JPS597175A - Amino and amide derivative of chloronitroamino pyrazine and alkylaminopyrazine useful as additive for radial ray treatment - 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 6-amino-3- This invention relates to substituted derivatives of chloro-5-nitropyrazine amino compounds and acid addition salts thereof. The invention also relates to a process for the preparation of such compounds, in which 3-amino-5,6-cyclovirazinecarboxylic acid is first prepared by nitrification in sulfuric acid/nitric acid. 3-nitrovirazinamine and subsequent treatment of the 5,6-dichloro compound in the presence of a base such as a tertiary amine to produce the desired 2-substituted compound and the desired If so, the method involves converting the 2-substituted pyrazine into its acid addition salt.

The present invention also relates to the formula: where A is defined as an amino substituent in which at least one of the hydrogens of the amino substituent is replaced by a lower furkyl group, a hydroxy-substituted lower alkyl group, an alkoxy-substituted lower alkyl group. Yes; relates to 2,6-disubstituted derivatives of chlornitropyrazine. The invention also relates to a method for preparing such compounds, including the corresponding 2-halo 5,6-
The present invention relates to a method starting from dichloro-3-nitropyrazine and replacing the 2-halo and 6-chloro substituents by reaction with a selected alkylamine or substituted alkylamine.

The present invention also provides 6-(alkylamino)-5, which is used to sensitize tumor cells to medical radiation and thereby increase the effective therapeutic rate of radiotherapy.
-N-acyl derivatives of chloro-3-nitropyrazinamine. The present invention also relates to a method for preparing such compounds, starting from 5+6-dichloro-3-nitropyrazine amine and first converting said pyrazine amine into an acylating agent derived from a lower aliphatic carboxylic acid. to provide the corresponding acylated pyrazine amine, and further treatment of the acylated pyrazine with a lower (alkyl or substituted alkyl) amine compound to replace one of the chloro substituents provides the 2-acylamino-6 The present invention relates to a method for producing (alkylamino)-5-chloro-3-nitropyrazine.

In addition, the present invention relates to pharmaceutical compositions comprising such pyrazine compounds, and for administering such compounds to patients undergoing radiotherapy to enhance the effectiveness of such therapy. It relates to a treatment method consisting of causing.

Currently, certain other unrelated compounds are used in experimental clinical practice as radiosensitizers.

However, these compounds, for example metronidazole and misonidazole, suffer from the drawback that they also cause neurotoxic syndromes, which limits their usefulness. It is believed that the compounds of the present invention are effective radiosensitizers and have a more favorable therapeutic rate.

One group of compounds of the invention useful as radiosensitizers have the formula; - or more of the alkyl hydrogens are hydroxy, alkoxy, carbalkoxy, phenyl, pyrimidinyl,
Replaced with pyridyl or imidazolyl;
Alternatively, when taken together with the nitrogen atom to which they are attached, they represent a 6-membered heterocycle, including morpholine, piperazine and N-lower alkylbiperazine. ), 6-
Disubstituted derivatives of amino-3-chloro-5-nitropyrazine and its acid addition salts in combination with a pharmaceutical carrier.

A preferred subgroup of novel compounds of the present invention has the following structural formula: wherein B2 and R3 are each independently hydrogen; halo, including hydroxy, fluorochloro, or bromo; a lower alkyl group substituted by a lower alkanoyl which is F-substituted in the hydroxy group of;
At least - of 12 and R3 is a substituent other than hydrogen. ), and the above amino compound, hydrochloric acid, hydrobromic acid,
It is represented by the corresponding acid addition salt formed by reaction with equimolar amounts of sulfuric acid and a strong inorganic acid such as phosphoric acid.

The above amines are prepared from the known 3-amino-5°6-cyclopyrazinecarboxylic acid. L Ja C
ragoe, Jr*1 o, waWolters
dorf, Jr., J.B., Bidein
g, S*FeKwong, Ja H, Jore
Author: J. Med, Chem.

Magazine, Vol. 10, p. 66 (1967) Carboxylic acids dissolve in sulfuric acid or fuming sulfuric acid.

