New azole antifungals. 3. Synthesis and antifungal activity of 3-substituted-4(3H)-quinazolinones

2-Anilino-3-(2-hy-droxy-phen-yl)quinazolin-4(3H)-one methanol monosolvate

In the title compound, C₂₀H₁₅N₃O₂·CH₃OH, the quinazolin­one ring system is approximately planar, the dihedral angle between the pyrimidinone ring and the adjacent benzene ring being 1.73 (6)°. The pyrimidinone ring makes dihedral angles of 77.58 (6) and 29.62 (6)°, respectively, with the hy­droxy­phenyl and phenyl rings. In the crystal, the components are connected by O—H⋯O and C—H⋯O hydrogen bonds, forming a zigzag chain along the b axis.

2-[2-(2-Anilino-4-oxo-3,4-dihydro-quinazolin-3-yl)phen-oxy]-3-phenyl-quinazolin-4(3H)-one methanol hemisolvate

In the title compound, C₃₄H₂₃N₅O₃·0.5CH₃OH, each pyrimid­in­one heterocycle and its adjacent benzene ring are almost coplanar, making dihedral angles of 0.69 (13) and 1.87 (13)°. The lower pyrimidinone ring makes a dihedral angle of 40.41 (15)° with the —NH— bonded phenyl ring. O—H⋯O hydrogen bonds and weak C—H⋯π inter­actions are observed in the crystal structure. The methanol solvent molecule is disordered over two positions of equal occupancy.

3-(2-Amino-eth-yl)-2-[4-(trifluoro-meth-oxy)anilino]quinazolin-4(3H)-one

In the title compound, C₁₇H₁₅F₃N₄O₂, the dihedral angle between the trifluoro­meth­oxy-substituted benzene ring and the pyrimidinone ring is 45.1 (5)°, while that between the fused benzene ring and the pyrimidinone ring is 0.67 (1)°. Part of one of the benzene rings and its trifluoro­meth­oxy substituent are disordered over two positions of approximately equal occupancy (0.51:0.49). Inter­molecular N—H⋯O and N—H⋯N hydrogen bonds contribute to the stability of the crystal structure. A weak intra­molecular C—H⋯F contact is also found. In addition, π–π stacking inter­actions, with centroid–centroid distances in the range 3.673 (6)–3.780 (8) Å, and weak C—H⋯π inter­actions are also observed.

Conazoles

This review provides a historical overview of the analog based drug discovery of miconazole and its congeners, and is focused on marketed azole antifungals bearing the generic suffix “conazole”. The antifungal activity of miconazole, one of the first broad-spectrum antimycotic agents has been mainly restricted to topical applications. The attractive in vitro antifungal spectrum was a starting point to design more potent and especially orally active antifungal agents such as ketoconazole, itraconazole, posaconazole, fluconazole and voriconazole. The chemistry, in vitro and in vivo antifungal activity, pharmacology, and clinical applications of these marketed conazoles has been described.

Synthesis, structure, and antifungal evaluation of some novel 1,2,4-triazolylmercaptoacetylthiosemicarbazide and 1,2,4-triazolylmercaptomethyl-1,3,4-thiadiazole analogs

Novel 1-[[4-(4-bromophenyl)-5-(2-furyl)-4H-1,2,4-triazole-3-yl]mercaptoacetyl]-4-alkyl/aryl-3-thiosemicarbazides (5-12) were synthesized by the reaction of 4-(4-bromophenyl)-5-(2-furyl)-4H-1,2,4-triazole-3-ylmercaptoacetylhydrazide (4) with substituted isothiocyanates. Cyclodehydration of thiosemicarbazides with concentrated sulfuric acid yielded 2-[4-(4-bromophenyl)-5-(2-furyl)-4H-1,2,4-triazole-3-yl]mercaptomethyl-5-alkyl/arylamino-1,3, 4-thiadiazoles (13-17). The new compounds were evaluated for in vitro antifungal activity using the microdilution method. The tested compounds showed varying degrees of activity against Microsporum gypseum NCPF-580, Microsporum canis, Trichophyton mentagrophytes, Trichophyton rubrum, and Candida albicans ATCC 10231 (MIC 8-4 microg/mL).

