FI61687C - PROCEDURE FOR THE FRAMEWORK OF THERAPEUTIC ANALYSIS ALA-METHYL-3,4-DIHYDROXIFENYLALANINDERIVAT - Google Patents

Description

>, - t fol, 44, ADVERTISEMENT A o o.

2 | 3Γα m 01) UTLÄGGNINCSSKRIFT 6Ί60 / C (45) Patent granted on 10 09 1932 Patent roeddlelat

(51) K ».ik? /Intxi.3 c 07 C 101/77, C 07 D 207AO

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Patent- och registerstyrelsen '' Antekan utiajd och uti. * Krifc * n publkmd 31.03.82 (32) (33) (31) Pyn «ty« tactile ) U00609, 482102 (71) Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey, USA (72) Walfred Spencer Island, Lansdale, Pennsylvania, USA (74) Oy Kolster Ab (54) Process for the preparation of therapeutically useful O-methyl-3,4-dihydroxyphenylalanine derivatives - For the preparation of therapeutically useful c * -methyl-3,4-dihydroxyphenylalanine derivatives

The present invention relates to a process for the preparation of novel ok-methyl-3,4-dihydroxyphenylalanine derivatives useful in the treatment of hypertension.

Various alanine compounds have been previously suggested to be useful in the treatment of hypertension (see U.S. Patent 2,868,818). In addition, it is known in the art that hypertension is more preferably treated with L-° (-methyl-3,4-dihydroxy: -phenylalanine because Form D of the compound is therapeutically inactive. Removal of Form D thus reduces toxicity and increases efficacy (see U.S. Patent 3,344,023 and British Patent 936,074), the L-isomer of o-4-methyl-3,4-dihydroxyphenylalanine is generally referred to as Lc <-methyldopa or methyldopa, and it is further known in the art that L- or DL-X- Outer esters of methyl 3,4-dihydroxyphenylalanine are useful in the emergency treatment of hypertension in parenteral administration (see U.S. Patent 3,230,143) It has now been found that DL- or L-N-methyl-3,4- other esters and derivatives of dihydroxyphenylalanine are also active in the treatment of hypertension and are thus alternatively compounds for use in this treatment, and it has been found that some of the new compounds have much higher activities ti, and thus require lower doses than in the case of known compounds.

Thus, the present invention relates to a method of novel formula

CH „0 R

i 3 y i1

- C - fc - o - c - <CH2, m - r3 I

For the preparation of O (-methyl-3,4-dihydroxyphenylalanine derivatives of H0-nh2 R2 and pharmaceutically acceptable acid addition salts thereof, wherein m is 0, 1 or 2, R1 and R2 are hydrogen or alkyl having 1 to 3 carbon atoms and R »is pivaloyl).

O

an oxy or succinimido group.

With respect to the L-isomer, it should be noted that an asymmetric carbon atom is an amino group in the acid portion of the molecule and a carbon atom containing a methyl group. When referring to the L-configuration, this part of the molecule is meant. It should be noted that the L-configuration refers to the stereoconfiguration and not the optical rotation, although in this case the L-stereoconfiguration is the 1- or resting form of the optical isomer. It should be noted, however, that in some cases, when and R 2 are different groups, the carbon atom to which they are attached is also asymmetric and may thus exist in either the L or D configuration. As shown below, both isomers of this portion of the compound are active. As further shown, both of these isomers are separated, but their stereoconfiguration was not determined, so only the et, and β isomers are denoted. In any case, the β, β isomers are active regardless of their stereoconfiguration.

3 616 8 7

The compounds of formula I are prepared according to the invention in such a way that

(a) hydrolyzed or reduced of formula II

CH, 0 R, ^ 1 3 li i1

r5 ° _ ^ \ _ CH2 - C - C - O - CC-CH2) m - R3 [T

V-VJ f R2 The protecting groups Rg, Rg and R1 of the acid derivative or the acid addition salt thereof according to R7, wherein m, R1, R2 and R8 have the same meanings as defined above, and Rg, Rg and R2 are as defined above. are hydrogen atoms or protecting groups, at least one of which is a protecting group, or

(b) esterifying an acid derivative of formula III, IV

or V

CH0 I 3

HO—- CH2— C — Y JIT

nO-NH 2 CHO 0

^ I 3 II

.10 - ^ \ -OHo-C- C

j I I iv

HO — L 1 NH JO

II

o r - - CH ~ I I d

I HO - - CH0 - C - CO ,, - S -> 0 V

I 2 I 2 H0_ NH2 J 2 61 687

or an acid addition salt thereof with a compound of formula VT

b x1-c - (- ai «) vt II L. mo R2 wherein Y is -COOK or -CO-halogen, m, R1, R2 and Rg are as defined above and are hydroxyl, halogen, or (c) is reduced a compound of formula I containing one or more reducible groups which is -HC = CH-, -C = C, halogen, NO 2 or CN, or (d) a compound of formula

CH „H

„I 3 i

H0—— CH9- C - C0 - C (-CH0) - OH

2 I 2 | 2 m vn HO-1, ^ nh2 h where m is the same as above to react with an acylating agent of the formula (CH3) 3C-C-X2, where X2 is Cl or Br O (e) cyclizing a compound of the formula CH, R, 0

I 3 I1 H

H0-hl-CH, -C-CO, -C (-CH,) - NHCCH, (CH,> -CO, H

ti 2 m 2 2 n ^ 2

H0 — L J NH R

* VIIT

wherein n 1 is 1, 2 or 3 and, R 2 and m are as defined above and if desired the stereoisomers are separated (1) by fractional crystallization of the second stereoisomer from solution or (2) by formation of diastereomers. with an optically active acid and crystallizing one of the diastereomers from solution.

The phrase "pharmaceutically acceptable acid addition salt" is a term well known in the art to include compounds prepared by the reaction of the free base with an inorganic or 61687 organic acid. It includes salts of hydrochloride, sulfuric acid, hydrobromide and the like.

The phrase "L-isomer substantially free of the D-isomer of the amino acid means that the D-isomer is present in amounts not exceeding about 10%. However, it is desirable that the D-isomer be virtually non-existent in the composition. In the examples shown, the L-isomer11a it is meant that the compound is substantially 100% (i.e., well above 99%) in the L-configuration.

The term "protecting group" means any group that protects amino or hydroxyl groups during a reaction. Suitable nitrogen protecting groups include carbobenzyloxy, para-methoxycarbobenzyloxy, trifluoroacetyl, HCl and the like. Suitable hydroxyl protecting groups include diphenyl ketal for both hydroxyl groups and acetyl and carbobenzyloxy for individual hydroxyl groups and other similar radicals. The substituent on the "substituted -SO 2 - w group" can be almost any radical, as these groups are easily cleaved in the esterification reaction and the quality of the group is not critical at all.

When preparing racemic mixtures according to the synthesis of the present invention, it is sometimes desirable to separate the mixtures into L- and D-isomers. The isomers can be separated at any stage of the synthesis and in most cases it is desirable to separate them before forming the final product. In other cases (such as when R 2 and R 2 are different groups and the acid moiety is in the L-configuration) the final product is formed as a mixture of diastereomers and these can be separated directly by crystallization or formation of simple derivatives as well as crystallization. However, it is much more preferable to use the desired isomer (i.e., the L-isomer) as the starting material when a separate isomer is desired. The separation can also be performed by forming diastereomers from the racemic mixtures obtained according to the present invention. In such a case, an optically active acid such as tartaric acid, 10-camphorsulfonic acid, malic acid, pyroglutamic acid, methoxyacetic acid and the like can be used, and the acid can be selected as desired, and this will not be difficult for a person skilled in the art.

In the treatment of hypertension, the novel compounds are generally administered as a medicament from about 0.005 to about 300 mg per kg of animal body weight i · 1 6 61687, and preferably from about 0.05 to about 100 mg / kg. In an even more preferred case, the compounds are administered in amounts of about 0.1 to 25 mg / kg body weight of the animal. In this regard, it should be noted that the dose should be adjusted according to the activity of the compound, the desired effect on blood pressure and also the weight of the animal. Out of the above dosage ranges, more active compounds could be administered at lower doses and less active compounds at higher doses.

When the L-isomer of formula I is administered as a drug substantially free of the D-isomer, the required dose of the L-isomer is approximately half the required dose of racemate because the D-isomer is not therapeutically effective. However, the activity of the new compounds varies to some extent, and thus the racemate of the less active compound may be required many times the dose required for the more active compound. In general, the compounds are administered as a drug within the above dosages.

In a single form, the active compound is generally present in the composition in amounts of about 1 to about 2,000 mg, more preferably about 5 to about 1,000 mg. In an even more preferred case, about 10 to about 500 mg of active compound is present. The unit dosage form of the compound may be administered as a single slow-acting dose or may be administered in divided doses into several small doses several times a day, usually in 2 to 8 separate doses.

As stated above, lower doses of the L-isomer, which is substantially free of the D-isomer, are required compared to doses of racemate. However, different activities of different compounds require the use of different doses. In some cases, some compounds are many times more active than others, and thus an even lower dose of the racemate of one compound than the L-isomer of another compound may be required. In general, however, dosages will be within the above limits.

The compounds of formula I can be used as compositions which are preferably administered in unit dosage form, such as tablets, pills, capsules, powders, granules, sterile parenteral solutions or suspensions, oral solutions or suspensions and the like. , such as corn starch, lactose, 7,61687 sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate, gums, and partially similar materials used as pharmaceutical diluents and carriers.

Tablets and pills of the compositions may be layered or otherwise compounded so as to provide a sustained or delayed action or a predetermined sustained release of the drug. For example, the tablet or pill can comprise an inner and an outer dosage component, the latter being in the form of an envelope over the former. Both components can be separated by an enteric layer designed to withstand undegradation in the stomach and allow the inner component to migrate unchanged to the duodenum or be released in a delayed manner. Many different materials can be used for such enteric layers or coatings, which are several polymeric acids or mixtures of polymeric acids with substances such as shellac and cetyl alcohol, cellulose acetate, etc. A particularly preferred enteric coating consists of a styrenic maleic acid copolymer with . The compounds may also be utilized by administration in the form of suppositories or in combination with a permeable agent such as dimethyl sulfoxy.

