JPS6193149A - Intermediate for branched chain amides of l-aspartyl-d-aminoacid dipeptide - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides L-aspartyl-D-alanine, L-aspartyl-D-2-amino acid L L- which is effective as a sweetener.
It relates to intermediates for the production of new amides of aspartyl-D-valine and L-aspartyl-D-norvaline.

The new amide compound is L-7 spartyl-D-amino acid sibutide amide of the following formula and physiologically appropriate cation salts and acid addition salts.

In the formula, Ra is methyl, ethyl, n-propyl, inpropyl, and R is a branched chain compound selected from the following group: sunawachi, fenthyl, diisopropylcarbonyl, eumethyl-ester carbinyl, bean-ethyl- t-butylcarbinyl, di-t-1 nanov carbinyl, 2-methylthio-2
, 4-dimethylpentan-3-yl, at least one of R3, H4, R5, and R6 has 1 carbon number
~4 alkyl, the remainder is hydrogen or an alkyl having 1 to 4 carbon atoms, and X is o, s, so2, C=O1CHOH.

m is 0. 1, 2.3.4; n and p are each 0 or 1°, and the total number of carbon atoms in H3, H4, H5, and R6 is 6 or less.

Ft3e When R' or both H5 and R6 are alkyl, methyl or ethyl; m is as specified above % R7t R8j One of R9 is alkyl having 1 to 4 carbon atoms, the remainder is hydrogen, and 1 to 4 carbon atoms
The total number of carbon atoms in alkyl, R', R8, and R9 is R
12, R13 are each methyl, ether; or R12 is hydrogen, R is alkyl having 1 to 4 carbon atoms, R17, R18,
R19 and R20 are each alkyl having 1 to 4 carbon atoms.

Intermediates of the invention useful in the preparation of compounds of formula (I) are D-amino acid amides of the formula:

Ra is the one obvious above and RQ is selected from the following group. That is, fentyl, diisopropibutylcarbinyl, cyclopropyl-t-butylcarbinyl, cyclobenthyl-t-butylcarbinyl, dicyclopropylcarbinyl, ml is 1, 2.3゜If ml is 1, R30, R2O , R50, H60 are each methyl, when mx is 2, R30 is methyl, ethyl,
Isopropyl, R40, R50, R60 are each hydrogen, m
When l is 3, (a) R30 hisoprovir, t -7' f k ;
R'' tR50 and R60 are each hydrogen, (b) R30 is ethyl; R50 is methyl; H40,
R60 is each hydrogen, (c) R30 and R40 are each methyl; R2O, R6
0 is hydrogen or methyl, n2. When p2 is each 0, R41 and R61 are each methyl, X2 is S, 802c=o, GHOH.

When n2 is o and p2 is 1, R41 and R61 are each methyl, X2haO2S, 5o2 When n2 is 1 and p2 is 1, R41 and R61 are each hydrogen, X2 is s, so The suffix "carvinyl" as used herein means a -CH- residue. For example, diisopropylcarbinyl (t-C
3H7) 2-CH-, dicyclopropylcarbinylamine represents (Δ)20HNH2.

A good method for producing dipeptide amides of formula (I) is shown below.

or carboxyl-activated derivative Q in the above-mentioned L-aspartic acid derivative is one of the known amino group-protecting groups, and
Advances in Or
Ganic Chem.

3, 159-190 (1963). Particularly good amino-protecting groups are insiloxycarbonyl and butyloxycarbonyl. R is an alkyl group having 1 to 4 carbon atoms or isyl. D-alanine, D-2-aminobutyric acid,
D-valine and D-norvari/ may be in the form of free amino acids in which R11 is hydrogen, but preferred are carboxylic acid protected derivatives in which R11 has an ester residue such as methyl or ethyl. Silyl groups such as triplekylsilyl having 3 to 12 carbon atoms are also preferred. A particularly good example of such a group is trimethylsilyl. This is because it is economical and efficient.

In the above reaction step, the diprotected L-as, lagic acid, is condensed with an appropriate monoamino acid or carboxy-protected derivative to produce the diprotected dipeptide of formula (I). It is preferable to use a carboxyl-activated derivative of di-protected aspartic acid, which is condensed with di-protected aspartic acid in the presence of a reactive condensation agent such as a carbodiimide. Good examples of such carboxyl-activated derivatives include chloride, The anhydride is a mixed anhydride, etc. Particularly good in terms of efficiency is the above-mentioned mixed anhydride of diprotected aspartic acid and chlorocarboxylic acid ester, especially the above-mentioned alkyl ester having 1 to 4 carbon atoms. Good mixed anhydrides are economically prepared from methyl and ethyl esters of chlorocarboxylic acids.

A particularly good method for preparing compounds of formula (1) involves reacting beta-indyl-N-benzyloxycarbonyl-L-aspartic acid with ethyl chlorocarbonate in a conventional manner to give the corresponding mixed anhydride. Commercial D in a separate container
- Amino acid, R'0H(NH2)COOH, or resolution of known racemic amino acids [Yamada et al.,
38.4408 (1973)] is reacted with an equivalent amount of trimethylsilyl chloride in an inert solvent to prepare the trimethylsilyl ester. Suitable solvents for this purpose are, for example, pyridine, dimethyl.

Among formamide, dimethylacetamide, etc., dimethylformamide is particularly good.

In a typical reaction according to this method, a D-amino acid,
For example, D-alanine is dissolved in dimethylformamide and an equivalent amount of trimethylkrylkloite 9 is added at room temperature. In a separate 7,7 sco, Eta was prepared by dissolving cryl N-<ndyloxycarbonyl-L-7 sppartic acid and a 1 molar excess of an acid binder (triethylamine is a good choice) in a mixture of dimethylformamide and tetrahydrofuran. Add an equivalent amount of ethyl chlorocarbonate at room temperature or below (-25 to 25°C, especially -10-0'C is good)
Prepare a mixture water. To this is added a solution of D-alanine trimethylsilyl ester at room temperature. The reaction is generally 1~
It is complete within 2 hours, after which the reaction mixture is poured into water or an acid such as hydrochloric acid, extracted with a water-insoluble solvent (eg chloroform, methylene chloride, ethyl ether) and isolated in the usual manner. The diprotected dipeptide (II) is usually of sufficient purity to be used in the next step, but if necessary is further purified, for example by column chromatography.

