EP1326826A1

EP1326826A1 - Use of amino acids for treating pain

Info

Publication number: EP1326826A1
Application number: EP01969790A
Authority: EP
Inventors: Boris Chizh; Claudia Katharina PÜTZ; Michael Haurand
Original assignee: Gruenenthal GmbH
Current assignee: Gruenenthal GmbH
Priority date: 2000-09-30
Filing date: 2001-09-28
Publication date: 2003-07-16
Also published as: HUP0302970A2; NZ525417A; WO2002030871A1; DE10048715A1; JP2004511459A; US20030229145A1; PL361629A1; MXPA03002740A; CA2424089A1; PE20030617A1; AR034265A1; AU2001289936A1

Abstract

The invention relates to amino acids, a method for the production thereof, medicaments containing said compounds and the use of amino acids in the production of medicaments for treating pain.

Description

Use of amino acids to treat pain

The present invention relates to amino acids, processes for their preparation, medicaments containing these compounds and the use of amino acids for the production of medicaments for the treatment of pain.

Cyclic GABA analog gabapentin is a clinically proven antiepileptic. Gabapentin also shows other interesting, medically relevant properties, especially as an analgesic. Interesting are therefore new structural classes that have affinity for the gabapentin binding site. For the indications mentioned, there is a further need for substances which have properties in common with gabapentin, for example in the analgesic effect.

The treatment of chronic and non-chronic pain conditions is of great importance in medicine. There is a worldwide need for effective pain therapies. The urgent need for action for a patient-oriented and goal-oriented treatment of chronic and non-chronic pain conditions, whereby this means the successful and satisfactory pain treatment for the patient, is documented in the large number of scientific papers in the field of applied analgesics and basic research on the nociception have appeared recently.

Classic opioids such as morphine are effective in treating severe to severe pain. However, their use is limited by the known side effects such as respiratory depression, vomiting, sedation, constipation and tolerance development. In addition, they are less effective in neuropathic or incidental pain, which particularly affects tumor patients. The object of the invention was therefore to find structures, preferably new structures, which have affinity for the gabapentin binding site and / or corresponding physiological activity, for example with regard to analgesia, but also have other GBP indications.

The invention therefore relates to the use of an amino acid of the general formula I,

, in which

F and R ^ are each independently selected from H; C 1-4 alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; Aryl, C 1-6 -cycloalkyl or heteroaryl, each unsubstituted or substituted one or more times; or

R1 and R2 together form a (CH2) 3_6 ring, saturated or unsaturated, substituted or unsubstituted, in which 0-2 C atoms can be replaced by S, O or NR ⁴ ,

with R ⁴ selected from: H; C 1-6 -alky !, saturated or unsaturated, branched or unbranched, mono- or polysubstituted or unsubstituted;

optionally in the form of their racemates, their pure stereoisomers, in particular enantiomers or diastereomers, or in the form of mixtures of the stereoisomers, in particular the enantiomers or diastereomers, in any mixing ratio; or in the form of their acids or their bases or in the form of their salts, in particular the physiologically tolerable salts, or in the form of their solvates, in particular the hydrates;

for the manufacture of a medicament for the treatment of pain, in particular neuropathic, chronic or acute pain, epilepsy and / or migraine

or

for the manufacture of a medicament for the treatment of hyperalgesia and allodynia, in particular thermal hyperalgesia, mechanical hyperalgesia and allodynia and cold allodynia, or of inflammatory or postoperative pain

or

for the manufacture of a medicament for the treatment of hot flashes, postmenopausal complaints, amyotropic lateral sclerosis (ALS), reflex sympasthetic dystrophy (RSD), spastic paralysis, restless leg syndrome, acquired nystagmus; psychiatric or neuropathological disorders, such as bipolar disorders, anxiety, panic attacks, mood changes, manic behavior, depression, manic-depressive behavior; painful diabetic neuropathy, symptoms and pain due to multiple sclerosis or Parkinson's disease, neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Parkinson's disease and epilepsy; gastrointestinal damage; erythromelalgic or post-poliomyelitic pain, trigeminal or post-herpetic neuralgia; or as an anticonvulsant, analgesic or anxiolytic.

In one embodiment of the invention, the amino acids used according to formula I R ^ and R ^ are each independently selected from H; C 1 -C 4 -alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; is preferably one of the radicals R ^ and R ^ C- _| _2-alkyl and the other C2_ιo ~ ^A '. preferably unsubstituted, unbranched and saturated, or

R1 and R2 together form cyclopropyl, cyclopentyl, cyclohexyl or cycloheptyl.

In a particularly preferred embodiment of the invention, in the amino acids of formula I used

R ^ and R ^ are each independently selected from C ^ g-alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; Aryl, C 1 -C 4 -cycloalkyl or heteroaryl, in each case unsubstituted or substituted one or more times;

or

R1 and R2 together form a ring and mean substituted or unsubstituted, in which 0-2 C atoms can be replaced by S, O or NR ⁴ ,

with R ⁴ selected from: H; C ^ g-Alky !, saturated or unsaturated, branched or unbranched, mono- or polysubstituted or unsubstituted.

These substances bind to the gabapentin binding site and show a pronounced analgesic effect.

For the purposes of this invention, alkyl or cycloalkyl radicals are taken to mean saturated and unsaturated (but not aromatic), branched, unbranched and cyclic hydrocarbons, which can be unsubstituted or mono- or polysubstituted. Here d- ₂ alkyl is C1- or C2-alkyl, C-. ₃ alkyl for C1-, C2- or C3-alkyl, Cu-alkyl for C1-, C2-, C3- or C4-alkyl, ds-alkyl for C1-, C2-, C3-, C4- or C5-alkyl, Cι _-6 -alkyl for C1-, C2-, C3-, C4-, C5- or C6-alkyl, Cι- ₇ alkyl for C1-, C2-, C3-, C4-, C5-, C6- or C7-alkyl, C _1-8 -alkyl for C1-, C2-, C3-, C4-, C5-, C6-, C7- or C8-alkyl, C ^ o-alkyl for C1-, C2-, C3-, C4-, C5-, C6-, C7-, C8-, C9- or C10- alkyl and d- ^ - alkyl for C1-, C2-, C3-, C4-, C5-, C6-, C7-, C8-, C9-, C10-, C11 -, C12, C13, C14, C15, C16, C17 or C18 alkyl. Furthermore, C ₃ - ₄ cycloalkyl stands for C3 or C4 cycloalkyl, C ₃ - ₅ cycloalkyl for C3, C4 or C5 cycloalkyl, C ₃ - ₆ cycloalkyl for C3, C4, C5 or C6 cycloalkyl, C _{_3-7} cycloalkyl for C3, C4, C5, C6 or C7 cycloalkyl, C _{_3-8} cycloalkyl for C3, C4, C5, C6, C7 or C8 Cycloalkyl, C ₄ . ₅ - cycloalkyl means C4 or C5 cycloalkyl, _C5 cycloalkyl for C4, C5 or C6 cycloalkyl, _C7 cycloalkyl for C4, C5, C6 or C7 -cycloalkyl, C ₅ - ₆ cycloalkyl of C5 or C6 cycloalkyl, and C _{_5-7} cycloalkyl for C5, C6 or C7 cycloalkyl. With regard to cycloalkyl, the term also includes saturated cycloalkyls in which one or two carbon atoms have been replaced by a hetero atom, S, N or O. The term cycloalkyl also includes, in particular, one or more, preferably mono-, unsaturated cycloalkyls without a hetero atom in the ring, as long as the cycloalkyl is not an aromatic system. The alkyl or cycloalkyl radicals are preferably methyl, ethyl, vinyl (ethenyl), propyl, allyl (2-propenyl), 1-propynyl, methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1, 1-di methylethyl , Pentyl, 1, 1-Dimethylpropyl, 1, 2-Dimethylpropyl, 2,2-Dimethylpropyl, Hexyl, 1-Methylpentyl, Cyclopropyl, 2-Methylcyclopropyl, Cyclopropylmethyl, Cyclobutyl, Cyclopentyl, Cyclopentylmethyl, Cyclohexyl, Cycloheptyl, Cyclooctyl, but also Adamantyl , CHF2, CF3 or CH2OH and pyrazolinone, oxopyrazolinone, [1, 4] dioxane or dioxolane.