QSAR studies of a number of triazole antifungal alcohols

The activity of fungicide agents containing a quinazolinone ring was described using the quantitative structure-activity relationship (QSAR) model by applying it to data taken from literature. The title compounds exhibit two important types of activity against certain fungal pathogens, i.e. activity against yeast and activity against filamentous fungi. A correlation between both antifungal activities (e.g. FA(yst) and FA(ff)) and physicochemical parameters such as the logarithm of the n-octanol/water partition coefficient (log P), the polarizability (P), the global minimum energy (TE), the energy difference between the frontier molecular orbital (DELH) and the molar refractivity (MR), was established using multiple linear regression. The molecular descriptors of the antifungal agents were obtained by quantum chemical calculations combined with molecular modeling calculations. Statistical analysis shows that the antifungal activity depends mainly on the calculated partition coefficients, log P, of the compounds. Bi-parametric models reveal that antifungal activity relates linearly to log P and P.

New triazoles and echinocandins: mode of action, in vitro activity and mechanisms of resistance

Different types of mycoses, especially invasive mycoses caused by yeasts and molds, are a growing problem in healthcare. The most notable explanation for this increase is a rise in the number of immunocompromised patients owing to advances in transplantation, the emergence of AIDS and a rise in the number of invasive surgical procedures. Despite advances in medical practice, some therapeutic problems remain. In addition, intrinsic or acquired antifungal resistance may pose a serious problem to antifungal therapy. A new generation of triazole agents (voriconazole, posaconazole, isavuconazole, ravuconazole and albaconazole) and the recent class of the echinocandins (caspofungin, micafungin and anidulafungin) have become available, and represent an alternative to conventional antifungals for serious fungal infection management. Currently, only two of the recent triazole generation (voriconazole and posaconazole) and all three echinocandins are available for clinical use. More precisely, voriconazole and posaconazole are indicated for the treatment of invasive fungal infections and the echinocandins for the treatment of specific candidiasis. Voriconazole and posaconazole have a very broad spectrum of antifungal activity that includes Candida species, and filamentous and dimorphic fungi. Their activity extends to both fluconazole- and itraconazole-resistant strains of Candida. A major difference between posaconazole and voriconazole is that posaconazole has activity against Zygomycetes including Mucor spp., Rhizopus spp. and Cunninghamella spp., and voriconazole has no activity against this class of fungi. Ravuconazole, isavuconazole and albaconazole have shown very potent in vitro activity against species of Candida, Cryptococcus and Aspergillus, and they are currently in various stages of development. All three echinocandin agents, caspofungin, micafungin and anidulafungin, are similar in their spectrum of activity. Echinocandins do not possess in vitro activity against important basidiomycetes, including Cryptococcus, Rhodotorula and Trichosporon. This review attempts to deliver the most up-to-date knowledge on the mode of action and mechanisms of resistance to triazoles and echinocandins in fungal pathogens. In addition, the in vitro activity data available on triazoles and echinocandins are reported.

Molecular and crystal structure of 5-amino-1H-[1,2,4]triazole-3-carboxylic acid derivatives

The analysis of molecular structures of three derivatives: 5-amino-3-carbomethoxy-1-methyl-1H-[1,2,4]-triazole (1), 1-acetyl-5-amino-3-carbomethoxy-1H-[1,2,4]-triazole (2) and 5-acetylamino-3-carbomethoxy-1-methyl-1H-[1,2,4]triazole (3) indicate the sensitivity of the N2–N1–C5 fragment of the triazole ring to the substitution. Molecular conformations are influenced by several intra- and intermolecular contacts. In all structures very extensive N–H···N/O and C–H(methyl)···O/N net of secondary interactions is formed. This kind of interactions is common in crystal structures which are proton-deficient and for this reason various types of multi-point interactions are forced. Besides, triazole π···π stacking interactions are observed.

3,3'-Bis(4-chloro-phen-yl)-2,2'-(m-phenyl-enedi-oxy)diquinazolin-4(3H)-one

In the title compound, C(34)H(20)Cl(2)N(4)O(4), the two quinazoline heterocyclic systems and the adjacent chloro-benzene rings are not coplanar, but oriented at dihedral angles of 66.66 (13) and 52.48 (12)°, respectively. The quinazoline ring systems are nearly planar, with dihedral angles between the planes of the two rings of 5.43 (16) and 3.40 (14)°, and are oriented at dihedral angles of 79.73 (13) and 83.52 (13)° with respect to the adjacent benzene ring between them. Inter-molecular C-H⋯O hydrogen bonds contribute to the stability of the structure. In addition, weak π-π stacking inter-actions [centroid-to-centroid distances = 3.872 (1) and 3.876 (1) Å] are observed in the crystal structure.