Liquid forms into which the composition may be incorporated include suitably flavored emulsions with edible oils, such as cottonseed oil, sesame oil, coconut oil, peanut oil, and the like, as well as elixirs and the like. Suitable dispersing or suspending agents for aqueous suspensions, for example, synthetic and natural gums such as tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, polyvinylpyrrolidone, gelatin and the like are required for parenteral suspension. Isotonic preparations containing suitable preservatives are also highly desirable for injection.

The term unit dosage form refers to physically discrete units suitable as unitary dosages for warm-blooded animal patients, each unit containing a predetermined quantity of active ingredient calculated to produce the desired therapeutic effect in association with the required pharmaceutical diluent, carrier or vehicle. The definitions of unit dosage forms are directly dependent on and determined by (a) the unique properties of the active material and the particular therapeutic effect obtained, and (b) the limitations associated with formulating such active material for use in warm-blooded animals, as described in detail in this patent. Examples of suitable oral unit dosage forms include tablets, capsules, pills, powder packets, granules, cachets, starch capsules, soft capsules, teaspoons, ampoules, vials, separated multiple forms of any of the above dosage forms, and other forms described herein.

The following table shows the relative antihypertensive activities of some esters of L-3- (3,4-dihydroxyphenyl) -2-methylalanine (L-methyldopa) for spontaneously elevated blood pressure in rats compared to the activity of L-methyldopa.

CH0 ^ I ^ 0

HO — CH.-C - C

2 | ^ 0R

HO —NH2

Relative antihypertensive effect

Example R Basic weight Molarity path 11a_basic path 11a

Control H (methyldopa) 1 1

Known “C2H5 1,2 1, 2 0 tt 6 -CH2-O-C-C (CH3) 3 1.4 1.9 CH ~ 0

I 3 M

5 -CH-O-C-C (CH3) 3 1.6 2.3 p.

616 8 7

The effect of lowering relative blood pressure t

Example R Basic pressure of molarity 'qj q tea 11a_ basic tea 1 ia »3 n 5 (-isomer) -CH-O-CC (CH3) 3 1.9 2.7 0 10 -CH0-N 2.5 3, i |

V

o o CH3 L-, i 3/12 B (ck-isomer) -CH-N 3.1 4.4

V

0 «3 I—, I 3/12 A (β -isomer) -CH-N 2,3 3.2

V

The following examples illustrate the invention. All parts refer to parts by weight unless otherwise indicated. The "reduced pressure" used in the following examples is 15-25 mm Hg at 25-35 ° C (unless otherwise indicated). When reduced pressure is used to remove solvents, the resulting product is most often a solvate, and thus in the example refers to a "concentrated" product, although all other parts of the solvent have been removed except the part bound to the product.

ίο 61687

Example 1 A. Preparation of L-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine hydrochloride

A mixture of 19.3 g (0.0777 moles) of L-3- (3,4-dihydroxyphenyl) -2-methylalanine hydrochloride, E-O-methyl hydrochloride and 37 g (0.156 moles) of dichlorodiphenylmethane, immersed in an oil bath preheated to 190 ° C with slow stirring. Upon initiation of the reaction, as indicated by vigorous gas evolution, the mixture is stirred rapidly for 6 minutes at 190 ° C, removed from the hot oil bath and allowed to cool to 25-30 ° C. The crude products from the 12 runs are combined, slurried in 3 liters of diethyl ether, filtered, washed with a further 2 liters of diethyl ether and dried at 30 ° C at 50 mm. Recrystallization is performed by dissolving the product in ethanol and adding ethyl acetate to precipitate the product. The process gives 255 g (66.4%) of L-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine hydrochloride, m.p. 267-268 ° C, dec.

Analysis calculated for NO 4 CHL: c 67.07 H 5.39 N 3.40 Found: C 66.91 H 5.29 N 3.34 B. LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2 preparation of methylalanine

A mixture of 175 g (0.325 mol) of L-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine hydrochloride, 1750 ml of acetone and 1750 ml of water is stirred under a nitrogen atmosphere at a temperature below 10 ° C, the pH being adjusted to 12 .0.0 slowly by adding 10% sodium hydroxide solution. 93 g (0.545 moles) of carbobenzyloxychloride are added dropwise to the reaction mixture at 20-30 ° C over a period of 5-7 minutes while 10% sodium hydroxide solution is added to maintain the pH at 12.0-12.2. After the addition of carbobenzyloxy chloride is complete, the reaction mixture is stirred at 25-30 ° C for 3 hours. Most of the acetone is then removed under reduced pressure at 25-35 ° C, whereupon the sodium salt of the desired N-carbobenzyloxy derivative precipitates. The sodium salt is extracted into 1.5 liters of ethyl acetate, washed with 200 ml of 5% sodium hydroxide solution and 200 ml of saturated sodium chloride solution and then dried over magnesium sulfate. 17.5 g of decolorizing carbon are added and the mixture is filtered through a pad of magnesium sulphate, then the solvents are removed under reduced pressure at 25-35 ° C. The residue is slurried 2 times in 1 liter of 20! ethyl ether-80% -hexane (v / v) and filtered to give the sodium salt of the desired IM-carbobenzyl oxy derivative. This sodium salt is dissolved in 1.5 liters of ethyl acetate, the solution is cooled to 10 ° C and acidified to pH 2 with 6N hydrochloric acid. The ethyl acetate extract is washed with 200 ml of saturated sodium chloride solution, dried over magnesium sulfate, filtered and concentrated under reduced pressure at 25-35 ° C. The 1-carbobenzyloxy derivative is further dried at 25-30 ° C at 0.2-0.3 mm Hg to give 169 g (76.0) of LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -. 2-methylalanine.

C. Preparation of Succinimidomethyl L-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate.

A solution of 13.5 g (0.0265 moles) of LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine, 2.7 g (0.027 moles) of triethylamine and 5.19 g (0.029 moles) IM-bromomethylsuccinimide in 35 ml of dry dimethylformamide, stirred at 25-30 ° C for 16 hours. The reaction mixture is poured into 400 ml of ice water and the product is extracted into 200 ml of a mixture of 50% chloroform-50% diethyl ether (v / v!). The organic extract is washed with 50 ml of dilute (5!) Sodium carbonate 1 solution and 50 ml of saturated sodium chloride solution and dried over anhydrous magnesium sulfate to remove water. After filtration and concentration under reduced pressure, the residue is recrystallized. Recrystallization is performed by dissolving the product in ethanol and adding hexane to precipitate the product. 12.1 g (73.6!) Of succinimidomethyl L-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate are obtained, m.p. 143.0-145.0 ° C.

Analysis calculated for C H 5.20 N 4.51 Found: C 69.83 H 5.14 N 4.52 D, Preparation of succinimidomethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate_

A suspension of 6.6 g (0.0106 mol) of succinimidomethyl LN-carbo, benzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine in 180 ml of absolute ethanol and 9 ml of 9 , 6-N hydrochloric acid (anhydrous) in ethanol, is hydrogenated with 3.3 g of 10! 61687 palladium-carbon catalyst at an initial pressure of 2.11 kg / cm, i.e. until hydrogen bonding has ceased. The catalyst is removed by filtration and the filtrate is concentrated under reduced pressure. The residue is extracted with 50 ml of benzene and then with 50 ml of ethyl acetate. The insoluble solid is then shaken with 10% ethanol-90% ethyl acetate (50 mL, v / v) and saturated sodium carbonate solution (10 mL). After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue is dissolved in 25 ml of absolute ethanol, the solution is treated with 5 ml of a 9.6 N solution of hydrogen chloride (anhydrous) in ethanol and concentrated under reduced pressure to give 2.5 (62.7%) of succinimidomethyl -L-3- (3 , 4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate, which is homogeneous by thin layer chromatography on a Z-fluorescent silica gel plate, Rf = 0.5 observed in 30% methanol-70% benzene solvent by volume. Analysis calculated from the formula C HOI. H 2 O: C 47.81 H 5.62 N 7.44 Found: C 48.09 H 5.74 N 7.42

Example 2 A. Preparation of N- (1-chloroethyl) succinimide 50.0 g (0.40 mol) of N-vinyl succinimide are dissolved in 1000 ml of carbon tetrachloride, 5.20 g (0.020 mol) of stannous chloride are added and the mixture is stirred while saturating it. hydrogen chloride for 6 hours at 20-30 ° C. After 24 hours, the mixture is again saturated with hydrogen chloride for 1.5 hours. After 48 hours, the solution is decanted and the gummy residue is washed with 10 ml of a 100 ml portion of carbon tetrachloride. 10 g of diatomaceous earth are slurried in the combined extracts, filtered and the filtrate is concentrated under reduced pressure to about 400 ml. The N- (1-chloroethyl) succinimide is filtered and dried at 20-30 ° C under reduced pressure to give 38.4 g (59%) of a white solid with a melting point of 83.5-84.5 ° C.

B. Preparation of succinimidoethyl L-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine

A mixture of 30.66 g (0.060 moles) of LN-carbobenzyloxy-2- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine, 9.70 g (0.060 moles) of N- (1-chloroethyl) succinimide, 6, 07 g (0.060 mol) of triethylamine and 75 ml of dry dimethylformamide are stirred at 95 ° C for 19 hours. The reaction mixture is poured into 750 ml of water and the product is extracted with 3 of 500 ml portions of ethyl acetate. The combined organic extracts are washed with 3 of 300 ml portions of 5% sodium hydroxide.

solution, then 3 times with 300 ml of saturated sodium chloride solution 13 61 687 and dried over anhydrous magnesium sulfate. After filtration, the solution is treated with 5 g of carbon, filtered and the solvent is evaporated off under reduced pressure to give 37.90 g (99%) of oC-succinimido-ethyl-LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate. as a mixture of diastereomeric isomers (oi and / 3).

