formulation may contain conventional compatible carriers such as cream bases, ethanol or oleyl alcohol for lotions.

Suitable cream, lotion, gel, ointment, aerosol or aerosol formulations for use with the compound of formula I or its hydrate, or its adducts with other solvents, or salts thereof, are well known in the art, for example, as described in standard texts on pharmacy and cosmetics, such as Harry's cosmetology, Remington's pharmaceutical science and the british pharmacopoeia and united states pharmacopoeia, published by Leonard Hill Books press.

In another aspect, the present invention provides adenosine derivatives of formula IaIa

In the formula: r₁' is hydroxy-substituted (C)_4～8) Cycloalkyl radical, R₂Is as defined above or preferably hydrogen, (C)_1～4) Alkyl or halogen of atomic number 9-35, and R₃As previously defined.

The compounds of formula Ia may be present as enantiomers or as a mixture of diastereomers.

In formula Ia, halogen with an atomic number of 9-35 is fluorine, chlorine or bromine; (C)_1～4) Alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, in particular methyl; (C)_4～8) Cycloalkyl is cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl, especially cyclohexyl or cyclopentyl.

The compounds of formula Ia can be prepared by a process which is characterized in that a compound of formula IIa is reacted with a compound of formula IIIa,

IIa

in the formula

R₂And R₃Have the meanings as given above, and

x is chlorine or bromine,

R₁′-NH₂ IIIa

in the formula

R₁' having the definitions as given above.

The above method is usually carried out by heating the compound of formula IIa and the compound of formula IIIa together in the presence of a solvent such as dioxane to 80 to 120 ℃ and preferably to the boiling point.

In the compounds of the formula IIa used as starting materials in this process, X is in particular chlorine. Compounds of formula IIa and processes for their preparation are described in published European patent application 269574.

A further process for preparing formula Ia comprises treating a compound of formula IVa with tetrabutylammonium fluoride trihydrate, wherein R₁′、R₂And R₃Having the definitions as given aboveIVa

The above reaction can be carried out in an organic solvent such as tetrahydrofuran at room temperature with stirring. Treatment of a compound of formula IIa with 1, 3-dichloro-1, 1, 3, 3-tetraisopropyl disiloxane in a basic solvent such as pyridine, reaction of the compound of formula Va thus obtained with a compound of formula IIIa affords a compound of formula IVa, X, R in formula Va₂And R₃Have the meaning as defined above.

Va

In examples 1-8 below, all temperatures are in degrees Celsius and are uncorrected.

Example 1: 6- [ (trans) -4-hydroxycyclohexyl ] -2' -O-methyladenosine

1g of 6- [ (trans) -4-hydroxycyclohexyl ] -9-purinyl-2 ' -O-methyl-3 ', 5 ' -O- (1, 1, 3, 3-tetraisopropyldisiloxan-1, 3-diyl) -D-ribose and 2g of tetramethylammonium fluoride trihydrate were stirred together in 20ml of tetrahydrofuran at room temperature for 15 minutes. The mixture was then evaporated to dryness on silica gel with ethyl acetate/methanol(85: 15) the mixture elutes the residue. The purified product was crystallized from methanol/ethyl acetate. The title compound is crystallized from 1 equivalent of methanol, m.p. 121-124 ℃. [ alpha ] to]_D ²⁰-50.2 ° (c ═ 1 in DMF).

The compound can also be recrystallized from ethanol and, after being left in a humid atmosphere, crystallized from 1 equivalent of water. The melting point is 114-117 ℃. [ alpha ] to]_D ²⁰＝-46.9°(c＝1，DMF)。

6- [ (trans) -4-hydroxycyclohexyl ] -9-purinyl-2 ' -O-methyl-3 ', 5 ' -O- (1, 1, 3, 3-tetraisopropyldisiloxan-1, 3-diyl) -D-ribose used as a raw material in the above-mentioned method can be produced as follows;

2g of 6-chloro-9-purinyl-2 ' -O-methyl-3 ', 5 ' -O- (1, 1, 3, 3-tetraisopropyldisiloxa-1, 3-diyl) -D-ribose were stirred in an oil bath at 105 ℃ for 6 hours with 1.32g of trans-4-hydroxycyclohexylamine and 1.4m of 1N-ethyl-diisopropylamine in 80ml of dioxane. The mixture was then cooled to room temperature, filtered and the filtrate was concentrated to dryness. For purification, the mixture thus obtained is eluted on silica gel with a hexane/ethyl acetate (7: 3) mixture and then with an ethyl acetate/methanol (95: 5) mixture. The oily compound thus purified had Rf of 0.3 (ethyl acetate/methanol, 95: 5).

Example 2: 6- [ (cis) -4-hydroxycyclohexyl ] -2' -O-thyrodenosine

Analogously to example 1, cis-4-hydroxycyclohexylamine was used instead of trans-4-hydroxycyclohexylamine to give the title compound.

The title compound thus obtained is crystallized from half an equivalent of ethyl acetate, m.p. 110-111 ℃. [ alpha ] to]_D ²⁰-48.6 ° (c ═ 1 in DMF).

Example 3: 6- [ (1S, trans) -2-hydroxycyclopentyl ] -2' -O-methyladenosine

Analogously to example 1, 1S, trans-2-hydroxycyclopentanamine was used instead of trans-4-hydroxycyclohexylamine to give the title compound.The title named compound thus obtained has the following characteristics: foamy, Rf 0.44, [ alpha ] in Ethyl acetate/ethanol 75: 25]_D ²⁰-25.5 ° (c ═ 1 in DMF).

