RU2083587C1 - Process for preparing triterpenic glycopeptides - Google Patents

Abstract

FIELD: organic chemistry, more particularly process for preparing triterpenic glycopeptides such as glycyrrhizic acid derivatives using unprotected glycoside (carboxy- component) and free amino acids or dipeptides (amino component, AC). SUBSTANCE: glycyrrihizic acid is treated with complex F in dimethyl formamide at 0 C for 1 hour and at room temperature for 4 hours. The whole is kept overnight at 4 to 8 C to give activated glycyrrhizic acid tris-pentafluorophenyl ester which is reacted in solution with amino acids of dipeptides in the presence of 1N NaOH solution at glycyrrhizic acid to complex F to amino component ratio of 1:3-3.5/3.4 mmole. Yield of the desired compounds is 62.5-90.9%. EFFECT: more efficient preparation process.

Description

Известен способ получения карбокси-защищенных гликопептидов ГК, состоящий в конденсации гликозида (карбокси-компонент) с эфирами аминокислот (метиловыми и трет-бутиловыми),

взятыми в виде их гидрохлоридов (аминокомпонент) (АК) с помощью N-гидроксисукцинимида (HOSu)-N, N'-дициклогексилкарбодиимида (ДЦГК) в среде тетрагидрофурана или диоксана в присутствии триэтиламина (ТЭА) (прототип), с последовательным выдерживанием реакционной массы при температуре 0-5^oC 3 ч, комнатной 6 ч, 4-8^oC 12 ч с последующим взаимодействием образовавшегося трисоксисукцинимидного эфира с АК при 0-5^oC и выдерживанием реакционной массы при комнатной температуре 24 ч при молярном соотношении реагентов ГК/HOSu/ДЦГК/АК/OCH= 2/10-10,4/6-6,4/6-7/9,8-10,8 ммоль, выход карбоксизащищенных гликопептидов ГК (IY) 46-86% (схема 1).The invention relates to a method for producing free triterpene glycopeptides of glycyrrhizic acid derivatives (HA) (I) of general formula (II) of interest for medicine as immunomodulators and anti-HIV agents

A known method for producing carboxy-protected glycopeptides HA, consisting in the condensation of a glycoside (carboxy component) with amino acid esters (methyl and tert-butyl),

taken in the form of their hydrochlorides (aminocomponent) (AK) using N-hydroxysuccinimide (HOSu) -N, N'-dicyclohexylcarbodiimide (DCCA) in tetrahydrofuran or dioxane in the presence of triethylamine (TEA) (prototype), with successive aging of the reaction mass at temperature 0-5 ^o C 3 h, room 6 h, 4-8 ^o C 12 h followed by the interaction of the resulting trisoxysuccinimide ether with AA at 0-5 ^o C and keeping the reaction mass at room temperature for 24 h at a molar ratio of HA / HOSu reagents / DTSGK / AK / OCH = 2 / 10-10.4 / 6-6.4 / 6-7 / 9.8-10.8 mmol, yield ka boksizaschischennyh glycopeptides HA (IY) 46-86% (Figure 1).

Кроме того, основным недостатком предложенного нами ранее способа является использование в качестве реагента (аминокомпонента) эфиров аминокислот или дипептидов в виде солей (HCI), в результате чего конечным продуктом реакции являются карбоксизамещенные гликопептиды формулы (IY), содержащие фрагменты метиловых и трет-бутиловых эфиров аминокислот или дипептидов. Для получения полностью деблокированных гликопептидов формулы (II), где R-фрагменты свободных аминокислот, необходимо проведение дополнительной стадии синтеза, связанной с уделением карбоксизащитных сложноэфирных групп:
а) обработка трифторуксусной кислотой в случае трет-бутиловых эфиров;
б) щелочной гидролиз (КОН или NaOH в метаноле) в случае метиловых эфиров.The disadvantage of this method is the occurrence of a side reaction of the formation of succinimidoxycarbonyl β alanine, which reduces the yield of the target products (in this case, glycopeptides HA):

In addition, the main disadvantage of the previously proposed method is the use of amino acid esters or dipeptides in the form of salts (HCI) as a reagent (amino component), as a result of which the carboxy-substituted glycopeptides of formula (IY) containing fragments of methyl and tert-butyl ethers are the final reaction product amino acids or dipeptides. To obtain fully unlocked glycopeptides of the formula (II), where R-fragments of free amino acids, it is necessary to carry out an additional stage of synthesis associated with the carboxy-protective ester groups:
a) treatment with trifluoroacetic acid in the case of tert-butyl esters;
b) alkaline hydrolysis (KOH or NaOH in methanol) in the case of methyl esters.

