DK149841B - METHOD OF ANALOGUE FOR THE PREPARATION OF ALFA-FLUOR-METHYL-ALFA AMINOALCANIC ACIDS OR PHARMACEUTICAL ACCEPTABLE ACID ADDITION SALTS. - Google Patents

Description

149841 i

The present invention relates to an analogous process for the preparation of novel substituted o-fluoromethyl-α-aminoalkanoic acids of the general formula I set forth in the preamble of claim 1 in the form of optically active compounds or any or racemic mixtures of such compounds or pharmaceutically acceptable acid addition salts. thereof.

An unsubstituted ot-fluoromethyl-α-aminoalkanoic acid is known, namely 2-fluoromethylalanine of the formula

CH0F

I 2

CIU-C-COOH

3 I

"> 2 (A) (Kollonitsch et al., J. Org. Chem. 4JD, 3808-9 (1975)).

The compound (A) prepared by fluorohydroxylation of the corresponding 2-hydroxymethylalanine is not believed to have any specific biological effect.

ot-Methylamino acids such as La-methyl-3,4-dihydroxyphenyl-alanine (α-methyldopa, an antihypertensive agent) are known to inhibit decarboxylase (Goodman et al., The Pharmacological Basis of Therapeutics, Mac Milian Company, New York, New York 1970, p. 577, Canadian Patent No. 737907).

The novel oi-fluoromethyl-α-aminoalkanoic acids perceived by this invention have an inhibitory effect on decarboxylase which is significantly stronger than that known from the α-methylamino acids.

Pharmaceutically acceptable acid addition salts of compounds of formula I can be formed with appropriate organic or inorganic acids. Preferred salts of inorganic acids are the hydrohalides, ie. hydrochlorides, iodides and bromides.

The compounds of formula I have a chiral center and thus can be present in optically active forms, i.e. as optical isomers. Such isomers are usually denoted by the symbols L and D, + and -, 1 and d, S and R or combinations thereof. Where no isomer designation is given for a compound name or formula, the name or formula denotes a mixture of isomers of the compound, both arbitrary and racemic mixtures.

Generally, S-configuration connections are preferred.

Preferably, the substituted alkyl group R is as defined in the characterizing portion of claim 3.

Preferred compounds of formula I are those in which R represents

H0 H

y ~ \ pc "2" W 2 --- i

The compounds of this invention have physiological and chemotherapeutic applications. The biological effect of these compounds is due to their significant inhibitory effect on decarboxylase. Decarboxylases are enzymes that act on α-amino acid substrates and induce decarboxylation, resulting in the formation of the corresponding amine. This can be illustrated by the following reaction scheme: U9841

L-CH-COoH decarboxylase L + CH

In 2 -: - i2 nh2 nh2 α-amino acid substrate ainin (L = alkyl or aromatically substituted alkyl)

By inhibiting this decarboxylation, one can modulate or inhibit the biosynthetic pathway to a number of biologically significant amines, which may have physiologically useful consequences. For example, dopa decarboxylase is inhibited by α-fluoromethyldopa, which can be used in combination with dopa to potentiate the latter's effect in the treatment of Parkinson's disease. α-Fluoromethylhistidine inhibits the biosynthesis of histamine via decarboxylation of histidine (ED5Q in mice ^ 0.4 mg / kg). Accordingly, it may be used, optionally in combination with histamine antagonists, for the prevention of gastric ulcer and for the treatment of allergic conditions. α-Fluoromethylornithine, by virtue of its inhibition of ornithine decarboxylase, can interrupt the biosynthesis of polyamines and is useful in the treatment of certain forms of neoplasm. α-Fluoromethylarginine is an effective antibacterial agent and α-fluoromethylglutamic acid stimulates the central nervous system.

Furthermore, the compounds of the present invention are very specific in their decarboxylase inhibition. This means that an α-fluoro-methyl-α-amino acid generally inhibits the decarboxylation of the corresponding α-fluoromethyl acid. For example, α-fluoromethyldopa inhibits the decarboxylation of dopa, α-fluoromethylhistidine inhibits the decarboxylation of histidine, etc. The compounds of the present invention are potent in-vivo irreversible inhibitors, while similarly known compounds, e.g. α-methylornithine and α-methylhistidine are reversible or weak inhibitors, cf. Tetrahedron Letters, 17, pp. 1455-1458 (1977), J. Hed. Chem. 18, 600 (1975) and Proc. Night. Acad. Sci. 73, 1626 (1976) and J. Hed. Chem. , 19, 945 (1975). α-Chloromethylhistidine is relatively unstable at neutral and basic pH, cf.

Bouclier et al., Biochem. Pharm. J52, (10), 1553-1556 (1983). α-Hethylhistidine is a weak inhibitor and α-butylhistidine has no inhibitory effect. In contrast, α-fluoromethylhistidine has a stronger effect than the ot-methyl analog and is irreversible.