In the context of alkyl and cycloalkyl - as long as this is not expressly defined otherwise - the term substituted in the sense of this invention means the substitution of at least one (possibly also several) hydrogen radicals by F, Cl, Br, I, NH ₂ , SH or OH, where “multiply substituted” or “substituted” is to be understood in the case of multiple substitution that the substitution takes place both on different and on the same atom several times with the same or different substituents, for example three times on the same carbon atom as in the case of CF ₃ or in different places as in the case of -CH (OH) -CH = CH-CHCI ₂ . Particularly preferred substituents here are F, Cl and OH. With regard to cycloalkyl, the hydrogen radical can also be substituted by OC _1-3 alkyl or Cι _-3 alkyl (each one or more times substituted or unsubstituted), in particular methyl, ethyl, n-propyl, i-propyl, CF ₃ , methoxy or ethoxy, to be replaced.

Under the term (CH ₂ ) ₃ -6 is -CH ₂ -CH ₂ -CH ₂ -, -CH2-CH2-CH2-CH2-, -CH ₂ -CH ₂ -CH ₂ -CH2-CH2- and CH2-CH2 -CH2-CH2-CH2-CH2- to understand, under (CH ₂ ) ι- is -CH ₂ -, - CH2-CH2-, -CH2-CH2-CH2- and -CH2-CH ₂ -CH ₂ -CH ₂ - to understand, under (CH ₂ ) _-5 is to be understood - CH2-CH2-CH2-CH2- and -CH2-CH2-CH2-CH2-CH2-CH2-, etc.

An aryl radical is understood to mean ring systems with at least one aromatic ring but without heteroatoms in even one of the rings. Examples are phenyl, naphthyl, fluoranthenyl, fluorenyl, tetralinyl or indanyl, in particular 9H-fluorenyl or anthracenyl radicals, which can be unsubstituted or mono- or polysubstituted.

A heteroaryl radical is understood to mean heterocyclic ring systems with at least one unsaturated ring which contain one or more heteroatoms from the group consisting of nitrogen, oxygen and / or sulfur and can also be mono- or polysubstituted. Examples from the group of heteroaryls are furan, benzofuran, thiophene, benzothiophene, pyrrole, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, phthalazine, benzo [1,2,5] thiadiazole, benzothiazole, indole, benzothazole, benzodioxolane and benzodioxane , Carbazole, indole and quinazoline.

In connection with aryl and heteroaryl, this is understood to mean the substitution of aryl or heteroaryl with R ²³ , OR ^23, a halogen, preferably F and / or Cl, a CF3, a CN, a NO2 or an NR ²⁴ R ²⁵ , a C. - _j .g- alkyl (saturated), a C ^ .g-alkoxy, a C3_3-cycloalkoxy, a C3_3-cycloal yl or a C2_6-alkylene.

The radical R ² ^ stands for H, a C _j .- _{j Q} alkyl, preferably a C- | _g alkyl, an aryl or heteroaryl or for a via C - ^ - alkyl, saturated or unsaturated , or a C] _3-alkylene group bound aryl or heteroaryl radical, these aryl and heteroaryl radicals themselves may not be substituted by aryl or heteroaryl radicals,

the radicals R ²⁴ and R ²⁵ , the same or different, for H, a C 1-6 -alky! -, preferably one Alkyl, saturated or unsaturated, or an aryl or heteroaryl radical bonded to a C 1-4 alkylene group, these aryl and heteroaryl radicals themselves not being substituted by aryl or heteroaryl radicals,

or the radicals R ²⁴ and R ²⁵ together mean CH2CH2OCH2CH2, CH ₂ CH2NR ²⁶ CH ₂ CH2 or (CH ₂ ) ₃ .g, and

the radical R ² ^ for H, a C 1-6 alkyl, preferably a C 1-6 alkyl, an aryl or heteroaryl radical or for a C 1-4 alkyl, saturated or unsaturated, or one C ^ -alkylene group bound aryl or heteroaryl radical, these aryl and heteroaryl radicals themselves may not be substituted with aryl or heteroaryl radicals.

The term salt is to be understood to mean any form of the active substance according to the invention in which it takes on an ionic form or is charged and is coupled to a counterion (a cation or anion) or is in solution. This also includes complexes of the active ingredient with other molecules and ions, in particular complexes that are complexed via ionic interactions. In particular, this means physiologically compatible salts with cations or bases and physiologically compatible salts with anions or acids.

For the purposes of this invention, the term “physiologically compatible salt with cations or bases” means salts of at least one of the compounds according to the invention - usually one (deprotonated) acid - as an anion with at least one, preferably inorganic, cation, which is physiologically - in particular when used in humans and / or mammal - are compatible. However, the salts of the alkali and alkaline earth metals are also particularly preferred NH ₄ ⁺ , but especially (mono-) or (di-) sodium, (mono-) or (di-) potassium, magnesium or calcium salts.

For the purposes of this invention, the term “physiologically compatible salt with anions or acids” is understood to mean salts of at least one of the compounds according to the invention - mostly protonated, for example on nitrogen - as a cation with at least one anion which is physiologically - in particular when used in humans and / or Mammal - are compatible. For the purposes of this invention, this is understood in particular to mean the salt formed with a physiologically compatible acid, namely salts of the respective active ingredient with inorganic or organic acids which are physiologically compatible, in particular when used in humans and / or mammals. Examples of physiologically compatible salts of certain acids are salts of: hydrochloric acid, hydrobromic acid, sulfuric acid, methanesulfonic acid, formic acid, acetic acid, oxalic acid, succinic acid, tartaric acid, mandelic acid, fumaric acid, lactic acid, citric acid, glutamic acid, 1, 1-dioxo-1, 2-dihydro1 ⁶ - benzo [d] isothiazol-3-one (saccharic acid), monomethylsebacic acid, 5-oxo-proline, hexane-1-sulfonic acid, nicotinic acid, 2-, 3- or 4-aminobenzoic acid, 2,4,6-trimethyl-benzoic acid , α-lipoic acid, acetylglycine, acetylsalicylic acid, hippuric acid and / or aspartic acid. The hydrochloride salt is particularly preferred.

All of the substances listed above and defined for use displace gabapentin from its binding site, which is still unknown in science. However, this implies that the substances according to the invention bind to the same binding site and will act physiologically via them, presumably with the same activity profile as gabapentin. The analgesic effect proves that this assumption of the same effect also applies to the same binding site. Thus, the compounds according to the invention not only displace gabapentin from its binding site but, like gabapentin, also have a clearly analgesic effect. Accordingly, the object of the invention is the use of the named and defined amino acids in the above-mentioned indications in which gabapentin acts, that is to say in particular in pain therapy, in the case of epilepsy or migraine, but especially also in neuropathic pain including hyperalgesia and allodynia and the other gabapentin indications.

Gabapentin is a well-known antiepileptic with an anticonvulsant effect. In addition to this, gabapentin is also used in various other indications, among others by doctors treating migraines and bipolar disorders as well as hot flashes (e.g. in postmenopause) (M. Schrope, Modern Drug Discovery, September 2000, p. 11). Other indications in which gabapentin shows therapeutic potential have been identified during human studies and clinical use (JS Bryans, D. Wustrow; "3-Substituted GABA Analogs with Central Nervous System Activity: A Review" in Med. Res. Rev. (1999), pp. 149-177) This review article lists the effects of gabapentin in detail: Gabapentin is effective in the treatment of chronic pain and behavioral disorders. In particular, the following are listed: anticonvulsive and antiepileptic effects, the use against chronic, neuropathic pain , in particular thermal hyperalgesia, mechanical allodynia, cold allodynia. It is also effective against neuropathy caused by nerve damage, especially neuropathic pain, as well as inflammatory and postoperative pain. Gabapentin is also successful in antipsychotic effects, especially as an anxiolytic Include: Amyotropic Lateral Sclerosis (ALS), Reflex Sympasthetic Dystrophy (RSD), Spastic Paralysis, Restless Leg Syndrome, Treatment of Symptoms and Pain due to Multiple Sclerosis, Acquired Nystagmus, Treatment of Symptoms of Parkinson's Disease, Painful Diabetic Neuropathy and Psychiatric Disorders , eg bipolar disorders, mood swings, manic behavior. The use of gabapentin in erythromelalgic pain, postpoliomyelitis pain, trigeminal neuralgia and postherpetic neuralgia was also successful (Bryans and Wustrow (1999), op. Cit.). The general effectiveness in neurodegenerative diseases is also generally known and can also be taken from the above-mentioned overview article using the examples. Such neurodegenerative diseases are, for example, Alzheimer's disease, Huntington's disease, Parkinson's disease and epilepsy. The effectiveness of gabapentin in gastrointestinal damage is also known. In a preferred embodiment of the invention, amino acids according to formula I are used for which

R ^ and R ^{2 are} each independently selected from C- ^ Q alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; aryl, or heteroaryl, each unsubstituted or mono- or polysubstituted;

or

R1 and R2 together form a ring and are (^ 2) 5, substituted or unsubstituted, so that a substituted or unsubstituted cyclohexyl is formed.

