Addition reactions of Acetylenic Esters to 6,7-Dihydrobenzo[B]Furan-4(5H)-One, 6,7-Dihydroindol-4(5H)-One, 5,6-Dihydrobenzo[B]Furan-7(6H)-One and 5,6-Dihydroindol-7(6H)-One Ketoximes. Formation of Reduced Furo[G]- and Pyrrolo[G]-Indoles

Thermal rearrangement of 6,7-dihydrobenzo[ b]furan-4(5 H)-one and 4,5,6,7-tetrahydroindol-4-one 4(7)- O-( E)-(1,2-dimethoxycarbonylvinyl)ketoximes gave 4,5-dihydrofuro[2,3 g]- and 4,5-dihydropyrrolo[2,3 g]- and [3,2- g] indoles, three novel tricyclic systems

Structure-based selectivity optimization of piperidine-pteridine derivatives as potent Leishmania pteridine reductase inhibitors

The upregulation of pteridine reductase (PTR1) is a major contributor to antifolate drug resistance in Leishmania spp., as it provides a salvage pathway that bypasses dihydrofolate reductase (DHFR) inhibition. The structure-based optimization of the PTR1 inhibitor methyl-1-[4-(2,4-diaminopteridin-6-ylmethylamino)benzoyl]piperidine-4-carboxylate (1) led to the synthesis of a focused compound library which showed significantly improved selectivity for the parasite's folate-dependent enzyme. When used in combination with pyrimethamine, a DHFR inhibitor, a synergistic effect was observed for compound 5b. This work represents a step forward in the identification of effective antileishmania agents.

Styrylbenzimidazoles. Synthesis and biological activity - part 3

As a follow up of an anti-Flaviviridae project, a new series of variously substituted 2-styryl-benzimidazoles were synthesized and tested in vitro for biological activity. Compounds were tested in cell-based assays against viruses representative of: i) two of the three genera of the Flaviviridae family, i.e. Pestiviruses and Flaviviruses; ii) other RNA virus families, such as Retroviridae, Picornaviridae, Paramyxoviridae, Rhabdoviridae and Reoviridae; iii) two DNA virus families (Herpesviridae and Poxviridae) as well as for cytotoxicity tests, run in parallel with antiviral assays,against MDBK, BHK and Vero 76 cells. In the series examined, new leads emerged against BVDV, CVB-2 and RSV. Compounds 11, 12, 17, 18, 24, 31 exhibited anti-BVDV activity in the concentration range 1.7-16 microM; among them, compound 17 was the most active, with an EC(50) = 1.7 microM. Compounds 18 and 21 were equally active against CVB-2, with EC(50) values of 7 - 8 microM, while the derivative 30 was active against RSV with EC(50)= 1 microM and represents a new lead compound.

Synthesis and in vitro antitumor activity of new quinoxaline derivatives

A series of novel 5,7-diamino-3-phenyl-2-benzylamino, 2-phenoxy, and 2-thiophenyl substituted quinoxalines has been designed, synthesized and evaluated for their in vitro antitumor activity towards cell lines of nine different types of human cancers. Some of these compounds exhibited inhibitory effects on the growth of a wide range of cancer cell lines generally at 10(-6) M, in some cases at 10(-7) M and 10(-8) M concentrations. Within this series the benzylamino quinoxaline derivatives 1b-7b were the most active, whereas compound 2c showed the highest MG_MD value (-5.66).

Synthesis of N-(5,7-diamino-3-phenyl-quinoxalin-2-yl)-3,4,5-substituted anilines and N-[4[(5,7-diamino-3-phenylquinoxalin-2-yl)amino]benzoyl]-l-glutamic acid diethyl ester: Evaluation of in vitro anti-cancer and anti-folate activities

Several diamino quinoxalines were designed, synthesized and evaluated as anti-tumor agents. Two compounds showed the most potent cytotoxic activities against the leukemia CCRF-CEM cell line (GI(50)<0.01microM) and the ovarian cancer cell line OVCAR-4 (GI(50)=0.03microM), respectively, with comparable/better activities than Methotrexate (MTX). Docking calculations of the complexes of hDHFR with the most active compounds identified the binding mode of the described molecules with respect to MTX.