The replacement of the carboxylic acid substitute by the nitro substitute is carried out by adding equal volumes of a mixture of sulfuric acid and nitric acid, or the corresponding amounts of oleum and oleum, to the solution prepared in this way. Nitric acid and sulfuric acid are used in equimolar amounts relative to the carboxylic acid reagent.

Preferably, however, these acids have between 10 and 10
Used in 0% molar excess. The reaction temperature is from 0.5 to 5.0
The reaction mixture is kept between 0 and 50''O for a period of time. The progress of the reaction is followed by observing the release of carbon dioxide from the reaction mixture.

This reaction is shown in the reaction scheme below; For example:

The product is conveniently recovered from the reaction mixture by pouring the entire mixture onto ice, thereby precipitating the product as a crude yellow solid. Further purification is accomplished by dissolving the crude product in a solvent such as ethyl acetate and washing with an alkaline solution such as aqueous sodium carbonate to remove traces of acid. The product solution is then filtered to remove insoluble impurities and the product is recovered from the filtrate by solvent evaporation, leaving the pure product as a solid residue.

The above compound (1) is then treated with an amine compound to convert it into a Rolo-substituted compound as illustrated in IIll below.

The reaction between dichloro-nitropyrazine■ and an amine reagent is
It is preferably carried out in a solvent for the reactants. The solvents used are lower alkanols, such as methanol, ethanol, isopropanol; dimethylformamide, such as tetrahydrofuran; and acetonitrile. The amine reactant is preferably present in a greater amount than the nitropyrazine, preferably in a 5 to 10 thymolar excess. The reagents are first mixed and then heated to a temperature of 20-80°C for a period of 0.5 to 24 hours. It is generally preferred to carry out the reaction in the presence of at least equimolar amounts of an organic base in addition to the reagents and solvent. Tertiary amines such as triethylamine and pyridine are preferred. The progress of the reaction is followed using thin film chromatography.

As indicated above, acid addition salts of compounds of formula I are prepared by combining a selected compound of formula I with equimolar amounts of a strong inorganic acid from 0 to 50'
It may be prepared by mixing in a solvent for the reactants at a temperature of 0.

Preferred solvents are lower alkanols such as methanol, ethanol, isopropanol, isopropanol. Precipitate the salts from the alcohol solution, filter, wash with a minimum amount of cold alcohol and air dry.

Another group of compounds of the invention useful as radiosensitizers are the di(alkylamino) dielectrics of chloronitropyrazine.

A preferred group of such compounds is represented by the following structural formula: where A is a lower alkyl group, a hydroxyl lower alkyl group, a polyhydroxy lower alkyl group, a lower alkoxy lower alkyl group, or a boria JL At least one of the amino groups replaced by a koxy lower alkyl group is an amino substituent having a hydrogen. A preferred subgroup of the compound of the present invention is represented by the following structural formula: where R, B, C1-6 lower alkyl, C1-6 branched lower alkyl, 01-6 hydroxy Alkyl, auto-C6 polyhydroxyalkyl, C,%C6 alkoxyalkyl or C1-6 polyalkoxyalkyl, p1R2 is
Hydrogen or R.

According to our invention, the starting compound 5,6-dichloro-3-
Nitrovirazine amine IV was prepared by heating 3-amino-5,6-cyclopyrazine-carboxylic acid with fuming sulfuric acid and fuming nitric acid as described above, and the residue was dianized and exchanged with halogen ions. Thus, an important new intermediate, 5,6-dichloro-2-halo(C11Br,I)-3
- to produce nitropyrazine VA, which in turn is treated with - or 2 moles of an alkyl or substituted alkylamine to produce 2-(alkylamino)-3-chloro-6- Hero 5-nitropyrazine A or 3-chloro-2,6-di(alkylamino)
-5-nitrovirazine IA is produced.

Go to Flow Sheet IA Here A is defined as above and X is a halogen selected from chloro, bromo or iotho. Intermediate VI A is separated and optionally reacted with different alkyl amines to form 2,6-disubstituted-3-chloro, where the substituents 2 and 6 can be different from each other, as shown in the flow sheet. -5-nitrovirazine is produced.