By conventional in vitro experiments, it has been shown that representative compounds have a decarboxylase inhibitory effect, cf. Biochemical Pharmacology 32, (10) (1983) pp. 1553-1556, and Br. J. Pharmac. 2 ° (1980) p.

571-576.

In addition, α-fluoromethyl 1-3,4-dihydroxyphenylalanine, ot-fluoromethyl-tyrosine and α-fluoromethyl-metatyrosine have been shown to have antihypertensive effects. This effect is determined by observing the antihypertensive effect (lowering of blood pressure) of administering (oral or parenteral) high blood pressure rats to the compound in question. The observed effect shows that the compounds can be used as antihypertensive agents for people with high blood pressure when administered in amounts by suitable administration forms. These forms of administration comprise well-known, pharmaceutically acceptable diluents.

The process according to the invention is peculiar to the characterizing part of claim 1.

Thus, the compounds of this invention are prepared by reaction of an α-hydroxymethyl-α-amino acid with SF₂ in liquid HF, as illustrated by the following reaction scheme:

CHo0II CH? F

I 2 I 2

R - <p —- COOH SF ^ / HF R— ~ C COOH

KH2 I® 2

The reaction is generally carried out at temperatures in the range of approx. -80 ° C to approx. 20 ° C. This general reaction is also referred to as "fluorohydroxylation" and is described in J. Org. Chem. 40, 3809 (1975).

To promote the course of the reaction, BF ^ or AlCl ^ can be used, since it has been found that the fluorohydroxylation of certain aryl-substituted ce-hydroxymethyl-α-amino acids is substantially promoted by using BF ^ or AlCl ^ as reactant with SF SF. In particular, this represents an improved process for preparing a compound of the formula

CHpF

i l ^

Rx -CH2-C-COOH (II) nh2. .

wherein R · * · is an aryl group, reacting a compound of formula III

CHoOH

In 2 R1 - ~ CHn-C-COOH (III) nh2 with a) SF ^ and b) BF ^ or AlCl-j in liquid HF at temperatures ranging from ca. -80 ° C to approx. 20 ° C. R 1 is an aryl group which e.g. may be 149841 6 »o'W '.

nz ~ 7r \ or \ y- · 9

H0 H

© 7.0? · · ““ Ar, Η _ Η N "preferred R 2 groups are

HOn_ H

Ηα / 7Λ ___ & .—. · W '^ .W "° 9 {v il

N-I

This process is preferably carried out at atmospheric pressure, although higher pressures can also be used. The preferred temperatures are in the range of approx. -80 ° C to approx. 0 ° C. You can perform the reaction by adding SF ^ and BF ^ (or AlCl ^) to the formula III / HF system immediately, or you can start by adding SF ^ to the system, allow the reaction to proceed for some time, and then add BF or AlCl 2 to the mixture and allow the reaction to proceed. The use of BF ^ or AlCl-gives a significantly improved yield of the compound of formula III.

Acid addition salts of the subject compounds can be prepared in known manner by treating the free cn amino acid with a suitable acid, usually in a suitable solvent.

149841 7

A single enantiomer of one of the compounds of this invention can be obtained by (1) separating the racemic fluorinated amino acid into optical isomers using well known separation methods or by (2) dividing the α-hydroxy-methyl-α-amino acid used as starting material. , in the optical isomers and then the enantiomeric acid is fluorinated. A common method for separating enantiomers consists of forming a salt of the α-amino acid with an optically active base and then extracting the specific enantiomer from the salt.

The invention is further illustrated by the following examples.

All temperature indications are in ° C. The fluoro-dehydroxylations described are carried out in reactors made from KEL-F® EXAMPLE 1

Preparation of R, S-α- (fluoromethyl) -3-hydroxytyrosine

CH-R

^ i

HO -sy 71-CIIO-C - COOH

In IIA \ NH2 1.5 g of R, S-α- (hydroxymethyl) -3-hydroxytyrosine hydrochloride (α-hydroxymethyl-DOPA HCl) was dissolved in 50 ml of anhydrous hydrogen fluoride under cooling in an ice-acetone bath. After removing the cooling bath, the solvent was evaporated by a stream of nitrogen. This operation converts the HCl salt of the starting material into the HF salt. (Alternatively, 1.3 g of the free amino acid can be used as starting material, thereby saving the above operation). The HF salt formed was redissolved by blowing the reactor with HF gas after cooling in a bath of dry ice and acetone. The flushing was continued until there were 30 ml of liquid HF in the reactor. SF 2 gas (1.2 ml, measured in liquid state at -78 ° C) was then thawed through, and the solids / acetone-Dadet Dlcv removed and replaced by a cooling bath at a temperature of -12 ° C. After standing for 15 hours, the solvent was removed by a stream of N 2, the residue was dissolved in 50 ml of 2.5 N HCl, evaporated to dryness in vacuo, and subjected to amino acid analysis with Spinco-Beckman amino acid analysis equipment. This analysis demonstrated the formation of α-fluoromethyl-3-hydroxytyrosine. The product R, S-α-fluoro-methyl-3-hydroxy-tyrosine is isolated by ion exchange chromatography in the same manner as described in Example 2 for S-α-fluoromethyl-3-hydroxy-tyrosine.