Preparation of C.C-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylaninate hydrochloride_

A suspension of 20 g (0.032 mol) of succinimidoethyl LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate in 275 ml of 25% absolute ethanol-75% ethyl acetate the tate mixture (% by volume) is hydrogenated with 8.5 g of 10% palladium on carbon catalyst at an initial pressure of 2.81 kg / cm 3 at room temperature. The catalyst is filtered off and the filtrate is evaporated under reduced pressure at 30-40 ° C. The residue is dissolved in 250 ml of a 10% (v / v) mixture of 10% ethanol-90% ethyl acetate and the solution is mixed with a saturated solution of sodium carbonate (20 ml) in anhydrous sodium carbonate (about 30 g). After filtration, the filtrate is dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The residue is dissolved in 130 ml of dry chloroform, the solution is cooled in an ice bath and saturated with hydrogen chloride for 15 minutes. The solid is collected, washed by suspending 3 times in 100 ml of anhydrous ether and then slurried in 300 ml of ethyl acetate and kept in a sealed flask under N2 at room temperature overnight. o6-Succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride is collected, stirred in 300 ml of hexane for 2 hours and dried in a vacuum desiccator over CaCl2 to give 0.32 g (62% ) hydrochloride as a mixture of <X and? isomers, observed Rf = 0.7 by thin layer chromatography Z 1 fluorescent silicon 1 plate, 50% methanol-50% benzene solvent (v / v% 7).

Analysis calculated for C 15 H 20 N 2 O 6 · HCl.1 / 2 CH 3 CO 2 C 2 H 5: C 51.86 H 6.05 N 6.7 Found: C 51.98 H 5.87 N 6.65

Example 3 A. Separation of isomers of O 6-succinimidoethyl L-N-carbobenzyloxy-3- (3,4-dihydroxyphenylmethylenedioxyphenyl) -2-methylalaninate_

A mixture of the diastereomeric isomers of Example 2 (150.5 g) is dissolved in a mixture of boiling benzene (1200 ml) and absolute methanol y * 1 (100 ml), filtered and the filtrate is concentrated to a volume of about 700 ml. Add 10D ml of absolute methanol to the solution, which is then diluted with 1000 ml of hexane until it begins to cloud, crystallization is initiated by inoculation and scraping. The mixture is cooled at 5 ° C for about 15 hours and then the crude crystalline oL isomer is collected, washed by suspending in 200 ml of a 50:50 mixture (volume) of benzene and hexane and dried at 70 ° C. The product weighs 68.1 g and melts at 185.5-191 ° C. After two recrystallizations, the analytical sample melts at 199.5-201.5 ° C.

Analysis calculated from the formula £ 37 ^ 34 ^ (^: C 70.02 H 5.40 N 4.41 Found: C 70.22 H 5.52 N 4.29 The combined mother liquors and washings of the OL isomer are evaporated to dryness under reduced pressure at 60 ° At C to give 79.3 g of the ^ isomer as a very thick oil.

Preparation of B.® (.-Succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride dihydrate (β-isomer)

A solution of 10.0 g (0.016 mol) of N-succinimidoethyl LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate (isomer) in 140 ml of 25% absolute ethanol-75% ethyl acetate- 4.2 g of 10% palladium-on-carbon catalyst at an initial pressure of 2.81 kg / cm 2 and at room temperature for 20 hours, i.e. until hydrogen uptake is complete, the catalyst is filtered off under a nitrogen atmosphere, the filtrate is acidified to 2.0 9.4% ethanolic hydrogen chloride solution and evaporated to dryness under reduced pressure at 30-40 [deg.] C. The amorphous solid residue is dissolved in 50 ml of warm 95% ethanol (5% water), filtered and the filtrate is diluted with anhydrous ether ( 58 ml) until it begins to cloud, then inoculate and scrape to initiate crystallization.The product is collected and mixed with 300 ml of anhydrous ether to remove any diphenylmethane.After one hour the solid is collected and dried at 70 ° C overnight to give 3.7 g of material with a melting point of 123-126 ° C (decomposes) are obtained. Recrystallization from 20 ml of 95% ethanol gives 3.36 g (51%) of N-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalanine hydrochloride dihydrate (p-isomer), melting at 129-%. At 131 ° C (decomposes) (dried at 70 ° C overnight) and homogeneous by thin-layer chromatography on a Z "fluorescent silica gel plate, 50% methanol-50% benzene solvent (t% by volume) _7, Rf = 0.7 Calculated for C 47 H 28 N 2 O 2 .HCl • 26 2 O: C 47.00 H 6.16 N 6.85 Found: C 46.85, 47.09 H 6.12, 6.16 N 6.76, 6.61 + 33.46 ° (c = 1.5 CH 3 OH) 15 616 δ 7

Example 4 A. Preparation of X-succinylmethyl L-'3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride (ox isomer) A solution of 10.0 g (0.016 mol) of β-succinimidoethyl LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate (X-isomer) in 140 ml of a 25% absolute ethanol-75% ethyl acetate mixture (% by volume) is hydrogenated with 4.2 g of 10% palladium-on-carbon catalyst at an initial pressure of 2.81 kg / cm 2 and at room temperature for 27 1/2 hours, i.e. until hydrogen bonding is complete. 2 ml of a 9.4 N solution of anhydrous hydrogen chloride are added and the catalyst is removed by filtration through a pad of diatomaceous earth. The solution is concentrated under reduced pressure and the residue is extracted by shaking with diethyl ether (200 ml), twice with benzene (200 ml) and finally twice with diethyl ether (200 ml). The material remaining after these extractions is the desired tX. -succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalanine hydrochloride (Ol isomer) as diethyl ether solvate, Rf = 0.7 Flash chromatography on a silica gel plate, 50% methanol-50% benzene solvent (v / v) With 12% diphenylmethane as an impurity.

- 18.75 (c = 1.68, CH 2 OH).

Example 5 A. Preparation of CX chloroethyl pivalate 400 mg of zinc chloride are melted at a pressure of 0.2-0.5 mm and cooled to 25-30 ° C under a nitrogen atmosphere. To the molten zinc chloride is added 48 g (0.40 mol) of pivaloyl chloride and then 19.2 g (0.44 mol) of acetaldehyde. During the addition of acetaldehyde, which is performed as quickly as possible, the reaction mixture is stirred and cooled to prevent acetaldehyde losses due to the exothermic nature of the reaction. Heat at reflux for 1 hour, then distill to give 36 g (55%) of <X-chloroethyl pivalate, m.p. 32-34 ° C / 4 mm.

B. Preparation of pivaloyloxyethyl L-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate

To a stirred solution of 9.0 g (0.018 mol) of LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine in 25 ml of dry dimethylformamide is added 1.80 g (0.018 mol) triethylamine and then 2.96 g (0.01 8-moles) of o-chloroethyl valate. Stir at 90-95 ° C for 20 hours, then pour the reaction mixture into 350 ml of water and extract the product 3 times with 100 ml. The ether extracts are combined, washed with 50 ml of 5% sodium hydroxide solution, 50 ml of water and dried over anhydrous magnesium sulphate After filtration, the solvents are removed under reduced pressure to give 7.9 g (68.9%) of ether. ) crude ¢ 5 (.-pi-valoyl-18 61 687 oxyethyl LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate.

C. Preparation of DC-pivaloyloxyethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride_

A solution of 7.8 g of n-pivaloyloxyethyl LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate in 140 ml of absolute ethanol and 11 ml of an ethanolic solution of 8-n anhydrous hydrogen chloride is hydrogenated. 3.7 g of 10% palladium-on-carbon catalyst at 20-25 ° C at an initial pressure of 2.46 kg / cm 2 for 19 hours, i.e. until hydrogen bonding is complete. After removal of the catalyst, the ethanol is removed by filtration under reduced pressure. The residue is stirred with benzene (80 ml) overnight. The benzene is removed by decane, replaced with 80 ml of hexane, stirred and the hexane is decanted off. The residue is dissolved in 300 ml of ethyl acetate, the solution is stirred briefly with a mixture of 5 g of solid sodium carbonate and 5 ml of saturated sodium carbonate solution and dried over anhydrous magnesium sulfate. After filtration, 3 ml of an ethanolic solution of 9.6% anhydrous hydrogen chloride are added, and the solution is concentrated to dryness under reduced pressure. Further drying at 65 ° C and 0.2 mm gives 2.16 g (47.2%) of oL-pivaloyloxyethyl ester hydrochloride.

Analysis calculated for C 54 H 22 NO 4 .HCl: C 54.32 H 6.97 N 3.73 Found: C 54.47 H 7.36 N 3.39

Example 6 A. Preparation of L-N-carbobenzyloxy-3- (3,4-dihydroxyphenyl) -2-methylalanine

To a stirred solution of 3.0 g (0.0126 mol) of L-3- (3,4-dihydroxyphenyl) -2-methylalanine sesquihydrate in 20 ml of 2N sodium hydroxide solution is added a solution under a nitrogen atmosphere at 0 ° C, with 3 ml of carbobenzyloxy chloride in 10 ml of diethyl ether. Stir for 1 hour at 0 ° C and then for 1 hour at 25 ° C, and extract the reaction mixture with 50 ml of diethyl ether. The aqueous phase is acidified to pH 3-4 with 6N hydrochloric acid solution and the crude product is extracted into 100 ml of ethyl acetate and washed 3 times with 25 ml of water. After drying over magnesium sulfate, the solvent is filtered off and the solvent is removed under reduced pressure to give 1.5 (34.5%) of L-N-carbobenzyloxy-3- (3,4-dihydroxyphenyl) -2-methylalanine as a viscous oil.