Example 4: 6- [ (1R, trans) -2-hydroxycyclopentyl ] -2' -O-methyladenosine

Analogously to example 1, 1R, trans-2-hydroxycyclopentanamine was used instead of trans-4-hydroxycyclohexylamine to give the title compound. The compound thus obtained has the following characteristics: melting point: 164 ℃ and 166 ℃ Rf 0.44, [ alpha ] in ethyl acetate/ethanol 75: 25]_D ²⁰-80.2 ° (c ═ 1 in DMF).

Example 5: 6- [ (1S, trans) -2-hydroxycyclohexyl ] -2' -O-methyladenosine

Analogously to example 1, 1S, trans-2-hydroxycyclohexylamine was used instead of trans-4-hydroxycyclohexylamine to give the title compound. The compound thus obtained has the following characteristics: foamy, Rf 0.42, [ alpha ] in Ethyl acetate/ethanol 75: 25]_D ²⁰-26.2 ° (c ═ 1 in DMF).

Example 6: 6- [ (trans) -4-hydroxycyclohexyl ] -2' -O-ethyladenosine was prepared in analogy to example 5. 0.4 hydrate is obtained, melting point 98 ℃ (liquefaction). [ alpha ] to]_D ²⁰-58 ° (c ═ 1 in DMF).

Example 7: 6- [ 1S, (trans) -2-hydroxycyclohexyl ] -2' -O-ethyladenosine

The preparation is carried out analogously to what is described in example 5.

Example 8: 6- [ (1R, trans) -2-hydroxycyclohexyl ] -2' -O-methyladenosine

In analogy to example 1, trans-4-hydroxycyclohexylamine was replaced by 1R, trans-2-hydroxycyclohexylamine to give the title compound. The compound so obtained, as named under the title, has the following characteristics: foam-like; rf in ethyl acetate/ethanol 75: 25 ═ 0.42; [ alpha ] to]_D ²⁰-69.5 ° (c ═ 1 in DMF).

The compounds according to the invention have interesting pharmacological properties. Therefore, they are useful as medicaments. For this purpose, the compounds of the present invention may be used in the form of hydrates or adducts with organic solvents such as methanol, ethanol or ethyl acetate. The most interesting compound of formula Ia is the compound in example 1 above, which is hereinafter designated compound number 1.

As analgesics as described above, the compounds of formula Ia are of interest, as are their other activities. Among these other activities, as indicated in the results of the following studies, the compounds of the present invention have antihypertensive activity.

Adenosine A is measured in membranes from the murine cortex or from the porcine cerebral cortex or striatum using the methods described in molecular pharmacology (MOLEC. PHARMACOL.)29, 331-346(1986) by R.F.BRUNS, G.H.LU and T.A.PUGSLEY₁And A₂Binding of the receptor. The activity of the compound was further tested in isolated and perfused murine kidneys for the following parameters:

renin secretion

Renal hemodynamics

Determination of the inhibitory effect of norepinephrine release from nerve terminals after electrical stimulation of the renal nerves according to the method described in P.M.VANHOUTTE, D.BROWNING, E.COEN, T.J.VERBEUREN, L.ZONNEKEYEN and M.G.COLLIS in hypertension 4, 251-

Blood pressure, heart rate, urine production and renin activity in plasma of conscious rats at NaCl withdrawal and NaCl filling, normotensive or spontaneous hypertension were measured using cannulas implanted in the abdominal aorta and vena cava following administration of the compounds of the invention by infusion or bolus injection according to the methods described in J.F.M.SMITS and J.M.BRODY in am.J.Physiol.247, R1003-R1008 (1984).

From the experimental results it can be concluded that both inhibition of renin secretion and inhibition of norepinephrine release from nerve terminals, as well as vasodilation, are involved in the antihypertensive activity of the compounds of formula Ia. In contrast to the decrease in blood pressure, the urine production and electrolyte secretion remain unchanged. It follows that the compounds of formula Ia are not only useful as antihypertensives but also have a coronary vasodilating effect. Furthermore, they protect the vascular endothelium by inhibiting platelet aggregation and activating leukocytes. They also lower blood lipid concentrations.

Among the compounds of formula Ia, the compound of example 1 is preferred for the above indications, preferably for vascular protection and analgesia.

In addition, as stated in test a) below, the compounds of the formula Ia are also active in the treatment of arrhythmias, as are adenosine A thereof₁Agonist activity of the receptor, shown below, against A₂The receptor activity is selective compared to it and its ability to prolong conduction through the atrioventricular (A-V) node of the heart as indicated in test b) below. Thus, they restore sinus rhythm in supraventricular tachycardia, particularly paroxysmal supraventricular tachycardia, reduce heart rhythm in arrhythmic atrial fibrillation, and restore ventricular arrhythmia induced by beta adrenergic stimulation of normal rhythm.

The compounds of formula Ia mimic the so-called "preconditioning" effect, which is mainly due to the short duration of ischemia that makes the heart tolerant to subsequent infarcts due to ischemia. Thus, in unstable angina periods, they can be used, with or without concomitant platelet therapy, to prevent myocardial infarction of the heart, or ischemic damage in patients undergoing procedures such as coronary bypass surgery, angioplasty, heart transplantation, or non-cardiac surgery.

