J. Med. Chem. 1984,27, 1621-1629 injection such that a level of 200,100,50, 25, or 12.5 mg of test compound/kg of mouse weight is maintained. Ten mice are employed per test compound at each dose level and survivors counted at 120-h postchallenge. Streptomycin sulfate at 100 mg/kg was used as the positive control.
Registry No. la, 932-22-9; lb, 1677-79-8; IC, 1445-55-2; 2a, 56707-86-9; 3a, 91777-77-4; 3b, 91777-76-3; 3c, 92187-06-9; 3a, 92187-07-0; 30, 92187-08-1; 4, 64882-65-1; 6, 91777-79-6; 7a, 91777-71-8; 7b, 92187-09-2; 8a, 91777-72-9; 8b, 92187-10-5; 9a, 91777-78-5; 9b, 92187-11-6; 9c, 92187-12-7; loa, 91777-70-7; lob,
1621
92187-13-8; lla, 92187-14-9; l l b , 92187-15-0; llc, 92187-16-1; lld, 92187-17-2; lle,92187-1&3; l l f , 92187-19-4; llg, 92187-20-7; llh, 92187-21-8; l-acetyl-2,3,5-tribenzoyl-~-ribofuranose, 14215-97-5; methyl fluorosulfate, 421-20-5; 2,3-dihydro-2-methyl-3-0~0pyridazine-4-carbonitrile,92187-25-2; 3-methoxypyridazine-4carbonitrile, 92187-22-9; 3-chloropyridazine-4-carbonitrile, 1445-56-3; 4,5-dichloro-3-oxid~l-methylpyridazinium, 33386-96-8; 2- (hydroxymethyl)-2,3-dihydro-3-oxopyridazine-4-carbonitrile, 92187-23-0; 2-(acetoxymethyl)-2,3-dihydro-3-oxopyridazine-4carbonitrile, 92187-24-1; O-(tetrahydropyran-2-yl)hydroxylamine, 6723-30-4; ribose tetraacetate, 28708-32-9.
Novel Pyrimidine and 1,3,5-Triazine Hypolipidemic Agents Gaetano d’Atri,*+Piero Gomarasca,? Giuseppe Resnati,? Giovanni Tronconi,+Carlo Scolastico,t and Cesare R. Sirtorir LPB Zstituto Farmaceutico S.p.A., 20092 Cinisello Balsamo, Milan, Institute of Organic Chemistry, 20133 Milan, and Center E. Grossi Paoletti, Department of Pharmacology, 20129 Milan, Italy. Received February 14, 1983
New compounds were synthesized by changing the substituents of a trisubstituted pyrimidine, i.e., [ [4-chloro-6[ (2,3-dimethylphenyl)amino]-2-pyrimidinyl]thio]acetic acid, a potent hypolipidemic agent, impaired, however, by a marked hepatomegaly-inducing effect. The structural variations led to the subsidence (14b, i.e., 4-chloro-2(dimethylamino)-6-[(2,3-dimethylphenyl)amino]pyrimidine)or to the reduction (18b, [ [4-chloro-6-[(2,3-dimethylphenyl)amino]-2-pyrimidinyl]amino]aceticacid) of said untoward effect but still maintained the hypolipidemic effect that, although markedly decreased, still proves significant for serum cholesterol and triglycerides (18b) or for serum triglycerides only (14b).