Chiral gamma-aryl-1H-1,2,4-triazole derivatives as highly potential antifungal agents: Design, synthesis, structure, and in vitro fungicidal activities

A novel series of chiral gamma-aryl-1H-1,2,4-triazole derivatives as highly potential antifungal agents have been designed and synthesized conveniently by using the chiral auxiliary as a controlling reagent. All of the compounds exhibit moderate to high ee values reaching up to 99%, and the preliminary bioassay results demonstrated that most of the target compounds take on a significantly wide spectrum activity against Fusarium oxysporium, Rhizoctonia solani, Botrytis cinereapers, Gibberella zeae, Dothiorella gregaria, and Colletotrichum gossypii species.

3-(2-Amino-ethyl)-2-(4-chloro-anilino)-quinazolin-4(3H)-one methanol 0.75-solvate

In the asymmetric unit of the title compound, C(16)H(15)ClN(4)O·0.75CH(3)OH, there are two independent quinazolin-4(3H)-one mol-ecules and one and a half methanol mol-ecules. One of the methanol mol-ecules is disordered over two positions with equal occupancies. The dihedral angles between the quinazoline ring system and the chloro-benzene ring in the two quinazolin-4(3H)-one mol-ecules are essentially the same, at 39.83 (1) and 39.84 (1)°. Intra-molecular N-H⋯N and O-H⋯O, and inter-molecular N-H⋯O and N-H⋯N hydrogen bonds are observed. In addition, π-π stacking inter-actions, with centroid-to-centroid distances of 3.654 (1), 3.766 (1) and 3.767 (1) Å, and weak C-H⋯π inter-actions, are observed.

3-(2-Hydroxy-ethyl)-2-(p-tolyl-amino)-quinazolin-4(3H)-one

In the title compound, C₁₇H₁₇N₃O₂, the quinazolinone ring system is essentially planar. The benzene ring is twisted with respect to it by a dihedral angle of 32.7 (5)°. The mol­ecular conformation is stabilized by an N—H⋯O hydrogen bond, and the crystal structure is stabilized by inter­molecular O—H⋯N inter­actions.

Solvent-free syntheses of some quinazolin-4(3H)-ones derivatives

Solvent-free syntheses of quinazolin-4(3H)-ones were performed by reaction of anthranillic acid with different amides, such as nicotinamide, benzamide, formamide, etc., on montmorillonite K-10. Products were confirmed by FTIR, 1HNMR, and 13CNMR spectroscopic techniques. All synthesized compounds exhibited antioxidant properties and have been compared with standard antioxidant BHT.Key words: quinazolinone, montmorillonite K-10, solvent-free conditions, antioxidant properties.

Synthesis, antitubercular and anticancer activities of substituted furyl-quinazolin-3(4H)-ones

Some novel substituted-3-{[(1E)-(substituted-2-furyl)-methylene]amino}quinazolin-4(3H)-one (5, 6, 7) a-f were synthesized by a multi-step process. These synthesized compounds are characterized by various spectroscopic techniques and evaluated for their antitubercular and anticancer activities. Biological activity indicated that some of the title compounds are potent antitubercular and anticancer agents.

Synthesis and antiviral bioactivities of 2-aryl- or 2-methyl-3-(substituted- benzalamino)-4(3H)-quinazolinone derivatives

A simple and general method has been developed for the synthesis of various4(3H)-quinazolinone derivatives by the treatment of the appropriate 3-amino-2-aryl-4(3H)-quinazolinone with a substituted benzaldehyde in ethanol. The structures of the compoundswere characterized by elemental analysis, IR, (1)H-NMR and (13)C-NMR spectra. The title 2-aryl- or 2-methyl-3-(substituted-benzalamino)-4(3H)-quinazolinone compounds III-1~III-31 were found to possess moderate to good antiviral activity. Semi-quantitative PCR andReal Time PCR assays were used to ascertain the target of action of compound III-31against TMV. The studies suggest that III-31 possesses antiviral activity due to inductionof up-regulation of PR-1a and PR-5, thereby inhibiting virus proliferation and movementby enhancement of the activity of some defensive enzyme.

