Folate antagonists. 13. 2,4-Diamino-6-](alpha,alpha,alpha-trifluoro-m-tolyl)thio]quinazoline and related 2,4-diamino-6-[(phenyl- and naphthyl)thio]quinazolines, a unique class of antimetabolites with extraordinary antimalarial and antibacterial effects.

An array of nonclassical thioquinazoline analogues (VIII) of methotrexate was prepared by cyclization of the requisite 2-amino-5-(arylthio)benzonitrile with chloroformamidine hydrochloride (28--79%). The aminonitrile precursors were obtained by SnCl2-HCl reduction (28--99%) of the corresponding 2-nitro-5-(arylthio)benzonitriles, which were synthesized by the condensation of the appropriate 5-chloro-2-nitrobenzonitriles with various arylthiols (36--83%). Many of the thioquinazolines (VIII) showed suppressive antimalarial activity comparable with or superior to chloroquine, cycloguanil, and pyrimethamine against drug-sensitive lines of Plasmodium berghei in mice and Plasmodium gallinaceum in chicks, and several displayed potent prophylactic activity with P. gallinaceum. Moreover, the thioquinazolines retained potent antimalarial effects against chloroquine-, cycloguanil-, pyrimethamine- and DDS-resistant lines of P. berghei in mice and against chloroquine- and pyrimethamine-resistant strains of Plasmodium falciparum in owl monkeys. The most active compound, namely, 2,4-diamino-6-[alpha,alpha,alpha-trifluoro-m-tolyl)thio]quinazoline, was designated for preclinical toxicological studies. Numerous substances exhibited in vitro activity against a broad spectrum of pathogenic bacteria at concentrations of less than 0.25 microgram/mL. The thioquinazolines also prove to be potent folate antagonists, causing 50% inhibition of Streptococcus faecalis R (ATCC 8043) at drug concentrations ranging from 0.2 to 2.0 ng/mL. Structure--activity relationships are discussed.     

Folate antagonists. 12. Antimalarial and antibacterial effects of 2,4-diamino-6-[(aralkyl and alicyclid)thio-, sulfinyl-, and sulfonyl]quinazolines.

A series of 2,4-diamino-6-[(aralkyl and alicyclic)thio-, sulfinyl-, and sulfonyl]quinazolines was prepared via condensation of 5-chloro-2-nitrobenzonitrile or 5,6-dichloro-2-nitrobenzonitrile with the appropriate aralkyl or alicyclic thiopseudourea, reduction of the resulting 2-nitro-5-[(aralkyl or alicyclic)thio]benzonitrile with stannous chloride to the amine, and cyclization with chloroformamidine hydrochloride. Oxidation was effected with hydrogen peroxide or the bromine complex of 1,4-diazabicyclo[2.2.2]octane. These analogues when examined for suppressive activity against drug-sensitive lines of Plasmodium berghei in mice were not as active as 2,4-diamino-6-[3,4-dichlorobenzyl)amino]quinazoline (Ia).     

Folate antagonists. 20. Synthesis and antitumor and antimalarial properties of trimetrexate and related 6-[(phenylamino)methyl]-2,4-quinazolinediamines

A series of 6-[(arylamino)methyl]-2,4-quinazolinediamines have been prepared by catalytic hydrogenation of the requisite 2,4-diamino-6-quinazolinecarbonitriles in the presence of the appropriate benzenamine. Formylation, acetylation, and nitrosation provided N omega derivatives of these compounds. A variety of the compounds exhibited potent antimalarial, antibacterial, and antitumor activity. In particular, 5-methyl-6-[[(3,4,5-trimethoxyphenyl)-amino]methyl]-2, 4-quinazolinediamine (trimetrexate, 15) has shown a broad spectrum of antitumor effects and is undergoing preclinical toxicology evaluation prior to trial in man.     

Folate antagonists. 21. Synthesis and antimalarial properties of 2,4-diamino-6-(benzylamino)pyrido[3,2-d]pyrimidines

The synthesis and antimalarial activity of a series of 2,4,6-triaminopyrido[3,2-d]pyrimidines (4) is described. Several 6-substituted benzylmethylamino analogues were more active against trophozoite induced Plasmodium berghei in mice than the corresponding quinazoline analogues. These agents, however, are cross-resistant to other antifolate compounds and are thus of limited potential as human agents.     