B. Preparation of Pivaloyloxymethyl L-3- (3,4-dihydroxyphenyl) -2-methyl- * alaninate hydrochloride A mixture of 2.1 g (6.1 mmol) of LN-carbobenzyloxy-3- (3 , 4-dihydroxyphenyl) -2-methylalanine, 0.93 g (6.2 mmol) of chloromethyl pivalate, 0.63 g (6.3 mmol) of potassium carbonate and 0.15 17 61637 g of potassium iodide in 60 ml of acetone and 4 in 1 ml of water, stir by boiling, refluxing under nitrogen for 18 hours. After concentrating the solution under reduced pressure, 50 ml of water are added thereto, and the N-carbobenzyl derivative of the desired ester is extracted with 3 50 ml portions of diethyl ether. The ether extract is washed with 50 ml of water, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. the oily residue is dissolved in 100 ml of absolute ethanol and H ml of 9.6% anhydrous hydrogen chloride solution and hydrogenated with 1 g of 10% palladium-on-carbon catalyst at an initial pressure of 2.74 kg / cm2 for 24 hours. After removal of the catalyst by filtration, the filtrate is concentrated under reduced pressure. The residue is dissolved in 5 ml of water, the solution is basified to pH 8 with saturated sodium carbonate solution and the insoluble product is extracted into 25 ml of ethyl acetate. Dry over anhydrous magnesium sulfate, filter, and add 1 mL of a 9.6 N solution of anhydrous hydrogen chloride in ethanol, and concentrate the solution under reduced pressure to give 0.50 g (22.6%) of pivaloyloxymethyl-L-3- (3,4- dihydroxyphenyl) -2-methylalaninate hydrochloride, Rf = 0.86 by thin layer chromatography / fluorescent silica gel plate developed in 5: 2: 3 (v / v) n-butanol: acetic acid: water /. Analysis calculated for C 18 H 28 NOO.HCl: C 53.11 H 6.69 N 3.87 Found: C 5 3.76 H 6.64 N 3.69

Example 7 A. 1, Preparation of chloro-1-succinimidopropane

Anhydrous hydrogen chloride is passed for 6 hours through a mixture of 10 g (0.072 mol) of N-propenyl succinimide and 1.04 g of tannic chloride. The solution is allowed to stand at room temperature for 10 days, at which time the solution is again saturated with hydrogen chloride gas after 3 and 4 days. The solvents are removed under reduced pressure at 30-40 ° C to give 1-chloro-1-succinimidopropane as a yellow oil.

B. Preparation of O (-succinimidopropyl L-N-carbobenzyl) -3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate _____

A solution of 10.2 g (0.020 moles) of LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -methylalanine α, 2.1 g, (0.021 moles) of triethylamine and 3.51 g (0.020 mol) of 1-chloro-1-succinimidopropane in 20 ml of dimethylformamide are heated at 90 ° C for 10 hours, then the solution is poured into 200 ml of water. The product is extracted 3 times with 100 ml portions of ethyl ether and washed with 50 ml of 5% sodium hydroxide, 50 ml of water and 50 ml of saturated sodium chloride solution. After drying over anhydrous magnesium sulfate, the solvents are removed under reduced pressure to give 8.6 g (68%) of (X-succinimidopropyl-LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate a, Rf = 0.2 by thin layer chromatography (fluorescent silica gel, evolution from chloroform).

C. Preparation of S-Succinimidopropyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride__

A solution of 8.6 g (0.014 mol) of O (, - succin midopropyl LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate in 120 ml of 25% ethanol-75% in ethyl acetate (% v / v), 4 g of palladium-on-carbon catalyst are hydrogenated at an initial pressure of 2.81 kg / cm for 18 hours, i.e. until hydrogen bonding is complete, after removal of the catalyst by filtration, the solvents are removed under reduced pressure. At 40. The residue is dissolved in 10% ethanol-90% ethyl acetate (v / v) and the solution is stirred with saturated sodium carbonate solution (5 ml) and solid sodium carbonate (excess) for 2 minutes, and 10 g of anhydrous magnesium sulfate are added. , and the mixture is filtered and the filtrate is acidified with 2 ml of a 9.6% solution of hydrogen chloride in ethanol, evaporated to dryness under reduced pressure, 100 ml of ethyl acetate are added and the mixture is again evaporated to dryness under reduced pressure. at 25 ° C for 1 hour and the product is removed by filtration and dried under reduced pressure to give 3.0 g (51.0%) of succinimidopropyl-L-3- (3,4-dihydroxyphenyl) - 2 methyl alaninate hydrochloride as ethanol solvate, Rf = 0.63 by thin layer chromatography on a fluorescent silica gel plate, evolution from 30% methanol to 70% benzene (11% v / v) 7.

Analysis calculated for C 13 H 22 N 2 O 8 .HCl 1 Cl 2 H 5 OH: C 52.71 H 6.75 N 6.47 Found: C 53.62 H 6.51 N 6.32

Example 8 A. Preparation of 2-succinimidoethyl L-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methyl alaninate

A solution of 4.5 g (8.8 mmol) of LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine, 0.90 g (9 mmol) of triethylamine and 1.85 g (9.3 mmol) of mmol) of N- (2-bromoethyl) -succinimide in 15 ml of dimethylformamide, heated at 95 ° C for 19 hours, then the solution is cooled and poured into 150 ml of water.

The product is extracted 3 times with 100 ml portions of ethyl ether, the extract is washed with 50 ml of 5% sodium hydroxide solution, 50 ml of water and 50 ml of saturated sodium chloride solution and dried over anhydrous magnesium sulfate. After filtration, the solvents are removed under reduced pressure to give 4.8 g (86%) of 2-succinimethyl-LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate, which is homogeneous by thin-layer chromatography. fluorescent silica gel plate, evolution with chloroform7, Rf = 0.2 7.

B. Preparation of 2-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride hemihydrate

A suspension of 2.5 g (3.94 mmol) of 2-succinimidoethyl LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate in 75 ml of methanol, 75 ml of ethanol and 3 in 7.6 ml of an ethanolic solution of anhydrous hydrogen chloride, 1.2 g of 10% palladium-on-carbon catalyst are hydrogenated at an initial pressure of 1.41 kg / cm @ 2 for 20 hours. After removal of the catalyst by filtration, the solvents are removed under reduced pressure, and the residue is mixed with benzene (25 ml) and then ethyl acetate (25 ml). The insoluble material is treated with 100 ml of a mixture of 10% ethanol-90% ethyl acetate (v / v), 5 ml of saturated sodium carbonate solution and 5 g of solid sodium carbonate a. The organic extract is dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. Add 1 ml of an ethanolic solution of 9.6% anhydrous hydrogen chloride. All solvents are removed under reduced pressure to give 0.5 g (33%) of 2-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalanine hydrochloride dihemihydrate as a homogeneous thin sheet. ograf i alla /{.fluorescent silica gel plate, development with 30% methanol-70% benzene mixture (ti% by volume) 2, Rf = 0.4.

Analysis calculated for C 18 H 21 QN 2 O 1 / 2H 2 O: C 50.33 H 5.54 N 7.34 Found: C 50.89 H 5.65 N 7.22

Example 9 A. Preparation of racemic N-carbobenzyloxy-3- (3,4-dihydroxyphenyl) -2-methylalaninate ________

To a stirred solution of 8.0 g (0.0378 moles) of racemic DL-3- (3,4-dihydroxyphenyl) -2-methylalanine in 60 ml of a 2-N sodium hydroxide solution under a nitrogen atmosphere is added a solution of 9 ml carbobenzyloxychloride in 25 ml of diethyl ether. Stir for 1 hour at 0 ° C, then for 1 hour at 25 ° C, then extract the reaction mixture with 50 ml of diethyl ether. The aqueous phase is acidified to pH 3 with 6N hydrochloric acid and the crude product is extracted into 100 ml of ethyl acetate, washed 3 times with 35 ml of water, dried over anhydrous magnesium sulphate and filtered, then the solvent is removed under reduced pressure to give 4.5 g (34 g). %) of racemic N-carbobenzyloxy-3- (3,4-dihydroxyphenyl) -2-methylalanine as a viscous oil.

B. Preparation of racemic pivaloyloxymethyl 3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride_

A solution of 4.2 g (0.012 mol) of racemic N-carbobenzyloxy-3- (3,4-dihydroxyphenyl) -2-methylalanine, 1.3 g (0.013 mol) of triethylamine and 1.26 g (0.013 mol) of ) chloromethyl pivalate in 20 ml of dimethylformamide, stirred at 90 ° C for 20 hours, then poured into 200 ml of water. The product is extracted into 100 ml of ethyl acetate and washed with 25 ml of saturated sodium bicarbonate solution and 25 ml of water. The solution is dried over anhydrous magnesium sulfate, filtered and the filtrate is concentrated under reduced pressure to give the N-carbobenzyloxy derivative of the desired ester. This material is dissolved in 100 ml of absolute ethanol containing 10 ml of a 9.6% solution of anhydrous hydrogen chloride in ethanol and hydrogenated with 3 g of 10% palladium on carbon catalyst at an initial pressure of 2.46 kg / cm 2 for 24 hours. After removing the catalyst by filtration, the filtrate is concentrated under reduced pressure. The residue is dissolved in 25 ml of water, basified to pH 8 with saturated sodium carbonate solution and the insoluble product is extracted with 100 ml of ethyl acetate. The solution is dried over anhydrous magnesium sulfate and filtered, 5 ml of a 9.6% solution of anhydrous hydrogen chloride in ethanol are added, and the solution is concentrated under reduced pressure to give 1.5 g (22.6%) of racemic pivaloyloxymethyl-3- (3,4-dihydroxyphenyl). ) -2-methylalaninate hydrochloride homogeneous by thin layer chromatography / fluorescent silica gel, development with 5% (v / v) n-butanol-acetic acid-water7, Rf = 0.86.

Example 10 A. Preparation of D, L-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine hydrochloride

A mixture of 38.6 g (0.155 mol) of racemic 3- (3,4-dihydro, ciphenyl) -2-methylalanine hydrochloride and 74 g (0.312 mol) of dichlorodiphenylmethane is immersed in an oil bath which is preheated. to 190 ° C and the mixture is stirred slowly. After the start of the reaction, the reaction mixture is stirred rapidly for 6 minutes at 190616 8 7 190 ° C, removed from the hot oil baths and allowed to cool to 25-30 ° C. The crude products from run 6 are combined, slurried in 2 liters of diethyl ether, filtered, washed with a further 2 liters of diethyl ether and dried at 30 ° C at 50 mm. The solid is recrystallized by dissolving in ethanol and adding ethyl acetate to precipitate D, L-3- (3,4-diphenylmethylenedioxylenyl) -2-methylalanine hydrochloride.