In carrying out the first step of our method, the starting material IV A is diisolated and exchanged with halogen ions, i.e. chlorine, bromine or iodine, to form the desired 2-halo 5,6-
Dichloro-3 nitropyrazine VA is produced. ! 1-J
- In a preferred example, the compound 5,6-dichloro-3-nitropyrazinamine is dissolved in bromoform, and in the solution there are compounds such as isoamyl nitrite, butyl nitrite, ethyl nitrite, and the like. Add at least one mole of alkyl nitrite compound. The nitrite reagent is preferably added in a molar excess of 50 to 200%, and the reaction mixture is heated at a temperature of 50 to 120° for 5 to 40 hours until the reaction is substantially complete, as determined by thin film chromatography. Heat. Following completion of the reaction, the desired product is separated from the cooled reaction mixture by first evaporating the excess bromoform in a Makabe, leaving the crude product as an oily residue. is further purified by chromatography on silica gel.

In the subsequent manufacturing process of the present invention, the intermediate V
A is enriched with -mole or two moles of an alkylamine, optionally substituted with one or more hydroxy or haalkoxy groups, and, if desired, of the monosubstituted pyrazine VIA described above. , one or more reaction steps involving intermediate formation are performed to produce the desired product IA. with alkylamino substitution,
This reaction results in the substitution of 2 and 6 halogen substituents by mixing a 2-halo-5,6-dichloro-3-nitropyran with at least a 100 molar excess of the selected amine compound and During the time, O~
The reaction temperature was maintained at 500 °C. Preferably,
The reaction is carried out in the presence of a propellant for the reactants. Suitably lower aliphatic alcohols such as methano-JL, ethanol, isopropanol; certain ethers such as tetrahydrofuran; dimethylformamide and acetonitrile are useful as solvents for the reaction. The progress of the reaction is followed using thin film chromatography by monitoring the disappearance of starting materials and the appearance of products.

Following completion of the reaction, the solvent is removed by evaporation in vacuo, leaving an oily residue that is further purified by chromatography on silica gel from trituration with a solvent such as an ethanol/chloroform mixture.

The products generated from Formula IA are varied by changing the amine reagent. Thus, for example, reaction of 2-bromo-5,6-dichloronitroviracine with - to 2 moles of the selected amine reagent produces the corresponding nitropyrazine, which is Or the 2-broro substitution product has been converted by amino 1h substitution.

Another group of compositions of the invention useful as radiosensitizers are acylated derivatives of 6-(alkylamino)-5-chloro-3-nitropyrazine amines in combination with a pharmaceutical carrier.

A preferred group of such compounds is represented by the following structural formula: where R and R are each hydrogen, C1-c6 lower alkyl and - or more amino C1-6 lower alkylamino or dialkylamino, lower alkoxy, hydroxy or substituted lower alkyl having 71 units, including fluoro, chloro or bromo, substituted lower alkenyl having 1 to C6 lower alkenyl and one or more 7 mino, C□ ~C6 AlkyA substituted lower alkenyl, lower alkoxy or hydroxy group with amino or dialkylamino or morpholine, piperazine or N-substituted when bonded with and through added nitrogen or added oxygen is hydrogen, C1%C
6 alkyl, C1-C6 hydroxyalkyl, C1-C
Consisting of a 5- to 7-membered saturated heterocycle consisting of an N-substituted piperazine that is any of 6 alkoxyalkyl; R
2 is a lower alkyl substituent; and a pharmaceutical carrier.

One preferred group of active compounds is represented by the following formula: where R is halo-lower alkyl (fluoro, chloro or bromoalkyl), hydroxy-lower alkyl and polyhydroxy-lower alkyl of 1-6 carbons. and R1 is hydrogen or as defined as R, and R2 is lower alkyl.

According to the invention, the acylaminopyrazine is prepared by acylation and alkylation of the corresponding 5,6-dichloro-3-nitropyrazine amino of the above-mentioned preparation method.

5.6-Dichloro-3-nitropyrazineamine is acylated by treatment with an acid halide or acid anhydride of a lower aromatic carboxylic acid. Preferably, 5,6-dichloro-3-nitrovirazinamine is prepared in the presence of a base such as sodium bicarbonate with a large excess of the acid halide, e.g. acetyl chloride, acetyl procyto, propionyl Treat with chloride, butyryl chloride and the like at room temperature. The reaction is preferably carried out by mixing the reactants without solvent addition at room temperature and heating the reactants at the reflux temperature of the mixture for a period of 5 hours to 4 days; This will ensure maximum yield of material. Following the reaction period, the entire mixture is vacuum evaporated to remove excess acylating agent, or alternatively, quenched in water and extracted with a solvent for the product. It is also advantageous to leave the product as a residue after removal of the volatile components by vacuum evaporation and to further purify it by chromatography on silica gel.