In the second step of the method, a diprotected dipeptide (II
) is reacted with an equivalent amount of a general amine of formula RNH2 to produce the corresponding diprotected dipeptide 9 amide intermediate of formula (1[). R&e Rt R10v Q is clear above.

As in the first step, intermediates of formula (III) can be prepared in the carboxylic acid form of the compound of formula (n) using a condensing agent, for example dicyclohexylcarbodiimide, but of formula (It ) to carboxyl-activated derivatives, such as chlorides, bromides, mixed anhydrides, etc. Mixed anhydrides are generally better. Thus, a mixed anhydride is prepared using a good compound of formula (II) in which R is benzyl and Q is insiloxycarbonyl. As mentioned above, good anhydrides are made from chlorocarboxylic esters. Its methyl or ethyl esters are good. The mixed anhydride of formula (II) is prepared using the reactants and reaction conditions described in the first step of this process. Typically, approximately equivalent amounts of the compound of formula (II) and triethylamine are used and combined in an inert solvent (eg, tetrahydrofuran), the mixture is cooled to about -10 DK, and ethyl chlorocarbonate is added to yield the mixed anhydride. Next, the equivalent formula R
NH2 or a solution thereof, for example in the same inert solvent, is added at -50 to 25<0>C. Generally, -35 to -5°C is good. After adding the amino, the mixture is warmed to room temperature and maintained at this temperature until the reaction is complete. Normal 1-2
It is 0 hours. The intermediate of formula (III) is then isolated and, if necessary, prepared as M in the manner described for the preparation of compounds of formula (II).

In the final step of the method, the carboxyl protecting group RIG
and the amino protecting group Q are removed to produce the desired sweetener of formula (1).

The method of removing the protecting group from the dibeptide amide 9 of formula (III) will vary depending on various factors. Two important factors are the nature of the protecting group RIG, Q, and the nature of the amide substituent. For example, RIO and q are each in %! Yoshi & Moto, -? When cryl, insiloxy-carbonyl and R does not contain a sulfur atom, a good method for removing the protecting group is hydrogenolysis. However, R is hecryl or the alkyl defined above, Q is tert-butyloxycarbonyl, R
When is one of the various groups mentioned above, it is usually convenient to remove the protecting group by hydrolysis. When RIG is alkyl, Q is benzoxycarbonyl, and R does not contain a sulfur atom,
It is preferable to use hydrolysis and hydrogenolysis together.

When using hydrogenolysis to remove the protecting group from the intermediate of formula (III) noble metal catalyst (Nori:)! It is preferable to carry out the reaction in an inert solvent in the presence of a solvent with a good molecular weight. Examples of such solvents include lower alkanols such as methanol, ethanol, isopropanol, n-butanol;
F2, ethyl ether, 1,2-dimethoxyethane,
Ethers such as diethylene glycol dimethyl ether; esters such as ethyl acetate, methyl propionate, dimethyl succinate, and dimethyl formamide. Particularly favorable such solvents are methanol and ethanol in terms of economy and efficiency. Hydrogenolysis can be carried out at high temperature and high pressure, but a temperature of 1 to 10 atm at room temperature is favorable from the viewpoint of economy and convenience. The process is usually completed in 30 minutes to 6 hours at a suitable temperature and pressure, after which time the catalyst is removed (generally treated), the solvent is distilled off and the product is purified, if necessary, according to conventional methods. For example, recrystallization methods or column chromatography.

When hydrolysis is used to remove one or both of the protecting groups R and Q, good results are obtained using methods known for alkaline or acid hydrolysis of esters. However, if the protecting group 0 must be removed by hydrolysis, alkaline hydrolysis is preferred. Particularly favorable conditions are at least an equivalent amount of a strong base, such as sodium hydroxide,
The reaction is carried out at room temperature using potassium hydroxide in the presence of water and lower alkanols, especially methanol and ethanol.

Under these conditions hydrolytic removal of the R group is usually complete within a few hours.

When the amino protecting group Q is tert-butyroxycarbonyl, acid hydrolysis is suitable for its removal. Particularly good ones are heated to reflux with dilute hydrochloric acid in methanol or ethanol. Under these conditions, hydrolysis is usually complete within a few hours.

After removing the protecting group by hydrolysis as described above, the product of formula (1) is isolated by conventional methods. For example, after acid hydrolysis, the solvent is distilled off, the remaining aqueous solution is washed with a non-polar solvent that is insoluble in water, such as ethyl ether, chloroform, and the aqueous layer is made alkaline. , for example, by extraction with ethyl acetate and distilling off the solvent. If necessary, further purify by recrystallization or column chromatography.

If alkaline hydrolysis is used to remove the protecting group R, followed by hydrogenolysis of the amino protecting group Q, the reaction mixture of the alkaline hydrolysis is neutralized with an acid, such as hydrochloric acid, and the mixture is prepared as described above. (Hydrogenolysis.

The industrial method for producing the compound of formula (1) is as shown below.

R"pL"0vQ is clear from above.

Amino group protection - Amino acid or its carboxyl activated derivative is reacted with an equivalent amount of RNH2 using the method and reaction conditions described for the preparation of intermediates (II) and (III) to protect the amino group of formula (IV). -Produce amino acid amide. The protecting group Q is removed by hydrogenolysis or hydrolysis as described above, and the resulting free amino acid (v) is converted to the formula C as described above.
As described in the preparation of the intermediate M), condensation with a diprotected L-asunochragic acid derivative or a carboxyl-activated derivative thereof to produce a diprotected dipeptide 9 amide of formula (III), and the above-mentioned Thus, a sweetener of formula (1) is obtained.

As an application of this method, intermediates of the formula (F/) in which R has a cyclic or non-cyclic sulfide residue (-8-') can be prepared by the formula (V
) is oxidized and converted into a sulfoxide or sulfone before being converted into an intermediate according to the method described above to produce a compound of formula (■) in which R is a sulfoxide or sulfone.