Synthesis and anti-picornaviridae in vitro activity of a new class of helicase inhibitors the N,N'-bis[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl] alkyldicarboxamides

A series N,N'-bis[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkyldicarboxamides (3a-f and 5a-j) were prepared starting from their already known (1a-d) and (4a-c) or new (4d) amine parents. Because of the antiviral activity of several N-[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkylcarboxamides previously reported, title compounds were evaluated in vitro for cytotoxicity and antiviral activity against viruses representative of Picornaviridae, [i.e. Enterovirus Coxsackie B2 (CVB-2) and Polio (Sb-1)] and of two of the three genera of the Flaviviridae [Bovine Viral Diarrhea Virus (BVDV) and Yellow Fever Virus (YFV)]. Furthermore, because of the in silico activity against the RNA-dependent RNA-helicase of Polio 1 previously reported, title compounds were evaluated against the 3D model of the Sb-1 helicase and against the 2D model of the CVB-2 helicase. As a reference we used the antiviral and in silico activities of an imidazo counterpart of the title compounds, N,N'-bis[4-(2-benzimidazolyl)phenyl]alkyldicarboxamides (III) that other authors reported to be able to inhibit the corresponding enzyme of Hepatitis C Virus (HCV). In cell-based antiviral assays, N,N'-bis[4-(1H-benzotriazol-1-yl)phenyl]alkyldicarboxamides (3a-f) resulted completely inactive whereas the bis-5,6-dimethyl-benzotriazol-2-yl derivatives (5d-f) exhibited good activity against the Enteroviruses, (EC(50)s ranged between 7 and 11 microM against CVB-2 and 19-52 against Sb-1). Interestingly, bis-5,6-dichloro-benzotriazol-2-yl derivatives (5h-j) showed very selective activity against CVB-2 (EC(50)s = 4-11 microM) whereas they resulted completely inactive against all the other viruses screened. In general, all title compounds showed a good cytotoxicity profile in MT-4 cells. Molecular modeling investigations showed that active compounds may interact with the binding site of the Sb-1 helicase and that their free binding energy values are in agreement with their EC(50)s values.

[1,2,3]Triazolo[4,5-h]quinolones. A new class of potent antitubercular agents against multidrug resistant Mycobacterium tuberculosis strains

In this preliminary study we report the activity of 3-methyl-9-substituted-6-oxo-6,9-dihydro-3H-[1,2,3]-triazolo[4,5-h]quinolone-carboxylic acids and their esters as a new class of antiinfective agents against MDR Mycobacterium tuberculosis. In antitubercular screening against H37Rv and 11 clinically isolated strains of M. tuberculosis several derivatives (1o,3a,c,i,j,p) showed MIC(90) in the range 0.5-3.2 microg/mL. 3c showed no cytotoxicity and proved to be the most potent derivative exhibiting MIC(90)=0.5 microg/mL against all M. tuberculosis strains and infected human macrophages (J774-A1) tested.

Design, synthesis, and preliminary in vitro and in silico antiviral activity of [4,7]phenantrolines and 1-oxo-1,4-dihydro-[4,7]phenantrolines against single-stranded positive-sense RNA genome viruses

Following the antiviral screening of a wide series of new angular and linear N-tricyclic systems both in silico and in vitro, the [4,7]phenantroline nucleus emerged as a new ring system endowed with activity against viruses containing single-stranded, positive-sense RNA genomes (ssRNA+). Here, we report our new pathway to the synthesis of this nucleus and of several related derivatives, as well as the results of both cell-based antiviral assays and molecular dynamics simulations. In the antiviral screening, several compounds (9 and 16-20) showed to be fairly active against BVDV, CVB-2, and Polio 1 (EC50, 6-25 microM). According to molecular dynamics simulations, compounds (15) and (17) emerged for its potency against the HCV NS5B, with a calculated IC50 of 11-12 microM.

