1,5-Benzodiazepines XIV. Synthesis of new substituted 9H-bis-[1,2,4]triazolo[4,3-a:3',4'-d] [1,5]benzodiazepines and relate compounds endowed with in vitro cytotoxic properties

A series of 11 new 9H-bis-[1,2,4]triazolo[4,3-a:3',4'-d] [1,5]benzodiazepine derivatives 8e-o was synthesized. Ten of these compounds (8e-m,o), along with four analogues (8a-d) (previously synthesized by us) were tested in vitro in order to evaluate their cytotoxic and anti-HIV-1 properties. In this connection other six original compounds, i.e., five 9-substituted compounds prepared starting from the 6,12-diphenylderivative 8c (compounds 10, 11, 12, 13a,b) and the bis-triazolone derivative 14, were synthesized and tested for the same purpose. While none of the 20 compounds tested exhibited any appreciable anti-HIV-1 activity, some of them exhibited interesting cytotoxic properties, the best results being shown by compounds 8c,d,k and 11 (CC(50) range=3-12 microM). Therefore, these four compounds were further evaluated for their antiproliferative activity against a panel of human tumor cell lines; actually, compounds 8d, 8k and 11 showed antiproliferative properties against either or both leukemia- and lymphoma-derived cell lines in the low micromolar range.     

Synthesis of N-[4-[1-ethyl-2-(2,4-diaminofuro[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-L-glutamic acid as an antifolate

N-[4-[1-Ethyl-2-(2,4-diaminofuro[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-L-glutamic acid 3 was designed and synthesized to investigate the effect of homologation of a C9-methyl to an ethyl on dihydrofolate reductase (DHFR) inhibition and on antitumor activity. Compound 3 was obtained via a concise seven step synthesis starting from palladium-catalyzed carbonylation of 4-propionylphenol, followed by a Wittig reaction with 2,4-diamino-5-(chloromethyl)furo[2,3-d]pyrimidine (6), catalytic hydrogenation, hydrolysis, and standard peptide coupling with diethyl L-glutamate. The biological results indicated that extending the C9-methyl group to an ethyl on the C8-C9 bridge region (analogue 3) doubled the inhibitory potency against recombinant human (rh) DHFR (IC(50) = 0.21 microM) as compared to the C9-methyl analogue 1 and was 4-fold more potent than the C9-H analogue 2. As compared to 1, compound 3 demonstrated increased growth inhibitory potency against several human tumor cell lines in culture with GI(50) values < 1.0 x 10(-8) M. Compound 3 was also a weak inhibitor of rh thymidylate synthase. Compounds 1 and 3 were efficient substrates of human folylpolyglutamate synthetase (FPGS). Further evaluation of the cytotoxicity of 3 in methotrexate-resistant CCRF-CEM cell sublines and metabolite protection studies implicated DHFR as the primary intracelluar target. Thus, alkylation of the C9 position in the C8-C9 bridge of the classical 5-substituted 2,4-diaminofuro[2,3-d]pyrimidine is highly conducive to DHFR and tumor inhibitory activity as well as FPGS substrate efficiency.     

Synthesis and antiproliferative activity in vitro of new pyrido[1,4-b]diazepine derivatives and imidazo[4,5-b]pyridine

A novel series of esters 8-10 and hydrazones 4-6 was synthesized from 4-aryl-2-phenacylidene-1,3,4,5-tetrahydropyrido[2,3-b][1,4]diazepine (1-3). Subsequent treatment of hydrazone 4 with p-chlorbenzaldehyde furnished azine 7. Long-standing heating of ester 8 with hydrazine hydrate afforded 3-[1-(p-chlorophenylene)-2-(5-phenyl-1H-pyrazol-3-yl)-ethyl]-1,3-dihydroimidazo[4,5-b]pyridin-2-one (11). The structures of 4-6 and 8-10 were identified by the results of elemental analysis and their IR, 1H-NMR and MS spectra. Additionally, the structure of 11 was confirmed by X-ray diffraction method. Compounds 8-10 and 11 were examined for their antiproliferative activity in vitro against the cells of 5 human cancer cell lines, using SRB or MTT technique. Among tested compounds, only 11 revealed cytotoxic activity in vitro against all cell lines applied with ID50 (inhibitory dose 50%) values lower than 4 microg/mL, which is an international activity criterion for synthetic compounds. All compounds inhibit the proliferation of HL-60 human promyelocytic leukemia cell line.     