 As our studies have shown, the release of protected HA glycopeptides containing fragments of amino acid methyl esters by alkaline hydrolysis leads to a complex mixture of products as a result of cleavage of glycosidic bonds. When trifluoroacetic acid was treated with HA glycopeptides containing fragments of tert-butyl amino acid esters, the yields of free glycopeptides were 43-47% (examples 8, 9). As an example, we give two methods for obtaining the target glycopeptides (IVd, h) according to the prototype method. Therefore, obtaining free triterpene glycopeptides of the HA of formula (II), which are of interest to medicine as potential immunomodulating and antiviral agents suitable for the production of injectable forms, is an urgent task. The proposed technical solution simplified the technology for producing free glycopeptides of HA of formula II, due to the principle of "minimal protection", excluding the release process.

Способ состоит в том, что глицирризиновую кислоту (I) (1 ммоль) обрабатывают при 0 -5^oC при перемешивании комплексом F (3 ммоль) в среде ДМФА в течение 1 ч, при комнатной температуре 4ч, получая активированный интермедиат (VI), который после отделения осадка N, N' -дициклогексилмочевины подвергают взаимодействию с аминокомпонентом (АК) (аминокислотами или дипептидами) формулы RNH ₂, где

в среде ДМФА в присутствии 1N раствора NaOH при молярном соотношении реагентов ГК/комплекс F/AK, равном 1/3/3-4 ммоль при 0^oС с последующим выдерживанием реакционной смеси при комнатной температуре в течение 24 ч. Целевые гликопептиды П (а-ж) выделяют путем разбавления реакционной смеси колодной водой и подкисления лимонной кислотой до pH≈3. Полученный осадок отфильтровывают и переосаждают из смеси хлороформ метанол (5:1) эфиром. Выход гликопептидов (П а-ж) составил 62,5-90,9% После очистки колоночной хроматографией выход продуктов составляет 44,4-57,9%
Отличия предлагаемого способа следующие.GC glycopeptides of formula (II) are formed as a result of condensation of the activated KG (VI) intermediate with amino acids or dipeptides in DMF in the presence of a 1N NaOH solution. To obtain an activated ester of HA (VI) (Scheme 2), HA is treated with complex F (a complex of pentafluorophenol with N, N'-dicyclohexylcarbodiimide with a composition of 3: 1) (Y) at 0-5 ^° C in DMF. The molar ratio of HA reagents / complex F / amine component is 1/3 / 3-4 mmol

The method consists in the fact that glycyrrhizic acid (I) (1 mmol) is treated at 0 -5 ^o C with stirring with complex F (3 mmol) in DMF for 1 h, at room temperature for 4 h, obtaining the activated intermediate (VI), which, after separation of the precipitate, N, N '-dicyclohexylurea is reacted with an amino component (AA) (amino acids or dipeptides) of the formula RNH ₂ , where

in DMF medium in the presence of a 1N NaOH solution at a molar ratio of HA / complex F / AK reagents equal to 1/3 / 3-4 mmol at 0 ^° C, followed by maintaining the reaction mixture at room temperature for 24 hours. Target glycopeptides P (a g) are isolated by diluting the reaction mixture with well water and acidifying with citric acid to pH≈3. The precipitate obtained is filtered off and reprecipitated from a mixture of chloroform methanol (5: 1) with ether. The yield of glycopeptides (P a-g) was 62.5-90.9%. After purification by column chromatography, the yield of products was 44.4-57.9%
The differences of the proposed method are as follows.

 1. To activate the carboxyl groups of glycyrrhizic acid, complex F is used (Scheme 2) together with N hydroxysuccinimide (HOSu) N, N '-dicyclohexylcarbodiimide (DCCH) in the known method [4] (Scheme 1). In this case, HA (VI) tris-pentafluorophenyl ether is formed as an activated intermediate.

 2. The solvent used is N, N-dimethylformamide (DMF).

 3. As the amino component (AK), free amino acids or dipeptides are used.

 4. As the base, a 1N NaOH solution is used instead of the tertiary amine (triethylamine) in the known method.

 Example 1. Tris-pentafluorophenyl ester of glycyrrhizic acid (VI).