Folate antagonists. 11. Synthesis and antimalarial effects of 6-[(aryloxy- and arylthio-)methyl]-2,4-pteridinediamines and -pteridinediamine 8-oxides.

Condensation of 3-amino-6-(bromomethyl)-2-pyrazinecarbonitrile 4-oxide with 4-chlorophenol gave 3-amino-6-[(4-chlorophenoxy)methyl]-2-pyrazinecarbonitrile 4-oxide (1), which was deoxygenated to obtain the de-N-oxide 4. Cyclization of 4 and 1 produced 6-[(4-chlorophenoxy)methyl]-2,4-pteridinediamine and the 8-oxide, respectively. 6-[(Arylthio)methyl]-2,4-pteridinediamines and their 8-oxides were produced analogously. Controlled oxidation of the former gave the anticipated sulfoxide 12 and sulfone 13. None of these compounds showed significant activity when tested against lethal Plasmodium berghei infections in mice or a select list of bacteria in vitro.     

疟疾防治药物的研究——Ⅸ.2,4-二氨基-6-[N-(取代苄基)-N-(取代氨基甲基)氨基]-喹唑啉类衍生物的合成

In searching for new antimalarial agents ten new compounds of 2,4-diamino-6-[N-(substituted benzyl)-N-(substituted aminomethyl)-amino]-quinazoline have been synthesized. Preliminary screening results showed that only one (Ⅳ₆) of these compounds displayed a slight degree of antimalarial activity against plasmodium berghei in mice. The intermediate compound (Ⅰ₂) showed suppressive effect on plasmodium berghei in mice and prophylactic activity against plasmodium gallinaceum in chicken.     

N-[(arylmethoxy)phenyl] and N-[(arylmethoxy)naphthyl] sulfonamides: potent orally active leukotriene D4 antagonists of novel structure

Two series of compounds, N-[(arylmethoxy)phenyl] sulfonamides and N-[(arylmethoxy)naphthyl] sulfonamides, were prepared as leukotriene D4 (LTD4) antagonists. In the phenyl series, N-[3-(2-quinolinylmethoxy)phenyl]-trifluoromethanesulfonamide (Wy-48,252, 16) was the most potent inhibitor of LTD4-induced bronchoconstriction in the guinea pig. With an intragastric ID50 of 0.1 mg/kg (2-h pretreatment), 16 was 300 times more potent than LY-171,883. Compound 16 also intragastrically inhibited ovalbumin-induced bronchoconstriction in the guinea pig with an ID50 of 0.6 mg/kg. In vitro against LTD4-induced contraction of isolated guinea pig trachea pretreated with indomethacin and L-cysteine, 16 produced a pKB value of 7.7. In the rat PMN assay 16 inhibited both 5-lipoxygenase and cyclooxygenase (IC50's = 4.6 and 3.3 microM). In the naphthyl series, N-[7-(2-quinolinylmethoxy)-2-naphthyl]trifluoromethanesulfonamide (Wy-48,090, 47) in addition to potent LTD4 antagonist activity (on isolated guinea pig trachea 47 had a pKB value of 7.04) also had antiinflammatory activity (63% inhibition at 50 mg/kg in the rat carrageenan paw edema assay and 34% inhibition of TPA-induced inflammation at 1 mg/ear in the mouse ear edema model). Perhaps the antiinflammatory activity of 47 was due to its additional activity of inhibiting both 5-lipoxygenase and cyclooxygenase enzymes (IC50's = 0.23 and 11.9 microM, respectively, in rat PMN).     