Synthesis and in vitro evaluation of the anti-viral activity of N-[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkylcarboxamides

A series N-[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkylcarboxamides (8e-k, 9e-i, k, l) and their parent amines (5a-c and 6a-d) were prepared according to Schemes (1 and 2). Compounds were evaluated in vitro for cytotoxicity and antiviral activity against a wide spectrum of RNA (positive- and negative-sense) viruses, like [Bovine Viral Diarrhea Virus (BVDV), Yellow Fever Virus (YFV), Coxsackie Virus B (CVB-2), Polio Virus (Sb-1), Human Immunodeficiency Virus (HIV-1), Respiratory Syncytial Virus (RSV)] or double-stranded (dsRNA) virus, like Reoviridae (Reo-1). The Entero (CVB-2 and Sb-1) were the only viruses inhibited by title compounds. In particular, two of them emerged for their selective, although not very potent, antiviral activity: 8i, which was the most active against CVB-2 (CC50 >100 microM; EC50 = 10 microM) and 9l, which was the most active against Sb-1 (CC50 90 microM; EC50 = 30 microm). Title compounds were evaluated in silico against the Sb-1 helicase, as the crystal structure of this enzyme was not available, the corresponding 3D model was obtained by homology techniques (see Fig. 2).

Chemistry, biological properties and SAR analysis of quinoxalinones

Quinoxaline derivatives have received much attention in recent years owing to their both biological properties and pharmaceutical applications. In this review we focus the attention on quinoxalin-2(3)-ones and quinoxalin-2,3-diones. These derivatives are particularly interesting since some of them showed antimicrobial (against several bacteria, viruses, fungi, etc), or anticancer activities. Furthermore, others are reported to be potent no-NMDA glutamate receptor antagonists, endowed with anxiolytic, deconditioning, analgesic, antispastic, antiallergic, antithrombotic activities. In this article we also report SAR studies and the most important methods of synthesis of the quinoxalin-2(3)-(di)ones.

4-Substituted anilino imidazo[1,2-a] and triazolo[4,3-a]quinoxalines. Synthesis and evaluation of in vitro biological activity

Fifteen imidazo[1,2-a] and [1,2,4]triazolo[4,3-a]quinoxalines were prepared. These compounds bear at position 4 various substituents related to the moieties present in classical and non-classical antifolic agents. And we evaluated in vitro antimicrobial, antiviral and antiproliferative activities. In particular, title compounds were evaluated in vitro against representative strains of Gram-positive and Gram-negative bacteria (S. aureus, Salmonella spp.), mycobacteria (M. fortuitum, M. smegmatis ATCC 19420 and M. tuberculosis ATCC 27294), yeast and moulds (C. albicans ATCC 10231 and A. fumigatus). Furthermore, their antiretroviral activity against HIV-1 was determined in MT-4 cells together with cytotoxicity. In these assays title compounds were tested for their capability to prevent MT-4 cell growth. Among the examined series, the compounds 5, 7 and 10 showed cytotoxicity against mock-infected MT-4 cells.

Synthesis of Variously Substituted 3-Phenoxymethyl Quinoxalin-2-Ones and Quinoxalines Capable to Potentiate In Vitro the Antiproliferative Activity of Anticancer Drugs in Multi-Drug Resistant Cell Lines

Two series of 1,6-dimethyl-3-phenoxymethylquinoxalin-2-ones and 1-benzyl-3-phenoxymethyl-7-trifluoromethylquinoxalin-2-ones, and a series of 2-benzyloxy-3-phenoxymethyl-7-trifluoromethylquinoxaline were synthesized. Their capability to restore/potentiate the antiproliferative activity of clinically useful drugs, such as doxorubicin (Doxo), vincristine (VCR) and etoposide (VP16), in drug-resistant human nasopharyngeal carcinoma KB cells (KB(WT), KB(MDR), KB(7D)and KB(V20C)) was evaluated. In vitro data show that many quinoxalin-2-ones and quinoxalines potentiate the antiproliferative activity of Doxo and VCR in tumor-derived MDR cell lines. In this series, 17a turned out to be the most potent quinoxaline derivative in potentiating the antiproliferative activity of doxorubicin and vincristine against KB(MDR) and KB(V20C) resistant cell lines, respectively.

Quinoxaline chemistry. Part XVII. Methyl [4-(substituted 2-quinoxalinyloxy) phenyl] acetates and ethyl N-{[4-(substituted 2-quinoxalinyloxy) phenyl] acetyl} glutamates analogs of methotrexate: synthesis and evaluation of in vitro anticancer activity

Fourteen out of 21 quinoxaline derivatives described in the present paper were selected at NCI for evaluation of their in vitro anticancer activity. Preliminary screening showed that some derivatives exhibited a moderate to strong growth inhibition activity on various tumor panel cell lines between 10(-5) and 10(-4) M concentrations. Interesting selectivities were also recorded between 10(-8) and 10(-6) M for the compounds 9 and 13.