In a particularly preferred embodiment of the invention, amino acids of the formula I are used, for which:

one of the radicals R ^ and R ² C-μ-alkyl, in particular methyl, ethyl n-propyl or i-propyl, each unsubstituted or substituted one or more times; means and the other of the radicals R ^ and R ² C3_- _{| Q-} alkyl, especially n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or one - or substituted several times; or aryl or heteroaryl, in particular phenyl, naphthyl, furanyl, thiphenyl, pirimidinyl or piridinyl, in each case unsubstituted or simply (preferably substituted with OCH ₃ , CH ₃ , OH, SH, CF ₃ , F, Cl, Br or I); or C ₃ . ₈ - cycloalkyl, in particular cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in each case unsubstituted or simply substituted; means

preferably

one of the radicals R ¹ and R ² C- _j - ^ - alkyl, in particular methyl, ethyl n-propyl or i-propyl, each unsubstituted or one or more times substituted; means and the other of the radicals R ^ and R ² C3_- _| 0-alkyl, especially n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or a - or substituted several times; or C4_7-cycloalkyl, preferably cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in particular cyclobutyl, cyclopentyl or cyclohexyl, in each case unsubstituted or simply substituted; means

in particular

one of the radicals R ^ and R ² C - ^ - alkyl, especially methyl, ethyl n-propyl or i-propyl, each unsubstituted or mono- or polysubstituted; means and the other of the radicals R ^ and R ² C3_- _| o-alkyl, especially n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or a - or substituted several times; means.

In a likewise particularly preferred embodiment of the invention (also) amino acids according to formula I are used, for which applies that

R1 and R2 together form a ring and are (CH2) g, substituted or unsubstituted, so that a substituted or unsubstituted cyclohexyl is formed,

preferably

R1 and R2 together form a ring and are (CH ₂ ) s, substituted or unsubstituted, so that a monosubstituted or unsubstituted cyclohexyl is formed, in particular an unsubstituted or methyl-substituted cyclohexyl.

The use of some of the aforementioned compounds may be excluded from the subject matter and thus protection of this application. This applies to a preferred one Form of the use according to the invention that under at least one of the following conditions ^ where under certain circumstances only one condition or all conditions can be selected) a compound or group of compounds of the amino acids of formula I used is excluded from use:

R ¹ and R ² are simultaneously CH ₃ ,

Or one of R ¹ and R ² is CH ₃ and the other is C ₂ H ₅ ,

• or one of R ¹ and R ² is CH3 and the other substituted phenyl,

• or R1 and R2 together form a ring and thus mean (CH2) φ form a cyclopentyl ring, substituted or unsubstituted,

• or R1 and R2 together form a ring and denote (^ 2) 5, ie form a cyclohexyl ring, substituted or unsubstituted.

In a preferred embodiment of the invention, the amino acids used are selected from the following group:

β 2-amino-3-methyl-heptanoic acid

• 2-amino-3-methyl-octanoic acid

• 2-amino-3-methyl-nonanoic acid

• 2-amino-3-methyl-decanoic acid

• 2-amino-3-ethyl-hexanoic acid

• 2-amino-3-methyl-undecanoic acid

• 2-amino-3-cyclobutyl-butanoic acid

• 2-amino-3-cyclohexyl-butanoic acid

• Amino- (3-methyl-cyclohexyl) ethanoic acid

• Amino- (2-methyl-cyclohexyl) ethanoic acid

optionally in the form of their racemates, their pure stereoisomers, in particular enantiomers or diastereomers, or in the form of mixtures of the stereoisomers, in particular the enantiomers or diastereomers, in any mixing ratio; in the form shown or in the form of their acids or their bases; or in the form of their salts, in particular the physiologically acceptable salts, preferably the hydrochloride or sodium salt; or in the form of their solvates, especially the hydrates.

The invention furthermore relates to the amino acids of the general formula I,

, in which

R1 and R ^{2 are} each independently selected from H; C ^ _ 1 Q-alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; Aryl, C 1 -C 4 -cycloalkyl or heteroaryl, in each case unsubstituted or substituted one or more times; or

R1 and R2 together form a (CH2) 3_g- ing, saturated or unsaturated, substituted or unsubstituted, in which 0-2 C atoms can be replaced by S, O or NR ⁴ ,

with R ⁴ selected from: H; C ^ _Q alkyl, saturated or unsaturated, branched or unbranched, mono- or polysubstituted or unsubstituted;

optionally in the form of their racemates, their pure stereoisomers, in particular enantiomers or diastereomers, or in the form of mixtures of the stereoisomers, in particular the enantiomers or diastereomers, in any mixing ratio; in the form shown or in the form of their acids or their bases or in the form of their salts, in particular the physiologically acceptable salts, or in the form of their solvates, in particular the hydrates.

It applies in one embodiment of the invention that in the amino acids of the formula I according to the invention

R ^ and R ^{2 are} each independently selected from H; C- _j . IQ-alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; preferably one of the radicals R1 and R ^{2 is} C ^ _ ₂ alkyl and the other C2_ιo-alkyl, preferably unsubstituted, unbranched and saturated, or

R1 and R2 together form cyclopropyl, cyclopentyl, cyclohexyl or cycloheptyl.

In a particularly preferred embodiment of the invention, the following applies to the amino acids of the formula I according to the invention

one of the radicals R ^ and R ² C ^ alkyl, in particular methyl, ethyl n-propyl or i-propyl, each unsubstituted or substituted one or more times; means and the other of the remnants in particular n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted ; or aryl or heteroaryl, in particular phenyl, naphthyl, furanyl, thiphenyl, pirimidinyl or piridinyl, in each case unsubstituted or simply (preferably substituted with OCH ₃ , CH ₃ , OH, SH, CF ₃ , F, Cl, Br or I); or C ₃ . ₈ - cycloalkyl, in particular cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in each case unsubstituted or simply substituted; means.

In a very preferred embodiment of this invention, the following applies to the amino acids of the formula I according to the invention one of the radicals R ¹ and R ^{2 is} C 1 -C 4 -alkyl, in particular methyl, ethyl n-propyl or i-propyl, in each case unsubstituted or mono- or polysubstituted; means and the other of the remnants Q-yl, in particular n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or substituted one or more times; or C 1 -C 6 -cycloalkyl, preferably cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in particular cyclobutyl, cyclopentyl or cyclohexyl, in each case unsubstituted or simply substituted; means

preferably

one of the radicals R1 and R2 C1-3-alkyl, in particular methyl, ethyl n-propyl or i-propyl, in each case unsubstituted or mono- or polysubstituted; means and the other of the radicals R1 and R2 C3-10-alkyl, in particular n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; means.

In a preferred embodiment of the invention, the amino acids according to the invention are selected from the following group:

• 2-amino-3-methyl-heptanoic acid

• 2-amino-3-methyl-octanoic acid

• 2-amino-3-methyl-nonanoic acid »2-amino-3-methyl-decanoic acid

• 2-amino-3-ethyl-hexanoic acid

• 2-amino-3-methyl-undecanoic acid

• 2-amino-3-cyclobutyl-butanoic acid

• 2-amino-3-cyclohexyl-butanoic acid

optionally in the form of their racemates, their pure stereoisomers, in particular enantiomers or diastereomers, or in the form of mixtures of the Stereoisomers, in particular the enantiomers or diastereomers, in the form shown in any mixing ratio n or in the form of their acids or their bases or in the form of their salts, in particular the physiologically tolerable salts, or in the form of their solvates, in particular the hydrates; preferably the hydrochloride or sodium salt.

The amino acids according to the invention are toxicologically harmless, so that they are suitable as active pharmaceutical ingredients in pharmaceuticals. The invention therefore furthermore relates to medicaments comprising at least one amino acid according to the invention, and, if appropriate, suitable additives and / or auxiliaries and / or optionally further active compounds.

The same applies to the amino acids used in the indications mentioned according to the invention, since the amino acids used according to the invention are naturally also toxicologically harmless, so that they are suitable as active pharmaceutical ingredients in pharmaceuticals. The invention therefore furthermore relates to medicaments comprising at least one of the amino acids used according to the invention, and, if appropriate, suitable additives and / or auxiliaries and / or optionally further active compounds.