In a third method for producing the compound of formula (1), the D-amino acid amide 9 of formula (V) described above is converted to L-aspartic acid N
- react with thiocarboxylic anhydride to directly prepare compounds of formula (I). When carrying out this process, intermediate (V) is mixed with half the amount of L-as/gragic acid N-thiocarboxylic anhydride in a suitable solvent at a mildly alkaline pH between -25 and 10.
A compound of formula (1) is prepared by reaction at .degree. For the alkaline pH of this reaction, a strong base such as sodium hydroxide or potassium carbonate is used. Suitable solvents for this reaction are those in which at least the reactants are soluble under the reaction conditions, do not react with both reactants, and allow the products formed to be isolated relatively easily. For example, water, tetrahydrofuran, 1,2-:
) Methoxyethane, diethylene glycol dimethyl ether, dimethyl sulfoxide, dimethyl formamide 9, and combinations thereof, etc. and water, and mixtures of tetrahydrofuran and water are good. The preferred pH range for this reaction is 8 to 10, with pH 9 being preferred.

A good temperature is between -10 and O<0>C.

Under the favorable conditions described above, the reaction is usually completed in 1 to 2 hours, and the product of formula (1) is isolated in a conventional manner.

For example, the pH of the reaction mixture is adjusted to the isoelectric pH of the product. Usually the pH is between 5.0 and 5.6 and the product of formula (1) is precipitated. The solvent is distilled off or filtered and the crude product is slurried in an organic solvent such as methanol, ethanol, ethyl ether, ethyl acetate, or mixtures thereof. The product of formula (1) is then isolated by filtration. If necessary, it may be purified by, for example, recrystallization or column chromatography.

The sweetness of the compound of formula (I) is determined by comparing the sweetness with sucrose. An aqueous solution of the compound of formula (1) diluted to an appropriate concentration range is compared with a standard sucrose by a professional taste tester. Comparisons are generally made with 7-9 tsucrose aqueous solution, i.e. 7-9
II/100d. High concentrations of sucrose result in a characteristic inhalation sensation, while low concentrations do not produce a condition that can be used normally. For example, if it is determined that the compound of formula (1) has the same sweetness as α014 tl-sucrose 7 tl solution, the sweetness of this compound is 710.01
4=500X! It is sugar. All sweetness values for the compounds of the invention presented herein were determined by this method. At the lowest concentration (i.e., the concentration at which sweetness is first experienced, typically 2-3% concentration for sucrose), the potency of sweeteners such as the compounds of this invention is generally 7-9% compared to a sucrose solution in terms of sweetness. twice that observed.

The invention is further illustrated in the following examples.

EXAMPLE A mixture of 1° 21 sodium acetate, 25 d ethanol is saturated with hydrogen sulfide gas. To this, 7.0.9 (Q
, 063 mol) of diimproynyl-ketone is added.

During this time, cool in a water bath until no longer exothermic. , the mixture is stirred at room temperature and hydrogen sulfide is introduced for 4 hours. Next, leave this overnight. Ethanol and excess H2S are distilled off under vacuum and the residue is dissolved in ethyl ether and washed successively with water, potassium carbonate, dilute hydrochloric acid and water. The ether extract is dried (Na 2 SO 4 ) and evaporated to give an oil of 6.89. Add this to 10 bites of Vigrea.
Vacuum distillation is performed using a ux) column to obtain the product 1,67.9. B, P, 83-86°C/9. This is used in the next step without further purification.

1,67 # (0,011 mol) was produced in the above step A.

Cyclic ketone, 1, 6. ! A mixture of 1r (0,023 mol) o-+dylamine hydrochloride, 1,9.9 (α023 mol) sodium acetate, 30.wj water, and 10 m ethanol is heated under reflux for 3 hours. Cooled. , filter the precipitate. 1:1 methanol-water! Crystallize, 1.
The oxime of 51 is obtained as a white solid. M, P, 60-
85° C., which is a mixture of isomers and is accurate enough to be used in the next step.

1,45 g (0,009-r-ole) of the oxime prepared in Step B was dissolved in 15111 ethanol, and 5I of metallic sodium was added little by little, followed by 253 E/l of ethanol, and the mixture was heated under reflux for 30 minutes. The reaction mixture is diluted with water and extracted with ethyl ether. The extract is washed with water, and the ether layer is extracted with dilute hydrochloric acid. Wash the aqueous layer with fresh ether. The aqueous layer is made alkaline with aqueous sodium hydroxide solution and extracted again with ether. Dry the organic layer (MgS
O4) The L ether is distilled off to give 1.1 g of a colorless oil. Gas chromatography (OV-1 column, 8
0-100℃), the product has two main components of 60/
They are present in a ratio of 40. 'H-NMR (CD(x3)) shows that the product is a mixture of 4-amino-3-trans-5-trans-dimethyltetrahydrothiopyran and the corresponding 3-cis*5-) lance-isomer. show.

D, N-t-butoxycarbonyl-D-alanine, 7 each
j! / in tetrahydrofuran and water, 2.71,9
(11 mmol) of N-(t-butoxycarbonyloxyimino)-2-phenylacetonitrile (BOG-O
N, manufactured by Aldrich Chemical Co.), 0.89 g (10 mmol) of D-araprone, and 1.5.9 g (15 mmol) of triethylamine are added, and the resulting biphasic mixture is stirred at room temperature. After about 2 hours, the mixture becomes homogeneous and stirring is continued overnight. The mixture is diluted with water and washed with ethyl acetate, then brought to pHts with dilute hydrochloric acid. Extract the acidic solution with ethyl acetate, wash the extract with water, saturated saline, and sulfuric acid)
Dry with IJum. The solvent was removed under reduced pressure to obtain the product 1,911 as a colorless oil. This has appropriate accuracy for use in the next step.

1,711 (8,9 mmol) of N-t-Boa-D-alanine, L9-8, prepared step by step under anhydrous conditions.
．． A mixture of V (I 9 mmol) triethylamine, 40-tetrahydro7rane was cooled to -10°C, and 0.
96.9 (8.9 mmol) of ethyl chloropormate are added dropwise. The mixture is stirred at this temperature for 20 minutes.