Synthesis and antiviral and cytostatic evaluations of the new C-5 substituted pyrimidine and furo[2,3-d]pyrimidine 4',5'-didehydro-L-ascorbic acid derivatives

The novel C-5 alkynyl substituted pyrimidine (1-11) and furo[2,3-d]pyrimidine derivatives (12-22) of l-ascorbic acid were synthesized by coupling of 5-iodouracil-4',5'-didehydro-5',6'-dideoxy-l-ascorbic acid with terminal alkynes by using Sonogashira cross-coupling reaction conditions. The new compounds were evaluated for their cytostatic and antiviral activities. Among all evaluated compounds, the octynyl-substituted uracil derivative of l-ascorbic acid (3) exhibited the most pronounced cytostatic activities against all examined tumor cell lines (IC50 = 2-12 microM). Pyrimidine derivatives of l-ascorbic acid containing p-substituted phenylacetylene groups (8-11) displayed also a rather pronounced (IC50 = 3-37 microM) inhibitory effect toward all tumor cell lines. From the bicyclic series of compounds, 6-butylfuro[2,3-d]pyrimidine derivative (12) and 6-p-bromophenylfuro[2,3-d]pyrimidine derivative (19) showed the highest cytostatic activity (IC50 = 4.5-20 microM), particularly against malignant leukemia (L1210) and T-lymphocyte (Molt4/C8 and CEM) cells. Compounds 3 and 9 showed specific albeit moderate activity against cytomegalovirus (CMV, Davis strain, EC50 = 1.8 and 3.8 microM, respectively, for compounds 3 and 9) at a approximately 5-fold lower concentration than that required to show cytotoxicity.     

Synthesis and antiproliferative activity in vitro of new derivatives of 3-aminopyrazolo[3,4-b]pyridine. Part 1. Reaction of 3-aminopyrazolo[3,4-b]pyridine with 1,3-, 1,4-diketones and alpha,beta-unsaturated ketones

The synthesis of several new pyrazolo[3,4-b]pyridine, pyrido[2',3':3,4]-pyrazolo[1,5-a]pyrimidine and imidazo[1',2':1,5]pyrazolo[3,4-b]pyridine derivatives is described. The obtained compounds were tested for their antiproliferative activity in vitro. One of them, 4-phenyl-2-(3,4,5-trimethoxy-beta-styrylo)pyrido- [2',3':3,4]pyrazolo[1,5-a]pyrimidine (9), revealed cytotoxic properties against the cells of all three human cancer cell lines applied. Another one, 2,4-dimethyl-pyrido[2',3':3,4]pyrazolo[1,5-a]-pyrimidine (2), revealed weak cytotoxic activity only against the cells of human bladder cancer cell line HCV29T. All other compounds tested did not reveal any cytotoxic activity.     

Synthesis and anticancer activities of 4-oxobenzopyrano[2,3-d]pyrimidines

Several 2-aryl-4-oxoxbenzopyrano[2,3-d]pyrimidines have previously been shown to exhibit in vivo antitumor activity in mice with P388 lymphocytic leukemia. In the present study, a series of novel substituted benzopyrano[2,3-d]pyrimidines have been prepared and tested for cytotoxic activity against a panel of cancer cell lines including the P388 lymphocytic leukemia cell line. The unsubstituted parent compound, some methoxylated derivatives and a cyclohexyl derivative all exhibited potent cytotoxic activity (IC50 values 0.3-0.64 microM). A number of derivatives, including the unsubstituted parent pyrimidine, were shown to cause a significant perturbation in cell cycle kinetics with an observed 2- to 3-fold increase in cells in the G2/M phase of the cell cycle. Furthermore, a polymethoxylated derivative, 2-(3,4,5-trimethoxyphenyl)-9-methoxy-4-oxo-2,3-dihydrobenzopyrano[ 2,3-d]pyrimidine 13, was shown to be selectively active against a number of human ovarian cell lines.     