B. D. Preparation of L-N-carbobenzyloxy-3- (3,4-diphenylated ethylenedioxyphenyl) -2-methylalanine

A mixture of 175 g (0.425 moles) of racemic 3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine hydrochloride, 1750 ml of acetone and 1750 ml of water is stirred under a nitrogen atmosphere at a temperature below 10 ° C while adjusting the pH to 12.0: slowly by the addition of 10 'sodium hydroxide solution. 94 g (0.5-5 mol) of carbobenzyloxychloride and at the same time 10% sodium hydroxide solution are added dropwise to the reaction mixture over a period of 5-7 minutes at 20-30 ° C to maintain the pH at 12.0-12.2. When the addition of carbobenzyloxy chloride is complete, the reaction mixture is stirred at 25-30 ° C for 3 hours. Most of the acetone is then removed under reduced pressure at 25-35 ° C to precipitate the sodium salt of the desired N-carbobenzyloxy derivative. The sodium salt is extracted into 1.5 liters of ethyl acetate, the solution is washed with 200 ml of 5% sodium hydroxide solution and 200 ml of saturated sodium chloride solution, then dried over anhydrous magnesium sulfate. 17.5 g of decolorizing carbon are added, filtered through a pad of magnesium sulphate, the solvents are removed under reduced pressure at 25-35 ° C. The residue is slurried twice with 1 liter of 20% ethyl ether-80% hexane (% v / v) and filtered to give the sodium salt of the desired N-carbobenzyloxy derivative. The sodium salt is dissolved in 1.5 liters of ethyl acetate, the solution is cooled to 10 ° 0 and acidified to pH 2 with 6N hydrochloric acid. The ethyl acetate extract is washed with 200 ml of saturated sodium chloride solution, dried over magnesium sulfate, filtered and concentrated under reduced pressure at 25-35 ° C. The N-carbobenzyloxy derivative is further dried at 25-30 ° C / 0.2-0.3 mm Hg to give D, L-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine.

C. Preparation of D, L-succinimidomethyl-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate

A solution of 13.5 g (0.0265 moles) of LN-carbobenzyloxy-3- (3,4-diphenylimethylenedioxyphenyl) -2-methyl ai anine α, g (0.027 moles) of triethylamine and 5.19 g (0.029 moles) of N-bromoethylsuccinimide in 35 ml of dry dimethylformamide are stirred at 61,687,225-30 ° C for 16 hours. The reaction mixture is poured into 400 ml without ice and the product is extracted into 200 ml of a mixture of 50% chloroform-50% diethyl ether (v / v). The organic extract is washed with 50 ml of dilute (5%) sodium carbonate solution and 50 ml of saturated sodium chloride solution, and then dried over anhydrous magnesium sulfate to remove water. After filtration and concentration under reduced pressure, the residue obtained is recrystallized, the crystallization is carried out by dissolving the product in ethanol and adding hexane to precipitate D, L-succinimidomethyl-N-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine.

D. Preparation of D, L-succinimidomethyl 3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate

A suspension of 6.6 g (0.0106 moles) of racemic succinic acid domeyl-N-carbobenzyloxy-3- (3,4-diphenylmethyleneoxyphenyl) -2-methylalaninate in 180 ml of absolute ethanol and In 9 ml of an ethanolic solution of 9.6% anhydrous hydrochloric acid, hydrogenate with 3.3 g of 10%. palladium on carbon catalyst initial pressure 1 la 2.11 kg / cm 2 until hydrogen bonding is complete. After removal of the catalyst by filtration, the filtrate is concentrated under reduced pressure. The residue is extracted with 50 ml of benzene and then with 50 ml of ethyl acetate. The insoluble material is shaken with a mixture of 10% ethanol-90% ethyl acetate (v / v) (50 ml) and saturated sodium carbonate 1 solution (10 ml). Filter and dry the filtrate over anhydrous magnesium sulfate, filter and concentrate under reduced pressure to give D, L-succinimidomethyl 3- (3,4-dihydroxyphenyl) -2-methylalaninate as a base.

E. Preparation of succinic stripomethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate by crystallization of diastereomeric salts_

A solution of 0.47 g (3.1 mmol) of (-) - tartaric acid in 10 ml of a 50% absolute ethanol-50% ethyl acetate mixture (v / v) is added under a nitrogen atmosphere at 20-25 ° C. to a solution of 1.0 g (3.1 mmol) of D, L-succinimidomethyl 3- (3,4-dihydroxyphenyl) -2-methylalaninate in 10 ml of absolute ethanol. The solution is heated to 40-60 ° C, ethyl acetate is added until it begins to cloud, then slowly cooled to 25 ° C and finally allowed to stand at 5-10 ° C for 2 hours. The insoluble crude tartrate salt is removed by filtration and dried at 20-25 ° C / θ, 2-0.5 mm.

This recrystallization is repeated until the melting and optical rotation of the tartrate salt are practically constant.

The mother liquor of the initial crystallization is concentrated at a pressure of 15-20 mm and a temperature of 40-50 ° C. The residue is shaken with a mixture of 10% ethanol-90% ethyl acetate-thia (v / v) (25 ml) and saturated sodium carbonate solution (10 ml). After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and concentrated at 40 ° C for 15-20 mm to give a gummy product. The residue is dissolved in 5 ml of absolute ethanol and the solution is added under a nitrogen atmosphere to a solution of 0.3 g of (+) - tartaric acid in 10 ml of a 50% absolute ethanol-50% ethyl acetate mixture (v / v). The solution is heated to 40-60 ° C, ethyl acetate is added until the solution begins to cloud, then slowly cooled to 25 ° C and stored at 5-10 ° C for 14 hours. The insoluble crude tartrate salt is removed by filtration. By repeating this recrystallization, a second optical antipode of succinimidomethyl-3- (3,4-dihydroxyphenyl) -2-methylalaninate is obtained as the tartrate salt.

The optically active tartrate salts are converted into optically active hydrochloride salts by the following method. The tartrate salt of succinimido-L-3- (3,4-dihydroxyphenyl) -2-methylalaninate is shaken with a mixture of 10 # ethanol-90 # ethyl acetate (v / v) (50 ml) and saturated sodium carbonate solution (10 ml). After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue is redissolved in 25 ml of absolute ethanol, the solution is treated with 5 ml of an ethanolic solution of 9.6 in anhydrous hydrogen chloride, and the solution is concentrated under reduced pressure to give succinimidomethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate. , which is homogeneous by thin layer chromatography / fluorescent silica gel plate, development 30 # methanol-70 # benzene mixture (volume - #) /, observed Rf = 0.5.

Example 11

Resolution of racemic pivaloyloxymethyl 3- (3,4-dihydroxyphenyl) -2-methylalaninate by direct crystallization

Racemic pivaloyloxymethyl 3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride is prepared as in Example 23.

Slurry 30 g of racemic pivaloyloxymethyl 3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride at 35 ° C in 100 ml of 1.0 N hydrochloric acid. The excess solid is filtered, the saturated solution is then inoculated at 35 ° C with pivaloyloxymethyl D-3- (3,4-dihydroxyphenyl) -2-methylcinninate hydrochloride hydrate. It is cooled to 20 ° C in 30 minutes and kept at 20 ° C for 0.5 hours. The separated material is filtered, washed twice with 5 ml of cold 2 * 61687 water and dried at 20-25 ° C / 0.1-0.5 mm for 20 hours to give pivaloyloxymethyl-D-3- (3,4-dihydroxyphenyl). ) -2-methylaneanate hydrochloride dihydrate a.

o

The mother liquor obtained from the previous step is heated to 35 DEG C. and inoculated at 35 DEG C. with p-light oxymethyl-L-3- (3,3 * -dihydroxyphenyl) -2-methylalaninate hydrochloride. The mixture is then cooled to 20 ° C in 30 minutes and allowed to stand at 20 ° C for 0.5 hours. The precipitated material is filtered off, washed twice with 5 ml of cold water and dried at 20-25 ° C / θ.1-0.5 mm for 20 hours to give pivaloyl-1 i oxymethyl iL-3- (3, N-dihydroxyphenyl) -2-methylaneanate hydrochloride dihydrate.

Example 12 A. Preparation of α-L-succinimidoethyl L-3- (3, 4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate (β-isomer) by fractional crystallization

Dissolve 10 g of the o6-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride (mixture of CC and β-isomers) obtained in Example 2 in 50 ml of warm 95% ethanol (5% water), the solution is diluted with anhydrous ether until it begins to cloud, inoculated and scraped to initiate crystallization. Cool to 5-10 ° C for 12 hours, collect the precipitated solid and dry at 70 ° C. Further similar crystallizations are performed from 95% ethanol-5% water (v / v) ethyl ether to give a material that melts at 123-126 ° C (decomposes). Final crystallization from 95% ethanol gives N-succinimidoethyl L-3- (3,3-dihydroxyphenyl) -2-methylalanine hydrochloride dihydrate (β-isomer), melting at 129-131 ° C (decomposes) (dried at 70 ° C). C overnight) and which is homogeneous by thin layer chromatography (fluorescent silica gel plate, 50% methanol-50% benzene solvent) (volume%) /, Itf = 0.7.

B. Preparation of s-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate (06-isomer) L-3- (3,4-dihydroxyphenyl) The mother liquor obtained from the first crystallization of the -2-methylalaninate hydrochloride hydrate / δ-isomer with a large amount of the corresponding β-isomer is concentrated at 40 ° C / 5 5-20 mm. The residue is dissolved in 20 ml of warm 95% ethanol (5% water), the solution is diluted with ethyl acetate until cloudy, inoculated and scraped with the enriched o-s-imidoe-L-3- (3,4-dihydroxyphenyl) - 2-Methylalanate precipitated the o6 isomer of the hydrochloride hydrate. Additional precipitation from 95% ethanol (5% water) and ethyl acetate gives the ρί isomer as ethyl acetate, Rf = 0.7 / thin layer chromatography, fluorescent silica gel plate, 50% methanol-50% benzene mixture. (v - ^) /.