In addition to at least one substituted amino acid according to the invention, the medicaments according to the invention optionally contain suitable additives and / or auxiliaries, including carrier materials, fillers, solvents, diluents, dyes and / or binders, and can be used as liquid medicament forms in the form of injection solutions, drops or juices semi-solid dosage forms in the form of granules, tablets, pellets, patches, capsules, plasters or aerosols can be administered. The choice of excipients etc. and the amounts to be used depend on whether the medication! Orally, orally, parenterally, intravenously, intraperitoneally, intradermally, intramuscularly, intranasally, buccally, rectally or locally, for example on the skin, the mucous membranes or in the eyes. Preparations in the form of tablets, dragees, capsules, granules, drops, juices and syrups are suitable for oral administration, and solutions, suspensions, easily reconstitutable dry preparations and sprays are suitable for parenteral, topical and inhalative administration. invention Amino acids in a depot, in dissolved form or in a plaster, optionally with the addition of agents that promote skin penetration, are suitable percutaneous application preparations. Formulations which can be used orally or percutaneously can release the amino acids according to the invention with a delay. In principle, other active substances known to the person skilled in the art can be added to the medicaments according to the invention.

The amount of active ingredient to be administered to the patient varies depending on the weight of the patient, the type of application, the indication and the severity of the disease. Usually 0.005 to 1000 mg / kg, preferably 0.05 to 5 mg / kg, of at least one amino acid according to the invention are applied.

In a preferred form of the medicaments according to the invention, an amino acid according to the invention is present as a pure diastereomer and / or enantiomer, as a racemate or as a non-equimolar or equimolar mixture of the diastereomers and / or enantiomers.

Another object of the invention is the use of an amino acid of the formula I according to the invention for the manufacture of a medicament for the treatment of pain, in particular neuropathic, chronic or acute pain, epilepsy and / or migraine

or

for the manufacture of a medicament for the treatment of hot flashes, complaints after the menopause, amyotropic lateral sclerosis (ALS), reflex sympasthetic dystrophy (RSD), spastic paralysis, restless leg Syndrome, acquired nystagmus; psychiatric or neuropathological disorders, such as bipolar disorders, anxiety, panic attacks, mood swings, manic behavior, depression, manic depressive behavior; painful diabetic neuropathy, symptoms and pain due to multiple sclerosis or Parkinson's disease, neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Parkinson's disease and epilepsy; gastrointestinal damage; erythromelalgic or post-poliomyelitic pain, trigeminal or post-herpetic neuralgia; or as an anticonvulsant, analgesic or anxiolytic.

In each of the aforementioned uses according to the invention, it may be preferred if an amino acid used is present as a pure diastereomer and / or enantiomer, as a racemate or as a non-equimolar or equimolar mixture of the diastereomers and / or enantiomers.

Another object of the invention is a method for the treatment of a non-human mammal or human being which needs treatment of medically relevant symptoms by administration of a therapeutically viable dose of an amino acid according to the invention or used according to the invention, or of a medicament according to the invention. The invention relates in particular to corresponding methods for the treatment of pain, in particular neuropathic, chronic or acute pain; Migraines, hyperalgesia and allodynia, in particular thermal hyperalgesia, mechanical hyperalgesia and allodynia and cold allodynia, or of inflammatory or postoperative pain; Epilepsy, hot flashes, postmenopausal complaints, amyotropic lateral sclerosis (ALS), reflex sympasthetic dystrophy (RSD), spastic paralysis, restless leg syndrome, acquired nystagmus; psychiatric or neuropathological disorders, such as bipolar disorders, anxiety, panic attacks, mood swings, manic behavior, depression, manic-depressive behavior; painful diabetic neuropathy, symptoms and pain due to multiple sclerosis or Parkinson's disease, neurodegenerative diseases such as Alzheimer's disease, Huntington ^'s disease, Parkinson's disease and epilepsy; of erythromelalgic or post-poliomyelitic pain, trigeminal or post-herpetic neuralgia

Another object of the invention is a method for producing an amino acid according to the invention in a form as described below.

General procedure for the preparation of the substituted α-amino acids

The reactions described in the literature have been used for the synthetic work, as well as in-house experience.

The subject of the invention is also a process for the preparation of a compound of formula 1 according to Schemal:

Schemal:

4 1

The deprotonation of the isocyanacetate with bases such as butyllithium, sodium hydride or potassium. -tert.butylate and subsequent reaction with ketones of the general formula 2 in tetrahydrofuran leads to (E, Z) ~ 2 ~ formylaminoacrylic acid ethyl esters of the general formula 3. By reaction of (E, Z) -2-formylaminoacrylic acid ethyl esters of the general formula 3 with Pd / H2, formylamino ethyl ester is obtained general formula 4. Reaction of the formylamino ethyl esters of the general formula 4 with hydrochloric acid leads to the amino acids of the general formula 1. The diastereomers are separated at a suitable stage by means of HPLC, column chromatography or crystallization. The enantiomer separation is also carried out on the final stage by means of HPLC, column chromatography or crystallization. The amino acids of the general formula 1 are obtained as hydrochlorides by this process. By releasing the base or reprecipitation by conventional methods, further salt forms are obtained.

Accordingly, a further subject is a process for the production of the amino acids according to the invention with the following steps:

2

3 a) deprotonation of the isocyanacetic acid ethyl ester with bases and subsequent reaction with ketones of the general formula 2, in which R1 and R2 have the meaning given in claim 7, preferably in tetrahydrofuran leads to (E, Z) -2-formylaminoacrylic acid ethyl esters of the general formula 3,

b) reaction of (E, Z) -2-formylaminoacrylic acid ethyl esters of the general form ⁾ 3 with Pd / H ₂ leads to formylaminoethyl ester of the general formula 4,

1

c) Reaction of the formylaminoethyl ester of the general formula 4 with acid, preferably hydrochloric acid, leads to the amino acids of the general formula 1 or formula I, optionally followed or interrupted by separation of diastereomers at a suitable stage by means of HPLC, column chromatography or crystallization or followed by Enantiomer separation by means of HPLC, column chromatography or

Crystallization.

salt formation

The compounds of formula I can be combined with physiologically acceptable acids, for example hydrochloric acid, hydrobromic acid, sulfuric acid, methanesulfonic acid, formic acid, acetic acid, oxalic acid, succinic acid, malic acid, tartaric acid, mandelic acid, fumaric acid, lactic acid, citric acid, glutamic acid, 1,1-dioxo-1 , 2-dihydro1λ ⁶ -benzo [c] isothiazol-3-one (saccharic acid), monomethylsebacic acid, 5-oxo-proline, hexane-1-sulfonic acid, nicotinic acid, 2-, 3- or 4-aminobenzoic acid, 2,4,6 -Trimethyl-benzoic acid, α-lipoic acid, acetylglycine, acetylsalicylic acid, hippuric acid and / or aspartic acid, convert into their salts in a known manner. Salt formation is preferably carried out in a solvent, for example diethyl ether, diisopropyl ether, alkyl acetate, acetone and / or 2-butanone or else water. Trimethylchlorosilane in aqueous solution is also suitable for the preparation of the hydrochlorides. It is also possible to convert them into basic salts using metal ions, for example: alkali and alkaline earth ions.

In the following the invention is further illustrated by examples, without being limited thereto. Examples

The following examples show compounds according to the invention and their representation and effectiveness studies carried out with them.

The following information generally applies:

The chemicals and solvents used were purchased commercially from conventional suppliers (Acros, Avocado, Aldrich, Fluka, Lancaster, Maybridge, Merck, Sigma, TCI etc. or synthesized).

The analysis was carried out using ESI mass spectrometry or HPLC.

syntheses:

Example 1)

Synthesized compounds:

The following are representative examples of the compounds used or claimed in the context of this invention:

Connection 1)

Rac-2-amino-3-methyl ~ heptanoic acid hydrochloride as a D / L: mixture of 1: 1 Connection 2)

rac-2-amino-3-methyl-octanoic acid hydrochloride as a D / L mixture of 1: 1

rac-D-2-amino-3-methyl-octanoic acid hydrochloride

Connection 4)

rac-D-2-amino-3-methyl-nonanoic acid hydrochloride

Connection 5)

rac-L-2-amino-3-methyl-nonanoic acid hydrochloride

Connection 6)

Rac-2-amino-3-methyl-decanoic acid hydrochloride as a D / L mixture of 1: 1

Connection 7)

Rac-amino-3-ethyl-hexanoic acid hydrochloride as a D / L mixture of 1: 1 Connection 8)

Rac-2-amino-3-methyl-undecanoic acid hydrochloride as a D / L mixture of 1: 1

Connection 9)

rac-2-amino-3-cyclobutyl-butanoic acid hydrochloride as a D / L mixture of 1: 1

Connection 10)

rac-2-amino-3-cyclohexyl-butanoic acid hydrochloride as a D / L mixture of 1: 1

Connection 11)

rac-amino- (3-methyl-cyclohexyl) -ethanoic acid hydrochloride

Connection 12)

Example 12

rac-amino- (2-methyl-cyclohexyl) -ethanoic acid hydrochloride

Connection 13)

Example 13 rac-2-amino-3-methyl-heptanoic sodium salt as a D / L mixture of 1: 1; Na salt for compound 1

Connection 14)

rac-2-amino-3-methyl-decanoic acid sodium salt as a D / L mixture of 1: 1; Na salt to compound 6 Connection 15)

rac-2-amino-3-methyl-undecanoic acid sodium salt as a D / L mixture of 1: 1; Na salt to compound 8

Connection 16)

rac-2-amino-3-ethyl-hexanoic acid sodium salt as a D / L mixture of 1: 1; Na salt of compound 7

Example 2)

Process for the production of synthesized or inventive

links

The following examples serve to explain the process according to the invention in more detail.