To a solution of 0.82 g (1 mmol) of glycyrrhizic acid in 30 ml of dimethylformamide (DMF) at 0 ^° C, 2.28 g (3 mmol) of complex F was added with stirring and the mixture was stirred at this temperature for 1 h at room temperature (20 -22 ^o C) 4 h. The reaction mixture was kept in the refrigerator (4 -8 ^o C) overnight and the dicyclohexylurea precipitate was filtered off. The resulting solution of HA (VI) pentafluorophenyl ether was used in the condensation reaction with amine components.

 Example 2. 3-0-2-0- [N- (β) D-glucopyranosyl uronol) - L-alanine -N- (b-D-glucopyranosyluronoyl) L-alanine} (3β, 20β), -11-oxo -30- (N-carbonyl-L-alanine) -30- norolean-12-ene (lla).

To a solution of 0.36 g (4 mmol) L alanine in 10 ml of IN solution of NaOH was added 10 ml of DMF, cooled to 0 ^° C and a solution of pentafluorophenyl ether of HA (VI) (1 mmol) in 30 ml of DMF was added dropwise with stirring Example 1), the mixture was stirred for 30 minutes under cooling and kept at room temperature for 24 hours with periodic stirring. The reaction mixture was diluted with 200 ml of cold water, acidified with citric acid to pH≈3. The precipitate was filtered off, washed with water and dried. 1.03 g (99.4%) of crude lla glycopeptide was obtained, which was reprecipitated from a mixture of chloroform methanol (5: 1, Y / Y) with ether. Yield 0.8 g (77.2%). Rf 0.47 (Chloroform methanol-water, 45: 10: 1); [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +55 ^° (s0.02; MeOH). An analytically pure sample of 0.6 g of 57.9% was obtained by silica gel L column chromatography, eluting with a chloroform-methanol-water system, 100: 10: 1.

IR spectrum, ν, cm ^-1 : 3600-3200 (OH, NH); 1720 (COOH); 1670 (C ₁₁ 0); 1540 (CONH). UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{Meoh}}{\text{max}}$ , nm, (logε) 248.5 nm (4.00). Found C, 58.93; H 7.10; N 3.74. C ₅₁ H ₇₇ N ₃ O ₁₉ . M.V. 1036.3. Calculated, C 59.11; H 7.50; N, 4.05.

 Example 3. 3-0- {2-0- [N- (bD-glucopyranosiuronoyl) -L-valine] -N- (bD-glucopyranosyluronoyl) -L valine} 3β, 20β-11-oxo-30- (N- carbonyl-L-valine) -30-norolean-12-ene (llb).

To a solution of 0.35 g (3 mmol) of L-valine in 10 ml of an IN NaOH solution was added 10 ml of DMF, cooled to 0 ^° C and a solution of 1 mmol of pentafluorophenyl ether of HA (VI) (example 1) in 30 was added dropwise. ml of DMF, the mixture was stirred at 0 ^° C for 30 minutes and kept at room temperature for 24 hours. The reaction mixture was diluted with 200 ml of cold water, acidified with citric acid to pH≈2. The precipitate was filtered off, washed with water and dried. 1.12 g (91.1%) of the crude glycopeptide (llb) was obtained, which was precipitated from acetone with hexane. Yield 0.9 g (80.4%). Rf 0.5 (chloroform-methanol-water, 45: 10: 1); [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +42.5 ^° (s 0.02; MeOH). An analytically pure sample of 0.56 g (50%) was obtained by column chromatography similarly to lla. IR spectrum, ν cm ^-1 : 3600-3200 (OH, NH); 1710 (COOH); 1670 (C ₁₁ 0); 1530 (CONH), UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{Meoh}}{\text{max}}$ nm (logε): 248 nm (3.93). Found, C, 61.46; H 7.96; N 3.23; C ₅₇ H ₈₉ N ₃ O ₁₉ . M.V. 1120.49. Calculated, C 61.09; H 8.02; N, 3.75.

 Example 4. 3-0- {2-0- [N- (b-D-glucopyranosyluranoyl) -L-methionine] -N- (b -D-glucopyranosyluronoyl) -L-methionine} (3β, 20β) -II- oxo-30- (N-carbonyl-L-methionine) -30-norolean-12-ene (llv).