EXAMPLE 2

Preparation of S-ct-fluoromethyl-3-hydroxytyrosine A) Preparation of Ra-hydroxymethyl-3-hydroxytyrosine 50 g of 3- (3 ', 4'-diacetoxyphenyl) -2-acetamino-2-acetoxy-methylpropionic acid are added to 204 ml of 4 M aqueous KOH solution with stirring. After stirring for 1 hour (under nitrogen), the solution contains the potassium salt of 3- (31,4 * - dihydroxyphenyl) -2-acetamino-2-hydroxymethylpropionic acid in largely quantitative yield. By methylation with dimethyl sulfate, this product is transferred, without isolation, into 3- (3 ', 4'-dimethoxyphenyl) -2-acetamino-2-hydroxymethylpropionic acid. This operation is carried out at room temperature in the ^ atmosphere by dropwise addition (about 1 hour) of ca. 64 ml of dimethyl sulfate and approx. 148 ml of 4 M KOH solution with vigorous stirring. The reaction mixture is stirred for another hour and left overnight. Then, the mixture is acidified with 55 ml of concentrated hydrochloric acid at 5-10 ° C, extracted with 12 x 300 ml of ethyl acetate, dried over 50 ° C and evaporated under vacuum to give R, S-3- (3 ', 4 (-dimethoxyphenyl) -2-acetamino-2-hydroxymethylpropionic acid which is purified by recrystallization (from 1325 ml of acetonitrile. The melting point of the product is 154 - 156 ° C (decomposition).

29.1 g of strychnine is suspended in 1.12 liters of ethanol heated to reflux and 26.1 g of the product obtained above is added. The solution is allowed to cool and left overnight, whereby crystals of the iron salt of antimeric "A" (optical isomer) precipitate. (Melting point 193 - 194 ° C, "HM").

The mother liquor from the precipitate is evaporated to dryness under vacuum and recrystallized from 270 ml of ethanol. The hot solution is allowed to cool to room temperature and left for 3 hours, then refrigerated for 4 hours.

The crystals formed are collected on a filter and, after drying, recrystallized from acetonitrile to give the strychnine salt of antimeric "B" of 3- (3 ', 4'-dimethoxy-phenyl) -2-hydroxymethyl-propionic acid (mp 130-132 ° C during decomposition). Yield 17.5 g.

17 g of this iron salt is decomposed by dissolving it in 160 ml of water and adding 31 ml of 1 M aqueous NaOH.

The separated iron is removed by filtration and the solution is evaporated to a small volume under vacuum and transferred to a small ion exchange column (150 ml AG-X2 cation exchange resin Dowex'0 50, 200/400 mesh). Elution with water, followed by vacuum evaporation of the fractions exhibiting absorption, is investigated on a LKB UV spectrophotometer (UVICORD II - 8300) to give antimeric "B" of 3- (3 ', 4'-dimethoxyphenyl) -2-acetamino 2-hydroxy-methyl-propionic acid. This compound exhibits [a] p: 78.3 + 0.5 ° (c, 1.425 in 0.1 M aqueous NaOH).

The above compound is converted to the corresponding U9S41 10 stereoisomers of α-hydroxymethyl-3-hydroxy tyrosine as follows: 4.43 g of antimeric "B" is dissolved in 100 ml of concentrated HCl in a closed Fisher-Porter tube which is heated for 90 minutes. by immersing in an oil bath at a temperature of 130 ° C. The solvent is evaporated in vacuo and the said treatment with HCl is repeated. The residue obtained is R-α-hydroxymethyl-3-hydroxytyrosine hydrochloride.

B) Fluorohydroxylation 8 g of R-α-hydroxymethyl-3-hydroxytyrosine hydrochloride is charged to a 1 liter reaction vessel. This is immersed in a dry ice and acetone cooling bath, and 80 ml of liquid HF is condensed on top of the substrate. To remove the HCl present, the cooling bath is removed and the solvent (HF) is removed by purging with N 2. The container is lowered again into the cooling bath and HF gas is blown in until the liquid volume is approx. 250 ml. Then 6.2 ml of SF 2 (17.6 mmol / ml, v109 mmol) is bubbled through the solution, which is left for one hour, after which the cooling bath is replaced with an ethylene glycol bath (-16 ° C). After a further 22 hours standing, BF 2 gas is saturated and the solution is left at -16 ° C for 46 hours. The cooling bath is removed and the solvent is removed by vigorous N 2 purging. The residue is rapidly cooled in 100 ml of ice-cooled 2.5 M hydrochloric acid, evaporated in vacuo, dissolved in water and transferred to a cation exchange column using 2.2 liters of AG 50-X-8 resin (200/400 mesh, 74 - 37 u).