2-acylamino-5,6- produced in this way
Dichloro-3-nitrovirazine is then prepared to replace the chloro substituent, as exemplified below;
Treat with amine compounds. Here, R, R, and R2 are
It is defined in the above IB compound.

The reaction of dichloroacylaminonitropyrazine IB with the amine compound is preferably carried out in a solvent for the reactants. The solvents used are lower alkanols such as methanol, ethanol or isopropanol; ethers such as tetrahydrofuran; N,N-dialkylamides such as dimethylformamide; and acetonitrile. The amine or thiol reagent is preferably present in a 5 to 10 molar excess over the nitropyrazine. The reagents are first mixed and then preferably 0.5 to 2
Heat to a temperature of 20-80°C for 4 hours. It is generally preferred to carry out the reaction in the presence of equimolar amounts of an organic base in addition to the reagents and solvent. Progress of the reaction is followed using thin film chromatography.

Following this reaction, the product is recovered after first evaporating the reactants and volatile solvent in vacuo, leaving the product as a residue. This residue is then dissolved in a water-immiscible solvent such as ethyl acetate, and the resulting product extract is washed with water and vacuum evaporation yields the Y pure product. A method of treatment of human patients or livestock in which radiation therapy is intended for progressive disease processes, including oral, injectable,
Preferably it is administered by intravenous injection. The compounds of the present invention are used in pharmaceutical compositions. The dose used will depend on each patient's individual radiation protocol.

In protocols where the radiation dose is divided into a number of fractions, the drug can be administered at planned intervals and not necessarily with each radiation treatment. Generally, the drug is taken 10 minutes to 5 hours prior to radiation therapy at a dose of between 0.25 and about 4.0 grams per square meter of body surface.

The preferred form of administration for intravenous injection is a sterile isotonic solution of the drug. Oral dosage forms such as tablets, capsules and syrups may also be used.

Capsules containing from 100 to soowPg of drug/capsule are satisfactory for use in the treatment methods of the present invention.

The following examples are intended to be illustrative, but are not intended to be limiting in terms of the manufacturing method, product, composition, or treatment method of the present invention.

Step A: Preparation of 5,6-dichloro-3-nitropyrazine amine (n) To 450 tnl of concentrated sulfuric acid cooled to 10° was added 50. O
Add N (0,2m). To this solution, cooled to 0-5°, a cold solution of oleum 15- in oleum nitric acid 15- is added dropwise over 15 minutes. The reaction mixture is stirred for 2 hours at 0-5° and then for 2 hours at ambient temperature. The reaction mixture is then poured onto ice and the yellow solid is collected. The solid is taken up in ethyl acetate, washed twice with saturated sodium carbonate solution, and the solution is then filtered through silica gel Pacado.

The resulting solution was evaporated in vacuo, melting point 169-1
35 g of 5,6-dichloro-3-nitrovirazinamine are obtained at 70°C.

Step B: Preparation of 2((6-amino-3-chloro-5-nitrovirazin-2yl)aminoethanol).

5,6-dichloro- in isopropanol 20 nd2
Add 1.0 g K of 3-nitrovirazinamine, 0.5-triethylamine, and then 0.3 ml of 2-aminoethanol. The reaction mixture is stirred for 3 hours and then concentrated in vacuo to a solid. The solid is admixed with hot chloroform and recrystallized from acetonitrile to give 2[(6-amino-3-chloro-5-nitropyrazin-2-yl)aminocoethanol 06y, melting point 196-197°C.

Using the same procedure as described in Example 1-1, but using the appropriate amine in step B, the following was produced.

p, o, o p
.

To Sanho (v) Sun no Rio
Op To ω ■ To C + O ■ - Example] -2 One animal, two A process: 2-bromo-5,6-cyclonitropyrazine 4.8 g of isoamyl nitrite in 150 - of bromoform heated to 95-1000 5゜6-cycloro 3-
Add nitro-pyrazine amine 5,09 in portions.