The yields of the compounds produced are not optimized.

All temperatures are uncorrected. Silica gel 60 (0.040-0.063 mm) from E. Merck, Darmstadt, was used as the stationary phase for column chromatography.

The thin-layer chromatographic investigations were carried out with ready-made HPTLC plates, silica gel 60 F 254, from E. Merck, Darmstadt.

The mixing ratios of the eluents for all chromatographic tests are always given in volume / volume.

The indication ether means diethyl ether.

Unless otherwise stated, petroleum ether with a boiling range of 50 ° C-70 ° C was used.

Regulation 1

Representation of compound 6 (prod. 1):

rac-2-amino-3-methyl-decanoic acid hydrochloride as a D / L mixture of 1: 1; Compound 6 (Prod. 1)

1. Glycine ethyl ester hydrochloride (Prod. 2)

247.3 g of thionyl chloride and 130 g of glycine were added to 1000 ml of ethanol at -10 ° C. After the ice bath was removed, a further equivalent of glycine was added in portions. The mixture was then stirred under reflux for 2 hours. After cooling to room temperature, the excess alcohol and the thionyl chloride were removed on a rotary evaporator. The white solid obtained was mixed twice with ethanol and this was again removed on a rotary evaporator in order to completely remove adhering thionyl chloride. After recrystallization from ethanol, 218.6 g (90.4% of theory) of the title compound (product 2) were obtained.

2. Formylaminoacetic acid ethyl ester (prod. 3)

218 g of glycine ethyl ester hydrochloride (Prod. 2) were suspended in 1340 ml of ethyl formate. 223 mg of toluenesulfonic acid were added and the mixture was heated to reflux. Now 178 g of triethylamine were added dropwise to the boiling solution and the reaction solution was stirred under reflux overnight. After cooling to RT, the precipitated ammonium chloride salt was filtered off, the filtrate was concentrated to about 20% of the original volume and cooled to -5 ° C. The again precipitated ammonium chloride salt was filtered off, the filtrate was again concentrated and distilled at 1 mbar. This gave 184 g (90.3% of theory) of the title compound (Prod. 3). 3. Isocyanacetic acid ethyl ester (prod. 4)

50 g of ethyl formylaminoacetate (Prod. 3) and 104 g of diisopropylamine were placed in 400 ml of dichloromethane and cooled to -3 ° C. Then 70.1 g of phosphoryl chloride in 400 ml of dichloromethane were added dropwise and the mixture was then stirred for a further hour at this temperature. After the ice bath was removed and room temperature was reached, it was carefully hydrolyzed with 400 ml of 20% sodium carbonate solution. After stirring at RT for 60 minutes, 400 ml of water and then 200 ml of dichloromethane were added. The phases were separated and the organic phase was washed twice with 100 ml of 5% Na ₂ CO ₃ solution and dried over MgSO ₄ . The solvent was evaporated on a rotary evaporator and the remaining brown oil was distilled. 34.16 g (79.3% of theory) of the title compound (product 4) are thus obtained.

4. (£) / (Z) -2-formylamino-3-methyldec-2-enoic acid ethyl ester (prod. 5)

A solution of 22 g of isocyanacetic acid ethyl ester (Prod. 4) in 49 ml of THF was added dropwise to a suspension of 23 g of potassium tert-butoxide in 148 ml of THF at -70 ° C. to -60 ° C. while stirring. The mixture was allowed to stir for 20 minutes; then 27.7 g of 2-nonanone in 24 ml of THF were added dropwise at this temperature. After warming to RT, 11.7 ml of glacial acetic acid were added. 15 min after the addition of glacial acetic acid (TLC control: ether: hexane 4: 1), the solvent was evaporated. The residue was mixed with 300 ml of diethyl ether and 200 ml of water. The organic phase was separated and the aqueous phase was washed twice with 120 ml of ether each time. The combined organic phases were washed with 80 ml of 2N NaHCO ₃ solution and rocked over MgSO ₄ . The solvent was then evaporated. The crude product thus obtained was digested with 200 n-hexane. The solid was filtered off, washed four times with 80 ml of hexane each time and dried in an oil pump vacuum. This gave 34.8 g (69.9% of theory) of (£) - and (Z) -2-formylamino-3-methyldec-2-enoic acid ethyl ester (Prod. 5) (E / Z ratio: 1: 1 ) as a white solid.

5. Ethyl 2-formylamino-3-methyl-decanoate as a D / L mixture of 1: 1 (prod. 6)

5 g (£) / (Z) -2-formylamino-3-methyldec-2-enoic acid ethyl ester (prod. 5) (E / Z ratio: 1: 1) were dissolved in 100 ml of methanol at RT under a nitrogen atmosphere and then mixed with 0.25 g Pd-C (5%). The mixture was then hydrogenated under a hydrogen atmosphere. After the hydrogenation had ended (TLC control: ether: hexane 4: 1), the mixture was filtered off with suction through 50 ml of filter earth and the filter earth was washed with methanol. The organic phase was freed from the solvent. 5.1 g (86% of theory) of ethyl 2-formylamino-3-methyl-decanoate were thus obtained as a D / L mixture of 1: 1 (prod. 6).

6. rac-2-amino-3-methyl-decanoic acid hydrochloride as a D / L mixture of 1: 1; Compound 6 (Prod. 1)

5 g of 2-formylamino-3-methyl-decanoic acid ethyl ester as a D / L mixture of 1: 1 (6) were added to 300 ml of 6N hydrochloric acid at RT and then stirred under reflux for 24 h (TLC control: dichloromethane: methanol: glacial acetic acid : 35: 5: 3). After cooling to RT, stirring was continued with ice cooling. The precipitated white solid was filtered off, washed with ether and then dried in vacuo. 4.2 g (94.9% of theory) of rac-2-amino-3-methyl-decanoic acid hydrochloride were thus obtained as a D / L mixture of 1: 1; Compound 6 (Prod. 1)

Regulation 2:

Representation of compound 1; (Prod. 7)

rac-2-amino-3-methyl-heptanoic acid hydrochloride as D / L: mixture of 1: 1; Connection 1 (Prod. 7)

By using 2-hexanone instead of 2-nonanone in method 1, rac-2-amino-3-methyl-heptanoic acid hydrochloride was obtained as a D / L: mixture of 1: 1; Connection 1 (Prod. 7) Regulation 3:

Representation of compound 2 (prod. 8)

rac-2-amino-3-methyl-octanoic acid hydrochloride as a D / L mixture of 1: 1; Connection 2 (Prod. 8)

By using 2-heptanone instead of 2-nonanone in method 1, rac-2-amino-3-methyl-octanoic acid hydrochloride was obtained as a D / L mixture of 1: 1; Connection 2 (Prod. 8)

Regulation 4: Representation of compound 7 (prod. 9)

rac-amino-3-ethyl-hexanoic acid hydrochloride as a D / L mixture of 1: 1; Connection 7 (Prod. 9)

By using 3-hexanone instead of 2-nonanone in method 1, rac-amino-3-ethyl-hexanoic acid hydrochloride was obtained as a D / L mixture of 1: 1; Connection 7 (Prod. 9) Regulation 5:

Representation of compound 3: (Prod. 10)

rac-D-2-amino-3-methyl ~ octanoic acid hydrochloride; Compound 3; (Prod. 10)

The procedure corresponded to that in regulation 1; Part 1, 2, 3, 4; only the 2-nonanone used in regulation 1 was replaced by 2-heptanone. Differences occurred from regulation 1 part 5.