Synthesis and antiproliferative activity in vitro of new 3-substituted aminoisoxazolo[5,4-b]pyridines

The synthesis of 3-aminoisoxazolo[5,4-b]pyridine [III] and of several new 3-substituted aminoisoxazolo[5,4-b]pyridines is described. 3-Aminoisoxazlo[5,4-b]pyridine [III] was subjected to reactions with the acid halides and substituted aromatic aldehydes, leading to the production of the corresponding amides IV-VII, IX, XI-XVI and new tricyclic pyridoisoxazolopyrimidine VIII and Schiff bases XX-XXIV. 4-Chlorobutyroamide IX cyclized into 3-(pyrrolidinon-1-yl)isoxazolo[5,4-b]pyridine [X]. 3-Chloroacetylaminoisoxaxolo[5,4-b]pyridine [V] in reaction with secondary amines gave 3-aminoacetylaminoisoxazolo[5,4-b]pyridines XVII-XIX. The structures of the products II-XXIV were established on the basis of elemental analysis and spectral data IR, 1H NMR and MS. Selected compounds were tested for their antiproliferative activity in vitro. Two of them: 3-chloroacetyl-[V] and 3-2-bromo-propionylaminoisoxazolo[5,4-b]pyridine [VI] revealed cytotoxic activity against the cells of 8 various human or mouse tumor cell lines applied. Their ID50 (inhibitory dose 50%) values are in the range of the international activity criterion for synthetic agents (4 microg/ml).     

Synthesis and antitumour activity of 1H,3H-thiazolo[3,4-a]benzimidazole derivatives

A series of 1H,3H-thiazolo[3,4-a]benzimidazoles were synthesized and tested for their in vitro antitumour activity against 60 human tumour cell lines. Some derivatives exhibited both tumour growth inhibition activity and cellular selectivity. In particular, compound 8c, the most active of the series, was very active towards all cell lines at concentrations ranging from 10(-7)-10(-5) M. Compound 4a, on the other hand, was highly selective against the CNS cancer cell line.     

Synthesis and cytotoxic evaluation of some new[1,3]dioxolo[4,5-g]chromen-8-one derivatives

Background

Homoisoflavonoids are naturally occurring compounds belong to flavonoid classes possessing various biological properties such as cytotoxicity. In this work, an efficient strategy for the synthesis of novel homoisoflavonoids, [1,3]dioxolo[4,5-g]chromen-8-ones, was developed and all compounds were evaluated for their cytotoxic activities on three breast cancer cell lines.

Methods

Our synthetic route started from benzo[d][1,3]dioxol-5-ol which was reacted with 3-bromopropanoic acid followed by the reaction of oxalyl chloride to afford 6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one. The aldol condensation of the later compound with aromatic aldehydes led to the formation of the title compounds. Five novel derivatives 4a-e were tested for their cytotoxic activity against three human breast cancer cell lines including MCF-7, T47D, and MDA-MB-231 using the MTT assay.

Results

Among the synthesized compounds, 7-benzylidene-6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one (4a) exhibited the highest activity against three cell lines. Also the analysis of acridine orange/ethidium bromide staining results revealed that 7-benzylidene-6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one (4a) and 7-(2-methoxybenzylidene)-6,7-dihydro-8H-[1,3]dioxolo[4,5-g]chromen-8-one (4b) induced apoptosis in T47D cell line.