Add to this 1.1 g (7.5 mmol) of 4 prepared in step C.
An isomer mixture of -amino-3,5-dimethyltetrahydrothiopyran is added, stirred at -10°C for 10 minutes, and then warmed to room temperature. The reaction mixture was diluted with water and extracted with ethyl acetate. The organic layer was washed successively with an aqueous sodium bicarbonate solution, dilute hydrochloric acid, water, and brine, and then dried (Na2S
04) Do. The solvent was removed under reduced pressure to obtain 2.41% of the product as a foam. Thin Layer Chroma Dog 2 Fee (TLC), 7
Rica gel plate, 1:1 ethyl acetate/hexane development, main points, product at Rf = α5, slight impurity Rf =
0.6.0.9 is shown.

Dissolve the t-Boa-amide prepared in step E in 15 d of ethanol and add a mixture of 5 d of concentrated hydrochloric acid and 10 d of water. The mixture is heated under reflux for 30 minutes, and after cooling, the ethanol is distilled off under vacuum. The residue is washed with ethyl ether, made alkaline with aqueous sodium hydroxide solution and extracted with ether.

Dry the ether extract (Na2So4) and evaporate the solvent to yield 11 (67%) as a colorless oil. Leave this to crystallize.

Dissolve D-alaninamide 1,1# (5.1 mmol) prepared in Step F in 5-tetrahydrofuran and add 5d of water. The clear solution was cooled in water and 0.89g (5,
1 mmol) of L-asnoceragic acid N-thiocarboxylic anhydride is added all at once. Add 0.5M sodium hydroxide solution to this to keep the pH at 9. After stirring for 30 minutes, the mixture is washed with ethyl ether and then with ethyl acetate. The washing solution is collected, the aqueous layer is adjusted to pH 5.6 with diluted hydrochloric acid, this is distilled off under reduced pressure, and the residue is dissolved in hot methanol (100 mA'). Filter and distill off methanol. The residue is dissolved again in hot methanol and filtered, and the liquid f is decolorized with activated carbon. This was filtered through a filter and the liquid f was distilled off to obtain a crude product of 1,67.9 as a powder. This was dissolved in hot water (111 Lt), filtered, and concentrated under a stream of nitrogen gas to 5 dK.

This is cooled with water to obtain the product as a gelatinous solid. The product is obtained by filtration, dried with suction and washed with 2 ml of cold water, 2 d of methanol, and then with a mixture of 1 d of methanol and 4 d of ethyl ether to give a granular product. This was dried at 50°C in a vacuum open state, and 0.
:1 of the desired product is obtained.

Melting point 225-227°C (decomposed); Rfo on silica gel 'rLc, 57 (4:1:1 mixture of butanol:acetic acid:water used as developing solvent) sweetening potency, 200 times that of sucrose.

72.5 g (2.4 mol) in sodium methoxide made from 75I metallic sodium, 250d methanol
of paraformaldehyde, then 250.9 (Z2
mol) of diisopropyl ketone.

Heat the mixture for 3 hours. The reaction is stopped by adding water, neutralized with hydrochloric acid, and extracted with ethyl ether. This is washed with water and brine, and the solvent is distilled off. Residue oil (901?)
is distilled under vacuum to obtain the desired product 281. boiling point 92-
98℃/16-20m. GLO with 0v-1 column had a retention time of 314 seconds at 107°C and a purity of 96%.

The above procedure was repeated and the reaction mixture was refluxed for 16 hours.
The same amount of reaction was carried out to give 311 products and 9 by GLG.
Shows 6% purity.

61 (0,48 mol) of 1-hydroxy-2,2,4-
A solution of 500 id of trimethylpentane in chloroform is stirred and brought to reflux. To this is added dropwise a solution of 77 & (0.48 mol) of bromine in 100 d chloroform. After the addition is complete, stir under reflux for 1 hour. This is cooled and left overnight at room temperature. The solvent is removed under reduced pressure to obtain the product 127I.

This is used in the next step without purification.

79 g (0.3 mol) of the product obtained in step B was transferred to 300 m
Dissolve in 1 liter of dry pyridine and cool to 0°C. 114#(
α6 mol) of p-toluenesulfonyl chloride at 0℃
Add it in several parts. The mixture was kept at this temperature for 3 hours 15
Stir for a minute, pour into ice water and extract with ethyl ether. The extract is washed with dilute hydrochloric acid, water, and brine, and dried over anhydrous magnesium sulfate.

The solvent was distilled off to obtain crystalline tosylate of 111,9 (98th).

tosylate, 94.9 (0.25 mol) dissolved in 1 liter of pyridine and 181 (0.75 mol) sulfurized)
Add IJum monohydrate and heat the mixture to 75°C.
Maintain this temperature for 1 hour. Leave this at room temperature overnight. Add water and extract with ether. The extract was treated with hydrochloric acid, saline solution,
and dry (MgSO4).

The solvent was distilled off to obtain 35Il of the title compound. 89ti yield. The product was analyzed by TLC on silica gel in ethyl acetate/hexane (
1:4 capacity), a single point is shown at Rf = 0.5.

"H-NMR spectral conforms to the structure of the indicated compound.

D, Leuukart reduction name of ketone 10.1 (0,
063 mol) of 2.2.4.4-tetramethyltetrahydrothiophene-3-one, 15.2 mJ (0.38 mol) of formamide, and 3.5 m/(0.092 mol) of formic acid and heat the mixture. Reflux (R61°C).

During this time, water is separated and removed. The reaction mixture was heated to 160
-180°C for 20 hours, during which time formic acid (10d)
Add at intervals. In this case the temperature rises to 200°C. The reaction mixture is extracted with ethyl acetate. The extract is evaporated under vacuum. 20. The mixture was refluxed with m7 of 6N hydrochloric acid for 2 hours, cooled, and then washed with ethyl ether. The aqueous layer is brought to pH 11 with an aqueous sodium hydroxide solution and extracted with ethyl ether. The extract was dried and evaporated to give 2 g of 3-amino-
2,2,4,4-tetramethyltetrahydrothiophene is obtained.

'H-NMR identifies this, and silica gel TLO also shows that it is homogeneous.

TLC Rf O, 65 using a mixture of ethyl acetate: hexane 7:4 as developing solvent; butanol: acetic acid: water 4:1
: Rfo of TLC using a mixture of 1 as a developing solvent, 53°, IJ reaction positive. The product is a yellow oil.