Elute with 0.25 M hydrochloric acid containing 5% methanol for approx. 8 1/2 hours as 7.2 liters of this solvent are pumped through the column. Continue with 7.2 liters of 0.4 M hydrochloric acid with 7.5% methanol for about 8 1/2 hours and finish with 0.6M hydrochloric acid with 10% methanol. Fractions of 22 ml, 10 glasses per ml are collected. series. The glasses in rows 45 - 66 contain the desired product. Evaporation in vacuo gives the HCl salt of the S-isomer of o-fluoro-methyl-3-hydroxytyrosine.

To separate the free amino acid, 4.826 g of the compound is dissolved in 90 ml of isopropanol and filtered through celite. 6.2 ml of propylene oxide are added to the filtrate and the suspension is left at room temperature for 3.5 hours and then at approx. 5 ° C for 2.5 hours. The resulting S-α-fluoro-methyl-3-hydroxytyrosine is collected by filtration, washed with isopropanol and dried overnight at 76 ° C. [οι] +: + 9.3 ° in 0.5 °, c, 1.82 in a 1: 1 mixture of trifluoroacetic acid and water.

EXAMPLE 3

Preparation of R-α-fluoromethyl-3-hydroxytyrosine

To prepare this compound, the strychnine salt of antimeric "A" of 3- (3 ', 4'-dimethoxyphenyl) -2-15 acetamino-2-hydroxymethylpropionic acid (Example 2, "HM") was subjected to a procedure analogous to that of Example 2 described. The final product showed [oe] p: -9 °, c, 2.5 in a 1: 1 mixture of trifluoroacetic acid and water.

EXAMPLE 4 R, 5-α-fluoromethyl tyrosine 1.05 g (0.005 mol) of R, Sa hydroxymethyl tyrosine is placed in a reaction vessel which is immersed in a cooling bath of dry ice and acetone and HF gas is sent through the vessel. is collected approx. 50 ml liquid 25 HF. During continued cooling, gaseous SF 2 (4 ml measured in liquid state at -78 ° C) is first passed into gaseous BF ^ into the vessel until saturation at -78 ° C. The cooling bath is removed and the solvent is evaporated by passing a stream of dry gas through the mixture.

The residue is dissolved in 20 ml of 2.5 M hydrochloric acid and evaporated to dryness in vacuo. The residue is dissolved in water and transferred to a strong acid-form cation exchange column containing 100 ml of AG 50-X-8 resin (200/400 mesh, 74 - 37 µl). The column is washed first with water (1.8 liters) and then with 0.5 M hydrochloric acid. 20 ml fractions of the effluent are collected and the elution process is monitored on UVIC0RD II. The fractions corresponding to the main fluctuation of the UV spectrum are pooled and evaporated to dryness under vacuum to give the hydrochloride salt of R, 5-fluoromethyl tyrosine. 400 mg of this salt is dissolved in 6 ml of water and after a few minutes R, S-fluoromethyl tyrosine begins to precipitate. After standing overnight at 5 ° C, the product is filtered off, extracted with water, ethanol and diethyl ether and dried in vacuo at 76 ° C to give R, S-α-fluoromethyl tyrosine.

Example 5 R, S-ffl-Fluoromethylhistidine (FM.HIST) H CH-,,

I I

.CIi5-C ~ C0 ~ H. Cilj-C-CO-H

N! 1) Race-meering Hi * I ij} 21 CnCf) Il i | L ·> IV '3 __ "- Ν' * 2 CH2C6h5 3> H2c = 0 CH2C6H5 (L) (D / I ·) (i) (1) 149841 13

f2 ° H CH2F

CII2-C ~ cq2H CH2 "C" COOH

Ma / 1% 'Qj ΗΡ / 8Γ4Β? 3_ ^ 2 «i

(D, L) FM-HIST

(1) (4) A) Racemic N (im) benzylhistidine 30 g of N (im) benzyl-L-histidine are dissolved in 600 ml of f 0 0 and the solution is heated in a high pressure autoclave at 200 ° C for 8 hours with shaking. The autoclave is cooled to room temperature and the clear surface liquid is evaporated in vacuo to dryness to give R, S-N (im) benzylhistidine in the form of colorless crystals.