Conclusion

Finally, the effect of methoxy group on the cytotoxicity of compounds 4b-4d was investigated in and it was revealed that it did not improve the activity of [1,3]dioxolo[4,5-g]chromen-8-ones against MCF-7, T47D, and MDA-MB-231.     

Design,synthesis and antitumor activity of C3/C3 bis-fluoroquonolones cross-linked with [1,2,4]triazolo[3,4-b] [1,3,4]thiadiazole

To contribute to the development of an efficient method for the conversion of antibacterial fluoroquinolones to antitumor fluoroquinolones, a series of C3/C3 bis-fluoroquinolone fused heterocycles cross-linked with a [1,2,4]-triazolo[3,4-b] [1,3,4]-thiadiazole core as a common bioisostere of two carboxylic acid groups was designed and synthesized as their hydrochloride salts. Structures were characterized by elemental analysis and spectral data and their in vitro antitumor activity against L1210, CHO and HL60 cell lines was screened by determination of their IC₅₀ values in the methylthiazole trazolium (MTT) assay. Two compounds were highly potent against the HL60 cell line and represent promising lead compounds for future development.     

Benzimidazole condensed ring systems: New synthesis and antineoplastic activity of substituted 3,4-dihydro- and 1,2,3,4-tetrahydro-benzo [4,5]imidazo[1,2-a]pyrinnidine derivatives

As part of an ongoing effort to develop new antineoplastic agents, a series of substituted 3,4-dihydro- and 1,2,3,4-tetrahydro-benzo[4,5]imidazo[1,2-a]pyrimidine derivatives (5-19) were synthesized. 1,2,3,4-Tetrahydrobenzo[4,5]imidazo[1,2-a]pyrimidine-2-one derivatives (5-7) were prepared via one-pot two-component thermal cyclization reaction of 2-aminobenzimidazole 1 and P-substituted methyl cinnamates (2-4). Vilsmir-Haack formylation of these derivatives (5-7) afforded the 2-chloro-3-carboxaldehyde targets (8-10) followed by nucleophilic displacement of the chloro atom in the 3-carboxaldehyde compounds (8-10) to yield the remaining final targets (11-19). The structures of the synthesized derivatives (5-19) were confirmed by means of IR, 1H NMR, MS and elemental analyses. The synthesized derivatives (5-19) were subjected to the National Cancer Institute (NCI) in vitro disease human cell screening panel assay. 2-Chloro-4-phenyl-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carboxyaldehyde (8, NCI 722731) and 4-(4-methoxyphenyl)-2-(4-methylpiperazin-1-yl)-3,4-dihydrobenzo[4,5]imidazo [1,2-a]pyrimidine-3-carboxaldehyde (18, NCI 722739) showed a variable degree of antineoplastic activity against some of the cell lines tested. 2-Chloro-4-(4-nitrophenyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carboxyaldehyde (10, NCI 722743) exhibited good in vitro antineoplastic activity with subpanel disease selectivity against all the cell lines tested with log10 G150 (M), the concentration that inhibits 50% of cell growth, values ranging from -5.08 to < -8.00.     

Synthesis and antitumor cytotoxicity evaluation of pyrido[4,3,2-de]quinolines and isoquinolino[6,5,4,3-cde]quinolines