The compounds of formula Ia are particularly useful for administration to subjects prone to myocardial infarction, such as people who have been diagnosed with or have had a history of myocardial infarction.

The compounds of formula Ia also lower the insulin levels in plasma without affecting glucose tolerance. It enhances the effect of insulin on increasing glucose uptake and reduces lipolysis in the fatty tissue, thereby reducing the concentration of free fatty acids in the plasma, see test d) below. Lowering the concentration of free fatty acids in plasma in turn results in lowering triglycerides, thereby increasing HDL cholesterol.

The reduction of the effects of insulin and/or the reduction of the free fatty acids makes the compounds of formula Ia useful for the treatment of type I diabetes and type II, i.e. non-insulin dependent diabetes.

The compounds of formula Ia lower plasma triglycerides and free fatty acids (see test e) below) and raise HDL cholesterol and are therefore useful in the treatment of lipid dysfunction, as well as those diseases associated with elevated free fatty acids and triglycerides and in which it is desirable to increase HIL cholesterol.

The compounds of formula Ia show good metabolic stability.

In another aspect, the present invention provides the use of a compound of formula Ia for the treatment of pain or for the manufacture of a medicament for the treatment of pain.

In a further aspect, the present invention provides a compound of formula Ia as hereinbefore defined for use in the treatment of pain.

In a further aspect, the present invention provides an analgesic composition comprising a compound of formula Ia as hereinbefore defined together with a pharmaceutically acceptable carrier or diluent. The applicants intend to use the compounds of formula Ia in the indications as described previously for compounds of formula I.

The pharmacological tests below illustrate the above-mentioned activity of the compounds of formula Ia.

a) Affinity for adenosine receptors

Porcine striatal membranes were prepared as described in H.Bruns et al, molecular pharmacology 29(1986) p 331-344. Using a non-selective membrane glycoside receptor agonist³H-NECA to mark A₁And A₂A receptor. By weighted nonlinear least squares curve fitting to the Langmuir equationSubstitution of the curves to obtain IC₅₀The value, then the pK is calculated_DThe value is obtained.

Compounds of formula Ia₁The receptor affinity is, for example, in the range of 1 to 500 nM.

b) Cardiac arrhythmia

Adenosine A measured as an increase in P-R interval₁Receptor activation reduces the incidence of arrhythmias such as paroxysmal supraventricular tachycardia, tachycardia atrial fibrillation, and other events resulting from slowed conduction through the Atrioventricular (AV) node of the heart. The test method included recording ECG changes in awake adult rhesus monkeys. In the test described in the journal of pharmacy 244, 595, 597(1990) by reference to C.Clarke et al, the compound of formula Ia may be administered orally at about 0.1-1000 mg/kg, or intravenously at about 0.03-30 mg/kg. For example, in this test, compound No. 1 extended the P-R interval on the surface Electrocardiogram (ECG), showing a slowing of conduction through the atrioventricular node at oral doses of 0.1, 0.3 and 0.6 mg/kg. As noted above, such action results in the termination of atrioventricular nodal reentry tachycardia, which reduces the heart rhythm in tachycardia atrial fibrillation.

c) Prevention of infarct by preconditioning

Preconditioning (5 min ischemia followed by 10 min recovery) makes the heart better resistant to subsequent infarcts resulting from ischemia (30 min) and reperfusion (3 h). The test methods are disclosed in the 1991-cycle (84) of G.S.Lin et al, 1, 350-356 and J.D.Thornton et al, 1992-cycle (85), 659-665. Rabbits are administered the compound of formula Ia intravenously at a dose of about 0.01-10 mg/kg. In this test, rabbits given 100 μ g/kg of compound 1 were protected to approximately the same extent as endogenous preconditioning of infarct production induced by 30 minutes of coronary occlusion.

d) Glucose transport and lipolysis in murine adipocytes

i) Adipocytes isolated from epididymal fat bodies of normal orally fed mice were digested with collagenase. Glucose transport was measured at 37 ℃ by pre-culturing the cells with adenosine deaminase (1U/ml) and with test compounds, such as compound No. 1, and other additives as indicated (final concentration 2% V/V).

After 30 minutes, add [ 3-³H glucose (final concentration 50. mu.M, 0.5. mu. Ci/ml). The incubation was continued for another 60 minutes. The cell suspension (0.5ml) was extracted with 5ml of toluene matrix scintillator and then the liquid scintillator was counted to evaluate the distribution by [ 3-³The radioactivity that glucose binds to adipocytes. (a measure of glucose transport); water-soluble metabolites and residual [ 3-³H ] glucose remained in the aqueous phase and could not be detected.

Lipolysis was measured by a conventional method. In one method, cells are cultured with or without 1 μ M isoproterenol and then incubated for an additional 60 minutes. After centrifugation through dinonyl phthalate, the supernatant was separated from the cells and lipolysis was estimated by measuring the amount of glycerol in the releasing agent supernatant with enzyme.

The compound of formula Ia is active at a concentration of 0.1 to 1000 nM.

Compound No. 1 attenuated lipolysis in murine adipocytes at concentrations ranging from 0.1 to 100 nM.