B) R, S-ffl-Hydroxymethyl-N (im) benzylhistidine (2) Dissolve 20 g of racemic N (im) benzylhistidine in 1 liter of warm water, then gradually add 40 g of basic copper carbonate and reflux the mixture under stirring and stirring. 1 hour. The hot mixture is filtered and the filtrate is evaporated in vacuo to give a copper-chelate complex of racemic N (im) benzylhistidine in the form of a blue solid.

A mixture of 31 ml of formalin (38 ° H 2 CO), 3.1 ml of pyridine and 2.13 g of Na 2 CO 2 is heated with stirring to 70 ° C, then 20 g of the above Cu chelate is added and heated to 73 ° C. QC and stir for 90 minutes.

Evaporation in vacuo gives a solid blue residue. This is dissolved in a mixture of 50 ml of H 2 O and 50 ml of concentrated NH 2 OH and transferred to a cation exchange column (Dowex 50-X-8, 300 ml of resin in NH 2 + form) where it is eluted with 2 M aqueous NH 4 OH solution. The effluent is subjected to UV spectroscopy and the portion of the effluent exhibiting absorption (1.1 L) is evaporated under vacuum to a solid.

This is dissolved in a mixture of 60 ml of 0 and 5 ml of concentrated aqueous NH 2 OH solution and transferred to an anion exchange column (300 ml of Dowex 1-X-2 resin in OH form).

The column is washed with 2 liters of water and eluted with 2 M hydrochloric acid. The portion of the effluent which exhibits UV absorption is evaporated to dryness to give very pure HCl salt of N (im) -benzyl-α-hydroxymethylhistidine (2) (novel compound). This compound is converted to α-hydroxymethylhistidine (3) as follows: Dissolve 12.5 g of compound (2) in 200 ml of liquid NH 2 (3-hull flask equipped with a "cold finger" cooler filled with dry ice and acetone ) and 5.5 g of metallic sodium are added in small pieces until the blue color is maintained for 10 minutes. Then, NH 2 Cl is added to consume excess Na (indicated by decolourization) and the solvent (ΝΗ ^) is evaporated by a stream of N 2 gas. The obtained product (3) is purified by chromatography in a cation exchange column (2.2 liters of Dowe> P ^ 50-X-8, 200/400 mesh, 74 - 37 µg), dissolving the crude product (3) in 100 ml H ^ O and charged to the column. This is first washed with water (4 liters) and then eluted with hydrochloric acid (first 1.5 M and then 2 M). Fractions of 20 ml are collected at a rate of 600 ml / hour:

Fraction No. Pauly Reaction 1 - 400 1.5 M HCl 401 - 670 2 M HCl 671 and above +

Fractions 671 - 760 are combined and evaporated to dryness in vacuo. This gives R, S-o-hydroxymethylhistidine. 2HC1 (novel compound).

C) R, S-g-Fluoromethylhistidine (4) 2.73 g of compound (3) is dissolved in 70 ml of liquid HF and evaporated to dryness by purging with Ng gas. The resulting substance is the hydrofluoride salt of α-hydroxymethylhistidine. It is redissolved in 200 ml of liquid HF (dry ice-acetone cooling bath) and the SF 2 is added to the solution (9 ml measured as liquid at -78 ° C). The solution is left to stand overnight in a cooling bath at -12 ° C.

It is then saturated with BF 2 gas, left for 5 hours, saturated again at -12 ° C and left at this temperature for 66 hours. Then the cooling bath is removed and the solvent is evaporated with ^ gas. The residue consists essentially of the HBF HB salt of α-fluoromethylhistidine. This is dissolved in 100 ml of 2.5 M hydrochloric acid, evaporated to dryness and converted to the HCl salt as follows: The residue is dissolved in water and transferred to a cation exchange column (100 ml of AG 50-X-2, 200/400 mesh) and eluted with H2O until the outlet is neutral and free of F. The product is then released from the column by means of 3 M hydrochloric acid and evaporated to dryness in vacuo to give a residue consisting essentially of the dihydrochloride of (4). For final purification, chromatograph in another AG 50-X-2 column (900 ml resin). Elute with: 0.5 M hydrochloric acid - 1 liter 1.0 M hydrochloric acid - 1.5 liters 1.5 M hydrochloric acid - 3.3 liters (here begins the collection, 20 ml fractions) 2.0 M hydrochloric acid - 8.0 liters.

The desired product (4) is detected by a Pauly test. Fractions 390 - 470 are combined and evaporated to dryness under vacuum to give the pure dihydrochloride of (4).

16 U9841

Recrystallization from water isopropanol (1: 9 v / v) gives the crystalline monohydrochloride salt of α-fluoromethylhistidine, m.p. 226 - 227 ° C (decomposition).

