Glycocyamidine derivatives

Abstract: The glycocyamidine derivatives of the present invention are represented by the following formula (I): wherein R₁, R₂ and R₃, which may be the same or different, is hydrogen or a lower alkyl group, preferably a straight or branched alkyl group having 1 to 3 carbon atoms, such as methyl, ethyl, propyl or isopropyl, and R represents hydrogen or an acetyl group, which are useful as test reagents for diagnosis of renal failure.

Description: The present invention relates to glycocyamidine derivatives and salts thereof, which are useful as test reagents for the diagnosis of renal failure. In renal failure such as uremia, chronic nephritis or urinary obstruction, lowering of glomerular filtration rate caused by functional decrease of kidney is observed. Measurement of the glomerular filtration rate is conventionally used to diagnose renal failure. In particular, the creatinine clearance test based on blood and urinary creatinine level is often used. A novel compound has now been isolated and identified from the urine of patients suffering from renal failure. This compound is increasingly produced and accumulated in the body during renal failure. Various types of renal failure can therefore be diagnosed based on the existence and the amount of the compound in fluids such as serum or cerebrospinal fluid and urine. An object of the present invention is to provide novel glycocyamidine derivatives which are useful as test reagents for the diagnosis of renal failure. The glycocyamidine derivatives of the present invention are represented by the following formula (I). In the above formula (I), R₁, R₂ and R₃, which may be the same or different represent hydrogen or a lower alkyl group having from 1 to 6 carbon atoms, preferably a straight or branched alkyl group having 1 to 3 carbon atoms, such as methyl, ethyl, propyl or isopropyl. R represents hydrogen or an acetyl group. The compounds of the above formula (I) can be represented by the following formula (II) or (III) as tautomeric isomers. wherein each of R₁, R₂, R₃ and R has the same meaning as in the formula (I). The glycocyamidine derivatives of the present invention include pharmaceutically acceptable salts of the compounds having above formula (I), for example, salts with alkali metal such as sodium or potassium, with alkaline-earth metal such as magnesium, calcium or barium, or with other metals such as aluminum, or salts as acid addition with an acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, citric acid or lactic acid, or salts with an organic base such as ammonia or the like. These salts can be prepared from free glycocyamidine derivatives or other salts of these derivatives by a known method. When optical isomers exist in the compounds of the invention, the present invention includes any of the DL-, D- and L-isomers. The glycocyamidine derivatives of the present invention can be prepared as follows. For example, the compounds represented by the following formula (IV) can be used as starting materials. wherein each of R₁, R₂ and R₃ has the same meaning as in the formula (I). The 1-position, 3-position and/or an amino group of 2-position of the compound of the formula (IV) are protected by a conventional amino-protecting group such as t-butoxycarbonyl group, and then an acetoxy group is introduced into the 5-position of the compound by treatment with an oxidizing agent such as lead tetraacetate. The amino-protecting group is removed by a conventional method, for example, t-butoxycarbonyl group is removed by using trifluoroacetic acid, and then the acetoxy group is reduced in a conventional manner to give 5-hydroxyglycocyamidine derivatives. The resulting compounds of the present invention can be purified by known methods such as distillation chromatography and recrystallization. Identification is established through melting point (m.p.), elemental analysis, IR, NMR, UV, mass spectrum, etc. The following examples, which are illustrative only and not intended to limit the scope of the invention, describe the preparation of the compounds of the present invention. Example 1. (1) 10 g of 1-methylglycocyamidine and 29 g of t-butoxycarbonyl anhydride were dissolved in 300 ml of dimethylformamide, and stirred overnight at 60°C. The solution was concentrated to dryness and 100 ml of water was added to the residue. The resulting product was extracted by 100 ml of acetic acid twice. The organic layer was concentrated to dryness under reduced pressure. The residue was purified by silica gel column chromatography (70% ethylacetate/hexane) to give 12.6 g of N²-t-butoxycarbonyl-1-methylglycocyamidine in the form of pale yellow needle crystals. m.p.: 109 - 110 °C In the same manner, the following compounds were obtained. N²-t-butoxycarbonyl-3-methylglycocyamidine 3-t-butoxycarbonyl-N²-methylglycocyamidine 1,N²-di-t-butoxycarbonylglycocyamidine (2) 11.6 g of N²-t-butoxycarbonyl-1-methylglycocyamidine and 36.2 g of lead tetraacetate were dissolved in 300 ml of dried benzene. The solution was refluxed with heating for 90 minutes and then cooled to room temperature. A small amount of water was added thereto. After removing the resulting precipitate and aqueous layer, the organic layer was dried over sodium sulfate anhydride. The resulting solution passed through a short column of silica gel and concentrated under reduced pressure to give 5-acetyl-N²-t-butoxycarbonyl-1-methylglycocyamidine as an oily substance. Without any further purifications, this oily residue was used in the following reaction. In the same manner, the following compounds were obtained. 5-acetyl-N²-t-butoxycarbonyl-3-methylglycocyamidine 5-acetyl-3-t-butoxycarbonyl-N²-methylglycocyamidine 5-acetyl-1,N²-di-t-butoxycarbonylglycocyamidine (3) 100 ml of trifluoroacetic acid was added to the resulting products as mentioned above. The solution was stirred for an hour at room temperature to remove the protecting group to give 5-acetyl-1-methylglycocyamidine, which was used in the following reaction without any further purifications. In the same manner, the following compounds were obtained. 5-acetyl-3-methylglycocyamidine 5-acetyl-N²-methylglycocyamidine 5-acetylglycocyamidine (4) The solvent was distilled off under reduced pressure. 100 ml of 1N hydrochloric acid was added to the residue and the reaction mixture was stirred for 2 days at room temperature. The solution was concentrated to dryness. The crude crystals were washed with ethyl acetate and recrystallized from ethanol to give 8.1 g of 5-hydroxy-1-methylglycocyamidine hydrochloride (Compound 1). m.p.: 191 °C (decomposition) Elementary Analysis: C₄H₈N₃O₂Cl C % H % N % Calculated 29.02 4.87 25.38 Found 29.10 4.82 25.70 MS (EI, 70eV): 129 (M⁺), 127, 101, 73, 56, 42 NMR(DMSO-d₆/TMS): δ=3.01(3H,s), 5.13(1H,d,J=6Hz), 7.69(1H,d,J=6Hz), 9.28(1H,s), 9.42(1H,s) In the same manner, the following compounds were obtained. 5-hydroxy-3-methylglycocyamidine hydrochloride (Compound 2) m.p.: 186 °C (decomposition) NMR(DMSO-d₆/TMS): δ=3.07(3H,s), 5.35(1H,d,J=9Hz), 7.43(1H,d,J=9Hz), 7.83(1H,br.s), 8.47(1H,br.s), 8.54(1H,br.s) 5-hydroxy-N²-methylglycocyamidine hydrochloride (Compound 3) m.p.: 172 °C (decomposition) NMR(DMSO-d₆/TMS): δ=2.92(3H,s), 5.30+5.36(1H,s), 7.39+7.54(1H,br.s), 9.54+9.65(1H,br.s), 9.97+10.50(1H,br.s), 12.48(1H,br.s) 5-hydroxyglycocyamidine hydrochloride (Compound 4) m.p.: 220 °C (decomposition) NMR (DMSO-d₆/TMS): δ=4.82(1H,d,J=7.8Hz), 6.21(1H,d,J=7.8Hz), 7.07(1H,br.s), 7.64(1H,br.s), 7.83(1H,br.s) The data given above of MS and NMR characteristics enable the compounds to be used as internal and external standards for mass spectrographic analysis and nuclear magnetic resonance by well established methods, eg of samples containing metabolic breakdown products, such as urine, blood and cerebrospinal fluid. Other analytical methods may, of course, be used depending on individual circumstances. Such analyses may be used eg for monitoring the progress of renal disorder in humans or animals, by a series of tests or assays. The physico-chemical characteristics given derive in general from the cyclodiamidine structure and the monitoring method is generally applicable to such structure. Furthermore, it is possible to utilize derivatives of the compounds described which exhibit essentially the same observable characteristics or certain of them and which have some other additional utility in the analytical method used. It was observed that the compound 1 of the present invention was increasingly produced and accumulated in the body in patients suffering from renal failure. It is very important for evaluating the diseased state to determine the compound 1 in the fluid such as serum or cerebrospinal fluid and the urine, particularly, the determination of the existence and the amount change of the compound in serum of renal failure patients is very useful for diagnosis of renal failure, and so that provides an easy diagnosis method. Therefore, the compounds of the present invention are useful as test reagents for diagnosis of renal failure such as uremia, chronic nephritis or urinary obstruction.