In the presence of adenosine deaminase (1U/m1), compound No. 1 was used in the absence of insulin [ 3-³The radioactivity of glucose bound to adipocytes has no significant effect, but only marginally in the presence of the maximal stimulated insulin concentration (8nM), but the stimulating effect on bound radioactivity increases significantly in a concentration-dependent manner when the insulin concentration is 0.1-50 nM. These observations indicate that the compound increases the sensitivity of glucose transport to insulin. In the presence of approximately the maximum effective concentration of compound No. 1, [ 3-³Incorporation of glucose into fat EC for insulin stimulation₅₀In the presence of adenosine deaminase and 1 mu M isoproterenol, the reduction of 2-3 times is required, and the 10-50 nM compound No. 1 not only increases the sensitivity to insulin but also increases the response degree; EC for insulin₅₀The stimulation at the maximum insulin concentration also increased significantly, down to 1/5.

ii) fat and glucose in Normal fasted 18hr mice

The weight of 2-3 month-old mice weighing about 250g was maintained for 7 days in a controlled room at 22 ℃ for 12/12hr day-night cycle.

Purina mice were fed food and water ad libitum. After 18 hours of fasting, 5 mice per group were gavaged with test compound in 0.5% CMC. The dosage is 1.0ml/100g animal body weight. 3 hours after administration. With CO₂Rats were anesthetized and blood was collected by cardiac puncture. Sera were collected for glucose, free fatty acid and beta hydroxybutyrate assays. Free fatty acids were measured using an acetyl COA peroxidase calorimeter assay, glucose was measured using a glucose oxidase assay (YSI Model27, Yellow Spring, Oh), and beta-hydroxybutyrate was measured using a beta-hydroxybutyrate dehydrogenase crosslinylase assay (Sigma Kit310-a, st. louis, Mo.). The compound of formula Ia is active at a dose of about 1 to about 5000. mu.g/kg.

The dose of compound No. 1 that reduces free fatty acids (preliminary result of effect on adipocytes) after 2hr is 5-100. mu.g/kg. This resulted in a dose reduction with decreasing levels of beta-hydroxybutyrate and blood glucose.

iii) Effect in non-insulin dependent diabetes mellitus (NIDD) mice

In NIDD screening experiments, 200-220 g of mice were fed freely with high-fat chow. In the fed state, 40mg streptozotocin per kg body weight was injected via tail vein. One week later, these mice were considered diabetic, and had blood glucose of 200mg/dl after feeding, and had blood glucose concentrations of 40-80 mg/dl 3 hours after the oral glucose tolerance test after fasting overnight. Four days later, the animals were examined to see if the blood glucose concentration was above 180 mg/dl. Blood glucose was measured with a YSI glucose analyzer. The long-term screening test was performed as follows:

on the first day, in the morning 9: 00 food was removed from the side of the mice and vehicle (control) or compound (9 mice at a time) was administered orally after an initial blood glucose reading was taken through the tip of the tail. Blood glucose concentrations were measured after 6 hours, after which time the rats were returned to feeding.

The same mice were given the vehicle or drug once a day for a continuous 11 day period. Blood glucose was measured at 0 and 6 hour fasting post-dose on days 4,8 and 11. A compound of formula Ia such as compound No. 1 at 100. mu.g/kg for 11 days resulted in a significant decrease in plasma free fatty acids, which resulted in a significant decrease in blood glucose production.

e) Lipemia characterised by high serum triglycerides

Several studies have shown a defined correlation between serum triglyceride concentrations (and the associated reduction in HDL cholesterol levels) and the risk of heart coronary disease (CHD) (see Grundy's cholesterol and atherosclerosis and diagnosis and treatment of Lippincott, philiadelphia (1990)). The value of lowering high triglyceride levels as a means of reducing the risk of developing CHD is seen in Helsinki's Heart research institute, where treatment with gemfibrozil minimizes the development of severe coronary disease in patients with type IIB hyperlipidemia, where both LDL cholesterol and serum total triglyceride levels are elevated and HDL cholesterol levels are generally reduced. The compounds of formula Ia are active in rhesus monkeys at doses of about 0.03-30 (e.g., 0.1-30) mg/kg (i.v.) and 0.1-100 (e.g., O.1-10) mg/kg (oral). Compound No. 1 produced a dose-dependent long-term reduction in plasma free fatty acids and triglycerides in rhesus monkeys at doses of 0.03-0.6 mg/kg (i.v.) and 0.1-1.2 mg/kg (oral), and representative results for compound No. 1 showed a reduction in free fatty acids of about 60% and triglycerides of 40% after 300 minutes compared to the control group at doses of 0.6mg/kg (oral).

The compounds of formula Ia were also active in anesthetized mice tested for mean arterial blood pressure, bradycardia, and peripheral vasodilation.

According to the method of Salzmann et al (J.Cardiovasc.Ph. J.Pharmacology)armaco1.)12, 451-460, 1988) were tested on male Wistar mice weighing 300-350 g under thiopental anesthesia (120mg/kg i.p.). The cannulae were inserted in the right jugular and femoral veins, in the left ventricle (inserted through the right carotid artery), left femoral artery and aorta (inserted through the right femoral artery). The following parameters were measured or calculated: systolic, diastolic and mean arterial blood pressure (mmHg; left femoral, Statham blood pressure transducer P23Gb), pulse pressure (mmHg), heart rate (beats/min, triggered by the blood pressure curve), left ventricular pressure ramp-up (dp/dt)_maxmmHg/s; statham blood pressure transducer P23Gb), cardiac output (ml/min/100g body weight, thermodilution, right jugular vein and aorta), total peripheral resistance (dyneess. cm.)^-5100g body weight), surface electrocardiogram. Continuous recording of arterial blood pressure, left ventricular pressure, dp/dt with Schwarzer multiwave plot_maxHeart rhythm and electrocardiogram. Parameters were measured 30, 20, 10 and 2 points before the test subjects and 1, 5, 10 and 15 minutes after the drug was injected into the right femoral vein. The compound of formula Ia is injected at a dose of about 0.001 to about 10mg/kg animal body weight. Compound No. 1 was assayed at cumulative doses of 0.003, 0.010 and 0.03mg/kg, using 3 animals per dose. Compound No. 1 causes blood pressure (ED)₅₀I.v.: 49 μ g/kg) and decreased heart rate, increased systemic vascular conductivity.