A series of novel pyrido[4,3,2-de]quinoline and isoquinolino[6,5,4,3-cde] quinoline compounds was synthesized and evaluated for cytotoxicity in the National Cancer Institute developmental therapeutics program. The tricyclic compound 7 was synthesized by the cyclization of 3,4-diamino-1,2dimethoxybenzene with diethyl 1,3-acetonedicarboxylate. Oxidation of monochloropyrido[4,3,2-de]quinoline 8 selectively produced 2,3-diketopyrido[4,3,2-de]quinoline 9 as deep violet crystals. Compound 9, when treated with acetone or acetophenone, affords the tetracyclic isoquinolino[6,5,4,3-cde]quinolines 13 and 14, respectively. 2,3-Diketopyrido[4,3,2-de]quinolines 9 and 10 exhibit higher cytotoxic potency than isoquinolino[6,5,4,3-cdelquinolines 13, 14, 15 and 16. Compound 9 selectively affects the cell growth against leukemia CCRF-CEM and HL-60 cell lines, the non-small cell lung cancer HOP-92 cell line, and breast cancer MDA-MB231/ ATCC and MDA-MB- 435 cell lines with GI(50) values of <2.0 microM. Modification of compound 9 with an ester group at the N-1 position afforded compound 10, which exhibits a wide spectrum of anticancer activities with a mean graph midpoint value of 1.8 microM against the 60 cancer cell lines.     

Synthesis of 2,8-disubstituted imidazo[1,5-a]pyrimidines with potent antitumor activity

Seventeen 1,2,3,4-tetrahydroimidazo[1,5-a]pyrimidine derivatives bearing electron-withdrawing substituents were designed and synthesized by novel ring closure as potential antitumor agents. They were screened for their activities against mouse leukemia L1210 and human oral epidermoid carcinoma KB cell lines, and relationships of structure and antitumor activity in vitro are discussed. It was found that 8-thiocarbamoyl-1,2,3,4-tetrahydroimidazo[1, 5-a]pyrimidin-2(1H)-thione (8c) exhibited activity comparable to that of 5-fluorouracil against both L1210 and KB cells. The existence of both 2-thioxo and 8-substituent with a thioxo group in the molecule is crucial for the cytotoxicity against L1210 and KB cells. A novel procedure for introduction of a double bond between C-3 and C-4 in 8c was developed. Introduction of the 3,4-double bond increased the activity against L1210, but against KB cells the activity decreased by 4-fold. Cytotoxicity of compounds 8c and 8-thiocarbamoyl-1,2-dihydroimidazo[1,5-a]pyrimidin-2(1H)-thione (11c) against human solid tumor and leukemia cell lines was further evaluated. The saturation of the 3,4-double bond led to a significant increase in cytotoxicity against tumor cell lines tested.     

Synthesis and anticancer activity of 5,6,8,13-tetrahydro-7H-naphtho[2,3-a][3]-benzazepine-8,13-diones

A series of naphthoquinones fused benzazepines, 5,6,8,13-tetrahydro-7H-naphtho[2,3-a][3]-benzazepine-8,13-diones, were synthesized and evaluated for their anticancer activity against four cell lines; human breast carcinoma cell line, human cervix carcinoma cell line, human hepatocellular carcinoma cell line and human keratinocyte cell line. The results showed that 5,6,8,13-tetrahydro-2,3,4,9-tetramethoxy-7H-naphtho[2,3-a][3]benzazepine-8,13-dione 4g and 5,6,8,13-tetrahydro-2,3,9-trimethoxy-7H-naphtho[2,3-a][3]benzazepine-8,13-dione 4h have significant cytotoxicity against a hepatocellular carcinoma cell line with IC(50) = 3.5 μg/mL and 3.0 μg/mL, respectively.     

Synthesis and antiproliferative activity in vitro of new 3-substituted aminopyrazolo[3,4-b]pyridines

The synthesis of several new 3-substituted aminopyrazolo[3,4-b]pyridines is described. The obtained compounds were tested for their antiproliferative activity in vitro. Two of them: 3-chloroacetylaminopyrazolo[3,4-b]pyridine [II] and 3-(2-bromopropionyl-amino)pyrazolo[3.4-b]pyridine [III] revealed cytotoxic activity against the cells of 5 human tumor cell lines applied. Their ID50 values were in the range of the international activity criterion for synthetic agents (4 microg/ml). The structures of the products II-XVII were established on the basis of elemental analysis and spectral data (IR, 1H NMR and MS).     