Claims: Claims for the following Contracting States : AT, BE, CH, DE, DK, FR, GB, IT, LI, LU, NL, SE A glycocyamidine derivative having the formula (I) and a salt thereof: wherein R₁, R₂ and R₃, which may be the same or different, represent hydrogen or a lower alkyl group having from 1 to 6 carbon atoms, and R is hydrogen or an acetyl group and pharmaceutically acceptable salts thereof. A glycocyamidine derivative according to claim 1 wherein R₁ is a lower alkyl group having from 1 to 6 carbon atoms and pharmaceutically acceptable salts thereof. A glycocyamidine derivative according to claim 1 or 2 wherein R₂, R₃ and R is hydrogen and pharmaceutically acceptable salts thereof. A glycocyamidine derivative according to any one of claims 1 to 3 wherein R₁ is methyl group and pharmaceutically acceptable salts thereof. 5-Hydroxy-1-methylglycocyamidine, 5-hydroxy-3-methylglycocyamidine, 5-hydroxy-N²-methylglycocyamidine, 5-hydroxyglycocyamidine and pharmaceutically acceptable salts thereof. Use as an internal or external analytical standard in diagnosing the presence and/or degree of renal failure in a fluid sample of one or more glycocyamidine derivatives or salts thereof according to any preceding claim. Use according to claim 6 wherein the derivative (or derivatives) and salts thereof is used as an internal or external standard in nuclear magnetic resonance analysis. Use according to claim 6 of the derivative of claim 4 or claim 5 or a salt thereof as an internal or external standard for mass spectrographic analysis. A method of monitoring the progress of renal disorder in a human or animal which comprises assaying for the presence and amount of change of 5-hydroxy-1-methylglycocyamidine in a fluid sample from said human or animal. A method according to claim 9 wherein the fluid sample contains material selected from urine, blood and cerebrospinal fluid. A method according to claim 9 or 10 wherein the assay makes use of an internal or external standard comprising a derivative according to any of claims 1 to 5. A process for the production of compounds of the general formula I given in claim 1 or a pharmaceutically acceptable salt thereof wherein R₁, R₂, R₃ and R have the meanings given in any one of claims 1 to 5 which comprises introducing an acetoxy group into the 5-position of a compound of the general formula Claims for the following Contracting States : ES, GR A process for the production of glycocyamidine derivatives having the following general formula I: wherein R₁, R₂ and R₃, which may be the same or different, represent hydrogen or a lower alkyl group having from 1 to 6 carbon atoms, and R is hydrogen or an acetyl group or pharmaceutically acceptable salts thereof which comprises introducing an acetoxy group into the 5-position of a compound of the general formula wherein each of R₁, R₂ and R₃ have the meanings given above and if desired reducing the 5-acetoxy group to give a 5-hydroxy group whereby amino groups present are protected by conventional amino-protecting groups such as a t-butoxycarbonyl group. A process according to claim 1 wherein R₁ is a lower alkyl group having from 1 to 6 carbon atoms and pharmaceutically acceptable salts thereof. A process according to claim 1 or 2 wherein R₂, R₃ and R is hydrogen and pharmaceutically acceptable salts thereof. A process according to any one of claims 1 to 3 wherein R₁ is methyl group and pharmaceutically acceptable salts thereof. A process according to any one of claims 1 to 4 for the production of 5-Hydroxy-1-methylglycocyamidine, 5-hydroxy-3-methylglycocyamidine, 5-hydroxy-N²-methylclycocyamidine, 5-hydroxyglycocyamidine and and pharmaceutically acceptable salts thereof. Use as an internal or external analytical standard in diagnosing the presence and/or degree of renal failure in a fluid sample of one or more glycocyamidine derivatives or salts thereof according to any preceding claim. Use according to claim 6 wherein the derivative (or derivatives) and salts thereof is used as an internal or external standard in nuclear magnetic resonance analysis. Use according to claim 6 of the derivative of claim 4 or claim 5 or a salt thereof as an internal or external standard for mass spectrographic analysis. A method of monitoring the progress of renal disorder in a human or animal which comprises assaying for the presence and amount of change of 5-hydroxy-1-methylglycocyamidine in a fluid sample from said human or animal. A method according to claim 9 wherein the fluid sample contains material selected from urine, blood and cerebrospinal fluid. A method according to claim 9 or 10 wherein the assay makes use of an internal or external standard comprising a derivative according to any of claims 1 to 5.

Inventors: IENAGA KAZUHARA, NAKAMURA KO, IENAGA, KAZUHARA, C/O INST. OF BIO-ACTIVE SCIENCE, NAKAMURA, KO, C/O INSTITUTE OF BIO-ACTIVE SCIENCE
Applicants: NIPPON ZOKI PHARMACEUTICAL CO, NIPPON ZOKI PHARMACEUTICAL CO. LTD.
Application year: 1990
Main classification: C07D233
IPC codes: G01N33, A61P9, A61K31, A61K49, C07D233