The dosage of the compound of formula Ia used in the above indications will vary in a general manner with the severity of the disease, the weight of the patient and the relative potency of the compound. However, as a general guide, suitable unit doses may be 0.1-1000 mg, such as 0.1-10, 0.5-200, 0.5-100 or 0.5-10 mg, such as 0.1, 0.5, 1, 2, 3, 4 or 5 mg; the unit dose may be administered more than once a day, such as 2, 3, 4, 5 or 6 times a day, but preferably 1 or 2 times a day, such that for a 70kg weight mammal, including a human, the total dose per day is about 0.1 to 1000mg (e.g. orally) or 0.003 to 300mg (intravenously), i.e. 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 mg/kg/day; such as 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.1 or 0.2 mg/kg/day; such treatment may last for weeks or months. For compound No. 1, for all indications of the invention, the preferred dose for a 70kg adult is 0.1 mg/day to 10 mg/day. For preferred indications, non-insulin dependent diabetes mellitus and hypertriglyceridemia, the indicated dose is 0.2-2 mg/day for humans (oral administration), 0.2-10 mg/day for the treatment of heart failure and other heart diseases, in particular for arrhythmia, such as tachycardia atrial fibrillation 0.5-5 mg/day (oral administration) or 0.25-5 mg (intravenous injection).

The compound of formula Ia may be formulated for administration by any suitable route, the preferred route depending on the condition to be treated, and is preferably in unit dose form or in a form which the patient himself may administer a single dose. The composition is preferably adapted for oral, rectal, topical, parenteral, intravenous or intramuscular administration when used for analgesia as described above.

Suitable unit dosage forms for oral administration may be tablets and capsules containing 0.05 to 20mg of a compound of formula Ia.

The compound according to the invention or its hydrate or its addition product with an organic solvent will suitably be present in an amount of from about 0.5 to about 20%, preferably from about 1 to about 10%, such as 2 to 5% by weight of the formulation.

Administering to warm-blooded animals such as mice, dogs and humans R in the formula₁Is (C)_4～8) Cycloalkyl radical, R₃When the compound of formula I is an alkyl group, R in the formula is detected as a metabolite₁' is hydroxy (C)_4～8) Cycloalkyl radical, R₃A compound of formula Ia which is alkyl.

Thus, administration of compound M results in production of hydroxycyclohexyl-2' -O-methyladenosine.

In yet another aspect, the invention provides a method of administering N to a warm-blooded animal⁶-cyclohexyl-2' -O-methyladenosine to produce N⁶-hydroxycyclohexyl-2' -O-methyladenosine.

In another aspect, the invention provides N in pure form, e.g., greater than 95% purity⁶-hydroxycycloalkyl-2' -O-alkyl adenosine. Book (I)The example compounds described herein meet this criteria.

In a further aspect, the invention provides N free of cyclohexyl-2' -O-methyladenosine⁶-hydroxycyclohexyl-2' -O-alkyl adenosine.

In another aspect, the invention provides a method of making 2' -O-alkyl adenosines, which comprises treating adenosine with a suitable alkyl sulfate in the presence of a phase transfer catalyst.

The 2' -O-alkyl adenosine is preferably any of the compounds defined above.

In a further aspect, the present invention provides a process for the manufacture of a compound of formula I as defined above, which comprises reacting a compound of formula VI

VI with formula (R)₃)₂SO₄A basic solution of the compound is reacted in a nonpolar solvent in the presence of tetrabutylammonium hydrogensulfate and the product is purified by recrystallization.

The reactive groups may be temporarily protected if necessary.

The alkyl sulfate is preferably di (C) sulfate_1～4) An alkyl ester.

The phase transfer catalyst is preferably tetrabutylammonium hydrogen sulfate.

This reaction is preferably carried out in a non-polar solvent as described below.

Define a group of compounds of formula I, wherein R₁Is (C)_3～8) Cycloalkyl radical, R₂Is hydrogen or (C)_1～4) Alkyl radical, R₃Is (C)_1～4) An alkyl group.

To date, the preparation of compounds of formula I typically goes through 6 steps, which include the preparation of 2 ', 3 ', 5 ' -triacetyl inosine; chlorinating and hydrolyzing 6-chloro-9-beta-D-ribofuranosyl-9H-purine; with tetraisopropyl disiloxane (TIPDS-CL)₂) Protection of the 3' -O-position and5' -O-position; 2' -O-alkylation and purification by silica gel chromatography; deprotecting the 3 '-O-and 5' -O-positions; and R₁NH₂Reaction and recrystallization to give the compound of formula I.