Discovery of novel indazole-linked triazoles as antifungal agents

The in vitro and in vivo activities of a series of (2R,3R)-2-(2,4-difluorophenyl)-3-(substituted indazol-1-yl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol as potential antifungal agents are described. In particular, the analog 12j having 5-bromo substitution on the indazole ring exhibited significant antifungal activity against a variety of fungal cultures (Candida spp. and Aspergillus spp.). In addition, oral administration of 12j showed its excellent efficacy against Candida albicans in a murine infection model and the significantly improved survival rates of the infected mice.

Newer triazole antifungal agents: pharmacology, spectrum, clinical efficacy and limitations

New triazole antifungals (voriconazole, posaconazole, ravuconazole and albaconazole) have been developed to meet the increasing need for new antifungals, and address the rising incidence of invasive fungal infections and the emergence of fungal resistance. This report describes the spectrum of activity of the newer-generation triazoles based on data from in vitro, animal and clinical studies. The authors discuss the use of these agents in combination with other antifungals, the extent of cross-resistance, their toxicity profile and pharmacokinetic properties. A total of two agents are currently available: voriconazole (which is becoming a primary treatment for the management of invasive aspergillosis) and posaconazole (which demonstrates a broad antifungal spectrum). A further two agents, albaconazole and ravuconazole, are undergoing early clinical evaluation and their future is uncertain. For all newer triazoles, concerns about emerging drug-resistant fungi and the incidence and management of breakthrough infections will dictate their role in antifungal prophylaxis and treatment.

In vitro activities of new and conventional antimycotics against fluconazole-susceptible and non-susceptible Brazilian Candida spp. isolates

The substantial increase in the rate of azole resistant Candida spp. yeast infections has become a serious treatment problem requiring new and more active antifungal agents. In this study, the in vitro activities of ravuconazole and albaconazole were compared with those of amphotericin B, flucytosine, itraconazole and fluconazole against 162 Brazilian isolates of Candida spp. from which 48 isolates had previously shown lower susceptibility or resistance to fluconazole. Ravuconazole susceptibility ranged from 84.6% (Candida albicans) to 100% for other species and albaconazole MIC(90) was < or =1.0 microg ml(-1) for all the species emphasising the potent activity of these triazoles. To our knowledge this is the first study evaluating the susceptibility of C. dubliniensis to albaconazole.

Cryptococcus gattii: in vitro susceptibility to the new antifungal albaconazole versus fluconazole and voriconazole

Minimal inhibitory concentrations (MIC) and minimal fungicidal activity of albaconazole, voriconazole and fluconazole against 55 strains of Cryptococcus gattii, clinically or environmentally isolated in Spain and some Latin American countries, were assessed. By means of the microbroth method (National Committee for Clinical Laboratory Standards; document M27-A2), the geometric mean value for fluconazole was 5.01 microg/ml; however, MIC for 12.7% of isolates ranged from 16 to 32 microg/ml, suggesting increased resistance against fluconazole. Geometric mean values of 0.02 and 0.03 microg/ml for albaconazole and voriconazole, respectively, were found, indicating not only a higher susceptibility to these new azoles but also a better performance of albaconazole (P = 0.003). Minimal fungicidal concentrations were also very low for albaconazole and voriconazole (P<0.001; geometric mean values of 0.023 microg/ml and 0.07 microg/ml, respectively). Both azoles may be good alternatives for the treatment of C. gattii cryptococcosis.

In vitro antifungal assay of traditional Argentine medicinal plants

Methanol extracts from 11 traditionally used Argentine medicinal plants were assayed in vitro for antifungal activity against yeasts, hialohyphomycetes as well as dermatophytes with the microbroth dilution method. Among them, the strongest effect was presented by Eupatorium buniifolium and Terminalia triflora, Trichophyton mentagrophytes and Trichophyton rubrum being the most susceptible species with MICs ranging from 100 to 250 microg/ml. Lithrea molleoides showed the broadest spectrum of action inhibiting all of the tested dermatophytes with MIC=250 microg/ml.