ammonium salt was alkylated with alkyl bromides or Development of drugs for the treatment of hyperliiodides, and the corresponding 2-(alkylthio)-4,6(1H,5H)pidemias has focused on (ary1oxy)aceticacid derivatives pyrimidinediones 4a-d were obtained (Scheme I). The (so-called “fibrates”),e.g., clofibrate, bezafibrate, tibric acid, pro~etofen,l-~ nicotinic acid derivatives: and agents of different chemical series, e.g., tiaden01.~ A promising Witiak, D. T.; Newman, H. A. J.; Feller, D. R. “Clofibrate hypolipidemic activity in the pharmacological and preAnalogs, A Comprehensive Review”; Marcel Dekker: New clinical testing was shown by [ [4-chloro-6-[(2,3-diYork, 1977. methylphenyl)amino] -2-pyrimidinyl]thio] acetic acid (la) Sirtori, C. R.; Zoppi, S.; Quarisa, B.; Agradi, E. Pharmacol. Res. and by its related ethanolamide All these new Commun. 1974,6, 445. hypolipidemic agents (with the exception of nicotinic acid Cayen, M. N.; Kallai-Sanfacon “Annual Reports in Medicinal derivatives) produce an increase in liver weight and volChemistry”; Academic Press: New York, 1980; Vol. 15, pp 162-171. ume, peroxisomal proliferation, and, although not mutaWeiner, M. Drug Metab. Rev. 1979,9, 99. genic, the onset of hepatomas in predisposed strains of rats, Franceschini, G.; Poli, A.; Catapano, A. L.; Gatti, E.; Sirtori, i.e., Fischer rats.l2-lg We therefore deemed it useful to M.; Gianfranceschi, G.; Sirtori, C. R. Atherosclerosis 1981,40, bring some structural changes to molecules Id and le, both 245. in the substituents and in the pyrimidine ring, so as to Sirtori, C. R.; Gomarasca, P.; d’Atri, G.; Cerutti, S.; Tronconi, maintain the hypolipidemic activity and prevent injurious G.; Scolastico, C. Atherosclerosis 1978, 30, 45. Santilli, A. A.; Scotese, A. C.; Tomarelli, R. M. Experientia effects on the liver cell. 1974, 30, 1110. Two types of compounds were selected, i.e., derivatives Bondesson, G.; Hebbom, C.; Magnusson, 0.;Stjernstroem, N. similar to Id and derivatives, recalling someway the E. Acta Pharm. Suec. 1974,11, 417. metformin structure, that, according to Sirtori et a1.16,20 d’Atri, G.; Gomarasca, P.; Galimberti, E.; Sirtori, C. R.; Kritcounteract the onset of an experimentally induced athechevsky, D. Atherosclerosis 1980,37,475. roma in the rabbit aorta. Najemnik, C.; Irsigler, K.; Sirtori, C. R. Pharmacol. Res. Commun. 1981, 13, 177. The resulting molecules were subjected to a first pharNunes, G. Curr. Ther. Res. 1982, 31, 193. macological investigation that checked their action on Reddy, J. K.; Krishnakantha, T. P. Science 1975, 190, 787. serum cholesterol, triglycerides, and lipoproteins and that Reddy, J. K.; Moody, D. E.; Azarnoff, D. L.; Tomarelli, R. M. assessed for the most active compounds their effect on liver Arch. Int. Pharmacodyn. Ther. 1977,255, 51. weight and increases in catalase and liver enzymes related Reddy, J. K.; Azarnoff, D. L.; Sirtori, C. R. Arch. Znt. Pharto the fatty acid 0-oxidation as well as their response to macodyn. Ther. 1978,234, 4. peroxisomal proliferation. Reddy, J. K.; Azarnoff, D. L.; Rao, M. S.; Qureshi, S. A. Fed. Proc., Fed. Am. SOC.Exp. Biol. 1978, 37, 232. Results Reddy, J. K.; Qureshi, S. A. Br. J. Cancer 1979, 40, 476. Chemistry. The synthesis of all 2,4,6-trisubstituted Reddy, J. K.; Azarnoff, D. L.; Hignite, C. E. Nature (London) 1980,283, 397. pyrimidines started from 1,2-dihydro-2-thioxo-4,6Reddy, J. K.; Rao, M. S.; Azarnoff, D. L.; Sell, S. Cancer Res. (lH,5H)pyrirnidinedione (3). Its sodium or tetrabutylLPB Istituto Farmaceutico S.p.A.
* Institute of Organic Chemistry. 8 Center
E. Grossi Paoletti.
1979, 39, 152. Lallwani, N. D.; Reddy, J. E.; Qureshi, S. A.; Sirtori, C. R.; Abiko, Y.; Reddy, J. K. Human Toxicol. 1983,2, 27. Sirtori, C. R.; Catapano, A.; Ghiselli, G. C.; Innocenti, A. L.; Rodriguez, J. Atherosclerosis 1977, 26, 9.
0022-262318411827-1621$01.50/0 0 1984 American Chemical Society
1622 Journal of Medicinal Chemistry, 1984, Vol. 27,No. 12
Scheme I
d'dtri et al.