The Applicant has found that the compounds of formula I can be prepared in good yields and purities without the need for protection and deprotection of the 3 '-O-and 5' -O-disiloxanes and without chromatography on silica gel. The applicants have found that inosine 2 ', 3', 5 '-tripropionate, which is a pungent lipid, can be advantageously used in place of the prior art method of inosine 2', 3 ', 5' -triacetate, thus doubling the yield and removing the harmful pyridine solvent.

In the present invention, the compound of formula I is prepared under phase transition catalyst conditions according to the following reaction scheme:

VII

in the formula R₁、R₂And R₃As previously defined

By reacting an alkaline aqueous solution of a compound of formula (VI) with di (C) sulfate in the presence of tetrabutylammonium hydrogen sulfate and a water-immiscible organic solvent_1-4) Alkyl ester reaction to prepare the compound of formula I. The base used for preparing the aqueous alkaline solution is preferably an alkali metal hydroxide, such as NaOH or KOH. The solvent may be any solvent which is incompatible or substantially incompatible with water in which the compound of formula I is soluble, such as dichloromethane or tert-amyl alcohol. The reaction is preferably carried out at a temperature of between about-20 and about 50 deg.C, especially at room temperature. The reaction time is not critical and is preferably within about 5 to about 10 hours, particularly within about 7 to about 8 hours. The crude compound of formula I is isolated by evaporation, followed by stirring with a 1: 1 mixture of water and an inert solvent, preferably toluene, at room temperature for 5-7 hours, followed by filtration and drying. The pure compound is obtained by fractional crystallization, preferably by the following steps:

1) recrystallizing with inert solvent such as toluene, dissolving the crude compound in 80 deg.C solvent, heating at about 55 deg.C for about 1hr, cooling to room temperature, seeding with pure compound, and filtering;

2) repeating the recrystallization operation of step 1) but heating at about 65 ℃ before cooling to room temperature; and

3) recrystallization from 100% ethanol, dissolution under reflux, dilution with water, seeding, then filtration and drying.

Many compounds of formula VI are known and can be prepared by methods described in documents such as the aforementioned USP4,843,066 and USP4,985,409. The compounds of the formula VI, which may advantageously also be prepared as indicated above, are prepared according to the following preferred reaction scheme:

VII VII

IX

where R is₁And R₂As previously defined.

Acylating inosine of formula VII with propionic anhydride to form a compound of formula VIII protected at the 2 ' -O-, 3 ' -O-and 5 ' -O-positions, halogenation of the compound of formula VIII with thionyl chloride forming an intermediate of formula IX; and simultaneous amination and hydrolysis of a compound of formula IX to produce a compound of formula VI. The inosine acylation reaction is preferably carried out in a mixture of toluene, tributylamine and 4-dimethylaminopyridine at a temperature of 100-110 ℃ for 4-5 hours. The compound of formula VIII is isolated by precipitation with heptane. The halogenation of the compound of formula VIII is preferably carried out at a temperature of 60 to 70 ℃ for 3 to 4hrs in a mixture of toluene and N, N-dimethylformamide, and the solution of the compound of formula IX may be used after washing with water and brine. Preferably by addition of an amine R₁NH₂And reacting at 100-110 ℃ for 15-20 hr to ammoniate and simultaneously hydrolyze the intermediate of formula IX. The compound of formula VI is isolated by filtration at room temperature and purified by recrystallization.

The process of the invention is illustrated by the following examples.

Method example 1: n is a radical of⁶-cyclohexyl-2 '-O-methyladenosine step A.2', 3 ', 5' -inosine tripropionate

A mixture of 271.2g of inosine, 966ml of tributylamine, 3.30g of 4-dimethylaminopyridine and 600ml of toluene was heated to an internal temperature of 104 to 105 ℃ and 453ml of propionic anhydride was added thereto over 35 minutes at a rate such that the internal temperature was maintained at 104 to 105 ℃. After stirring at this temperature for another 4hr, the mixture is cooled to 5-10 ℃ with an ice bath and 1000ml heptane is added. The resulting suspension is stirred at room temperature (20-22 ℃) for 30 minutes and then filtered, for example, on a Bucbner funnel. 150ml each time (three equal portions of heptane wash the solid and dry overnight (14hr) at 45-50 ℃ under 25 mmHg) with a total of 450ml, gives 425.9g of inosine 2 ', 3 ', 5 ' -tripropionate as a white solid (m.p171-172 ℃ C.; yield 96.5%). step B.N⁶-cyclohexyl adenosine

A mixture of 270.6g of inosine 2 ', 3 ', 5 ' -tripropionate, 240ml of N.N-dimethylformamide and 600ml of toluene was heated to 65 ℃ and 67.84ml of thionyl chloride was added thereto over 1 hour at a rate such that the internal temperature was kept at 62 to 65 ℃. The mixture was stirred at this temperature for a further 2.5hr and then cooled to 10 ℃ with an ice bath. 600ml of cold water precooled to 10-15 ℃ in an ice bath were added at such a rate as to keep the temperature below 20 ℃ and then the organic layer was separated and washed with a total of 800ml of 10% aqueous NaCl in 4 aliquots of 200 ml. The organic layer containing the crude 6-chloro-9- (2, 3, 5-tri-O-propionyl-. beta. -ribofuranosyl) -9H-purine was added to 620ml of cyclohexylamine heated to 105 ℃ over 2 hours with stirring, the rate of addition being controlled so as to maintain the internal temperature at 105 ℃. After stirring the mixture at this temperature for a further 17 hours, it is brought to room temperature (25 ℃) over about 2 hours by stirring thoroughly and is then filtered with suction, for example with a Buchner funnel. The N-containing fraction was washed with a total of 460ml portions of 4 aliquots of 115ml portions of toluene⁶-cyclohexyladenosine and cyclohexylamine hydrochloride, then transferred while wet to a 5L flask equipped with mechanical stirring. After addition of 2L of saturated NaHCO₃After the aqueous solution and 2.5L of ethyl acetate, the mixture was stirred until all solids were dissolved (approx10-15 minutes). The organic layer was separated, and the aqueous layer was extracted with 1.5L of ethyl acetate in 1L and 500mL portions, respectively.