Synthesis, anti-mycobacterial, anti-trichomonas and anti-candida in vitro activities of 2-substituted-6,7-difluoro-3-methylquinoxaline 1,4-dioxides

A new series of 23 6,7-difluoro-3-methyl-2-phenylthio/phenylsulfonyl/phenylsulfinyl/benzylamino/phenylamino-quinoxaline 1,4-dioxides variously substituted in the phenyl moiety, was synthesized and submitted to in vitro evaluation for anti-mycobacterial, anti-trichomonas, anti-candida, anti-mycoplasma and antibacterial activities. In anti-mycobacterial assays, several compounds resulted active (MIC90 = 2.0-4.0 microg/ml) against Mycobacterium tuberculosis H37Rv. Anti-trichomonas screening showed a generally good activity of all compounds (MBC = 0.39-25.0 microg/ml) versus Trichomonas vaginalis, in particular the derivatives 5a,d, 7a, 9 and 11c ranged 0.39-0.78 microg/ml (metronidazole MBC = 12.5 microg/ml). Results of anti-candida assays showed that derivatives 7a, 8a,d and 9 were active against several species of Candida (C. albicans, C. krusei, C. parapsilosis and C. glabrata), having MIC50 between 3.9 and 31.25 microg/ml. The latter compounds were also submitted to anti-mycoplasma assay against Mycoplasma hominis, the results obtained showed that 7a, 8a,d and 9 inhibited the growth of the mycoplasma at the concentration of 0.1 mg/ml. In antibacterial tests only a few compounds showed an MIC50 lower than 62.5 microg/ml against representative strains of Gram-positive and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio alginolyticus and Pseudomonas aeruginosa).

Synthesis, anti-mycobacterial, anti-trichomonas and anti-candida in vitro activities of 2-substituted-6,7-difluoro-3-methylquinoxaline 1,4-dioxides

A new series of 23 6,7-difluoro-3-methyl-2-phenylthio/phenylsulfonyl/phenylsulfinyl/benzylamino/phenylamino-quinoxaline 1,4-dioxides variously substituted in the phenyl moiety, was synthesized and submitted to in vitro evaluation for anti-mycobacterial, anti-trichomonas, anti-candida, anti-mycoplasma and antibacterial activities. In anti-mycobacterial assays, several compounds resulted active (MIC90 = 2.0-4.0 microg/ml) against Mycobacterium tuberculosis H37Rv. Anti-trichomonas screening showed a generally good activity of all compounds (MBC = 0.39-25.0 microg/ml) versus Trichomonas vaginalis, in particular the derivatives 5a,d, 7a, 9 and 11c ranged 0.39-0.78 microg/ml (metronidazole MBC = 12.5 microg/ml). Results of anti-candida assays showed that derivatives 7a, 8a,d and 9 were active against several species of Candida (C. albicans, C. krusei, C. parapsilosis and C. glabrata), having MIC50 between 3.9 and 31.25 microg/ml. The latter compounds were also submitted to anti-mycoplasma assay against Mycoplasma hominis, the results obtained showed that 7a, 8a,d and 9 inhibited the growth of the mycoplasma at the concentration of 0.1 mg/ml. In antibacterial tests only a few compounds showed an MIC50 lower than 62.5 microg/ml against representative strains of Gram-positive and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio alginolyticus and Pseudomonas aeruginosa).

Quinoxaline chemistry. Part 16. 4-Substituted anilino and 4-substituted phenoxymethyl pyrrolo[1,2-a]quinoxalines and N-[4-(pyrrolo[1,2-a]quinoxalin-4-yl)amino and hydroxymethyl]benzoyl glutamates. Synthesis and evaluation of in vitro biological activity

Twenty eight pyrrolo[1,2-a]quinoxalines bearing at position 4 various substituents related to the moieties present in classical and non classical antifolic agents were prepared and evaluated in vitro for antiproliferative activity. In an in vitro screening performed at NCI, several compounds emerged as potent antiproliferative agents at concentrations ranging between 10 and 100 microM. Interestingly, some of these compounds proved active also against bovine and murine DHFR (Farmaco 53 (1998) 480). More recently, a compound of classical antifolate type has been reported to be a potent inhibitor of hDHFR in vitro (Farmaco 58 (2003) 51). We then synthesized new derivatives that, in our hands, were endowed with in vitro antiproliferative activities as low as 3.4 microM against a panel of cell lines derived from hematological and solid tumours. In addition, a complete screening of cytotoxicity, antiretroviral HIV-1 and antimicrobial activity has been carried out.