The reaction mixture is heated at reflux for 18 hours. After cooling, the proroform is removed in vacuo to give an oil which is chromatographed on silica gel. The initial components eluted are 5,
6-dichloro-2-promonitropyrazine, which is obtained as a viscous oil (2.6.p).

To a solution of 1.0 g of 2-bromo-5,6-cyclonitropyrazine in 0-10° of isopropanol is added 0.72, V of triethylamine, and then 0.72 V of triethylamine is added to 2-amine ethanol. Add .44g. The reaction mixture is stirred at O~100 for 0.5 h and then at room temperature for 0.5 h. The solvent is then removed in vacuo and the residue is triturated with an ethanol/chloroform solution to give a yellow solid, which is collected by p-filtration. This solid was chromatographed on silica gel, and the initial component eluted was 2,2'-
[(3-chloro-5-nitropyrazin-2゜6-yl)
Diamino]jetanol 05g.

2- in 10 ml of isopropanol at O ~ 10°
1.8.9 of bromo-5,6-cyclonitropyrazine
To the solution, add 0.6 g of triethylamine, and then add 0.31 g of ethanolamine. The reaction mixture was heated between 0 and 10°
Stir for 0.5 hour, then stir at room temperature for 15 minutes.

The solvent was then removed in vacuo and the resulting oil was
Chromatograph on silica gel, eluting with methanol/chloroform. The desired product was collected as a clear oil and its identity was confirmed by mass spectrometry. This oil was treated with 0.30 g of ethanolamine and 0.6 I of triethylamine, 2.2'-[(3-chloro-5
-nitropyrazine-2°6-yl)diaminosigetanol is formed.

Using a procedure similar to that described in Examples 1-2B, but using appropriate reagents in step B, the product as shown in J
I made E.

Mino)-5-nitrobifunno Example 3-2 Reagent Product Diethylamine 3-chloro-2,6-diethylamino-5-nitropyrazine 15 tnl of acetyl chloride at room temperature under nitrogen atmosphere
1.0 of 5,6-cyclonitrovirazine amine in
g, anhydrous sodium bicarbonate 0,84,! Add 9. The reaction mixture is then stirred and heated at reflux for 4 days. Excess acetyl chloride is then removed in vacuo,
The residue is chromatographed on silica gel. The desired product is eluted from the column with chloroform.

Step B: N-45-chloro-6(2,3-cyhydroxypropyl)amino-3-di-0, . 20g
of acetamide, o, s g of triethylamine,
Then 0.73.9 of 3-amino-1,2-propanediol is added. The reaction product is stirred at room temperature for 1 hour. The solvent is then removed in vacuo and the residue taken up in ethyl acetate and washed twice with 10 ml of water. The dry ethyl acetate extract was removed in vacuo to give a yellow solid, which was recrystallized from acetonitrile, mp 130-131.
° The title compound is obtained.

Using a procedure similar to that described in Examples 1-2, but using the equivalent amount of the appropriate amine reagent shown in Step B, this is what was made.

Examples Reagents Product N-[5-chloro-6-(2,3-dihydroxypropyl)amino-3-nitropyrazinyl]propionamide-3 N-[5-chloro-6-(2,3-dihydroxypropyl)acin- 3-nitropyrazinylcobutyramide-3 N-[5-chloro-6(2-hydroxyethyl)amino-3-nitropyrazinyl]acetamide-3 N-[5-chloro-6-(4-methyl-1-biperazinyl) -3- Nitrovirazinyl]ace,doamide-3lN-[5-Chloro-6(dimethylaminoethyl)-3-nitropyrazinyl]acetamide A suitable prescription preparation for injection is an isotonic solution, according to previous practices. The example compounds are prepared by dissolving them at a concentration of about ITq/- and sterilizing the resulting solution, which is suitable for intravenous injection.

Example 8-3 A formulation suitable for oral administration in capsules consists of 9 parts ioo+n and 50 parts each of the compounds produced according to the preceding examples.
0.71111 parts to fill individual capsules of appropriate size.