EXAMPLE 6

Synthesis of R, 5-α-fluoromethylomithine A) R, S-oi-Hydroxymethyl ^ PN-benzoylornithine 7,995 g of copper chelate of R, S-β-N-benzoylornithine are added in small portions to a mixture of formalin (38% 12.45 ml), pyridine (1.25 ml) and sodium carbonate (0.81 g) at 70 ° C with mechanical stirring. After a further 90 minutes of stirring at 75 ° C, evaporate to dryness in vacuo and dissolve the dark blue residue in a mixture of 30 ml of 1 O and 30 ml of concentrated ammonia water and transfer to a cation exchange column (130 ml of Dowe> 50 x X 8 on NH 2 + form) to remove Cu 2+. The column is eluted with 250 ml of 2 M ammonia water and the outlet is evaporated to dryness under vacuum. The evaporation residue is redissolved in H 2 O and transferred to an anion exchange column (Dou / ex 1-X-2 in OH form, 130 ml of resin). The column is washed with 250 ml and eluted with 3 M hydrochloric acid. The outlet from the elution is concentrated in vacuo to give R, S-α-hydroxymethyl - N - benzoylornithine.

B) R, S-O-Hydroxymethylornithine dihydrochloride 3.50 g of the product obtained are dissolved in 40 ml of 6 M hydrochloric acid and heated under reflux for 21 hours. The solution is then extracted with 2 x 40 ml of toluene and the aqueous phase is evaporated to dryness in vacuo to give R, S-α-hydroxymethylornithine dihydrochloride (novel compound).

C) R, S-α-Fluoromethylornithine 1.10 g of the product obtained under B) is placed in a reaction vessel which is immersed in a dry ice and acetone cooling bath. HF gas is blown through the reactor until 25 ml of liquid phase is formed. The cooling bath is removed and the solvent is evaporated with ^ gas. The evaporation residue represents the HF salt of R, S-α-hydroxymethylorni-thin. This residue is redissolved in 50 ml of liquid HF and then gaseous SF 2 (4 ml measured in liquid state at -78 ° C) is added. The mixture is allowed to stand at -15 ° C for 16 hours, after which BF 2 gas is allowed to saturate.

After another 5 hours standing, the cooling bath is removed and the solvent is evaporated by gaseous N 2. The residue is dissolved in 6 M hydrochloric acid, evaporated to dryness under vacuum and redissolved in 10 ml of H 2 O. This solution is transferred to a Dowe> 50-X-8 cation exchanger (400 ml resin in H + form). The column is washed with 800 ml of H2O and eluted with 2N hydrochloric acid, collecting 15 ml of fractions. Flow rate: 600 ml / hour. Every fifth fraction is chromatographed on thin layer with ninhydrin spray.

Fractions 171 - 220 are combined and evaporated to dryness under vacuum, resulting in a mixture of amino acids wherein the major constituent is R, S-α-fluoromethyl-ornithine, 2 HCl. For further purification, the product is re-chromatographed in another cation exchange column (Dou / ex * 50-X-8). The column is washed with water and eluted with 1.5 N hydrochloric acid, flow rate 0.6 liters / hour. Evaporation of fractions 521-540 (20 ml fractions) gives pure R, S-o-fluoromethylornithine dihydrochloride.

Synthesis of Sa-fluoromethyl tyrosine 18 EXAMPLE 7 A) Preparation of the copper chelate of tyrosine methyl ester 25 g of R, S-tyrosine methyl ester (128 mmol) is dissolved in 646 ml of 0.2 N NaOH at 80 ° C, and this solution is added 16.1 g of CuSO Dissolved in 1600 ml of water at 80 ° C. A precipitate is formed immediately which is filtered off after standing overnight. 28.9 g of the copper chelate of R, S-tyrosine methyl ester is obtained.

B) R, S-α-hydroxymethyl tyrosine methyl ester 29 g of the copper chelate (Cu) of tyrosine methyl ester (0.064 mol) is added with stirring at 70 ° C a solution of 3.9 g of sodium carbonate, 52 ml of 37 ° aqueous formaldehyde and 5.2 ml of pyridine. Then add an additional 18 ml of formaldehyde solution and 1.6 ml of pyridine. After heating to 70 ° C for 3.5 hours, the mixture is allowed to cool to melting temperature and allowed to stand overnight. In the morning, a full precipitate of blue crystals is obtained which is filtered off and the filtrate is evaporated under vacuum. After dissolving the residue in water and again evaporating to dryness, the residue is dissolved in 90 ml of 4 N HCl. This solution is used after filtration to dissolve the above blue crystals. For this, another 300 ml of 4 N HCl is required. Then the solution is treated with H £ S, filtered through a filter of diatomaceous earth and concentrated to ca. 40 g of crude product. This is transferred to a strong acid cation exchange resin (0.5¾ Dowex 50-X-8) and eluted with 4 liters of water and then 2 N of ammonia water.