Quinoxaline chemistry. Part 15. 4-[2-Quinoxalylmethylenimino]-benzoylglutamates and -benzoates, 4-[2-quinoxalylmethyl-N-methylamino]-benzoylglutamates as analogues of classical antifolate agents. Synthesis, elucidation of structures and in vitro evaluation of antifolate and anticancer activities

We report on an extension of our previous discovery of in vitro anticancer activity of trifluoromethylquinoxalines as analogues of classical and non-classical antifolic methotrexate and trimetrexate. In this case a small number of Schiff bases were obtained from the reaction of 2-bromethyl-3-R-6(7)trifluoromethylquinoxaline and ethyl p-aminobenzoylglutamate, ethyl p-aminobenzoate, p-toluidine instead of the expected 4-[2-quinoxalyl]methyl-N-methylanilino derivatives, which in turn formed with N-methylanilino derivatives. The reaction mechanism has been put forward. Structure elucidation of both Schiff bases and N-methylanilino analogues was achieved by a combination of 1H and 13C NMR spectra and hetcor experiments. Compounds 3a, 3b, 3c, 8, 11, 12, 13, Ie were tested in antifolic enzyme assay [Lactobacillus casei (LcTS), Leishmania major (LmTs), human Thymidylate synthase (hTs), human TS, human dihydrofolate reductase (hDHFR)] while compounds 3a, 3b, 3c were tested for anticancer activity. These results seem to indicate that the Schiff bases are somewhat active either as anticancer or as folate inhibitors, while compound Ie was selectively active against hDHFR with an inhibition constant (Ki) of 200 nM with a specificity of about 1000-folds with respect to hTS.

Novel substituted quinoxaline 1,4-dioxides with in vitro antimycobacterial and anticandida activity

Thirty-six 6(7)-substituted-3-methyl- or 3-halogenomethyl-2-phenylthio-phenylsulphonyl-chloro-quinoxaline 1,4-dioxides belonging to series 3-6 were synthesised and submitted to a preliminary in vitro evaluation for antimycobacterial, anticandida and antibacterial activities. Antitubercular screening showed a generally good activity of 3-methyl-2-phenylthioquinoxaline 1,4-dioxides (3d,e,h-j) against Mycobacterium tuberculosis, and exhibited MIC between 0.39 and 0.78 microg mL(-1) (rifampicin MIC=0.25 microg mL(-1)), whereas in compounds 4d,e, 5a,b,d,e,l and 6b-e,j,l MIC ranged between 1.56 and 6.25 microg mL(-1). Results of the antibacterial and anticandida screening showed that 6e and 6l exhibited MIC=0.4 and 1.9 microg mL(-1), respectively, against Candida krusei (miconazole MIC=0.9 microg mL(-1)), and 4i, 5b,d, 6e, MIC=3.9 microg mL(-1) against Candida glabrata (miconazole MIC=0.4 microg mL(-1)), while compounds 3d,l, 5e,l, and 6b,d,e,l showed MIC=15.6 microg mL(-1) against Vibrio alginolyticus.

Quinoxaline chemistry. Part 14. 4-(2-Quinoxalylamino)-phenylacetates and 4-(2-quinoxalylamino)-phenylacetyl-L-glutamates as analogues--homologues of classical antifolate agents. Synthesis and evaluation of in vitro anticancer activity

Among a new series of 26 4-(3-substituted-2-quinoxalylamino)phenylacetates and 4-(3-substituted-2-quinoxalylamino)-phenylacetyl-L-glutamates, eight were selected at NCI for evaluation of their in vitro anticancer activity. The results obtained in comparison with the corresponding nor-compounds series seem to indicate that this type of homologation is not helpful.