2,4-Diamino-5-benzylpyrimidines and analogues as antibacterial agents. 10. 2,4-Diamino-5-(6-quinolylmethyl)- and -[(tetrahydro-6-quinolyl)methyl]pyrimidine derivatives. Further specificity studies

A series of 18 2,4-diamino-5-[(1,2,3,4-tetrahydro-6-quinolyl)methyl]pyrimidines has been prepared by the condensation of 2,4-diamino-5-(hydroxymethyl)pyrimidine with 1,2,3,4-tetrahydroquinolines in acidic medium. Several derivatives were catalytically aromatized; others were synthesized from these by routine aromatic substitution or by condensations of (anilinomethyl)pyrimidines to give quinolinylmethyl analogues. Compounds with 4-methyl-8-methoxy substitution are closely related to trimethoprim (1a) in structure and are excellent inhibitors of bacterial dihydrofolate reductase, with activity at least equivalent to that of 1a. The highest degree of inhibition was achieved with the rigid aromatic series, but greater specificity was accomplished among the tetrahydroquinoline derivatives. This was directly related to N-1 substitution of 4-methyl-8-methoxy derivatives. The spatial relationships around N-1 and protonation at this site may both affect selectivity. Such compounds also had excellent broad-spectrum in vitro antibacterial activity.     

Enzymatic assays for 2,4-diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)methyl]quinazoline, a promising new "nonclassical" antifolate

2,4-Diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)-methyl]quinazoline (I) is a promising new "nonclassical" antifolate. Inhibition of dihydrofolate reductase from bacterial (Lactobacillus casei)and mammalian (beef liver) sources was employed to develop useful enzymatic assays for this compound. A linear relationship was obtained by plotting the I concentration versus 1/V. The resultant standard curves maintained linearity particularly well between the 30 and 70% control range, with a correlation coefficient of 0.99 for both enzyme systems. The two enzyme systems are characterized by differences in sensitivity, stability, and day-to-day variation. The ID50 for the beef liver reductase system was 1.6 X 10(-9) M (+/-0.03); for the L. casei system, it was 1.35 X 10(-8) M (+/- 0.2). The apparent advantage for the beef liver enzyme was offset somewhat by its relative instability and its higher day-to-day variability. Studies in mice demonstrated that these assays are suitable for pharmacokinetic studies in vivo. Such studies indicated that I has a serum t1/2 of 45 min in mice; a similar serum t1/2 (50 min) was estimated in studies with 14C-labeled I in position 6.     

Folate antagonists. 10. Synthesis and antimalarial effects of 6-[[(aryl and aralkyl)amino]methyl]-2,4-pteridinediamines and -pteridinediamine 8-oxides.

Various 6-[[(aryl and aralkyl)amino]methyl]-2,4-pteridinediamines and their 8-oxides have been synthesized for antimalarial evaluation. Condensation of 3-amino-6-(bromomethyl)-2-pyrazinecarbonitrile 4-oxide (V) with the appropriately substituted amine afforded a series of 3-amino-6-[[(aryl and aralkyl)amino]methyl]-2-pyrazinecarbonitrile 4-oxides VI. Deoxygenation gave the corresponding pyrazines VII. Cyclization of VI and VII with guanidine then produced the desired 6-(aminomethyl)-2,4-pteridinediamine N-oxides VIII and teridinediamines IX, respectively. Formylation of 6-[[(3,4-dichlorophenyl)amino]methyl]-2,4-pteridinediamine gave N-[(2,4-diamino-6-pteridinyl)-methyl]-N-(3,4-dichlorophenyl)formamide. The N-oxides VIII did not exhibit significant activity against Plasmodium berghei infections in mice. Activity among the 2,4-pteridinediamines IX was generally poor with the exception of the 3,4,5-trimethoxyphenyl and 1-naphthalenyl analogues which showed strong suppressive activity at doses ranging from 80 to 640 mg/kg. Furthermore, several of the 2,4-pteridinediamines exhibited potent prophylactic activity against Plasmodium gallinaceum infections in the chick and also showed strong antibacterial action against Streptococcus faecalis and Staphylococcus aureus.     

2,4-Diamino-5-benzylpyrimidines as antibacterial agents. 14. 2,3-Dihydro-1-(2,4-diamino-5-pyrimidyl)-1H-indenes as conformationally restricted analogues of trimethoprim

A conformationally restricted analogue of trimethoprim (1a) has been prepared by connecting the ortho position of the benzene ring to the methylene linkage with two methylene groups, thus forming a dihydroindene derivative (2b). The chemistry involved the condensation of barbituric acid with an indanone derivative, followed by a three-step conversion to a 2,4-diaminopyrimidine. The S isomer of 2b was found to have a minimum-energy conformation very similar to that of 1a when bound to Escherichia coli dihydrofolate reductase, in contrast to that of 1a in vertebrate DHFR. Theoretically such a derivative might have increased specificity and activity against the bacterial enzyme. Molecular modeling experiments suggested that the actual decreased activity was due to crowding in the enzyme, caused by the extra atoms needed to restrict the conformation.     