Example Z1) Z09 N (1
1,47 iu (10 mmol) of triethylamine is added to a solution of Nt-butoxy-carbonyl-D-alanine (1 mmol) and the mixture is cooled to -10°C.

At this temperature 0.96 d (10 mmol) of ethyl chloroformate is added and stirred for 15 minutes. After cooling to -20 °C, prefecture of 1,6 & (10 mmol)-3-amino-2
,2,4,4-tetramethyltetrahydrothiophene is added and the mixture is allowed to warm to room temperature.

Add ethyl acetate and mix the mixture twice with 50d each of 5t (
, it) Washed with aqueous citric acid solution, then washed with sodium bicarbonate (txsOd), saturated saline (1 x 5011 Ll)
). Dry the organic layer (N a 2 SO 4 )
After distillation under reduced pressure, 3y N-(2,2,4,4-tetramethyltetrahydrothio7en-3-yl-t-butoxycarbonyl-D-72ninamide is obtained as an oil.The structure of the product is Confirmed with the H-NMR spectrum.

Essentially homogeneous on silica gel TLC.

This product is used in the next step without further purification.

To the product obtained from step A, 5d of methanol, 30g of 1
Add M hydrochloric acid and heat on water bath for 30 minutes. The methanol was distilled off and the residue was extracted with ether. The ether was discarded, and the aqueous layer was adjusted to pH 11.0 with an aqueous sodium hydroxide solution. Extract this with ethyl acetate and dry (NazSO4)
The residue was distilled off to obtain 1,0# N-(2,2,4,4-tetramethyltetrahydrothio7en-3-yl)-D-alaninamide. This was identified using a nuclear magnetic resonance quictor.

Uniformly filter using silica gel TLC.

°C, 0.97 g (4.25 mmol) of D-alanine amide obtained in condensation step B to prepare dipeptide amide 3 was mixed with 10 d of water, cooled in water and diluted with 0.5 N aqueous sodium hydroxide solution. Adjust the pH to 9.2.

To this, 0.8N (4.25 mmol) of L-asunolaginic acid N-thiocarboxylic anhydride is added little by little while stirring. During this time, the pH of the mixture was adjusted to a sodium hydroxide aqueous solution (0,
5N) to keep it at 9. After addition, the mixture was kept at 0°C for 45 minutes.
The mixture was stirred with water, adjusted to pH 5.2 with hydrochloric acid, and distilled off. The residue is slurried with methanol, filtered to remove the precipitate, liquid f is distilled off under reduced pressure, and ethyl ether is added to form a solid.

This is removed by filtration, reslurried with ethyl ether, filtered and the solid is recrystallized from 8-m water. After drying in open vacuum, 1y product is obtained. A second product is obtained from the mother liquor. Sweetening potency 500 times that of sucrose.

Levorotatory 3-amino-2,2,4,4-tetramethyltetrahydrothiophene resolved in a conventional manner was used as a substitute for the racemic amine in the manner described above to obtain L-aspartyl-D-alaninamide, which was It has 800 times the sweetening power of sucrose.

Example 3〜〉α1 (11 mmol) N-t-butoxycarbonyl-
1 in a 75 iu solution of D-alanine in tetrahydrofuran.
Add 47d (10 mmol) of triethylamine.

The mixture was cooled to -10°C and ethyl chloroformate α9
6ytl (10 mmol) was added and the mixture was stirred for 10 minutes and then cooled to -20°C.
-amino-2,2,4,4-tetramethylchetane 5
Add 1111 tetrahydrofuran solution. Warm the reaction mixture to room temperature and add ethyl acetate. This is washed with 5 g (by weight) citric acid solution (2 x 50 g), washed with sodium bicarbonate solution until neutralized, and then washed with saline.

The organic layer was dried (Na2so,) 1, the solvent was distilled off,
2-71 (78%) of the desired solid product is obtained. The H-NMR spectrum of the product is consistent with the expected values. TLC on silica gel was developed with 1:1 ethyl acetate/hexane and the product showed uniform values. R, 0,77° T produced here using the method described in Example 1, Step F
-Boa-D-azininamide is hydrolyzed to obtain free alpha aminoamide in 43% yield.

The product was homogeneous by silica gel TLC.
The R squictor is consistent with its structure.

C. Condensation to make dibutide amide, described above, step B
Alpha aminoamide 0.7. F (3.2 mmol) is mixed with 10 E/l of water, adjusted to pH 10.1, cooled in a water bath and L-aspartic acid N-thiocarboxylic anhydride of α 567.9 (3.2 mmol) is added in portions. During this time, add 0.5N sodium hydroxide solution to adjust the pH.
Keep it at 9.0. The mixture was then stirred at 0 °C for 45 min and the pH
The mixture was heated to 5.2K and evaporated under vacuum. The residue is slurried with methanol, filtered to remove solids, and liquid f is distilled off. Add 150 m of ethyl ether to the residue and filter off the precipitated product. Dry this in a vacuum open overnight and
．． A composite material of P is obtained. After two more slurries with ethyl ether, the α9I product is obtained (85%).

Sweetening potency, 2000 times stronger than sucrose.

Example Present l)amide 9: N-t-butoxycarbonyl-D-alanine N-(2,
2,4,4-tetramethylthietan-3-yl)amide 9 is dissolved in 500 m chloroform and cooled to 10-20°C. 41,3,F (0.24 mol) of m-chloroperbenzoic acid is slowly added. During this time, the temperature was increased to 45℃.
Keep below. Stir the mixture for 1 hour and dilute it with chloroform. 5 Sodium hydrogen carbonate aqueous solution, 0, IN
Wash sequentially with hydrochloric acid, an aqueous solution of sodium 5-thiothiosulfate, and saline. Dry the organic layer (Mg504) and distill off L33
．． 7.9 oil is obtained (97 g).

This is of sufficient purity to be used in the next step.

t of 34.8.9 (α10 mol) produced in the above step A
-Boa-amide in 50 ad concentrated hydrochloric acid, 100 ad in water,
Dissolve in a mixture of 100-g of ethanol. This is heated under reflux for 1 hour. Cool the mixture and wash with ethyl ether. (50% hydroxide of the aqueous layer) pH with IJum solution
12 and extracted with ethyl acetate. Dry the extract (Mg
SO4) L was distilled off to obtain 1&7 g (75 g) of crystals.