Novel derivatives of benzo[b]thieno[2,3-c]quinolones: synthesis, photochemical synthesis, and antitumor evaluation

Novel derivatives of benzo[b]thieno[2,3-c]quinolones 3a-j were synthesized in a multistep synthesis starting from substituted benzo[b]thiophene-2-carbonyl chlorides, to their corresponding benzo[b]thiophene-2-carboxamides, which were photochemically dehydrohalogenated to their corresponding substituted benzo[b]thieno[2,3-c]quinolones. Compound 4 was prepared from 3i by alkylation with 3-dimethylaminopropyl chloride in the presence of NaH. Compounds 7a,b were prepared from 3g in the multistep synthesis from compounds 5 and 6. Compounds 3b, 3c-f, 3h, 7a, and 7b were found to exert cytostatic activity against malignant cell lines: pancreatic carcinoma (MiaPaCa2), breast carcinoma (MCF7), cervical carcinoma (HeLa), laryngeal carcinoma (Hep2), colon carcinoma (CaCo-2), melanoma (HBL), human fibroblast cell lines (WI-38). The compounds that bear a 3-dimethylaminopropyl substituent on the quinolone nitrogen (3b, 3c-f, 3h) showed higher antitumor activity than compounds bearing the same substituent on the amidic nitrogen (7a and 7b). The compound 3h, which has a 3-dimethylaminopropyl substituent on the quinolone nitrogen and a methoxycarbonyl substituent at position 9, had marked antitumor activity. Because of strong cytotoxic effect of compound 4 on melanoma cells (HBL, ME 67.3, and ME 67.1), a potential mechanism of action was examined. Analysis of DNA and Annexin-V-FLUOS staining indicated that compound 4 causes cell death by apoptosis.     

Effect of C9-methyl substitution and C8-C9 conformational restriction on antifolate and antitumor activity of classical 5-substituted 2,4-diaminofuro[2,3-d]pyrimidines

N-[4-[1-methyl-2-(2,4-diaminofuro[2, 3-d]pyrimidin-5-yl)ethyl]benzoyl]-L-glutamic acid (5) and its C8-C9 conformationally restricted E- and Z-isomers (6 and 7) were designed and synthesized in order to investigate the effect of incorporating a methyl group at the C9 position and of conformational restriction at the C8-C9 bridge of N-[4-[2-(2,4-diaminofuro[2, 3-d]pyrimidin-5-yl)ethyl]benzoyl]-L-glutamic acid (1) with respect to dihydrofolate reductase (DHFR) inhibitory activity as well as antitumor activity. The compounds were synthesized by a Wittig reaction of 2,4-diamino-5-(chloromethyl)furo[2,3-d]pyrimidine with ethyl 4-acetylbenzoate followed by catalytic reduction, hydrolysis, and standard peptide coupling with diethyl L-glutamate. The biological results indicated that the addition of a 9-methyl group to the C8-C9 bridge, as in 5, increased recombinant human (rh) DHFR inhibitory potency (IC(50) = 0.42 microM) as well as the potency against the growth inhibition of tumor cells in culture (CCRF-CEM EC(50) = 29 nM, A253 EC(50) = 28.5 nM, and FaDu EC(50) = 17.5 nM) compared with the 9-desmethyl analogue 1. However, the conformationally restricted 4:1 Z/E mixture of 7 and 6 was less potent than 5 in both assays, and the pure E-isomer 6 was essentially inactive. These three classical analogues were also evaluated as inhibitors of Lactobacillus casei, Escherichia coli, and rat and rh thymidylate synthase (TS) and were found to be weak inhibitors. All three analogues 5-7 were good substrates for human folylpolyglutamate synthetase (FPGS). These data suggested that FPGS is relatively tolerant to different conformations in the bridge region. Further evaluation of the cytotoxicity of 5 and 7 in methotrexate (MTX)-resistant CCRF-CEM cell sublines suggested that polyglutamylation was crucial for their mechanism of action. Metabolite protection studies of 5 implicated DHFR as the primary intracellular target. Compound 5 showed GI(50) values in 10(-9)-10(-7) M range against more than 30 tumor cell lines in culture.     