Example 13

Preparation of pivaloyloxymethyl L-3- (3,4-dihydroxyphenyl) -2-methylalanine hydrochloride

A solution of 0.95 mmol) of L-3- (3,4-dihydroxyphenyl) -2-methylalanine sesquihydrate and 0.61 g (4.06 mmol) of pivaloyloxymethyl chloride in 5 ml of dimethyl sulfoxide is stirred at 20-25 ° C. at 23 hours. The solution is diluted with 10 ml of distilled water and passed through a column of 5 g of a weakly basic anion exchange resin in the basic phase. The elution is carried out by aqueous fraction and the fractions giving a positive ferric chloride test are combined and added to a column containing 3 g of a weakly acidic cation exchange resin in an acidic phase. Unreacted L-3- (3,4-dihydroxyphenyl) -2-methylalanine is eluted with distilled water until a negative ferric chloride test is obtained, then the ester is eluted with 1N acetic acid. The ester fraction, 50 ml (pH 3.2), is acidified to pH 2.0 with 1N hydrochloric acid and lyophilized at 0.3 mm for 20 hours to give pivaloyloxymethyl L-3- (3,4-dihydroxyphenyl). ) -2-methylalaninate hydrochloride as the acetic acid solvate. Analysis calculated for C 52 H 9 N 2 O 2 .HCl · 1 / HCl H 2 O 2: C 52.11 H 6.69 N 3.58 Found: C 52.11 H 6.94 N 3.73

Example 14 Preparation of s-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride

A solution of 0.95 g (4.0 mmol) of L-3- (3,4-dihydroxyphenyl) -2-methylalanine sesquihydrate and 0.65 g (4.0 mmol) of N- (06-chloroethyl) - succinimide in 5 ml of dimethyl sulfoxide, stirred at 20-25 ° C for 23 hours. The solution is diluted with 10 ml of distilled water and passed through a column containing 5 g of a weakly basic anion exchange resin in the basic phase. Elute with aqueous fraction and combine the fractions which give a positive result in the Ferri chloride test and transfer them to a column containing 3 g of weakly acidic cation exchange resin in the acidic phase. Unreacted L-3- (3,4-dihydroxyphenyl) -2-methylalanine is eluted with distilled water until a negative ferric chloride test result is obtained, and the ester is then eluted with 1N acetic acid. The ester fraction, 55 ml (pH 3.2), is adjusted to pH 2.0 with 1N hydrochloric acid and lyophilized in the name of 0.1-0.3 x A for 20 hours to give the ού-succinimidone. - (3,4-di-61,687 26 hydroxyphenyl) -2-methylalaninate hydrochloride as the acetic acid solvate. Analysis calculated for C 16 H 20 N 2 O 6, HCl.1 / 3C? H 4 O 2: C 60.96 H 6.73 N 7.13 Found: C 5 0.48 H 6.13 N 6.77

Example 15 A. Preparation of L-3- (3,4-diacetoxyphenyl) -2-methylalanine hydrochloride To a mixture of 320 ml of glacial acetic acid and 24 ml of acetyl chloride a is added in one portion 69.4 g (0.291 mol). ) L-3- (3,4-dihydroxy-phenyl) -2-methylalanine sesquihydrate. The temperature of the reaction mixture rises to about 50 ° C to give a clear solution. At this temperature, 85 ml of acetyl chloride a are added over a further 10 minutes. The resulting clear pale yellow solution is allowed to stand at 20-25 ° C for 14 hours. Add 15 ml of anhydrous ethyl ether over 15 minutes. When the addition is almost complete, a white precipitate begins to form. The mixture is stirred at 20-25 ° C for 30 minutes, at 5-10 ° C for one hour and then cooled at -10 ° C for 2 hours. The solid is removed by filtration, suspended in 150 ml of 30% acetic acid-70% ethyl ether (v / v), filtered and washed with 500 ml of ethyl ether. After drying for 2 hours at 70 [deg.] C., 83.7 g (88%) of L-3- (3,4-diacetoxyphenyl) -2-methylalanine hydrochloride are obtained, m.p. 196.0 to 197.0 ° C.

B. Preparation of L-3- (3,9-diacetylphenyl) -2-methylalanine Chloride hydrochloride A mixture of 6.60 g (0.020 moles) of L-3- (3,4-diacetoxy) phenyl ) -2-methylalanine hydrochloride and 40 ml of thionyl chloride are stirred at 60 ° C for 2 hours until dissolution has taken place. Excess thionyl chloride is removed at 15-20 mm at 40-50 ° C. 50 ml of methylene chloride are added and the mixture is reconcentrated at 40-5 ° C for 15-20 mm. This is repeated once more with a further 50 ml of methylene chloride. Dry at 40 ° C / 0.2-0.5 mm for 30 minutes to give L-3- (3,4-di-acetoxy phenyl). -2-metyylialanyylikloridia.

C. Succinim Preparation of Dome style L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate_

A solution of 3.50 g (10 mmol) of L-3- (3,4-diacoxyphenyl) -2-methylalanyl chloride hydrochloride in 20 ml of chloroform is added at 25 ° C to a solution of 3.87 g. (30 mmol) of N-hydroxymethylsuccinimide in 20 ml of chloroform. Stir at reflux for 20 hours, remove most of the chloroform at 30-40 ° C and 15-20 mm. The residue is diluted with 10 ml of 1N hydrochloric acid and extracted with 2 x 20 ml portions of ethyl ether. The aqueous phase is stirred under a nitrogen atmosphere at 20-25 ° C for 5 hours. Lyophilize at 0.1-0.3 mm for 20 hours, treat the residue with 50 ml of 10% ethanol-90% ethyl acetate (v / v), 5 ml of saturated sodium carbonate solution and 5 g of solid solid. 61,687 sodium carbonate. After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and concentrated at 30 ° C / 15-20 mm. The residue is dissolved in 25 ml of absolute ethanol, the solution is treated with 5 ml of a 9.6% solution of anhydrous hydrogen chloride in ethanol and concentrated under reduced pressure to give succinimidomethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride dihydrate. homogeneous by thin-layer chromatography (fluorescent silica gel plate, 30% methanol-70% benzene (v / v)), Kf = 0.5 observed.

Example 16 A. Preparation of N-carboxylic anhydride of L-3- (3,4-dihydroxyphenyl) -2-methylalanine

Phosgene gas is introduced into a mixture of 9.0 g (0.038 mol) of L-3- (3,4-dihydroxyphenyl) -2-methylalanine sesquihydrate in 500 [mu] l of tetrahydrofuran for 25 minutes until the solution is saturated. During the addition, the temperature of the reaction mixture rises to 55 ° C. The solution is stirred for a further 50 minutes, passing nitrogen gas through the solution. The insoluble matter is removed by filtration through a diatomaceous earth plug and the filtrate is concentrated to an oil at 30-35 ° 0 / 15-20 mm. The residue is dissolved in 75 ml of ethyl acetate, and hexane is added to the solution until turbidity begins. Cool for several days at 0-5 ° C, then remove the precipitated solid by filtration and dry at 25 ° C / 0.1-0.3 mm to give L-3- (3,5-dihydroxylenyl) - N-carboxyanhydride of 2-methylalanine.

B. Preparation of succinimidomethyl L-3- (3, β-dihydroxyphenyl) -2-methylalaninate hydrochloride hydrate_

A solution of 2.37 g (10 mmol) of N-carboxyanhydride of L-3- (3,4-dihydroxy-1'-phenyl) -2-methylalanine and 1.29 g (10 mmol) of N-hydroxymethylsuccinimide, heat to reflux until all N-carboxyanhydride has reacted. Concentrate at 30-40 ° C / 15-20 mm, extract the residue with 50 ml of benzene and then with 50 ml of ethyl acetate. The insoluble solid is then shaken with a mixture of 10% ethanol-90% ethyl acetate (v / v; 50) (50 mL) and saturated sodium carbonate solution (10 mL). After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue is dissolved in 25 ml of absolute ethanol, the solution is treated with 5 ml of a 9.6 N solution of anhydrous hydrogen chloride in ethanol, then concentrated under reduced pressure to give the succinimide type 1-L-3- (3, A- dihydroxyphenyl) -2-methylalaninate hydrochloride dihydrate a, 28 616 87 which is homogeneous by thin layer chromatography / fluorescent silica gel plate, 30% methanol-70% benzene mixture (v / v) / 7, observed Hf = 0.5.

Example 17 A. Preparation of L-3- (3, A-diphenylmethylenedioxyphenyl) -2-methylalanine hydrochloride

A mixture of 19.3 g (0.0777 moles) of L-3- (3,3-dihydroxyphenyl) -2-methylalanine hydrochloride and 37 g (0.156 moles) of dichlorodiphenylmethane is slowly immersed with stirring at 190 ° C: heated oil bath. After the reaction has started, as evidenced by the vigorous evolution of gas, the reaction mixture is stirred vigorously for 6 minutes at 190 ° C, the mixture is removed from the hot oil bath and allowed to cool to 25-30 ° C. The crude products from 12 runs are combined, slurried in 3 liters of diethyl ether, filtered and washed with a further 2 liters of diethyl ether, then dried at 30 ° C / 50 mm, budelle crystallization is carried out by dissolving the product in ethanol and adding ethyl acetate to precipitate the product. The process gives 255 g (66%) of L-3- (3, A-diphenylmethylenedioxyphenyl) -2-methylalanine hydrochloride, m.p. 267-268 ° C, dec.

B. Preparation of succinimidoethyl L-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate

A solution of 1.0 g (4.0 mmol) of L-3- (3,1-diphenylmethylenedioxyphenyl) -2-methylalanine and 0.65 g (4.0 mmol) of N- (o6-chloroethyl) - succinimide in 5 ml of dimethyl sulfoxide, stirred at 20-25 ° C for 23 hours. Add 150 ml of water and then saturated sodium carbonate solution until pH 8. The product is extracted into 500 ml of ethyl ether, the extract is washed with 4 25 ml portions of water, dried over anhydrous magnesium sulfate and filtered. Concentration at 35-40 ° C at 15-20 mm gives crude o6-succinimidoethyl L-3- (3, A-diphenylmethylenedioxyphenyl) -2-methylaninate which is sufficiently pure to be used in the next step. .