Synthesis and antimalarial and antitumor effects of 2-amino-4-(hydrazino and hydroxyamino)-6-[(aryl)thio]quinazolines

A variety of analogues of 2,4-diamino-6-[(aryl)thio]quinazolines with known antimalarial properties were prepared wherein the 4-amino group was replaced by hydrazino and hydroxyamino moieties. Such changes were found to reduce markedly the antimalarial and antitumor properties of this series.     

2,4-diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)methyl]quinazoline (tmq), a potent non-classical folate antagonist inhibitor--I effect on dihydrofolate reductase and growth of rodent tumors in vitro and in vivo.

Seventeen non-classical 2,4-diamino-6-[(anilino)methyl]quinazoline antifolates were tested as inhibitors of dihydrofolate reductase from L1210 leukemia cells and from human leukemia cells (acute lymphocytic leukemia). Several potent inhibitors of this enzyme were found, some with I₅₀ values of 10^?9 M, thus displaying activity comparable to that of methotrexate. In general, the potency of dihydrofolate reductase inhibition correlated with the inhibition of cell growth in vitro against L1210 cells. Two of these compounds, compound 14 (2,4-diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)methyl]quinazoline; TMQ, JB-11, NSC 249008) and compound 3 (2,4-diamino-5-chloro-6-[(3,4-dichloroanilino)methyl]quinazoline; NSC 208652), were further evaluated against murine tumors in vivo and both showed a broad spectrum of antitumor effects. The results of these studies encourage further evaluation of these compounds, in particular compound 14, as possible anti-neoplastic agents in the treatment of human disease.     

11,12-Secoprostaglandins. 3. 8-Alkylthio(sulfinyl and sulfonyl)-12-hydroxyalkanoic acids and related compounds.

A series of 8-alkylthio(sulfinyl and sulfonyl)-12-hydroxyalkanoic acids which embody structural features of 11,12-secoprostaglandins was synthesized and evaluated for their ability to mimic the E series prostaglandins in stimulating cAMP formation in the mouse ovary and in binding to the rat lipocyte prostaglandin receptor. A key member of the series, 8-methylsulfonyl-12-hydroxyheptadecanoic acid, markedly stimulated cAMP formation at reasonable pharmacological concentrations, shows significant affinity for a prostaglandin receptor, and effectively inhibits antigen-induced lymphocyte transformation. In contrast, this compound is not a substrate for 15-hydroxyprostaglandin dehydrogenase, the major prostaglandin-metabolizing enzyme.     

Inhibition of metabolism of the 'nonclassical' antifolate, trimetrexate (2,4-diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)methyl]quinazoline) by drugs containing an imidazole moiety

2,4-Diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)methyl]quinazoline (TMQ; NSC No. 249008) is a 'nonclassical' antifolate which is advocated as an alternative to methotrexate. TMQ is rapidly and extensively demethylated by a cytochrome P-450-mediated oxidation to a weakly cytotoxic compound of increased polarity. In this study, the effects of clinically used imidazole drugs ketoconazole, miconazole, clotrimazole, cimetidine, etintidine, clonidine and cibenzoline on the rat hepatic microsomal demethylation of TMQ in vitro was investigated. The nitrogen-substituted imidazole drugs (ketoconazole, miconazole, and clotrimazole) were potent non-competitive inhibitors of TMQ metabolism with IC50 values obtainable at therapeutic doses (less than 2 microM). Cimetidine and etintidine were comparatively weak, competitive inhibitors of TMQ metabolism (IC50 greater than 300 microM) and clonidine and cibenzoline were even less inhibitory (IC50 greater than 1 mM). The nitrogen-substituted imidazole drugs have the potential to dramatically alter the pharmacokinetic and pharmacodynamic profile of TMQ as well as other drugs in vivo.