Antifungal evaluation of bis Mannich bases derived from acetophenones and their corresponding piperidinols and stability studies

The development of resistance to current antifungal therapeutics drives the search for effective new agents. The fact that some acetophenone-derived Mannich bases had shown antifungal activities in our previous studies led us to design and synthesize acetophenone-derived bis Mannich bases, B1-B5, bis(beta-aroylethyl)methylamine hydrochlorides, to evaluate their antifungal activity. These bis Mannich bases were then converted to the corresponding piperidinols, C1-C5, which are structural isomers of bis derivatives, 3-aroyl-4-aryl-1-methyl-4-piperidinol hydrochlorides, to see alterations in biological activity. A stability study of B1 and Cl was also carried out to estimate whether they alkylate the thiols. All compounds studied have shown antifungal activity, especially against dermatophytes (Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton tonsurans, and Microsporum canis), in the concentration range studied (2-128 microng/ml). The activity was especially apparent against T. tonsurans. All compounds had at least equal antifungal activity compared with the reference compound amphotericin-B against T. tonsurans. Bis Mannich bases were generally found to be more potent compounds than their structural isomer piperidinols. The results of our stability studies suggest that thiol alkylation may contribute to the antifungal activity of the Mannich bases synthesized. Even though all compounds showed antifungal activity against dermatophytes, bis Mannich bases B1, B2, B4, and B5 appear to have potential for developing novel antifungal agents against dermatophytes.     

Cytotoxic activities of some mono and bis Mannich bases derived from acetophenone in brine shrimp bioassay

Some mono Mannich bases (1-phenyl-3-amino-1-propanone salts) and bis Mannich bases (1-phenyl-3-amino-2-amino-methyl-1-propanone salts) derived from acetophenone and a few representative quaternary derivatives were synthesised and their cytotoxicity was tested using the brine shrimp bioassay. This assay may serve as an intermediate test before further in vivo animal experiments in large scale, since brine shrimp nauplii as whole organisms were used in this test. Mono Mannich bases were generally more cytotoxic than their corresponding bis Mannich bases. Mannich bases synthesised were cytotoxic in both brine shrimp bioassay in this study and cell culture tests using Jurkat and Renca cells in a previous study. However, the order of the cytotoxic potency of the compounds were reverse, which may result from faster deamination of bis derivatives than optimal level, and different species and test media used in the two test systems. Faster deamination of bis derivatives might have led to elimination of active metabolites before reaching its target. The cytotoxicity of the compounds might have been altered by amino acids and proteins present in cell culture medium but not in sea water used in brine shrimp bioassay affecting their transport through the cell membrane and metabolism in the cell by binding with the compounds. With higher cytotoxic activity compared with 5-fluorouracil (CAS 51-21-8) in brine shrimp bioassay, mono Mannich base 1 and its quaternary derivative 4 and quaternary bis derivative 8 seem to be candidate compounds for further drug design.     

Cytotoxic activities of mono and bis Mannich bases derived from acetophenone against Renca and Jurkat cells

Mannich bases of acetophenones have been disclosed to have antitumour and cytotoxic activities. 1-Phenyl-3-dimethylaminopropan-1-one hydrochloride, 1, and related piperidino, 2, and morpholino, 3, derivatives, and compound 4, which is a quaternary form of 1, were synthesized as mono Mannich bases derived from acetophenone. They were converted to corresponding bis Mannich bases, 5-8, to see whether it increases the bioactivity. The biological activity of the compounds was examined by cytotoxicity against mouse renal carcinoma (Renca) and transformed human T-lymphocyte (Jurkat) cell lines. Conversion of mono Mannich bases to corresponding bis Mannich bases remarkably increased the cytotoxicity in most cases. Quaternization procedure also improved the bioactivity in mono derivatives against Jurkat cells. Bis mannich bases 5-7 were found to be more active than 5-fluorouracil (6-23 fold) and melphalan (1.25-5 fold) against Renca cells. Except 2 and 8, the compounds synthesised were found to be more active than 5-fluorouracil (1.2-33 fold) against Jurkat cells.     