This was recrystallized with carbon tetrachloride to obtain 80%.

4.4. Into a solution of 14.28 g (0.04 mol) of C6 diprotected dipeptide amide betabenzyl N-insiloxycarbonyl-L-asnortate in 700 gotetrahydrofuran. Add wj (α04 moles) of N-methylmorpholine. Heat the mixture to -10℃
Cool to 3.9 d (α04 mol) of ethyl chloroformate. After stirring the mixture for 15 minutes at -10°C -
Cool to 20°C. 9,921 (α04
mol) of D-alanine N-(2,2,4,4-tetramethyl-1,1-dioxothietan-3-yl)amide in 50-nato-2hydrofuran is added and stirred at room temperature for 1 hour. Pour the mixture into 700 d of ethyl acetate.
N hydrochloric acid, sodium bicarbonate solution, 0. Wash sequentially with IN sodium hydroxide and saline. Dry this (
MgSO, ) t, X mini-distilled. Make a slurry of the residue with ethyl ether and filter out the solids! 1) 19.8
Take g (84%) of diprotected di-4-butide amide. This was recrystallized from ethylene glycol dimethyl ether/isopropyl ether to obtain 77.

D, 10. obtained in 01 above. 3 to the 25017 methanol solution of the product of P! i of 5 cm Pa/C (50% wet),
Add IWll of concentrated hydrochloric acid. The mixture was heated to 50 psi (15
2 to 4/cIn2) for 1 hour. The catalyst was removed by filtration, and the solution was brought to pH 2 with sodium hydroxide solution and evaporated under vacuum. 5. Mix the residue with ethyl ether, filter the solid, and dry at 45°C in an open vacuum.5.
5g (89g) of the target dibutide amide is obtained.

Sweetening potency: 1000 times stronger than sucrose.

Example 5 4.75.9 (0.020 mol) of N-insiloxycarbonyl-D-2-aminobutyric acid is dissolved in 200 d of tetrahydro7ran. This is cooled to -15°C under nitrogen gas. N-methylmorphine Z0219 (0,020 mol) and hyethylchloroforme), 2-179 (0,0
20 mol) and the mixture was stirred at -15 to -10°C for 30 minutes. The solution was cooled by -20'CK to 122.9 (α0
10 of dicyclopropylcarbinylamine (20 mol)
- Add tetrahydro7rane solution.

Continue stirring for 15 minutes at -20 to -15°C. The mixture was warmed to room temperature, 150 d of ethyl acetate was added and the mixture was diluted with 2 x 100 ml of IN hydrochloric acid, 2 x 100 ml of 5
Wash with an aqueous solution of hydrogen carbonate and 100 d of saturated saline. The organic layer was dried (MgSO4) and the solvent was distilled off under reduced pressure to obtain 6.62.9 (100 cm) of a colorless solid. RfO,68 (solvent:
Ether acetate/hexane 1:1 (by volume), sprayed with 3% vanillin).

Cbz-amino-protected amide 6 prepared in step A above
．． 62N (0,020 mol) is dissolved in 25011 g of reagent grade methanol. 5chipa 5dium-carbon catalyst L5g
Add 50p81 (3,52 to 4/crIL2) to make 45
Contact reduction for minutes. The catalyst is removed by filtration and the liquid is distilled off under vacuum to obtain an oil. Add 25 xi of IN hydrochloric acid, stir, and extract with ethyl ether.

The aqueous layer is made strongly alkaline with IOM sodium hydroxide (・p
H14'). Combine the mixture into 3 x 25yLl! Extract with ether. The extracts were combined and dried (MgSO4
) and distilling off the ether gives 3.21 (83.9ch),
A colorless solid is obtained. M, P, 63-64°C. RfO,
60 (butanol/acetic acid/water, v/v; ninhydrin: 7'L/-); (Full 77) D-46,7' (C=
2, INHCl)'H-NMR spectra are consistent with the structure of D-2-aminobutyric acid N-()cyclopropylcarbinyl)amide.

CO diprotected dipeptide amide 50d dissolved in tetrahydrofuran! i61 F(
0.0157 mol) of betabenzyl N-indyloxycarbonyl-L-aspartate in a solution of 159I!
(0,0157 mol of N-methylmorpholine is added. To this is added 1,7 (1 (0,0157 mol) of ethyl chloroformate and the mixture is stirred for 30 minutes at -15°C. To this is added 15- D- dissolved in tetrahydrofuran
A solution of 2-aminobutyric acid N-(dicyclopropylcarvinyl)amide is added dropwise.

After stirring for 15 minutes at −15° C., warm to room temperature.

The solvent is removed under vacuum to obtain a solid. This is 150ii
The suspension is washed with 2 x 75-IN hydrochloric acid and the clear organic layer is washed with 2 x 75 d of 5-hCl sodium bicarbonate, 75 d of brine and dried (MgS).
O4). The solvent was distilled off under vacuum to obtain 8.36 g (99.5 g) of a colorless solid. TL, C in RfO, 36 (ethyl acetate/hexane 1:1, vanillin plate). Recrystallize with ethyl acetate to obtain crystals of 6.12.9 (73). M, P, 167-168°C.

D. The Nihojikadi produced in step C is butidoamide 1-25
0-methanol solution at 15.9% (W/W')P
Add a/C (50 wet) catalyst and sop day i (3,5
2-42) for 45 minutes. During this time, a stoichiometric amount of hydrogen is absorbed. The catalyst is removed by filtration, and the liquid is concentrated under vacuum to give 75d.The condensate is filtered to remove the precipitated product. This was washed with methanol and dried under vacuum.2.
851! A colorless powder is obtained. M.

P, 225-227°C (decomposed). Furthermore, 0.7 from the mother liquor
Get 61. Overall yield 100%. RfO, 56 (butanol/#11/water, 4:1:1; ninhydrin spray)
.

Sweetening potency 500 times that of sucrose.