C. Preparation of oC-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride_

A suspension of 1.0 g (2.0 mmol) of α-succinyl derivative L-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalaninate in 25% of 25% absolute ethanol-75% ethyl acetate mixture (% v / v), hydrogenate with 1.0 g of 10% palladium-on-carbon catalyst at an initial pressure of 2.81 kg / cm 2 at room temperature for 25 hours, filter the catalyst and evaporate the filtrate under reduced pressure 616 8 7 29 30- 40 ° Crssä. The residue is dissolved in 50 ml of a mixture of 10% ethanol-90 'ethyl acetate (v / v) and stirred with saturated sodium carbonate solution (5 ml) and anhydrous sodium carbonate (about 5 g) for 10 minutes. After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and evaporated to dryness under reduced pressure. The residue is dissolved in 20 ml of dry chloroform, the solution is cooled in an ice bath and saturated with hydrogen chloride gas for 15 minutes. The solid is collected, washed 3 times with 25 ml of anhydrous ether, then suspended in 25 ml of ethyl acetate and allowed to stand under Ng in a sealed flask at room temperature overnight. The insoluble solid was removed by filtration, stirred with hexane (30 mL) for 2 hours, dried in a vacuum desiccator over CaCl 2 to give o6-succinimidoethyl-L-3- (3,4-dihydroxyphenyl) -2-methylalanine 11-hydrogen. chloride as a mixture of 06 and someers, found Rf = 0.7 by thin layer chromatography / fluorescent silica gel plate, 50 # methanol-50 # benzene (volume #)].

Example IB

A. Preparation of L-3- (3,4-diacetoxyphenyl) -2-methylalanine hydrochloride

To a mixture of 320 ml of glacial acetic acid and 24 ml of acetyl chloride is added in one portion 69.4 g (0.291 mol) of L-3- (3,4-dihydroxyphenyl) -2-methylalanine sesquihydrate. The temperature of the reaction mixture rises to about 50 ° C and a clear solution is obtained. At this temperature, a further 85 ml of acetyl chloride are added over 10 minutes. The resulting pale yellow solution is allowed to stand at 20 ° C to 25 ° C for 14 hours. Add 400 ml of anhydrous ethyl ether within 15 minutes, when the addition is almost complete, a white precipitate begins to form. The mixture is stirred at 20-25 ° C for 30 minutes, 5-10 ° C for 1 hour, and allowed to stand for 2 hours at -10 ° C. The solid is filtered, suspended in 150 ml of a 30% mixture of acetic acid and 70% ethyl ether (v / v), filtered and washed with 500 ml of ethyl ether. Dry at 70 ° C for 2 hours to give 83.7 g of (88 #) L-3- (3,4-diacetoxyphenyl) -2-methylalanine hydrochloride, m.p. 196.0 to 197.0 ° C.

13. Preparation of oC-succinimidoethyl L-3- (3,4-diacetoxyphenyl) -2-methylalaninate hydrochloride

A solution of 1.66 g (5 mmol) of L-3- (3,4-diacetoxyphenyl) -2-methylalanine hydrochloride, 0.51 g (5 mmol) of triethylamine and 0.8 l ( 5 mmol) of N- (06-chloroethyl) -succinimide in 5 ml of dimethyl sulfoxide, stirred at 20-25 ° C for 20-24 hours. The dimethyl sulfide is removed by stirring the mixture with ethyl ether (20 mL) 61687 for several minutes and then decanting the ethyl ether. This extraction process is performed 3 times. The residue is dissolved in 10 ml of absolute ethanol and the product is precipitated by adding excess ethyl ether. The precipitation process is repeated 2 more times to give pure O-succinimidoethyl L-3- (3,4-diacetoxyphenyl) -2-methylalaninate hydrochloride.

Example 19 Preparation of O-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride

A solution of 1.8 g (3 * 9 mmol) of O 6-succinido stripethyl L-3- (3,4-diacetoxyphenyl) -2-methylalaninate hydrochloride (from Example 37) in 10 ml of 1N hydrochloric acid, stirred under a nitrogen atmosphere at 20-25 ° C for 5 hours. Lyophilize at 0.1-0.3 mm for 20 hours, treat the residue with 50 ml of a mixture of 10% ethanol-90% ethyl acetate (v / v), 5 ml of saturated sodium carbonate solution and 5 g of solid sodium carbonate. . After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and evaporated to dryness under reduced pressure. The residue is dissolved in 20 ml of dry chloroform, the solution is cooled in an ice bath and saturated with hydrogen chloride gas for 15 minutes. the solid is collected, washed by suspending 3 times in 25 ml of anhydrous ethyl ether and then slurrying in 25 ml of ethyl acetate and keeping it in a sealed flask at room temperature overnight. CC-succinimidoethyl-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride is collected and dried in a vacuum desiccator over CaCl 2 to give the hydrochloride as a mixture of 06 and isomers, found Rf = 0.7 by thin layer chromatography / fluorescent silica gel plate, 50% methanol-50% benzene solvent (v / v).

Example 20 A. Preparation of N- (1-chloroethyl) -maleimide

Stannous chloride, 5.20 g (0.020 mol), is added to a solution of 9.2 g (0.40 mol) of n-vinylmaleimide in 1 liter of carbon tetrachloride, the mixture being stirred while being saturated with hydrogen chloride for 6 hours at 20- At 30 ° C, after 24 hours, the mixture is re-saturated with hydrogen chloride for 1.5 hours. After 48 hours, the solution is decanted and the gummy residue is washed with 10 100 ml portions of carbon tetrachloride. The diatomaceous earth (10 g) slurried in the combined extracts is filtered and the filtrate is concentrated under reduced pressure to about 400 ml. The N- (1-chloroethyl) -maleimide is filtered off and dried at 20-30 °.

. V? · "

, i i. .'I

31 616 8 7 B. Preparation of Qtf-maleimido-1-L-3- (3,4-dihydroxyphenyl) -2-methyl-ninate hydrochloride

A solution of 0.93 g (4.0 mmol) of L-3- (3,4-dihydroxy-phenyl) -2-methylalanine sesquihydrate and 0.64 g (4.0 mmol) of N- (1,5-chloroethyl) -maleimide In 5 ml of dimethyl sulfoxide, stirred at 20-25 ° C for 23 hours. The solution is diluted with 10 ml of distilled water and passed through a column containing 3 g of a weakly basic anion exchange resin in the basic phase. The fractions are eluted with water, and the fractions giving the positive ferric chloride test are combined and taken up in a column containing 3 g of a weakly acidic cation exchange resin in the acidic step. Unreacted L-3- (3,4-dihydroxy-phenyl) -2-methylalanine is eluted with distilled water until a negative ferric chloride test is obtained, and the ester is then eluted with i-n acetic acid. The ester fraction, 55 mL (pH 3.2), is treated with 1 N hydrochloric acid to pH 2.0 and lyophilized at 0.1-0.3 mm for 20 hours to give o6-maleimido-L-3- (3.4 -dihydroxyphenyl) -2-methylalanine hydrochloride.

C. Preparation of OC-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalanate hydrochloride

A solution of 1.0 g (2.7 mmol) of β-mal. eimidoelyl-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride 2 in 5 ml of absolute ethanol, hydrogenated with 1.0 g of 10% palladium on carbon catalyst at normal pressure at 25 ° C, until 1 equivalent of hydrogen is bound. The catalyst is filtered off and the filtrate is evaporated under reduced pressure at 30-4 ° C. The residue is dissolved in 50 ml of a mixture of 10 ° ethanol-90% ethyl acetate (v / v) and the solution is stirred with saturated sodium carbonate solution (5 ml) and anhydrous sodium carbonate (about 5 g) for 10 minutes. After filtration, the filtrate is dried over anhydrous magnesium sulfate, filtered and evaporated to dryness under reduced pressure. The residue is dissolved in 20 ml of dry chloroform, the solution is cooled in an ice bath and saturated with hydrogen chloride for 15 minutes. The solid is collected, washed by suspending 3 times in 25 ml of anhydrous ether, then slurried in ethyl acetate (25 ml) and allowed to stand under a nitrogen atmosphere in a sealed flask at 20-25 ° C overnight. The insoluble solid was removed by filtration, stirred with hexane (30 mL) for 2 hours and dried in a vacuum desiccator over CaCl 2 to give O 6-succinimidoethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride. and / ^ - isomee- '* v' / -. observed as Rf = 0.7 by thin layer chromatography / fluorescence 616 8 7 3? except silica gel plate, 50 c / 0 inethanol and 50% bercenene-1 iodine n (U) avnus-5) J.

Example 21 Λ. Preparation of α-chloroethyl 1-3-chloro-2,2-dimethylpropylene 400 mg of zinc chloride are melted at 0.2-0.5 mm and cooled to 25-30 ° C under a nitrogen atmosphere. To the molten zinc i) is added fc> 2 g (0.40 moles) of 3-chloro-2,2-dimethylpropionyl chloride, followed by 19.2 g (0.44 moles) of acetaldehyde. During the addition of acetaldehyde, which is performed as quickly as possible, the reaction mixture is stirred and cooled to prevent loss of acetaldehyde due to the exothermic nature of the reaction. The mixture is heated under reflux for 1 hour, then the ethyl-3-chloro-2,2-dimethylpropionate is separated by distillation.