The organic layers were combined and evaporated (at 40 ℃ C., 100-200 mbar) until about 3L of ethyl acetate was removed. 500m1 heptane was added to the residue and the resulting mixture was stirred for 30 minutes. The solid was separated on a Buchner funnel and washed with a total of 300ml heptane in 3 equal portions of 100ml each. Drying the solid at 45-50 deg.C and 30-35 mbar for about 3hr to obtain 148g of white solid N⁶-crude cyclohexyladenosine. It was transferred to a 1L round bottom flask equipped with mechanical stirring and 175ml of 95% ethanol was added. The suspension is stirred for 15 to 20 minutes and 175ml of tert-butylethyl ether are added. After stirring for 5 minutes, the suspension was cooled in an ice bath and stirred for a further 15 minutes. The suspension is filtered on a Buchner funnel and washed with a total of 50ml of tert-butyl methyl ether in two 25ml portions.

Drying the filtered solid at 45-50 ℃ and 30-35 mbar for 14 hours to obtain 130g of white solid N⁶-cyclohexyl adenosine. (m.p185-187 ℃ C.; yield 60.0%)

Step C.N⁶-cyclohexyl-2' -O-methyladenosine

Stirring at room temperature (24-25 deg.C) 94.33g N⁶A suspension of cyclohexyladenosine and 720g of 5% aqueous NaOH until all solids were dissolved (approximately 5 minutes). 850ml of methylene chloride and 5.5g of tetrabutylammonium hydrogensulfate are added via an addition funnel, followed by 61.3g of dimethyl sulfate over 5 to 10 minutes, while maintaining an internal temperature of 24 to 25 ℃. The addition funnel was washed with 50ml of dichloromethane and the washings were added to the reaction vessel. After stirring the two-phase mixture at 24 to 25 ℃ C (internal temperature) for 7.5hr, the organic layer is separated and evaporated at 40 ℃ and 270 to 290 mbar. Until no solvent distilled off. The residue is dissolved in 200ml of toluene and evaporated at 45-50 ℃ and 30mmHg until no more solvent is distilled off.

A mixture of the crude product and 2470ml of toluene was stirred at room temperature for 10 minutes, and then 2470ml of water was added over 22 minutes. The resulting suspension is stirred at room temperature for a further 6 hours and the solid product is collected by suction filtration, for example on a Buchner funnel. After washing the solid with 114ml of toluene and a total of 285ml, divided into 3 equal portions of water, each of 95ml, the solid was dried overnight (14hr) at 48-50 ℃ and 25mmHg to give 53.0g of a white solid. The suspension of this solid in 397m1 toluene was heated to 80 ℃ with stirring to form a clear solution, which was cooled to 56 ℃ in 45 minutes and seeded with 10mg of pure substance. The mixture was stirred at 55-56 ℃ for 45 minutes and then cooled to room temperature over 1 hour. After stirring at this temperature for a further 1 hour, the solid product is collected by suction filtration, for example on a Buchner funnel. The solid was washed with a total of 75ml, divided into 3 equal portions of 25ml toluene, to give 60g of a white solid. The suspension of the solid in 159ml of toluene was then heated to 80 ℃ and the seeding operation was carried out at 65-66 ℃.

After cooling to room temperature over 1 hour and stirring at the same temperature for a further 1hr, the solid was filtered and washed with 42ml of toluene in 3 aliquots of 14ml and dried at 48-50 ℃ and 25mmHg overnight (14hr) to give 57.7g of a white solid. This solid and 122ml 100% ethanol were heated under reflux with stirring to give a clear solution, and 288ml of water pre-warmed to 55 ℃ was added over 25 minutes. The mixture was cooled to 55 ℃ and seeded with 20mg of pure substance. The mixture was cooled to room temperature over 1 hour and stirred at this temperature overnight (16 hr). The solid was collected by suction filtration on a Buchner funnel and washed with a total of 57ml of 100% ethanol and water mixture (1: 2.36v/v) divided into 3 equal portions of 19m1 each. The solid was dried at room temperature under 29mmHg to give 62.2g of 1.5 hydrated product as a white solid (m.p88-91 ℃, 42.5% yield).

Method example 2

By the above procedure, only equivalent amounts of N are used⁶-cyclopentyladenosine to yield N⁶-cyclopentyl-2' -O-methyladenosine.

Method example 3

The procedure is as in example 1, except that, after the dichloromethane is replaced by tert-amyl alcohol in step c) and subsequent preliminary crystallization with ethanol/water,the product was recrystallized from ethanol and water. 32.1g of N with a purity of more than 98% are obtained⁶-cyclohexyl-2' -O-methyladenosine in about 30% yield.