Synthesis and cytotoxicity of bis(benzo[g]indole-3-carboxamides) and related compounds

A series of bis(benzo[g]indoles) bridged by CX-(CH2)nN(Me)(CH2)n-CX (X = O, S, H2; n = 2,3) was synthesized as bifunctional antitumor agents and evaluated for cytotoxic activity against diverse human cancer cell lines by the National Cancer Institute. The parent compounds 2a,b exhibited a good level of activity and derivates 2c-g,i,k demonstrated significant inhibitory effects, all with IC50 values in the low micromolar range. The thioamide analogue 2j showed less potency. It is interesting to note that introduction of substituents on the benzene ring of the benzo[g]indole portion of 2a,b did not affect activity, with the only exception of the 7,8-dichloro derivative 2h which became less potent. One member of this series, 2i, was then tested in the hollow fiber cell assay to evaluate, in a preliminary fashion, its in vivo antineoplastic activity. Molecular modelling studies were performed on amide 2a and thioamide 2j to explain the loss of activity of 2j as to 2a. Finally, compound 2a behaved as a typical DNA intercalating agent, as judged from viscosity measurements with Poly(dA-dT)...poly(dA-dT).

Quinoxaline chemistry. Part 13: 3-Carboxy-2-benzylamino-substituted quinoxalines and N-[4-[(3-carboxyquinoxalin-2-yl) aminomethyl]benzoyl]-L-glutamates: synthesis and evaluation of in vitro anticancer activity

Among a new series of 28 3-carboxy or carbethoxy quinoxalines bearing a substituted benzylamino or N-[4-(aminomethyl)benzoyl]glutamate group on position 2 of the ring and various substituents at C-6, 7 positions, 21 were selected at the National Cancer Institute for evaluation of their in vitro anticancer activity. The results obtained seem to confirm that the carboxy or carbethoxy group on position 3 is not helpful, with a few exceptions, for the anticancer activity.

Quinoxaline chemistry. Part 12. 3-Carboxy-2[phenoxy]-6(7)substituted quinoxalines and N-[4-(6(7) substituted-3-carboxyquinoxalin-2-yl)hydroxy] benzoylglutamates. Synthesis and evaluation of in vitro anticancer activity

Thirty quinoxalines bearing a substituted phenoxy or hydroxybenzoylglutamate group on position 2, a carboethoxy or carboxy group on position 3 and a trifluoromethyl group on position 6 or 7 of the heterocycle were prepared in order to evaluate the in vitro anticancer activity. Screening over 21 compounds selected at the National Cancer Institute (Bethesda, MD) showed that only few derivatives exhibited a moderate growth inhibition activity on various tumor panel cell lines at 10(-4) molar concentration. The acid derivatives showed no growth inhibition activity. The results obtained in this series seem to indicate that in general carboxy or carboethoxy groups close to O-link with phenyl or benzoyl glutamates on position 2 are detrimental for anticancer activity.

Quinoxaline chemistry. Part 11. 3-Phenyl-2[phenoxy- and phenoxymethyl]-6(7) or 6,8-substituted quinoxalines and N-[4-(6(7)-substituted or 6,8-disubstituted-3-phenylquinoxalin-2-yl)hydroxy or hydroxymethyl] benzoylglutamates. Synthesis and evaluation of in vitro anticancer activity and enzymatic inhibitory activity against dihydrofolate reductase and thymidylate synthase

Twenty-four out of twenty-nine quinoxalines were selected at the National Cancer Institute, Bethesda, Md, USA, for in vitro anticancer screening. Among these, 10 derivatives exhibited high values of percent tumor growth inhibition at a concentration of 10(-4) M in all cancer cell lines. Four of these compounds maintained these values at 10(-5) M, whereas a certain number exhibited significant values of percent inhibition at the most diluted concentrations (10(-8)-10(-6) M). Inhibitory activity against dihydrofolate reductase (DHFR) (bovine and rat liver) was determined for the most active compounds. This test showed that this type of quinoxaline exhibited an appreciable activity in comparison with the previously described aza analogues. In the other test (Lactobacillus casei, thymidylate synthase (TS), human HTS) no or poor activity was detected in both series of compounds.