5) ethyl D-2-formylamino-3-methyl-octanoate (Prod. 11)

5 g (£) / (Z) -2-formylamino-3-methyloct-2-enoic acid ethyl ester (Prod. 12) (E / Z ratio: 1: 1) were dissolved in 100 ml of methanol at RT under a nitrogen atmosphere and then mixed with 0.25 g Pd-C (5%). The mixture was then hydrogenated under a hydrogen atmosphere. After the hydrogenation had ended (TLC control: ether: hexane 4: 1), the batch was filtered off with suction over 50 ml of filter earth and the filter earth was washed with methanol. The organic phase was freed from the solvent and chromatographed on silica gel with ether / hexane (4: 1). As The first fraction gave 2.2 g (40% of theory) of ethyl D-2-formylamino-3-methyl-octanoate (Prod. 11).

6. rac-D-2-amino-3-methyl-octanoic acid hydrochloride; Connection 3 (Prod. 10)

2.2 g of ethyl D-2-formylamino-3-methyl-octanoate (Prod. 11) were added to 300 ml of 6N hydrochloric acid at RT and then stirred under reflux for 24 h (TLC control: dichloromethane: methanol: glacial acetic acid: 35: 5: 3 ). After cooling to RT, stirring was continued with ice cooling. The precipitated white solid was filtered off, washed with ether and then dried in vacuo. This gave 2 g (90% of theory) of rac-D-2-amino-3-methyl-octanoic acid hydrochloride; Compound 3 (Prod. 10).

Regulation 7:

Representation of compound 4 (prod. 13) and compound 5 (prod. 14)

The procedure corresponded to that in regulation 1; Part 1, 2, 3, 4; only the 2-nonanone used in regulation 1 was replaced by 2-octanone. Differences occurred from regulation 1 part 5.

5) ethyl D-2-formylamino-3-methyl-nonanoate (Prod. 15) and ethyl L-2-formylamino-3-methyl-nonanoate (Prod. 16)

5 g of (E) / (Z) -2-formylamino-3-methylnon-2-enoic acid ethyl ester (Prod. 17) (E / Z ratio: 1: 1) were dissolved in 100 ml of methanol at RT under a nitrogen atmosphere and then mixed with 0.25 g Pd-C (5%). The mixture was then hydrogenated under a hydrogen atmosphere. After the hydrogenation had ended (TLC control: ether: hexane 4: 1), the batch was filtered off with suction over 50 ml of filter earth and the filter earth was washed with methanol. The organic phase was freed from the solvent and chromatographed on silica gel with ether / hexane (4: 1). The first fraction obtained was 2.2 g (40% of theory) of ethyl D-2-formylamino-3-methyl-nonanoate (Prod. 15) and the second fraction was 1 g (22% of theory) of L-2-formylamino -3-methyl-nonanoic acid ethyl ester (Prod. 16) 6. rac-D-2-amino-3-methyl-nonanoic acid hydrochloride; Compound 4 (Prod. 13) and rac-L-2-amino-3-methyl-nonanoic acid hydrochloride; Compound 5 (Prod. 14)

1 g of D-2-formylamino-3-methyl-nonanoic acid ethyl ester (Prod. 15) or 1 g of L-2-formylamino-3-methyl-nonanoic acid ethyl ester (Prod. 16) were added at RT to 150 ml of 6N hydrochloric acid and then for 24 h Reflux stirred (TLC control: dichloromethane: methanol: glacial acetic acid: 35: 5: 3). After cooling to RT, stirring was continued with ice cooling. The precipitated white solid was filtered off, washed with ether and then dried in vacuo. This gave 0.9 g (90% of theory) of rac-D-2-amino-3-methyl-nonanoic acid hydrochloride; Compound 4 (Prod. 13) or 0.9 g (90% of theory) of rac-L-2-amino-3-methyl-nonanoic acid hydrochloride; Compound 5 (Prod. 14).

Pharmacological examinations

Example 3: Binding Assay

The binding assay uses gabapentin to test the binding and affinities of the selected compounds. The affinity of the compounds according to the invention is measured by the displacement of gabapentin from its binding site. If the selected compounds can displace gabapentin from its binding site, it can be expected that it will develop pharmacological properties comparable to gabapentin, for example as an agent against pain or epilepsy. The compounds of the invention show good gabapentin inhibition in this assay. The examined In this biochemical assay, compounds therefore have an affinity for the previously unknown gabapentin binding site.

An ICso value of 60 nM was determined for gabapentin. Some of the synthesized compounds of general formula 1 show a significantly better affinity than the comparison substance gabapentin (see Table 1).

Table 1 :

Example 4:

Analgesia test in the writhing test on the mouse The antinociceptive activity of the compounds according to the invention was modified in the phenylquinone-induced writhing test, modified according to IC Hendershot, J. Forsaith, J.Pharmacol. Exp. Ther. 125, 237-240 (1959) on the mouse. Male NMRI mice weighing 25-30 g were used for this. Groups of 10 animals per substance dose were given 10 minutes after intravenous administration of a compound according to the invention to 0.3 ml / mouse of a 0.02% strength aqueous solution of phenylquinone (phenylbenzoquinone, from Sigma, Deisenhofen; preparation of the solution with addition of 5% ethanol and storage in Water bath at 45 ° C) applied intraperitoneally. The animals were placed individually in observation cages. The number of pain-induced stretching movements (so-called writhing reactions = pushing through the body with stretching of the rear extremities) was counted 5-20 minutes after the phenylquinone administration using a push-button counter. Animals that received physiological saline iv and phenyylquinone iv were included as a control.

All substances were tested in the standard dose of 10 mg / kg. The percentage inhibition (% inhibition) of the writhing reactions by a substance was calculated using the following formula:

% Inhibition = 100 - [WR treated animals / WR control X 100]

All investigated compounds according to the invention showed an effect in the writhing test.

The results of selected writhing tests are summarized in Table 2. Gabapentin shows an ED ₅₀ of 38 mg / kg.

Table 2: Analgesia test in the writhing test on the mouse

Example 5:

Microiontophoresis in anesthetized rats

(Derivation of evoked ascending potentials of individual cells in the dorsal horn of the spinal cord of anesthetized rats after microiontophoretic application of exicatoric amino acids (EAA ^'s ))