To a solution of 0.58 g (4 mmol) of L-methionine in 10 ml of DMF was added 10 ml of a 1N NaOH solution, cooled to 0 ^° C and a solution of 1 mmol of HA (VI) pentafluorophenyl ether in 30 ml of DMF was added dropwise with stirring (example 1). The reaction mixture was stirred at this temperature for 24 hours. The mixture was diluted with 200 ml of cold water, acidified with citric acid to pH≈3. The precipitate was filtered off, washed with water and dried. Received 1.07 g (87.7%) of crude glycopeptide (llv), which was reprecipitated from a mixture of chloroform methanol (5: 1) with ether. Yield 0.86 g (70.0%), Rf 0.56 (chloroform-methanol-water, 45: 10: 1); [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +34 ^° (c 0.02; MeOH). An analytically pure sample was obtained by column chromatography similarly to lla.

IR spectrum, ν, cm ^-1 3600-3200 (OH, NH); 1715 (COOH); 1660 (C ₁₁ = 0); 1530 (CONH). UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{Meoh}}{\text{max}}$ nm (logε): 249 nm (3.92). Found, C 56.18; H 7.32; N, 2.82. C ₅₇ H ₈₉ N ₃ O ₁₉ S ₃ . M.V. 1216.48. Calculated, C 56.27; H 7.37; N, 3.45.

 Example 5. 3-0- {2-0- [N- β D-glucopyranosyluronoyl) -L-isoleucine] -N-b -D-glucopyranosyluronoyl) -L-isoleucine (3β, 20β) -II-oxo-30- (N-carbonyl-L-isoleucine) -30- norolean-12-ene (llg).

To a solution of 0.52 g (4 mmol) L of isoleucine in 10 ml of DMF, cooled to 0 ^° , 10 ml of a 1N NaOH solution was added and with stirring a solution of 1 mmol of pentafluorophenyl ester of HA (VI) in 30 ml of DMF was added dropwise (example 1 ) The mixture was stirred for 30 min at 0 ^o C and kept with periodic stirring at room temperature for 24 hours. The mixture was diluted with 200 ml of cold water, acidified with citric acid to pH≈3. The precipitate was filtered off, washed with water and dried. 1.14 g (98.3%) of the glycopeptide (llg) were obtained, which was reprecipitated from acetone-hexane. Yield 1.0 g (86.2%). An analytical pure sample was obtained in a yield of 0.6 g (51.8%) by column chromatography similar to lla. Rf 0.5 (chloroform-methanol-water, 45: 10: 1). [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +45 ^° (s 0.02; MeOH);
IR spectrum, ν cm ^-1 : 3600-3200 (OH, NH); 1720 (COOH); 1660 (C ₁₁ = 0); 1530 (CONH). UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{Meoh}}{\text{max}}$ nm (logε): 248 nm (4.10). Found, C, 61.76; H 8.14; N, 3.57. C ₆₀ H ₉₅ N ₃ O ₁₉ . M.V. 1162.5. Calculated, C 61.59; H 8.25; N, 3.61.

 Example 6. 3-0- {2-0- [N- (bD-glucopyranosyluronoyl) -L-glutamic acid] -N- (bD-glucopyranosyluronoyl) -L-glutamic acid} - (3β, 20β) -11-oxo- 30- (N-carbonyl-β-glutamic acid) -30- norolean-12 en (lld).

To a solution of 0.59 g (4 mmol) L of glutamic acid in 10 ml of DMF, cooled to 0 ^° C., 20 ml of a 1N NaOH solution were added and, with stirring, a solution of 1 mmol of pentafluorophenyl ester of HA (VI) in 30 ml of DMF was added dropwise (example 1). The mixture was kept with periodic stirring at room temperature for 24 h and diluted with 300 ml of cold water, acidified with citric acid to pH≈3. The precipitate was filtered off, washed with water and dried. Received 1.20 g (99.1%) of crude glycopeptide (lld), which was reprecipitated from a mixture of chloroform-methanol (5: 1) with ether. Yield 1.1 g (90.9%). Rf 0.49 (chlorofom-methanol-water, 45: 10: 1). [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +49 ^° (s 0.02; MeOH).

IR spectrum, ν, cm ^-1 : 3600-3200 (OH, NH); 1710 (COOh); 1660 (C ₁₁ = 0); 1530 (CONH). UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{Meoh}}{\text{max}}$ nm (logε); 248 nm (4.07). Found, C 57.06; H 7.23; N, 3.52. C ₅₇ H ₈₃ N ₃ O ₂₅ . M.V. 1210.4. Calculated, C 56.56; H 6.93; N, 3.47.

 Example 7. 3 -0- {2-O- (N- (β-D-glucopyranosyluronoyl) -glycine-L-phenylalanine] -N- (bD-glucopyranosyluronoyl) -glycine-L-phenylalanine} (3β, 20β) - 11-oxo-30- (N-carbonyl-glycine-L-phenylalanine) -30- norolean-12-ene lzh).