Scheme 11
-
3
I NYR N Cl
Sa-d
/'
0
w
7
le
I
5N
c1
lNyNC02Et
w
I
0
W
CI
Ty-co2 W
16b.c
150-c
I
I
8
9
reaction of these compounds with phosphorus oxychloride gave 2-(alkylthio)-4,6-dichloropyrimidines 5a-d in good yields. The 6-C1 group in ethyl [ [4,6-dichloro-2-pyrimidinyl]thiolacetate (Sa) was substituted by diethylamine, 2,3-dimethylphenol, and 2,3-dimethylaniline and its N methyl derivative in the presence of NaOH or Na2C03. The hydrolysis of ester groups of the so obtained compounds 6s-d was made by briefly heating in diluted sodium hydroxide. A stronger basic treatment with sodium ethylate in refluxing ethanol transformed [ [4-chloro-6[(2,3-dimethylphenyl)atnino]-2-pyrimidinyl]thio]aceticacid (la)into its 4-ethoxy derivative 7, which gave the amide 8 by reaction with ethyl chloroformate and ethanolamine (Table I). The N-(2-hydroxyethy1)amide l e was formed by boiling Id with aziridine. Treatment of this compound
with sodium nitrite afforded the N-nitroso derivative 9. The 2(1H)-pyrimidinethiones1la,b were synthesized by reacting 4,6-dichloro-2-[4-methoxybenzyl)thio]pyrimidine (5b) with properly substituted anilines, subsequently cleaving thio ethers 10a,b by means of trifluoroacetic acid (Scheme 11). Similarly, the condensation of 24methylthio)- and 2(mocty1thio)pyrimidines5c and 5d, respectively, with the above-cited nucleophiles gave adduds 12a-d (Scheme 111). The oxidation of the 2-methylthio group of 12a-c with Hz02in acetic acid, in the presence of catalytic amounts of Na2W04,21,22furnished the 4-chloro-2-(methylsu1fonyl)pyrimidines 13a-c. The selective displacement of the methylsulfonyl group by diethylamine, ethyl glycolate, or ethyl glycinate afforded (21) Zaechke, H. Z. Chem. 1977, 17, 63; Chem. Abstr. 1977, 87, 5897d. ( 2 2 ) Lamm, B.; Gustafsson, K. Acta Chem. Scund., Ser. B 1974,
B28,701.
Journal of Medicinal Chemistry, 1984, Vol. 27, No. 12 1623
Pyrimidine and 1,3,5- Triazine Hypolipidemic Agents
Table 1.O Physical and Chemical Properties of Compounds Tested as Hypolipidemic Agents
w
z
no. X l a C1
Y SCHzCOzH
lb
C1
SCHzCOzH
CH A"
IC
C1
SCHzCOzH
CH C
8
OEt SCHzCONH(CHz)zOH
w
SM (wt, reagent 9) (L) 6a (4.8) NaOH (22Y 6b (1.2) NaOH (7.2)b 60 (5.0) NaOH (2Vb 7 (5.0) HO(CHJ2~I
CH B
solvent (mL) temp, OC time, h yield % crystn solv. mp, "C EtOH (40) 60 5 rnin 72 acetone 187-189 . . EtOH (16)
60
5 min
41
EtOH (45)
60
5 min
76
CHC13 (65)
20
1.5
58
2"
AcOEtlnhexane AcOEtlnhexane AcOEt/pet. ether
123-125 174-176 112-114
lla C1
SH
CH B
10a (8.0)
(1.0)C CFaCOzH
CF3COzH
77
50 rnin
89
Et20
>250
l l b C1
SH
CH C
10a (6.0) CF3C02H
CF3C02H
77
1.5
60
AcOEt/ EtzO EtOH
>290
149-150 45 80 18 EtOH (40) 5c (4.0) B' (2.9)f oil 80 20 49 EtOH (25) 5d (3.0) B' (1.5)g 72-73 30 rnin 79 pet. ether 20 13a (5.0) "Mez C6H6(100) (4.4)h 146-147 AcOEtln78 80 18 CH B C & 3(50) 13b (5.0) HNM& 14b C1 (CHJzN hexane (4.5)h n-hexane 99-101 67 20 18 CHC13 (50) CH C 13c (5.2) "Mez 1 4 ~C1 (CH,)zN (6.0)h AcOEtln129-130 5 min 76 60 EtOH (10) CH A 15a (1.3) NaOH 178 C1 OCHzCOpH hexane (5.5)b 190-191 acetone 5 min 90 60 EtOH (40) CH B 15b (5.2) NaOH 17b C1 OCHzCOzH (20)* 154-155 AcOEt 5 min 75 60 EtOH (20) 15c (2.5) NaOH CH C 1 7 ~C1 OCHzCOzH (10.4Ib 205-206 AcOEt 60 5 min 79 EtOH (27) 16b (2.2) NaOH CH B 18b C1 HNCHZCOZH (13.5) 96-98 dec AcOEtln10 min 70 EtOH (10) 60 16c (1.4) NaOH CH C 180 C1 HNCHzCOzH . , hexane (5.0)b 167-168 4 AcOEt 15 rnin 62 CHC13 (150) 22 (4.3) "Me, N B 23d C1 (CH3)2N (2.7)' AcOEtln185-186 5 min 75 60 EtOH (37) 23a (5.0) NaOH 24a C1 CH3NCHzCO2H N B hexane (21.0)b AcOEt 168-169 5 min 60 60 EtOH (30) N B 23b (3.7) NaOH 24b C1 OCHzCOzH (16.2)b 220-221 60 AcOEt 20 min 68 EtOH (75) N B 23c (7.2) NaOH 240 OEt SCHzCOzH (44.0)b i-PrOH/ 0 2 68-69 65 25 C1 (CH&N N (CH3)zN 21 (4.5) HN(CH3)z acetone (35)k (13)j HZO 0 2.5 AcOEt 223-225 55 D (3.3) N HZN 26 C1 (CH3)zN "(CHh Hz0 (80)' (6.1)l 40 50 rnin MeOH/HzO 51-52 42 27 C1 (CH,)zN CH (CH3)zN 19 (5.0) NH(CH3)z EtOH (25)m @.oV 28 C1 (CH8)zN CH HzN E (6.1) NH3?3O)" EtOH 120 18 52 EtOH/H20 153-155 "All reported compounds showed correct microanalyses (C, H, N); structural elucidation was made by 'H NMR, IR, and/or mass spectra. b lN aqueous solution. 'The carboxylic group was activated by 2.5 mL (26.1 mmol) of ethyl chloroformate and 2.5 mL (17.9 mmol) of Et3N. dThis reaction was made in the presence of 2.7 mL (24.7 mmol) of anisole. eThis reaction was made in the presence of 2.0 mL (18.4 mmol) of anisole. '2.50 g (23.6 mmol) of NaZCO3was added. 81.30 g (12.3 mmol) of NaZCO3was added and the product was purified by chromatography on Kieselgel. h33% aqueous solution; this reaction was made in the presence of 4.6 mL (33.0 mmol) of Et3N. '33% aqueous solution; this reaction was made in the presence of 2.3 mL (16.5 mmol) of Et3N. 133% aqueous solution. kThe hot solution of E in acetone was poured on 150 g of cracked ice and dimethylamine was slowly added; mp (n-PrOH/H20) 66-68 OC, ref 9b. 'Mp (EtOH) 220-222 "C, ref 9b. mMp(sublimation) 52.5 O C , ref 9a. "10% ethanolic solution; this reaction was made in a Carius tube; mp (EtOH/H,O) 151 "C, ref 9a. "A = 2,3-(CH3)2CeH30,B = 2,3-(CH3)2CsHSNH,B' = 2,3-(CHJZCsH3NH2,C = 2,3-(CH3),C6H3NCH3,D = 2,4-dichloro-6-amino-1,3,5-triazine, E = 4,6-dichloro-2-(dimethylamino)pyrimidine. 12b C1 12d C1 14a C1
SCH3 SCaH1, (CH3)zN
CH B CH B CH A
'
the derivatives 14a-c, 15a-c, and 16b,c, respectively. The hydrolysis of esters 15a-c and 16b,c to the related acids 17a-c and 18b could be carried out in diluted ethanolic sodium hydroxide. A shorter synthesis was set up to prepare 14b and 18b on a large scale. 2,3-Dimethylaniline was condensed with 2,4,6-tri~hloropyrimidine~~ to give 2,4-dichloro-6-[ (2,3-dirnethylphenyl)amin0]pyrimidine,2~which was transformed subsequently into 14b by reacting with dimethylamine and into 18b by treatment with ethyl glycinate and subsequent basic hydrolysis of the ester group (Scheme IV).
The condensation of cyanuric chloride with 2,3-dimethylaniline afforded 2,4-dichloro-6-[(2,3-dimethylphenyl)amin0]-1,3,5-triazine,~~ which provided the monochlorotriazines 23a-d by reaction with dimethylamine or ethyl esters of glycolic acid, thioglycolic acid, or N methylglycine (Scheme V). The hydrolysis of the ester groups of 23a,b with diluted ethanolic sodium hydroxide provided the acids 24a,b; under the same reaction conditions, starting from ethyl [ [4-chloro-6-[(2,3-dimethylphenyl)amino]-l,3,5-triazin-2-yl]thio]acetate (23c),the acid [ [4-ethoxy-6-[ (2,3-dimethylphenyl)amino]-1,3,5-triazin-2-
1624 Journal of Medicinal Chemistry, 1984, Vol. 27, No. 12
d’dtri et al.
Table 11. Serum Cholesterol, Triglycerides, and a-Lipoprotein Cholesterol in Control R a b or Rats Given the Standards (la, le, 2) or the Investigational Compounds a-cholesterol, % vs. no. cholesterol, mg/100 mL cholesterol triglycerides, mg/ 100 mL of % Pvs. % Pvs. % Pvs. LD,, anidose, conconconconconconcompds mals std mg/kg M f SE trols trols M f SE trols trols M f SE trols trols mg/kg control 40 72.0 f 1.87 69.5 f 2.12 105.9 f 4.11 std Id 30 50 55.1 f 1.87 -23.5