Male rats (Sprague Dawley, Janvier) with a body weight of 280g to 350g were used. To initiate anesthesia, inhalation anesthesia was carried out with 4.0-5.0% halothane in a mixture of 200 ml / min oxygen (O ₂ ) and 400 ml / min nitrous oxide (N ₂ O) in a plexiglass anesthetic box. During the preparation phase, the halothane concentration was reduced to 1.0-1.5%. For the rest of the experiment, inhalation anesthesia was then replaced by bolus application of 40 mg / kg chloralose in 3.5% Haemaccel solution (iv) and maintained by continuous infusion of 20 mg / kg / 2.0 ml / h chloralose. After induction anesthesia (4.0-5.0% halothane see above), the tracheal tube was tied in at a 2.5% halothane concentration using a syringe cylinder (20ml Ommnifix, Luer) that was shortened to approx. 20mm and placed over the mouth and nose of the animals. The halothane concentration has now been reduced to approximately 1.5%. Exhaled air was removed via a closed system. A PE-20 (1.09 * 0.38mm) catheter was inserted into the dorsal branch of the left jugular vein to apply test substances, and a PE-50 tube (0.9569mm * 0.58mm) was inserted into the left one as a catheter for continuous monitoring of blood pressure Carotid artery introduced. For the laminectomy, the animals were now placed in the prone position. There was an incision along the midline from the neck to the pelvic area. A drop in blood pressure that was frequently observed afterwards was treated with adrenaline (xylocitin 2% with adrenaline 0.001%, Jenapharm) by applying lidocaine HCI locally. The superficial layers of tissue on both sides of the spine were removed in the area of the vertebral bodies from sacral 2 (S2) to thoracic 8 (Th8). The muscles belonging to the vertebral bodies were also removed by careful scraping with a scalpel. The actual laminectomy begins with vertebral body L2 (lumbar 2) after removal of the spinal process from vertebra L3 and extends into the area rostral from TH8 to where the large dorsal vein turns laterally and caudally. The bones of each vertebral body were Carefully removed in small steps using fine bone rippers (rongeurs). The muscles around TH8 / 9 and L1 / S2 were also removed so that immobilization clamps could be attached later. Exposed tissue was protected against drying out by applying 0.9% NaCl solution or thin PVC strips. The temperature was controlled in all animals from the beginning of the catheterization to the end of the experiment using an electronically controlled heating pad and rectal thermal sensor between 36.5 ° C and 37.5 ° C (Harvard Homeothermic Blanket System). After a laminectomy, the animals were transferred to a self-made fixation frame. The horizontal fastening was carried out using modified clamps (Harvard General Purpose Clamp) in the area T8 / 9 and S2. The lateral fixation was done by side clamps in the area of the intended lead (segment L5 / 6). A pool was formed by skin pulled up and attached to the fixation frame by threads. The dura mater was removed over the entire exposed area and the spinal cord was covered with liquid paraffin oil (pool). After switching from halothane to chloralose, the animals spontaneously breathed additional oxygen-enriched room air (200 ml / min). The blood pressure was continuously monitored via the arterial catheter, which was connected to a pressure transmitter (Elcomatic EM751A, filled with paraffin oil), and the blood pressure preamplifier NL108 (Neurolog) (Spike 2, Cambridge Electronic). The systolic pressure should be close to 100 mmHg or above. In addition to blood pressure, the local blood circulation was assessed visually, with a rosy skin color on the paws indicating normal microcirculation. An intact blood supply to the spinal cord was seen in a cherry red dorsal vein and rapid blood flow in the smaller veins. Self-made multibarrel glass microelectrodes were used to derive action potentials and eject excitatory amino acids (EAA s). The outer angled capillaries were temporarily fixed with shrink tubing (Shrink-KON HSB 250 6.4 to 3.2 mm; RS order no. RS 208- 9005) so that the central capillary protrudes approx. 35 mm. The final fixation was now carried out using fast-curing epoxy adhesive (RS Quick Set Epoxy Adhesive RS 850-940). These electrode blanks were processed further. A usable electrode has a diameter of 15-20μm at a distance of approx. 100μm from the tip. Before the individual capillaries were filled, the tips of the electrodes were checked under a microscope (Olympus BH-2 microscope; Zeiss Measuring eyepiece; magnification x 20; x 40) broken back to a diameter of 3-5μm. The electrode tips were brought into the immediate vicinity (mirror image of the electrode visible) of a glass rod and broken by carefully tapping the fine adjustment screw of the cross table. The electrodes were filled with Microfil MF34G syringe capillaries (WPI) using 1 ml Ommnifix-F (B.Braun) disposable syringes and stored in a self-made holder between experiments in the refrigerator (4-6 ° C). Good electrodes can be used several times after a corresponding check. The individual capillaries (barrels) were marked in color with a permanent fiber pen and filled accordingly.

Barrel 1: Mark: red; NMDA 100mM in 100mM NaCI; pH 7.5 - 8.0 barrel 2: marrow: green; AMPA 10mM in 200mM NaCI; pH 7.5 - 8.0 barrel 3: Mark: blue; Kainate 5mM in 200mM NaCI; pH 7.5 - 8.0 barrel 4: marrow: without; Current balance 150mM NaCI

Barrel 5: Mark: without; Extracellular lead 3.5M NaCI

To protect against dehydration, all barrels were sealed with thin paraffin oil (slightly stained with Sudan black). Before use, the electrical resistance of the central capillary in NaCI solution against a silver-silver chloride pellet should be measured and should be between 1 and 5 Mohm (measuring device: Multimeter Voltcraft 4550B; measuring range 20MOhm). It has proven to be practical to use the resistance of the outer barrels only after inserting the electrode (depth approx. 200-400μm) into the spinal cord of the test animal using the IP-2 microiontophoresis pumps. Usable values are around 20-100MOhm. Electrodes with too high resistances (especially the central capillary) can be broken back under microscopic control and checked again.

If gabapentin was examined in this test model, this substance showed a dose-dependent and selective inhibition of the AMPA response of spinal neurons in the dorsal horn in the spinal cord of anesthetized rats. The ED50 was 106 mg / kg. Gabapentin has no affinity for the AM PA receptor. An identical behavior was observed for connection 16. This compound also showed a selective inhibition of the AMPA response without having an AM PA affinity. The ED50 was 60 mg / kg. The following literature provides a further overview of the experimental procedure and is therefore fully part of the disclosure of this invention:

Chizh BA, Cumberbatch MJ, Herrero JF, Stirk GC, Headley PM. Stimulus intensity, cell excitation and the N-methyl-D-aspartate receptor component of sensory responses in the rat spinal cord in vivo. Neuroscience. 1997 Sep; 80 (1): 251-65.

Chizh BA, Headley PM. Thyrotropin-releasing hormone (TRH) -induced facilitation of spinal neurotransmission: a role for NMDA receptors. Neuropharmacology. 1994 Jaπ; 33 (1): 115-21.

Example 6:

Mechanical hyperalgesia after paw incision on the rat (Paw incision-

Model):

1 INTRODUCTION

In this model, wound pain around an incision on the plantar side of a rat's rear paw is examined as a model for postoperative pain (Brennan, T.J., Vandermeulen, E.P., Gebhart, G.F., Pain (1996) 493-501). For this purpose, the pull-away latency is determined after punctiform mechanical stimulation with an electronic von Frey filament. After the paw incision, a mechanical hyperalgesia develops that remains stable for several days.

2. Material and methods

paw incision:

Male Sprague Dawley rats (body weight 200-300 g) are used. Under halothane anesthesia, a 1 cm long incision, starting 0.5 cm from the proximal end of the heel, is made through the skin, fascia and plantaris muscle and closed with two sutures. 3. Carrying out the experiment:

Using an electronic von Frey filament (Digital Transducer Indicator Model 1601 C, IITC ine.), The pull-away threshold of the paw, expressed in grams, is determined after punctiform mechanical stimulation. For this purpose, the withdrawal threshold is measured five times per measuring point at intervals of 30 seconds and the individual median is determined, on the basis of which the mean value of the animal collective is calculated. 10 rats are tested per experimental animal group.

To investigate primary hyperalgesia, the withdrawal threshold is determined on the ipsilateral paw in the immediate vicinity of the incision and in the same position on the contralateral paw. The measurements are taken twice before the surgical intervention to determine the pre-test mean, postoperatively immediately before the substance is administered and at different times after substance administration (usually 15, 30, 60, 90, 120 min per application). The examinations of substances can take place within a period of 2 hours to 3 days postoperatively.

4. Evaluation:

THE EFFECTIVENESS OF A SUBSTANCE IS DESCRIBED BY THE INFLUENCE OF THE DEPTH OF THE IPSILATERAL PAW:

% MPE = 100 - [(WTH SUB - WTH _PRA-OP ) / (WTH _POST - _OP - WTH _PRA . _OP ) * 100]

MPE: Maximum Possible Effect

WTH _SUB : DRIVING THRESHOLD ACCORDING TO SUBSTANCE

WThpr _a - _o p: withdrawal threshold before the operation (pre-test average)

WThpost-op'- withdrawal threshold after surgery and before substance administration

The Mann-Whitney U test is used for the significance calculation (p <0.05). In the case of dose-dependent effects, the ED 50 value is determined using a regression analysis.

5. Results: The results are summarized in Table 5:

Table 3: Analgesia test in the Paw Incision rat

Gabapentin shows a value of 66% MPE at 100 mg / kg.

Example 7: Parenteral application form.

38.5 g of compound 7 are dissolved in 1 liter of water for injections at room temperature and then adjusted to isotonic conditions by adding anhydrous glucose for injections.

Claims

claims

1. Use of an amino acid of the general formula

, in which

R ^ and R ^ are each independently selected from C ^ Q alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; Aryl, Cβ- ^ _Q cycloalkyl or heteroaryl, each unsubstituted or mono- or polysubstituted; or

R1 and R2 together form a ring and mean (CH2) 3_6, unsuubbssttiittuuiieertrt ooddeerr unsubstituted, in which 0-2 C atoms can be replaced by S, O or NR ⁴ ,

optionally in the form of their racemates, their pure stereoisomers, in particular enantiomers or diastereomers, or in the form of mixtures of the stereoisomers, in particular the enantiomers or diastereomers, in any mixing ratio. in the form shown or in the form of their acids or their bases or in the form of their salts , in particular the physiologically tolerated salts, or in the form of their solvates, in particular the hydrates; for the manufacture of a medicament for the treatment of pain, in particular neuropathic, chronic or acute pain, epilepsy and / or migraine

or

for the manufacture of a medicament for the treatment of hot flashes, postmenopausal complaints, amyotropic lateral sclerosis (ALS), reflex sympasthetic dystrophy (RSD), spastic paralysis, restless leg syndrome, acquired nystagmus; psychiatric or neuropathological disorders, such as bipolar disorders, anxiety, panic attacks, mood swings, manic behavior,

Depression, manic-depressive behavior; painful diabetic neuropathy, symptoms and pain due to multiple sclerosis or Parkinson's disease, neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Parkinson's disease and epilepsy; gastrointestinal damage; erythromelalgic or post-poliomyelitic pain, trigeminal or post-herpetic neuralgia; or as an anticonvulsant, analgesic or anxiolytic.