Example 6゜Example 5, Substitution of dicyclopropical vinylamine in the method of step A,! Fc3-amino-2,2゜4.4-
N- using tetramethylethane 1,1-dioxide
Benzyloxycarbonyl-D-2-aminobutyric acid N-(
2,2,4,4-tetramethyl-1<1-dioquinchetan-3-yl)amide is prepared in a yield of 99%. Rfα
50°B, the above product was hydrogenolyzed by the method of Example 5, Step B to give D-2-aminobutyric acid N-(2,2,4°4-
tetramethyl-1,1-dioxothietan-3-yl)
The amide is obtained in 181 yield. Rfα41jC1 Example 5
, 99% yield R2α68. according to the method of step C. Manufacture.

D, the product (i, 1tl) obtained in step C was prepared in Example 5,
Hydrogenolysis using α4y at 5 Pa/G (50% wet) according to the step procedure gives the title compound in a yield of 92. M, P, 155-167°C (decomposition), Rfα4° sweetening potency, 200 times that of sucrose.

Example 7 D-2-aminobutyric acid is obtained as a diisopropyl carbinyl amitra oil in a yield of 85% by hydrogenolysis using the appropriate amine in Example 5, Step A and the method of Example 5, Step B. . Rfo, 56°B, the corresponding diprotected amine F: is obtained in a yield of 76° by the method of Example 5, Step C. This was hydrogenated by the method described in Example 5 to obtain the title compound in a yield of 89% (total yield 68%).
%). M-P, 213-215°C (decomposition) Rfo, 5
4゜Sweetness potency: 100 times that of sucrose.

Example & , A, (CH3)2CHCHOONH(Δ)2H
Cbz Using commercially available D-no2line, N-benzyloxycarbonyl-D-valine is obtained as a white powder with a yield of 82%. M
, P, 55-57°C, Rfo, 45°.
It is reacted with dicyclopropylcarbinylamine according to the method of Step A to obtain the desired diprotected amide in a yield of 100%. RfQ, 35°B, the above product was hydrogenolyzed by the method of Example 5, Step B to yield D-valine N-(dicyclopropylcarhinyl)amiY as a colorless solid at 83.7
% yield. RfO, 53°C0 According to the method of Example 5, Step C, the corresponding diprotected dibutyptioamide 9: is obtained as a colorless solid in a yield of 14%. R2α55°D, the product of Step C was hydrogenolyzed by the method of Example 5, Step 1 to obtain the title compound as a colorless solid in a yield of 85%. Rfα54゜ Sweetening effect 110 times that of crab M sugar.

Example 9°! Otsu This compound is J, Chew, Soc, Perki
n I, 2087 (1976), and the same, 1797
(1974). Hexane (80i
u), sodium sand (1 & 411
) to a well-stirred suspension of pivalonitrile (,33,2#) and Pteruk, loride (44#) in a nitrogen gas stream.
, 4, fr) over 1 hour at 15-20°C. The mixture was stirred for 3 hours and 90 francs of tetrahydrochloride (5 m
) of chloroinine (2I) solution is added dropwise over a period of 10 minutes. Continue stirring for 1 hour. Methanol (20d
) carefully (over 0.5 hours, then water is added until the phases separate. The aqueous layer is extracted with ether, the combined organic layers are dried and evaporated under vacuum. The residue is distilled. , G
Obtain t-butylketoneimine. b, p, 62-63℃
/ 19 We Imine (14Ii) dissolved in dry ether (50d)
) is added to a suspension of lithium aluminum hydride (1,7,9) in dry ether (50 Ml) wA. The mixture is stirred at room temperature for 24 hours, refluxed for 2 hours and cooled.

Water (L7t/), 15% hydroxide) IJum solution (5
Carefully add water (5d) one after the other. 1 of the mixture
Filter, concentrate, and distill the residue to obtain the desired amine. b
, p, 79-81 °C/40 vm.

B, 7.59 d in 170 yd of methylene chloride containing 4.88 d (0,035 mol) of triethylamine.
9 (0,034 mol) of N-ynesiloxycarbonyl-
Add D-alanine. Cool the m solution to -10℃ 3.3
5W: ethyl chloroformy of t(o, o3s3g))
Add wo. The mixture was stirred for 25 min at -10 to -5 °C &
Add 0# (0,034 mol) of 2.2.4.4-tetramethyl-3-aminotanthane and stir overnight after warming to room temperature. The reaction mixture was washed with 2×100ml of 3M hydrochloric acid, 2×100ml of 3M hydrochloric acid, dried (MgSO4), and the solvent was removed under vacuum to yield 9.99g (82%) of N-Cbz-D-alanine N. −
(2°2,4,4-tetramethyl-3-pentyl)-amide remains. It is identified by its H-NMR spectrum.

Rf 0.72 (TLC, ethyl acetate/hexane, 1
: 1, phosphorus morphthenic acid spray).

C0 Dissolve the above Cbz-D-alaninamide 9.99 N in 250 d of methanol. 1.6g of 5%Pa/
Add C catalyst (50 ml wet), 45-75p day 1 (11
8-21,3 KV/crrL2) for 30 minutes.

The catalyst is removed by filtration and the liquid is distilled off under vacuum to obtain a white solid. Add 100 d of IN hydrochloric acid to this and stir for 2 hours. Wash this with ethyl ether to 40% (W/W)
Make alkaline with sodium hydroxide and extract with ethyl ether. The ether extract is dried over magnesium sulfate and evaporated to yield a colorless product of LIF. This was identified as D-alanine N-(2,2,4°4-tetramethyl-3- is methyl)amir.

Rfo, 59 (butanol/water/acetic acid, 4:1:1, ninhydrin then phosphomolybutenic acid spray).

D, Amide 9 prepared above is monotabecryl N-Cb
Using 0.005 mol each of z-L-aspaldate,
The diprotected dibutyamide is prepared according to the method of Example 5, Step C using triethylamine, ethyl chloroformate in acetone (50 m/s) in 80% yield. Rf
Using silica gel with 25.9 O,4 (TLC, ethyl acetate/bequitene, 1:1, phosphomolybutenic acid spray),
Purification by chromatography, eluting with ethyl acetate/hexane, 2:3 (by volume) affords a pure liquid product of 1,65 &.