B. Preparation of O- (3-chloro-2,2-diacetylpropyloxy) -ethyl L-3- (3, -dihydroxyphenyl) -2-methylalaninate hydrochloride

A solution of 0.95 g (4.0 mmol) of L-3- (3,4-dihydroxyphenyl) -2-methylalanine squihydrate and 0.81 g (4.00 mmol) of o ( -chloroethyl 3-chloro-2,2-dimethylpropionate in 5 ml of dimethyl sulfoxide, stirred for 23 hours at 20 to 25 ° C. Solution 1 is taken up in 10 ml of distilled water and taken up in a column, containing 5 g of a weakly basic anion exchange resin in a basic step, water fractions and fractions with a positive iervi kl or idi test are combined and transferred to a column containing 3 g of a weakly acidic ka ti oni nvai ht ohar t. s Unreacted L-3- (3,4-dihydroxyphenyl) -2-methylalanine is eluted with distilled water until a negative test for ferric chloride is obtained, then the ester is eluted in acetic acid. Asterl fraction, 50 ml (pH 3.2) acidify to pH 2.0 with 1N hydrochloric acid and lyophilize at 0.1-0.3 mm for 20 hours to give o - (3-chloro-2,2-dimethylpropionyloxy) -ethyl-L- 3- (3,4- hydroxyphenyl) -2-methylalaninate hydrochloride as an acetic acid solvate.

L. Preparation of O-pivaloyl oxyethyl L-3- (3,4-dihydroxyphenyl) -2-methylaninate hydrochloride

A solution of 1.5 g (3.66 mmol) of O- (3-chloro-2,2-dimethylpropionyloxy) -ethyl-L-3- (3,4-dihydroxyphenyl) -2-methyl- alaninate hydrochloride in 20 ml of absolute ethanol, hydrated with 1.0 g of 10% palladium-on-carbon catalyst at 20-25 ° L and normal pressure until 1 equivalent of hydrogen is bound. After removal of the catalyst by filtration, the ethanol is removed at 30-35 ° C / 15-26 mm. The residue is dissolved in 40 ml of ethyl acetate, the solution is stirred briefly with solid sodium carbonate (2 g) and saturated sodium carbonate solution (2 ml) and dried over anhydrous magnesium sulphate. After filtration, 1 ml of ethanolic anhydrous hydrogen chloride solution is added and the solution is evaporated to dryness under reduced pressure. Further drying at 65 ° C / 0.2 mm gives β-pivaloyloxyethyl ester hydrochloride.

Example 22 A. Preparation of benzyl succamate

A mixture of 23.4 g (0.20 mol) of succinic acid, 25.4 g (0.20 mol) of benzyl chloride, 29.2 g (0.20 mol) of triethylamine and 250 ml of dimethylformamide is stirred at 95 ° C. at 20 hours. The reaction mixture is diluted with 500 ml of water and the product is extracted with two 200 ml portions of ethyl ether. The combined ether extracts are washed with two 50 ml portions of saturated sodium carbonate solution, then with two 50 ml portions of water and dried over anhydrous magnesium sulfate. After filtration, the solution is concentrated at 15-20 mm and 40 ° C to give benzyl succinate.

B. Preparation of benzyl N-hydroxymethyl succamate

To a stirred solution of 20.7 g (0.10 mol) of benzyl succinate in 150 ml of ethyl acetate are added, at 25 ° C, 3.0 g of paraformaldehyde and 1 ml of 20% (w / w) potassium hydroxide. ethanol solution. Stir at 25 ° C for 20 hours, then add hexane until the solution begins to cloud and cool the mixture at 5 ° C for 24 hours. The solvents are decanted off and the residue is washed with 25 ml of hexane to give benzyl N-hydroxymethylsuccinamate.

C. Preparation of benzyl N-chloromethyl succinamate

A solution of 24.2 g (0.10 moles) of benzyl N-hydroxymethyl succinate and 28.9 g (0.11 moles) of triphenylphosphine in 500 ml of carbon tetrachloride is stirred at reflux for 12 hours. After filtration and washing of the precipitate with benzene, the organic solutions are removed at 30-40 ° C / 15-20 mm to give benzyl N-chloromethylsuccinamate in sufficient purity for use in the next step.

D. Preparation of benzyl isuccinamidomethyl-L-N-carbobenzyl oxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine

A solution of 10.2 g (0.020 mol) of LN-carbobenzyloxy-3- (3,4-diphenylmethylenedioxyphenyl) -2-methylalanine, 2.02 g (0.020 mol) of triethylamine and 5.12 g (0.020 mol) of benzyl N-chloromethylsuccinamate in 20 ml of dimethylformamide, is stirred at 70 DEG C. for 5 hours, then at 20 DEG-30 DEG C. for 5 hours, and finally the solution is poured into 200 ml of water. The product is extracted with 3 of 100 ml portions of ethyl acetate, the extract is washed with 50 ml of 5% sodium hydroxide solution, 50 ml of water and 50 ml of saturated sodium chloride solution and dried over anhydrous magnesium sulfate. After filtration, the solvents are removed at 30 ° C / 15-20 mm to give Bent cause 1 isomer name Dome style IL-carboxylate cause 3-oxy-3- (3,4-diphenyl). -methylenedioxyphenyl) -2-methylalanine.

F. Preparation of dock style -L-3- (3,4-dihydro diphenyl) -2-methylalaninate hydrochloride _

A solution of 13.8 g (0.0189 moles) of Bent, a dichloromethane DOM-LN-carbobenzyl Yloxy-3- (3,4-diphenylmethylidene di li) -2-methylalanine in 130 ml of a 25% absolute ethanol-75 '/ ethyl acetate mixture (v / v) is hydrogenated with 5 g of 10% palladium on carbon catalyst at 20-25 ° C at an initial pressure of 2.81 kg / cm-18 hours, i.e. until hydrogen bonding ceases, after removal of the catalyst by filtration, the solution is evaporated to dryness under reduced pressure, the residue is dissolved in 200 ml of 10% absolute ethanol-90 5% ethyl acetate (v / v) and the solution is stirred with saturated sodium urea carbonate solution (5%). ml) and solid sodium carbonate (excess) for 2 minutes. 10 g of anhydrous magnesium sulphate are added and after a few minutes it is removed by filtration. The solvents are removed under reduced pressure, the residue is washed with 25 ml of hexane and then with 25 ml of ethyl acetate and dried under reduced pressure. The residue is re-treated with sodium carbonate as above to remove the last traces of methyl-3,4-dihydroxyphenylalanine, then converted into the hydrochloride salt with 3 ml of an ethanolic solution of anhydrous hydrogen chloride in 9. succinamidomethyl L-3- (3,4-dihydroxyphenyl) -2-racethylalaninate hydrochloride is obtained.

F. Preparation of Succinic Iridomethyl L-3- (3,3-dihydroxyphenyl) -2-methylalanine hydrochloride hydrate__

A mixture of 3.95 g (10 ramoles) of succinamidomethyl L-3- (3,4-dihydroxyphenyl) -2-methylalaninate hydrochloride and 100 ml of acetyl chloride is stirred at 25 ° C for 6 hours. The solution is concentrated at 35 [deg.] C./15-20 mm, and the residue is dissolved in 25 ml of 1N hydrochloric acid, and the solution is stirred under an atmosphere of 20-25 [deg.] C. for 5 hours. The solution is lyophilized at 0.1-0.3 mm for 20 hours, the residue is treated with 50 ml of a 10% ethanol-90% ethyl acetate mixture (t-4 '), 5 ml of saturated sodium carbonate solution and 5 Ktlla 616 8 7 35 solid sodium carbonate. After filtration, the filtrate is dried over anhydrous magnesium sulfate, the solution is filtered and concentrated at 30-40 ° C / 15-20 mm. The residue is dissolved in 25 ml of absolute ethanol, treated with 5 ml of a 9.6% solution of anhydrous hydrogen chloride in ethanol and concentrated under reduced pressure to give succinimidomethyl-L-3- (3,4-dihydroxyphenyl) -2-methyl -alaninate hydrochloride hydrate homogeneous by thin layer chromatography / fluorescent silica, 30% methanol -70% benzene solvent (t / v%) _7, found Rf = 0.5.

Claims (2)

61 687 36 A process for the use of therapeutically useful compounds of formula I CHq O R, For the preparation of 3-methyl-3α-dihydroxyphenylalanine derivatives and their pharmaceutically acceptable acid addition salts according to the formula wherein m is 0, 1 or 2, R 1 and R 2 represent hydrogen or alkyl having 1 to 3 carbon atoms. , and R 3 is a pivaloyloxy or succinimido group, characterized in that (a) hydrolysis or reduction of the formula II CHO 0 R, 11 II 11 R, O-C-C-O-C (-CH 0) -R 2 | | In the formula m, R 1, R 2 and R 2 have the same meaning as above, and R 2, R 8 and R 7 have the same protecting groups as the above, and are hydrogen atoms or protecting groups, at least one of which is a protecting group, or (b) esterifying an acid derivative of formula III, IV or V CH0 | 3 HO - \ - CH -c - YI i H0 -_ ^ 1J NH III 61 687 37 CH „OI II II TV N ^ c / ° II 0 CH„ ai CH2-C-CO2-s -VO V NH2 J 2 or an acid addition salt thereof with a compound of formula VI? 1 ΧΓ? - (- σΐ2 ^> m-R3 VI R2 wherein Y is -COOH or -CO-halogen, m, R., R0 and R "have the same meaning as above and is hydroxyl, halogen, or (c) reducing a compound of formula I wherein R 9 contains one or more reducible groups which is -HC = CH, -C = C- halogen NO 2 or CN, or (d) introducing a compound of formula VII CH- HI 3 i HO— ^ \ _CH -C - CO „-C (-CHO) -OH VII ij 2 IL m HO-J ^^ J NH2 h where m is as defined above, to react with an acylating agent with the formula (CH3) 3C-C-X2, wherein X2 is Cl or Br, or> 'v II 0 616 8 7 38 (e) cyclizing a compound of the formula VIII 9H3 Rt 0 I | 1 || I '= H2' | 'CO2' (j :( 'CH2) m'NHCCH2 <cH2) n' CO2H7111 NH2 R21 wherein n1 is 1, 2 or 3 and R2, R2 and m are as defined above, and if desired, separating the stereoisomers by (1) fractional crystallization of one s stereoisomer from solution or (2) formation of di astereoisomers with an optically active acid and crystallization of one of the diastereomers from solution. Process according to Claim 1, characterized in that an L-methyl-3α-dihydroxyphenylalanine derivative of the formula I is prepared in which R 1 and R 2 represent hydrogen or methyl, R 3 is a pivaloyloxy or succinimido group and m is 0. 61687 39