Synthesis and in vitro anticancer activity evaluation of biscarbamic esters of 2,3-bis(hydroxymethyl)-1-methyl-7- and 7,8-substituted-benzo[g]indoles

A series of various bis(hydroxymethyl) carbamate derivatives of 7-mono- and 7,8-disubstituted-1-methyl-benzo[g]indoles was prepared in order to evaluate their cytostatic and cytotoxic activities in vitro. Compounds 2a-h showed significant tumor growth inhibition activity and were more potent than the 4,5-dihydrobenzo[g]indole analogues previously described. Compound 2a was the most active in this series, showing high activity and selectivity for some human cancer cell lines in the National Cancer Institute screen.

Quinoxaline chemistry. Part 9. Quinoxaline analogues of trimetrexate (TMQ) and 10-propargyl-5,8-dideazafolic acid (CB 3717) and its precursors. Synthesis and evaluation of in vitro anticancer activity

Eighteen quinoxalines bearing a methyleneanilino or methyleneaminobenzoylglutamate group on position 6 of the ring and various lipophilic substituents on positions 2 and 3 were prepared in order to discover if their structural analogy with both trimetrexate (TMQ) and 10-propargyl-5,8-dideazafolic acid (CB 3717) might display in vitro anticancer activity. Among these, 12 compounds were selected at the National Cancer Institute, Bethesda, MD, USA; they exhibited moderate (4b,d,i,l,m and 8) to strong (4f,h and 5a,e) cell-growth inhibition at a concentration of 10(-4) M. Interesting selectivities were also recorded between 10(-8) and 10(-6) M. These analogues proved to be less potent inhibitors of tumor cells than other classical and non-classical antifolate analogues previously described by us.

Quinoxaline chemistry. Part 10. Quinoxaline 10-oxa-analogues of trimetrexate (TMQ) and of 5,8-dideazafolic acid. Synthesis and evaluation of in vitro anticancer activity

Among twenty-eight novel compounds (twenty-two 2,3-disubstituted-6-[(substituted-phenoxy)methyl-quinoxalines and six 4-[(2,3-disubstituted-quinoxalin-6-yl)methoxy]benzoylglutamates ) only thirteen were selected at NCI for evaluation of their in vitro anticancer activity. The results have shown that compounds 3l,c,b,e and 4b were endowed with significantly high values of percent tumor growth inhibition on several tumor cell lines at 10(-4) M, while compound 3t was characterized by a high selectivity, being still strongly inhibiting on three cell lines at 10(-5) M. Comparison of the presently observed activity with that of the previously described aza-analogues confirms that the effected isosteric substitution is highly valuable in some cases.

Quinoxaline chemistry. Part 8. 2-[Anilino]-3-[carboxy]-6(7)-substituted quinoxalines as non classical antifolate agents. Synthesis and evaluation of in vitro anticancer, anti-HIV and antifungal activity

Thirty quinoxalines bearing a substituted anilino group on position 2, a carboethoxy or carboxy group on position 3 and a trifluoromethyl group on position 6 or 7 of the heterocycle were prepared in order to evaluate in vitro anticancer activity. Preliminary screening performed at NCI showed that most derivatives exhibited a moderate to strong growth inhibition activity on various tumor panel cell lines between 10(-5) and 10(-4) molar concentrations. Interesting selectivities were also recorded between 10(-8) and 10(-6) M for a few compounds. One single compound exhibited good activity against Candida albicans.

Quinoxaline chemistry. Part 7. 2-[aminobenzoates]- and 2-[aminobenzoylglutamate]-quinoxalines as classical antifolate agents. Synthesis and evaluation of in vitro anticancer, anti-HIV and antifungal activity

Thirty-three quinoxalines bearing an aminobenzoyl or aminobenzoylglutamate group on position 2 and various substituents on position 3,6,7 of the heterocycle were prepared in order to evaluate in vitro anticancer activity. Preliminary screening performed at NCI showed that most derivatives exhibited a moderate to strong growth inhibition activity on various tumor panel cell lines between 10(-5) and 10(-4) Molar concentrations. Interesting selectivities were also recorded between 10(-8) and 10(-6) M. Among the series examined one compound (29) which was the most active also exhibited both in vitro anti-HIV protection and antifungal activity while in other two (31, 37) the antifungal activity was prevailing.