To a solution of 0.89 g (4 mmol) of glycyl-L phenylalanine in 10 ml of 1N NaOH, cooled to 0 ^° C, 10 ml of DMF was added dropwise a solution of 1 mol of pentafluorophenyl ester of HA (U) in 30 ml of DMF was added dropwise (Example 1) . The mixture was stirred for 30 min at 0 ^o C and kept with periodic stirring at room temperature for 24 hours. The mixture was diluted with 300 ml of cold water, acidified with citric acid to pH≈2-3. The precipitate was filtered off, washed with water and dried. Received 1.21 g (84.0%) of crude glycopeptide (llzh), which was reprecipitated from a mixture of chloroform-methanol (5: 1) with ether. Yield 0.9 g (62.5%). An analytical pure sample was obtained by column chromatography similar to lla in a yield of 0.64 g (44.4%). Rf 0.45 (chloroform-methanol-water, 45: 10: 1). [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +35 ^° (s 0.02; MeOH).

IR spectrum, ν, cm ^-1 : 3600-3200 (OH, NH); 1720 (COOH); 1660 (C ₁₁ = 0), 1540 (CoNH). UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{Meoh}}{\text{max}}$ nm (logε); 245 nm (3.95). Found, C, 61.74; H 7.51; N, 5.55. C ₇₅ H ₁₀ N ₆ O ₂₂ . M.V. 1438.76. Calculated, C 62.61; H 7.09; N, 5.84.

 Example 8. 3-0- {2-0- [N- (β) -D-glucopyranosyluronoyl) -L-isoleucine tert-butyl ether] -N- (bD-glucopyranosyluronoyl) -L-isoleucine butyl ether} (3β , 20β) 11.30 dioxi-30-L-isoleucine tert-butyl ether -30-norolean-12-ene (IVd).

1. To a solution of 1.64 g (2 mmol) of glycyrrhizic acid in 50 ml of dioxane at 0-5 ^° C was added 1.2 g (10.4 mmol) of HOSu, 1.3 g (6 mmol) of DCCA and stirred with this 3 hours at room temperature for 6 hours. The mixture was left to stand overnight in the refrigerator, the precipitate of dicyclohexylurea was filtered off and 1.5 g (6 mmol) of L-isoleucine tert-butyl ether hydrochloride and 1.3 ml were added to the filtrate, which was cooled in an ice bath. (9.5 mmol) of triethylamine. The mixture was stirred under cooling for 1 h and kept at room temperature for 24 h. The solvent was evaporated in vacuo at ≈45 ^o C, the residue was dissolved in methylene chloride (200 ml) and washed with 5% citric acid solution, water, 5% NH ₄ solution OH and again with water. Dried over MgSO _{4, the} solvent was evaporated in vacuo at ≈30 ^° C. 2.0 g (75.2%) of the crude protected product (IVd) were obtained, which was reprecipitated from acetone-hexane. Yield 1.28 g (48.1%). Rf 0.66 (chloroform-methanol-water 45: 10: 1); 0.36 (chloroform-alcohol, 10: 1). [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +29 ^° (s 0.086; εtOH),
IR spectrum ν, cm ^-1 ; 3600-3200 (OH, NH); 1740 (COOR); 1660 (C ₁₁ = 0); 1530 (CONH). UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{etOH}}{\text{max}}$ , (logε): 246 nm (3.93). Found, C, 64.86; H 8.96; N, 3.52. C ₇₂ H ₁₁₉ N ₃ O ₁₉ . Calculated, C 64.98; H 9.01; N, 3.16.

 Release of protected glycopeptide (IYd).

1.0 g (0.86 mmol) of the protected glycopeptide (IY) in 20 ml of CF ₃ COOH was held for 30 minutes at 20-22 ^° C and the mixture was evaporated to dryness in vacuo. The residue (0.9 g) was chromatographed on a silica gel column L (40/100 μm /), eluting with a chloroform methanol-water mixture, 200: 10: 1, 100: 10: 1, 50: 10: 1, 25: 10: 1 A mixture of 50: 10: 1 was washed with 0.5 g (43%) of a homogeneous product (ll g) as an amorphous substance Rf 0.48 (chloroform-methanol water, 45: 10: 1); [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +55 ^° (s 0.015; εtOH).