655-

Claims (1)

[Claims] 1 Formula: (wherein R and R1 each represent (1/l-C6 lower alkyl and one or more amino, C16 lower alkylamino, or dialkylamino, lower alkoxy, Substituted lower alkyl, ci C6 lower alkenyl with hydroxy or halo including fluoro, chloro or bumolo and one or more 7mino, c, -c6
alkylamino or dialkylamino, substituted lower alkenyl with lower alkoxy or hydroxy groups, or when combined with and through additional nitrogen or oxygen, morpholine;
radiation of a 5- to 7-membered saturated heterocycle consisting of an N-substituted piperazine in which the piperazine or triN substituent is hydrogen, ClC6 alkyl, c, -c6 hydroxyalkyl, or cl-c6 alkoxyalkyl. A pharmaceutical composition useful for enhancing the therapeutic effects of radiotherapy, comprising an effective amount of an enhancing compound and a pharmaceutical antibody. 2. contacting a 5,6-dichloro-3-nitropyrazine amine with an amine of the formula: where R and R' are as defined in claim 1. ). 3. An effective sensitizing amount of a compound having the formula: (wherein R'R' is defined in claim 1) is determined by R1.
and R2 are lower alkyl substituted directly with one or more hydroxy or halogen groups, including fluoro, chloro, bromo, or lower substituted with one or more hydroxy groups, respectively. A pyrazine compound of formula; which is alkenyl. 5. Formula; (wherein A has at least one hydrogen of the amino group replaced by a hydroxy-substituted lower alkyl or an alkoxy-substituted lower alkyl,
(defined as an amino substituent). 6. A compound of the formula: where X is defined as chloro, bromo or iodo. 7 A compound of the formula: wherein A is defined in claim 5 and X is halogen, including chloro, bromo and iodo. 8. Contacting a compound having the formula; with a compound selected from hydroxy lower alkyl amines or alkoxy lower alkyl amines in the presence of an organic base; (as defined in ). 9, comprising administering to a patient in need of such radiotherapy an effective sensitizing amount of a compound having the formula: where A is defined in claim 5. , a method to enhance the therapeutic effects of radiotherapy. 10; characterized in that it consists of a compound of formula: wherein A is defined in claim 5; and a pharmaceutical carrier.
A composition useful for enhancing the therapeutic effect of radiotherapy. 11, Formula; (wherein R and R1 are each hydrogen, C. -C6 lower alkyl and one or more amino, ci-6 lower alkylamino or dialkylamino, lower alkoxy, hydroxy or fluoro, chloro or substituted lower alkyl with halo, including bromo, c, -c66 lower alkenyl and substituted lower alkenyl with one or more amino, C1'-C6 alkylamino or dialkylamino lower alkoxy or hydroxy groups, or additional When combined with nitrogen or oxygen and bonded through it, the morpholine, piperazine or N substituent represents hydrogen, cl-c6 alkyl, auto-
06 hydroxyalkyl, ClC6 alkoxyalkyl, constitutes a 5-7 membered saturated heterocycle consisting of N-substituted piperazine, R2 is a lower alkyl substituent; Effective amounts of radiation-enhancing compounds and pharmaceuticals A pharmaceutical composition useful for enhancing the therapeutic effect of radiotherapy, comprising: a carrier; 12. Formula; (wherein R is hydroxy lower alkyl, polyhydroxy lower alkyl, or halo lower alkyl, R1 is hydrogen or R1% R2 is a lower alkyl group) Chloronitropyrazine compound. 13. A chloronitropyrazine compound according to claim 10, which is N'-[5-chloro-6(2,3-dihydroxypropyl)amino-3-nitropyrazinyl]acetamide. 14. A chloronitropyrazine compound according to claim 10 which is N-[5-chloro-6(2,3-dihydroxypropyl)amino-3-nitropyrazinylsibutyramide. 15. Contacting 5゜6-dichloro-3-nitropyrazine amine with a halide or anhydride of a lower aliphatic acid to produce an acylated 5,6-cyclo-3-ditropyrazine amine of the formula; , and the acylated nitropyrazine amine is contacted with an amine of the formula: (wherein R and R1 are as defined in claim 11): , R% R1 and R2 as defined in claim 11). 16, in which R, R1 and R2 are defined in Claim 11, is administered to a patient in need of such radiotherapy. A method for enhancing the therapeutic effects of radiation therapy.