1-苯胺基-5H-哒嗪并[4,5-b]吲哚类化合物的合成及体外抗肿瘤活性

目的设计并合成1-苯胺基-5H-哒嗪并[4,5-b]吲哚类化合物,评价其体外抗肿瘤活性。方法以5-乙酰氧基-6-溴-2-溴甲基-1-环丙基-1H-吲哚-3-羧酸乙酯为起始原料,经8～9步反应合成目标化合物;采用MTT法,测定了目标化合物对肿瘤细胞株Bel-7402和HT-1080的抑制活性。结果与结论合成了12个新化合物,其结构经1H-NMR和MS确证;多个化合物显示出良好的抗肿瘤活性,化合物10a和10d活性突出,对肿瘤细胞株Bel-7402和HT-1080的抑制活性分别是阳性对照药gefitinib的4倍和5倍,值得进一步研究。     

Synthesis and cytotoxicity evaluation of thiophene analogues of 1-methyl-2, 3-bis(hydroxymethyl)benzo[g]indole bis[N-(2-propyl)carbamate

The cytotoxicity of the bis[N-(2-propyl)carbamates] 2 and 3 which are linked to thieno[i,j-g]indole scaffolds through methylene bridges were studied as thiophene analogues of prototype 1. Compounds 2 and 3 were evaluated in vitro against 60 human-tumor cell lines derived from nine cancer-cell types and demonstrated, for compound 3 not only strong growth-inhibitory activities against leukemia cancer cells, but also fairly good activities against the growth of certain renal and ovarian cancer cell lines. Compound 2, the thieno[2,3-g]indole bis-carbamate, possessed only significant (MG-MID log10 GI50 = -4.89) and selective cytoxicity against NCI-HOP92 (non-small cell lung), MALME 3M (melanoma) and IGROV 1 (ovarian) cancer cell with log10 GI50 values of -5.66, -5.48 and -5.47, respectively.     

Synthesis of N-{4-[(2,4-diamino-5-methyl-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-6-yl)thio]benzoyl}-L-glutamic acid and N-{4-[(2-amino-4-oxo-5-methyl-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-6-yl)thio]benzoyl}-L-glutamic acid as dual inhibitors of dihydrofolate reductase and thymidylate synthase and as potential antitumor agents

Two novel classical antifolates N-{4-[(2,4-diamino-5-methyl-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-6-yl)thio]benzoyl}-L-glutamic acid 3 and N-{4-[(2-amino-4-oxo-5-methyl-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidin-6-yl)thio]benzoyl}-L-glutamic acid 4 were designed, synthesized, and evaluated as antitumor agents. Compounds 3 and 4 were obtained from 2,4-diamino-5-methylpyrrolo[2,3-d]pyrimidine 7 and 2-amino-4-oxo-5-methylpyrrolo[2,3-d]pyrimidine 12, respectively, in a concise three-step sequence. Compound 3 is the first example, to our knowledge, of a 2,4-diamino classical antifolate that has potent inhibitory activity against both human dihydrofolate reductase (DHFR) and human thymidylate synthase (TS). Compound 4 was a dual DHFR-TS inhibitor against the bifunctional enzyme derived from Toxoplasma gondii (tg). Further evaluation of the mechanism of action of 3 implicated DHFR as its primary intracellular target. Both 3 and 4 were folylpolyglutamate synthetase (FPGS) substrates. Compound 3 also inhibited the growth of several human tumor cell lines in culture with GI50 < 10(-8) M. This study shows that the pyrrolo[2,3-d]pyrimidine scaffold is conducive to dual DHFR-TS and tumor inhibitory activity, and the potency is determined by the 4-position substituent.