 Example 9. 3-0- {2-0- [N- (β-D-glucopyranosyluronoyl) -L-valine tert-butyl ether] -N- (b-D-glucopyranosyluronoyl) -L-valine tert-butyl ether} (3β, 20β) 11.30 dioxo-30-L-valine tert-butyl ether-30-norolean-12-ene (VIc).

To a solution of 1.64 g (2 mmol) of glycyrrhizic acid in 50 ml of dry dioxane at 0-5 ^° C were added 1.2 g (10.4 mmol) of HOSu 1.4 g (6.4 mmol) of DCCA and the mixture was stirred at this temperature for 3 hours at room temperature (20-22 ^° C) for 6 hours. The mixture was kept overnight at 4-6 ^° C in a refrigerator, the dicyclohexylurea precipitate was filtered off, the filtrate was cooled to 0-5 ^° C and 1.47 was added to it. g (7 mmol) of L-valine tert-butyl ester hydrochloride, 1.3 ml (9.5 mmol) of triethylamine and stirred under cooling for 1 h, 24 h at room temperature. The solvent was evaporated in vacuo, the residue was dissolved in methylene chloride (200 ml) and washed with 5% hydrochloric acid, water, 5% NaHCO ₃ , dried with MgSO ₄ and evaporated in vacuo. Received 1.9 g (80%) of crude glycopeptide (IV3), which was reprecipitated from acetone with hexane. The yield of the protected glycopeptide is 1.2 g (48%). Rf 0.48 (chloroform alcohol, 7: 1); [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +30 ^° (s 0.02; MeOH).

IR spectrum, ν, cm ^-1 : 3600-3200 (OH, NH); 1740 (COOP); 1670 (C ₁₁ = 0); 1540 (CONH). UV spectrum, λ $\genfrac{}{}{0ex}{}{\text{Meoh}}{\text{max}}$ , (logε): 249 nm (3.99). Found C 63.96; H 8.85; N, 3.47. C ₆₉ H ₁₁₆ N ₃ O ₁₉ . Calculated, C 63.16; X 9.04; N, 3.25.

 The release of glycopeptide (IV3).

1.0 g (0.8 mmol) of the protected glycopeptide in 20 ml of CF ₃ COOH was stirred at room temperature for 1 h and evaporated in vacuo. The residue was triturated with dry ether and dried in vacuo at 40-45 ^° C for 3 hours. The dry residue (0.84 g) was chromatographed on a silica gel column L (40/100 μm), eluting with a mixture of chloroform-methanol-water 100: 10: 1 , 50: 10: 1, 25: 10: 1, 10: 10: 1. A mixture of 50: 10: 1 washed out 0.42 g (46.7%) of a GC homogeneous glycopeptide (P3) as a yellow amorphous substance. Rf 0.5 (chloroform methanol-water 45: 10: 1), [α] $\genfrac{}{}{0ex}{}{\text{twenty}}{\text{D}}$ +45 ^° (s 0.02; εtOH).

 The advantages of the proposed method are as follows.

 1. As the amino components (AK) in the proposed method, free amino acids and dipeptides are used, rather than esters, as in methods [1] and [4], which simplifies and cheapens the process of producing HA glycopeptides (for example, the cost of 1 g of amino acid ester is more expensive than the cost of amino acids )

 2. As the final products, free glycopeptides of the general formula (II) are formed (with free COOH groups), i.e. there is no need for a deblocking step [5], which also simplifies the process of obtaining HA glycopeptides.

 3. As the base in the proposed method, a 1N NaOH solution is used instead of the tertiary base (triethylamine) in the known method [1, 4], which also significantly reduces the cost of the process of obtaining glycopeptides HA.

Claims (1)

A method for producing triterpene glycopeptides of glycyrrhizic acid derivatives of the general formula

where RL Ala, L Val, L Met, L Ile, L Glu, Gly L Phe
by activating the carboxyl groups of unprotected glycyrrhizic acid (HA) with an activating complex through a condensation step to form an activated intermediate in a solvent in the presence of a base to form a glycopeptide bond for 24 hours, characterized in that the glycoside is reacted with a complex of pentafluorophenol N, N'-dicyclohexylcarbodi in the ratio of 3 1 (complex F) at 0 - 5 ^o C for 1 h, at room temperature for 4 h, followed by aging at 4 8 ^o C overnight and condensation ia activated intermediate with amino acids (AK) of the formula RNH ₂ ,
where R CH ₃ CH (L Ala) (a);

in the presence of 1 n. NaOH solution at a molar ratio of HA reagents complex F AK respectively 1 3.0 3.5 3 4.