E, using the method of Example 5, Step 1, diprotected dipeptide amide L15.9 (0,021 mol) was added to 15011 L.
0.2 in l of methanol! Catalytic reduction at 5% Pa/C of i gives 0.64 g (93%) of the title compound. M.P.
145-149℃ (decomposition), RfO, 50 450 times the sweetening effect of crab sucrose.

Preparation Example 1° Sodium 50 thihydride suspension in mineral oil 14.3.9 (0
, 30 mol) are suspended in tetrahydrofuran.

Decant off the supernatant, suspend it in tetrahydrofuran, and decant the supernatant again to remove the mineral oil. 15
．． 9 (0,12 mol) of 2,6-cystylcyclohexanone were added, then 11 g of t-butanol, 20I11
! ! A mixture of tetrahydrofuran and a-furan is added dropwise (vigorous evolution of hydrogen gas). The mixture is refluxed to complete hydrogen gas generation. To this 37-8.9 (0.30 mol)
of methyl sulfuric acid was added dropwise and heated under reflux for 24 hours. Dilute with water, extract with ethyl ether, wash with water and dry. 40
The solvent was distilled off at a temperature below 0.degree. C. to obtain 17 g of tetramethyl ketone. This is distilled to obtain the product 14.6.9. B,
P, 62-64°C/1511I + 1°
5. Reduction according to the method of step (2) to obtain the desired amine L4,9 as a colorless liquid. This is of sufficient purity to be used as an intermediate.

IIl, 2.2.5.5-Tetramethylcyclo is added to a slurry of 2.0 moles of sodium hydride (washed to remove mineral oil) in tetrahydrofuran at 19
0. Quickly add w/ (2-0 mol) of methyl sulfate. Next 35.7. A solution of F (0,425 mol) in cyclopentanone in 5011 Lt tetrahydrofuran at 90 furan is slowly added. Hydrogen gas is vigorously evolved when the reaction mixture is allowed to warm to mild reflux. Once the addition is complete, mix and stir overnight at room temperature. After heating under reflux for an additional 2 hours, a mixture of t-butanol in tetrahydrofuran is added and refluxed for 3 hours. The reaction mixture is diluted with water, extracted with ethyl ether and washed with water and brine. This was dried over anhydrous MgSO4 and the solvent was distilled off to obtain 4&2 g of a crude product. Distill this to obtain the tetramethyl ketone of 24.2.9.

B, P, 63-68℃740-0 Using the same method and using methyl sulfate/cyclo-tantanone at a low molar ratio, 2-methylcyclo-4-tantanone, 2.5-dimethylcyclopentanone, 2.2.5-trimethylcyclo Obtain Pentano 7.

Preparation Example 2 2,4-:) Methyl-3-amino acid 0.29% platinum oxide and 10% water are placed in a shaking container. This slurry was heated at 50 psi (3,5 KVcIIL2)
Catalytic reduce for 5 minutes. 34. to the resulting platinum-black slurry.
26.9 (0.30 mol) of 2,4-dimethyl-3-
pentanone, zo, oy (o, 37 mol) of ammonium chloride, 225 m/m of ammonia gas saturated methanol,
Add 25 rttt of concentrated ammonia water. This is 60
Catalytic reduction is carried out at room temperature for 20 hours at psi (4.2 Ky/cut). Filter and reflux for 1 hour to cool. The mixture was adjusted to pH 2.0 with concentrated hydrochloric acid and concentrated under reduced pressure to reduce the volume. After washing with 75d of ethyl ether, the aqueous solution is adjusted to pH 13 with 10M aqueous sodium hydroxide solution.

Extract with ether three times with 10M' each, and the combined extracts are dried over anhydrous MgSO4 and saturated with hydrogen chloride gas. The precipitated amine hydrochloride is filtered off and air-dried. This is 75
Decompose with a 10M aqueous sodium hydroxide solution of y11, separate the oily amine layer, and distill it under normal pressure. B, P, 129-13
2℃, Yield 17.6.9゜Representative Patent Attorney Kyo Yuasa Gozaj, 1, ・-11-1 Procedural amendment January 2nd, 1985

Claims (3)

[Claims] (1) Formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ D-amino acid amide compound. (R^a in the formula is methyl, ethyl, isopropyl or n-propyl, R^c is phenthyl, diisopropylcarbinyl, d-
Methyl-\t\-butylcarbinyl, \d\-ethyl-
t-Butylcarbinyl, di-\t\-butylcarbinyl, cyclopropyl-\t\-butylcarbinyl, cyclopentyl-\t\-butylcarbinyl, dicyclopropylcarbinyl, ▲Mathematical formula, chemical formula, table, etc. There is▼ (m_1 is 1, 2 or 3, and when m_1 is 1; R^3^0, R^4^0, R^5^0
, R^6^0 are each methyl, when m_1 is 2; R^3^
0 is methyl, ethyl or isopropyl, R^4^0, R
^5^0 and R^6^0 are each hydrogen, or R^3^0 and R^5^0 are each methyl, R^4^0 and R^6^0 are each hydrogen, when m_1 is 3 (a) R^3^0 is isopropyl or \t\-butyl, R^4^0, R^5^0, R^6^0 are each hydrogen, (b) R^3^0 is Ethyl, R^5^0 is methyl, R
^4^0 and R^6^0 are each hydrogen, or (c) R^3^0 and R^4^0 are each methyl, R^5^
0 and R^6^0 are each hydrogen or methyl. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (When n_2 and p_2 are each 0, R^4^1 and R^
6^1 is each methyl, X_2 is S, SO_2, C=O or CHOH; if n_2 is 0 and p_2 is 1, R^4^
1 and R^6^1 are each methyl, X_2 is O, S or SO
_2; when n_2 is 1 and p_2 is 1, R^4^1
and R^6^1 are each hydrogen, and X_2 is S or SO_2. ) (2) R^a is methyl or ethyl, and R^c is dicyclopropylcarbinyl, 2,2,4,4-tetramethylthietan-3-yl or 2,2,4,4-tetramethyl The compound according to claim 1, which is -1,1-dioxothietan-3-yl. (3) The compound according to claim 2, wherein R^a is methyl.