The effluent is examined on UVICORD II (recording UV spectrophotometer) and the portion exhibiting UU absorption is concentrated in vacuo to give 22.16 g of pure R, S-α-hydroxymethyl tyrosine methyl ester.

C) R, 5-N-acetyl-oi-hydroxymethyltrosine methyl ester 19.7 g of R, S-ot-hydroxymethyltyrosine methyl ester (87.5 mmol) are suspended in 200 ml of dry pyridine and 68 ml of acetic anhydride are added. After standing overnight at room temperature, the solution is evaporated to dryness in vacuo and then azeotropically distilled with 2 x 50 ml of toluene. The residue is dissolved in 118 ml of methanol and 130 ml of 2.5 N NaOH and stirred at room temperature for 3.5 hours. The mixture is acidified with 30 ml of concentrated hydrochloric acid and extracted with 4 x 200 ml of ethyl acetate, then dried and concentrated. There is thus obtained 21 g of crude product which is recrystallized from 75 ml of acetonitrile to give 9.35 g of R, S-N-acetyl-α-hydroxymethyl tyrosine methyl ester which melts at 151 - 152 ° C during decomposition.

D) Optical cleavage of R, S-N-acetyl-α-hydroxymethyl-tyrosine methyl ester 1 g of the substance prepared under C) and 6.18 g of d-ephedrine is dissolved in 50 ml of methanol. The solution is concentrated to dryness in vacuo and then redissolved in 50 ml of hot acetonitrile. Crystallization gives 7.34 g of the d-ephedrine salt of R-N-acetyl-α-hydroxymethyl tyrosine methyl ester, m.p. 125-131 ° C (yield A). This yield A is recrystallized from 40 ml of acetonitrile to give 4.78 g (yield B), m.p. 130 - 134 ° C. The mother liquors from A and B are collected and concentrated and dissolved in 22.4 ml of 2.5 N NaOH and 50 ml of water. The aqueous solution is extracted with 2 x 75 ml of ethyl acetate, cooled and acidified with 5 ml of wife. HCl, then the resulting solution is extracted with 3 x 70 ml of ethyl acetate. The dried organic solution is concentrated to 7.73 g (yield C). This yield C is dissolved together with 4.7 g of 1-ephedrine in 50 ml of methanol and concentrated to 12.39 g (yield D). This is recrystallized from 50 ml of acetonitrile to give 5.06 g of the 1-ephedrine salt of S-N-acetyl-α-hydroxymethyl-tyrosine methyl ester (yield E) melting during decomposition at 131.5 - 133.5 ° C. Yield E is recrystallized from 27 ml of acetonitrile to yield F (4.72 g, mp 130.5 - 134.5 ° C (decomp.)). The mother liquor of Yields F and E is concentrated to 7.31 g of Yield G which is converted back to the free acid by the method used to obtain Yield C, and 3.0 g of Yield H. is obtained. as the R, S starting material with 1.9 g of d-ephedrine. Recrystallization of the salt from 17 ml of acetonitrile affords 2.4 g of yield J (mp 127-130 ° C), which is recrystallized to 2.06 g of yield K (mp 130-134 ° C with decomposition). Yields B and K (6.52 g in total) are recrystallized from 40 ml of acetonitrile to give 6.06 g of the d-ephedrine salt of R-N-acetyl-α-hydroxy-methyltyrosine methyl ester (75.8% in total). The free acid is regenerated in the same way as the mother liquor from yields A and B were converted to yield C and 3.50 g of RN-acetyl-α-hydroxymethyltyrosine methyl ester are obtained: [a] p = + 92 ° (c, 1 , 35, 0.27 N NaOH).

E) R-ct-Hydroxymethyl tyrosine 3.30 g of R-N-acetyl-α-hydroxymethyl tyrosine methyl ester is dissolved in 100 ml of concentrated hydrochloric acid and heated in a closed tube at 130 ° C for 2 hours. The solution is concentrated to dryness and the residue is dissolved in 35 ml of water, filtered and treated with 1 ml of pyridine to crystallize 2.11 g of pure R-o-hydroxymethyl tyrosine (81%): [ot] D = 0.86 ° (c, 1.15, 50% aqueous trifluoroacetic acid). The circular dichroism spectrum (CD) has the same meaning as the CD spectrum of 5-α-methyl tyrosine.

F) S-ot-Fluoromethyltrosine 21 US $ 41

This product is prepared from R-α-hydroxymethyl tyrosine by the same procedure as described in Example 4.