2. Use according to claim 1, characterized in that

R ¹ and R ^ are each independently selected from C-μ- _{j Q} - alkyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; Aryl, C 1-6 -cycloalkyl or heteroaryl, each unsubstituted or substituted one or more times; or

3. Use according to one of claims 1 or 2, characterized in that

one of the radicals R ¹ and R ² in particular methyl, ethyl n-propyl or i-propyl, in each case unsubstituted or mono- or polysubstituted; means and the other of the radicals R ^ and R ² C .- _{j Q} - l yl, especially n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl , Heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; or aryl or heteroaryl, in particular phenyl, naphthyl, furanyl, thiphenyl, pirimidinyl or piridinyl, in each case unsubstituted or simply (preferably substituted with OCH ₃ , CH ₃ , OH, SH, CF ₃ , F, Cl, Br or I); or C ₃ _ ₈ - cycloalkyl, in particular cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in each case unsubstituted or simply substituted; means

preferably

one of the remains in particular methyl, ethyl n-propyl or i-propyl, in each case unsubstituted or mono- or polysubstituted; means and the other of the radicals R ^ and R ² C ^ -JQ-alkyl, especially n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; or C4_7-cycloalkyl, preferably cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in particular cyclobutyl, cyclopentyl or cyclohexyl, in each case unsubstituted or simply substituted; means

in particular one of the radicals R ^ and R ² C- _j - ^ - alkyl, in particular methyl, ethyl n-propyl or i-propyl, each unsubstituted or mono- or polysubstituted; means and the other of the radicals R ^ and R ² C3_- | o- l yl, in particular n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, Heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; means.

4. Use according to one of claims 1 or 2, characterized in that

R1 and R2 together form a ring and are (^ 2) 5, substituted or unsubstituted, so that a substituted or unsubstituted cyclohexyl is formed,

preferably

5. Use according to one of claims 1 to 4, characterized in that a compound or group of compounds is excluded from use under at least one of the following conditions:

R ¹ and R ² are simultaneously CH ₃ ,

Or one of R and R is CH ₃ and the other is C ₂ H ₅ ,

"Or one of R ¹ and R ² is CH3 and the other substituted phenyl,

• or R1 and R2 together form a ring and thus mean (CH2) form a cyclopentyl ring, substituted or unsubstituted,

6. Use according to one of claims 1 to 5, characterized in that at least one amino acid used is selected from the following group:

β 2-amino-3-methyl-heptanoic acid

• 2-amino-3-methyl-octanoic acid »2-amino-3-methyl-nonanoic acid

• 2-amino-3-methy! Decanoic acid

• 2-amino-3-ethyl-hexanoic acid β 2-amino-3-methyl-undecanoic acid

• 2-amino-3-cyclobutyl-butanoic acid

• 2-amino-3-cyclohexyl-butanoic acid β amino- (3-methyl-cyclohexyl) -ethanoic acid

»Amino- (2-methyl-cyclohexyl) ethanoic acid

optionally in the form of their racemates, their pure stereoisomers, in particular enantiomers or diastereomers, or in the form of mixtures of the stereoisomers, in particular the enantiomers or diastereomers, in any mixing ratio; in the form shown or in the form of their acids or their bases or in the form of their salts , in particular the physiologically tolerated salts, or in the form of their solvates, in particular the hydrates; preferably the hydrochloride or sodium salt.

7. amino acids of the general formula I,

I

, in which one of the radicals R ¹ and R ^{2 is} C _1-8 alkyl, in particular methyl, ethyl n-propyl or i-propyl, in each case unsubstituted or mono- or polysubstituted; means and the other of the radicals R ¹ and R ² C3_- _| Q-alkyl, especially n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or a - or substituted several times; or aryl or heteroaryl, in particular phenyl, naphthyl, furanyl, thiphenyl, pirimidinyl or piridinyl, in each case unsubstituted or simply (preferably substituted with OCH ₃ , CH ₃ , OH, SH, CF ₃ , F, Cl, Br or I); or C ₃ . ₈ - cycloalkyl, in particular cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in each case unsubstituted or simply substituted; means

optionally in the form of their racemates, their pure stereoisomers, in particular enantiomers or diastereomers, or in the form of mixtures of the stereoisomers, in particular the enantiomers or diastereomers, in any mixing ratio; in the form shown or in the form of their acids or their bases or in the form of their salts , in particular the physiologically tolerated salts, or in the form of their solvates, in particular the hydrates.

8. Amino acid according to claim 7, characterized in that

one of the radicals R ^ and R ² Cι_3-alkyl, especially methyl, ethyl n-propyl or i-propyl, each unsubstituted or substituted one or more times; means and the other of the radicals R ¹ and R ² C3_ι o-alkyl, especially n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl , branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted; or C4_7-cycloalkyl, preferably cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, in particular cyclobutyl, cyclopentyl or cyclohexyl, in each case unsubstituted or simply substituted; means

preferably one of the radicals R ¹ and R ^{2 is} C 1 -C 4 -alkyl, in particular methyl, ethyl n-propyl or i-propyl, in each case unsubstituted or mono- or polysubstituted; means and the other of the radicals R ¹ and R ² in particular n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl or octyl, branched or unbranched, saturated or unsaturated, unsubstituted or mono- or polysubstituted ; means.

9. Amino acids according to one of claims 7 or 8, characterized in that they are selected from the following group:

• 2-amino-3-methyl-heptanoic acid

• 2-amino ~ 3-methyl-octanoic acid

• 2-amino-3-methyl-nonanoic acid

• 2-amino-3-methyl-decanoic acid

• 2-amino-3-ethyl-hexanoic acid

• 2-amino-3-methyl-undecanoic acid

• 2-amino-3-cyclobutyl-butanoic acid β 2-amino-3-cyclohexyl-butanoic acid

10. Medicaments containing at least one amino acid according to one of the

Claims 7 to 9, and optionally suitable additives and / or auxiliaries and / or optionally further active ingredients.

11. Medicament according to claim 10, characterized in that an amino acid contained according to one of claims 7 to 9, as a pure diastereomer and / or enantiomer, as a racemate or as a non-equimolar or equimolar mixture of the diastereomers and / or enantiomers is present.

12. Use of an amino acid according to any one of claims 7 to 9 for the manufacture of a medicament for the treatment of pain, in particular neuropathic, chronic or acute pain, epilepsy and / or migraine

or

for the manufacture of a medicament for the treatment of hot flashes, postmenopausal complaints, amyotropic lateral sclerosis (ALS), reflex sympasthetic dystrophy (RSD), spastic paralysis, restless leg syndrome, acquired nystagmus; psychiatric or neuropathological disorders, such as bipolar disorders, anxiety, panic attacks, mood swings, manic behavior, depression, manic-depressive behavior; painful diabetic neuropathy, symptoms and pain due to multiple sclerosis or Parkinson's disease, neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Parkinson's disease and epilepsy; gastrointestinal damage; erythromelalgic or post-poliomyelitic pain, trigeminal or post-herpetic neuralgia; or as an anticonvulsant, analgesic or anxiolytic.

13. Use according to one of claims 1 to 6 or 12, characterized in that an amino acid used according to one of claims 7 to 9, as a pure diastereomer and / or enantiomer, as a racemate or as a non-equimolar or equimolar mixture of the diastereomers and / or enantiomers.

14. A method for producing an amino acid according to one of claims 7 to 9, comprising the following steps:

a) Deprotonation of the Isocyanessigsäurethylesters with bases and subsequent reaction with ketones of the general formula 2, in which R1 and R2 have the meaning given in claim 7, preferably in tetrahydrofuran, leads to (E, Z) -2-formylaminoacrylic acid ethyl esters of the general formula 3 .

b) reaction of (E, Z) -2-formylaminoacrylic acid ethyl esters of the general formula 3 with Pd / H ₂ leads to formylamino-ethyl ester of the general formula 4,

1

Reaction of the formylamino-ethyl ester of the general formula 4 with acid, preferably hydrochloric acid, leads to the amino acids of the general formula 1 or formula I, optionally followed or interrupted by diastereomer separation at a suitable stage by means of HPLC, column chromatography or crystallization or followed by enantiomer separation by means of HPLC, column chromatography or

Crystallization.