The contribution of animal models of aspergillosis to understanding pathogenesis, therapy and virulence

Animal models of aspergillosis have been used extensively to study various aspects of pathogenesis, innate and acquired host-response, disease transmission and therapy. Several different animal models of aspergillosis have been developed. Because aspergillosis is an important pulmonary disease in birds, avian models have been used successfully to study preventative vaccines. Studies done to emulate human disease have relied on models using common laboratory animal species. Guinea pig models have primarily been used in therapy studies of invasive pulmonary aspergillosis (IPA). Rabbits have been used to study IPA and systemic disease, as well as fungal keratitis. Rodent, particularly mouse, models of aspergillosis predominate as the choice for most investigators. The availability of genetically defined strains of mice, immunological reagents, cost and ease of handling are factors. Both normal and immunosuppressed animals are used routinely. These models have been used to determine efficacy of experimental therapeutics, comparative virulence of different isolates of Aspergillus, genes involved in virulence, and susceptibility to infection with Aspergillus. Mice with genetic immunological deficiency and cytokine gene-specific knockout mice facilitate studies of the roles cells, and cytokines and chemokines, play in host-resistance to Aspergillus. Overall, these models have been critical to the advancement of therapy, and our current understanding of pathogenesis and host-resistance.

Activity of the new triazole derivative albaconazole against Trypanosoma (Schizotrypanum) cruzi in dog hosts

Albaconazole is an experimental triazole derivative with potent and broad-spectrum antifungal activity and a remarkably long half-life in dogs, monkeys, and humans. In the present work, we investigated the in vivo activity of this compound against two strains of the protozoan parasite Trypanosoma (Schizotrypanum) cruzi, the causative agent of Chagas' disease, using dogs as hosts. The T. cruzi strains used in the study were previously characterized (murine model) as susceptible (strain Berenice-78) and partially resistant (strain Y) to the drugs currently in clinical use, nifurtimox and benznidazole. Our results demonstrated that albaconazole is very effective in suppressing the proliferation of the parasite and preventing the death of infected animals. Furthermore, the parasitological, PCR, serological, and proliferative assay results indicated parasitological cure indices of 25 and 100% among animals inoculated with T. cruzi strain Y when they were treated with albaconazole at 1.5 mg/kg of body weight/day for 60 and 90 days, respectively. On the other hand, although albaconazole given at 1.5 mg/kg/day was very effective in suppressing the proliferation of the parasite in animals infected with the Berenice-78 T. cruzi strain, no parasitological cure was observed among them, even when a longer treatment period (150 doses) was used. In conclusion, our results demonstrate that albaconazole has trypanocidal activity in vivo and is capable of inducing radical parasitological cure, although natural resistance to this compound was also indicated. Furthermore, the compound can be used in long-term treatment schemes (60 to 150 days) with minimal toxicity and thus represents a potentially useful candidate for the treatment of human Chagas' disease.

Synthesis and Evaluation of some Novel Quinazolinone Derivatives as Diuretic Agents

A new series of quinazolin-4(3H)-one derivatives containing either a thiazole or a 1, 3, 4-thiadiazole moiety were prepared in order to study the effect of such a heterocyclic combination on the expected diuretic activity. Synthesis of the target compounds (2, 4, and 6) has been achieved through an interaction of the starting 7-chloro-2-methyl-4H-3, 1-benzoxazin-4-one 1 with different heterocyclic amines. Alkylation of 3-(2-mercapto-1, 3, 4-thiadiazol-5-yl)quinazolin-4(3H)-one derivative 4 with different alkyl halides or chloroacetic acid afforded the corresponding thioethers 5 while interaction of 2-methyl-3-(1, 3, 4-thiadiazol-5-yl or thiazol-5-yl)quinazolin-4(3H)-ones (2 and 6) with various aromatic aldehydes resulted in the formation of the arylvinyl analogs 3 and 7, respectively. On the other hand, 2-morpholinomethyl-3-(2-sulfamoyl or mercapto-1, 3, 4-thiadiazol-5-yl)quinazolin-4(3H)-one derivatives 10 have also been synthesized through an interaction of the sulfonamide or thiol analog 9 with the appropriate amine. Biological evaluation of some of the target compounds as diuretic agents was carried out. The results showed that 2-[2-(4-chlorophenyl)vinyl]-7-chloro-3-(2-sulfamoyl-1, 3, 4-thiadiazol-5-yl)quinazolin-4(3H)-one 7b exhibited significant diuretic activity. The detailed synthesis, spectroscopic and biological data are reported.