EXAMPLE 8 (-) -α-Fluoromethylglutamic acid 6.56 g of α-methylglutamic acid semihydrate is photofluorinated in liquid HF by the technique described in J. Am. Chem. Soc. J? 2, 7494 (1970) and ibid. J? 8, 5591 (1976). The substrate is dissolved in 120 ml of liquid HF and illuminated with a 2500 W ultraviolet light source with stirring, while gaseous fluoroxytrifluoromethane (CF 2 OF, 3.0 ml measured in liquid state at -78 ° C) is passed through a period of 80 minutes while cooling in a bath of dry ice and acetone. After stirring for an additional 80 minutes, a further flow of CF 2 OF gas is passed over a period of 3 hours while stirring, cooling and illuminating with UV light. The mixture is left in the cooling bath overnight, after which it is further fluorinated with 3 ml of CF 2 OF, added over 5 hours while illuminated with UV light. To remove the solvent, it is purged with nitrogen and the residue is evaporated twice in vacuo with 2.5 N hydrochloric acid. The residue is dissolved in 40 ml of water. To 10 ml of this solution is added 10 ml of concentrated hydrochloric acid and the mixture is heated under reflux for approx. 68 hours.

After filtration with DARCO G-60, the filtrate is evaporated in vacuo and the residue is heated under reflux with 30 ml of wife. hydrochloric acid for an additional 68 hours. Filter and evaporate to dryness and dissolve the residue in 10 ml of the wife. hydrochloric acid and heated in a melted gias-tube for 24 hours in an oil bath at 130 - 135 ° C. Evaporation to dryness under vacuum gives a residue which is dissolved in water and chromatographed in a cation exchange column filled with 360 ml of AG 50-X-12. Eluents: 2.6 liters of H 2 O followed by 0.1 N HCl (1.5 liters) and then 0.15 N HCl. UV absorption of the outlet is measured at 206 nm. 15 ml fractions of the effluent are collected and 20 such fractions corresponding to the first UV absorption are combined and evaporated in vacuo to dryness to give o-fluoromethylglutamic acid hydrochloride. To release the amino acid, the product is dissolved in isopropanol and filtered and then propylene oxide is added. α-Fluoromethylglutamic acid.0.7 H 2 O crystallizes from the solution. This compound has a time-dependent inhibitory effect on glutamic acid decarboxylase.

spectral

Amino acid if value group Q 1 -Fluoromethyl-3- 3.13 ArCH2 hydroxytyrosine 3.22 do

4.82 CH

5.03 do ^ 6.78 ArH (H2) 6.90 do (H-) 6.70 do (Hg) ce-Fluoromethylhistidine 2.63 ArCH

3.97 CH2 FZ

4.05 do ^ 6.63 Imidazole (Ης) 7.82 do (H2) α-Fluoromethylornithine 1.7-2.2 (ca.) -CH2CH2 ~

3.1 "CH? N

4.88 "CH7F

4.93 "άοΔ fi-Fluoromethyl tyrosine 3.13 ArCH" 3.32 do

4.87 CH F

4.99 do 6.87 ArH (Hg) 7.10 do (Hb)

Claims (2)

149841 Amino acid K value group ce-Fluoromethylarginine 2.0 (m) α- and P-CH CH 3.33 CH? N 4.98 CH7F 5.03 άοΔ ce-Fluoromethyl-meta- 3.33 ArCH2 tyrosine 3.57 do 5.07 CH „F 5.22 άοΔ 7.20 ArH 7.40 do α-Fluoromethylglutamic acid 2.5 (2.07-2.80) β- and X-CH? 4.94 CH, F 5.02 doz a-Fluoromethyltryptophan 3.17 ArCH? 3.38 do 4.60 CH? F 4.93 do ^ 7.00 Benzimidazole H (H, -) 7.07 do (H,) 7.20 do (Η;) 7.40 do (H7) 7.50 do (h ') An analogous process for the preparation of substituted ot-fluoromethyl-α-aminoalkanoic acids of the general formula CH-F1 RC-COOH (I) nh2 in the form of optically active compounds or any or racemic mixtures of such compounds, or pharmaceutically acceptable acid addition salts thereof wherein R represents a substituted alkyl group of the formula r'V 149841 R20 - - C1-12 - wherein R2 is hydrogen or H alkanoyl having 2-6 C atoms, ^ _____ 'CH2 - (I \ N -. itr »h2n- ( cii?) 2-ch2-, ch2-, ho -— CII2 ~ »II0 \ ^ NH I \ 'H2N-C * -NII-C! UCH2CH2-, HOOC-CII2-CII2- _____ or F | jj cli2' characterized L1 Ji by reacting a tx-hydroxymethyl-α-aminoalkanoic acid of the formula CH 2 OH R - C - COOII ii2 wherein R is as defined above, with SF 2 in liquid HF at a temperature between about - 80 ° C and about 20 ° C, optionally with the addition of BF 3 or AlCl 2 to the reaction system, whereupon, if desired, a resulting racemic mixture is split into optical isomers and / or o forming the resulting compound into a pharmaceutically acceptable acid addition salt thereof.