The process of the present invention is more economical in both time and cost than the various processes heretofore known. The process provides for the conversion of N under phase transition conditions⁶-cyclohexyladenosine and processes for the purification of 2' -O-methyl derivatives. The use of expensive protecting groups is avoided, as is the use of chromatography.

Claims

1. The use of a compound of formula 1 as an analgesic in the manufacture of a medicament suitable for the treatment of pain,

I

wherein R is₁Is hydrogen, (C)_1～4) Alkyl, allyl, methallyl; straight-chain or branched (C)_3～7) Alkynyl (C)_3～8) Cycloalkyl, hydroxy (C)_4～8) Cycloalkyl, by 1 or two independent halogens with atomic numbers of 9-35, (C)_1～4) Alkyl, (C)_1～4) Alkoxy or CF₃Substituted phenyl; or phenyl (C)_1～4) Alkyl, wherein the benzene ring is unsubstituted or substituted by 1 or two independent halogens with atomic numbers of 9-35, (C)_1～4) Alkyl, (C)_1～4) Alkoxy or CF₃Substituted; (C) having at least one hydroxyl group or at least two phenyl groups_1～4) Alkyl, bicycloalkyl, e.g. endo-or exobicyclo [ 2,2, 1 ] heptyl, naphthyl (C)_1～4) Alkyl, acenaphthenyl (C)_1～4) Alkyl or a radical of the formula A or BOr

Wherein Z is hydrogen, hydroxy or (C)_1～4) Alkoxy, Q is hydrogen or hydroxy, A is-CH₂-, -O-, -S-or a direct bond,

y is- (CH)₂)_n-or a bond directly attached to it,

n is an integer of 1 to 3,

and the dotted line in (A) represents a bond which may or may not be present, R₂Is hydrogen, (C)_1～4) Alkyl, amino, (C)_3～5) Cycloalkyl or halogen of atomic number 9 to 35, and R₃Is (C)_1～4) An alkyl group.

2. The use according to claim 1, wherein the compound of formula I is selected from 6' -hydroxy (C)_4～8) Cycloalkyl-2' -O-methyladenosine.

3. The use of claim 1, wherein R is₁Is not hydroxycycloalkyl.

4. Use according to claim 3, wherein the compound of formula I is 6-cyclohexyl-2' -O-methyl-adenosine.

5. Use according to any preceding claim for the treatment of acute pain.

6. The use according to any preceding claim for the treatment of chronic neuropathic pain.

7. Use of a compound as defined in any preceding claim for the treatment of pain as defined in any preceding claim, or a method of treatment of 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 together with a pharmaceutical carrier or diluent.

8. Compounds of formula Ia

Ia

In the formula R₁Represents hydroxy-substituted (C)_4～8) Cycloalkyl radical, R₂And R₃As defined in claim 1.

9. The compound as in claim 8, wherein R₂Is hydrogen, (C)_1～4) Alkyl or halogen with atomic number 9-35.

10. A compound selected from the group consisting of:

6- [ (trans) -4-hydroxycyclohexyl ] -2' -O-methyladenosine

6- [ (cis) -4-hydroxycyclohexyl ] -2' -O-methyladenosine

6- [ (1S, trans) -2-hydroxycyclopentyl ] -2' -O-methyladenosine

6- [ (1R, trans) -2-hydroxycyclopentyl ] -2' -O-methyladenosine

6- [ (1S, trans) -2-hydroxycyclohexyl ] -2' -O-methyladenosine

6- [ (1R, trans) -2-hydroxycyclohexyl ] -2' -O-methyladenosine

6- [ (trans) -4-hydroxycyclohexyl ] -2' -O-ethyladenosine, and

6- [ (1S, trans) -2-hydroxycyclohexyl ] -2' -O-ethyladenosine.

11. A compound according to claim 8, 9 or 10 in 95% purity.

12. Does not contain N⁶-cycloalkyl-2' -O-methyladenosine a compound according to claim 8, 9 or 10.

13. The use of a compound of formula Ia as defined in any one of claims 8 to 12 for the preparation of a medicament suitable for the treatment of pain, the prevention and treatment of hypertension, as a coronary vasodilator, for inhibiting platelet aggregation or activating leukocytes, for lowering blood lipid levels, combating congestive heart failure, myocardial infarction, sudden cardiac necrosis, renal insufficiency, and for the treatment of high triglyceride/low HDL cholesterol levels, lipid dysfunction, high free fatty acids and/or type I and type II diabetes, arrhythmia or prevention of myocardial infarction.

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

15. A compound according to any one of claims 8 to 12 for use in the treatment of pain, hypertension, coronary artery constriction, platelet aggregation, hyperlipidemia, congestive heart failure, sudden cardiac necrosis, renal insufficiency, high triglyceride/low HDL cholesterol, lipid dysfunction, high free fatty acids or type I or type II diabetes, arrhythmia and prevention of myocardial infarction. Or a method of using such a compound, comprising administering to a subject in need of such treatment a compound of formula Ia.

16. A method of making 2' -O-alkyl adenosines comprising treating adenosine with a suitable alkyl sulphate in the presence of a phase transfer catalyst.

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

18. A method as claimed in claim 16 or 17 wherein the compound produced is N-cycloalkyl-2' -O-methyladenosine.

19. A compound made by the method of claim 16, 17, or 18.

20. Administering N to warm-blooded animals⁶-cyclohexyl-2' -O-methyladenosine to produce N⁶-hydroxycyclohexyl-2' -O-methyladenosine.