Effect of acetophenone derived Mannich bases on cellular glutathione level in Jurkat cells. A possible mechanism of action

The effect of the acetophenone derived mono Mannich bases 1-3 and bis Mannich base 7 (bis derivative of compound 3) on cellular glutathione level was investigated in Jurkat cells. The cells were exposed to the compounds in phosphate buffered saline for 1 h in 37 degrees C with gentle shaking and then glutathione level was measured. Especially, mono Mannich base 3 and its bis derivative 7 decreased total glutathione level in a dose-dependent manner. The results provide further support for the thiol alkylation mechanism explaining the cytotoxic activity of Mannich bases.     

Evaluation of antimicrobial activities of several mannich bases and their derivatives

The aim of this study was to evaluate the antimicrobial activities of several Mannich bases and their derivatives against pathogenic bacteria and fungi. 3-Dimethylamino-1-phenyl-1-propanone hydrochloride (Ig1) as mono-Mannich base, bis(beta-aroylethyl)methylamine hydrochlorides (B1, B5) as bis-Mannich bases, 3-aroyl-4-aryl-1-methyl-4-piperidinol hydrochlorides (C1, C5) as piperidinol derivatives, which are structural isomers of bis-Mannich bases, N,N'-Bis(3-dimethylamino-1-phenylpropylidene)hydra zine dihydrochlorides (D1) as azine derivative of mono-Mannich base Ig1, and some representative quaternary derivatives (Ig4 and C6), which are quaternary derivatives of Ig1 and C1, respectively, have been synthesized. Aryl parts were phenyl in B1 and C1, and 2-thienyl in B5 and C5. Bis-Mannich bases and quaternary Mannich bases were found to be effective antifungal derivatives. Quaternary mono-Mannich base Ig4 has shown twice the amount of higher antifungal potency against the human pathogenic fungus Microsporum canis compared with the reference drug amphotericin-B and it had equal potency against many other fungi species pathogenic in humans and plants. Ig4 was effective against Staphylococcus aureus among the bacteria tested. Preparation of bis-Mannich bases and qua ternization procedure seemed suitable chemical modifications to prepare effective antifungal compounds. Especially quaternary derivatives Ig4, and to some extent C6, seem to be model compounds to develop new antimicrobial agents for further studies.     

Syntheses and stability studies of some Mannich bases of acetophenones and evaluation of their cytotoxicity against Jurkat cells

Mannich bases, namely 1-aryl-3-dimethylamino-1-propanone hydrochlorides (Ia-f) as mono-Mannich bases (series I), bis(beta-aroylethyl)ethylamine hydrochlorides (IIa, IIb, IId, IIe) as bis-Mannich bases (series II), 3-aroyl-4-aryl-1-ethyl-4-piperidinol hydrochlorides (series III), which are structural isomers of bis derivatives and some representative quaternary salts (Ig, IIIf, IIIg), were synthesized to investigate the effect of chemical structure and ring substituents on cytotoxic activity in Jurkat cells. Stability studies of some representative compounds have also been realised. Compounds IIb, IId, IIe, and IIIe were reported for the first time. Id-g, IIa, IId, IIe, IIIf,g were 1.25-6.55 times more potent than 5-fluorouracil (CAS 51-21-8). However, the cytotoxic activity of the most potent compounds. Ig and IIIf, were one fifth of that of melphalan (CAS 148-82-3). The formation of compound IV during the stability studies of Ig, IIa, and IIIf suggested that they may be thiol alkylators. Bis-Mannich base IIa in nonsubstituted derivatives, piperidinol derivative IIIb in methyl substituted compounds, mono derivative Id in chloro substituted compounds were the most potent compounds when the cytotoxicity of the compound series which have the same substituents in benzene ring are compared. Replacement of the benzene with thiophene improved the cytotoxicity in both series I and II. Quaternization procedure also increased the cytotoxicity in both series I and III. Quaternary derivatives seem to be promising compounds for further studies to develop new anticancer drugs.     

Antimicrobial evaluation of some Mannich bases of acetophenones and representative quaternary derivatives

1-Aryl-3-dimethylamino-1-propanone hydrochlorides Ia-f (series I) as mono-Mannich bases bis(beta-aroylethyl)ethylamine hydrochlorides IIa, IIb, IId, IIe (series II) as bis-Mannich bases, 3-aroyl-4-aryl-1-ethyl-4-piperidinol hydrochlorides (structural isomer of bis derivatives IIIa-e, series III), and some of their representative quaternary salts (Ig, IIIf, IIIg) were synthesized. Antimicrobial activities of the compounds were evaluated against some bacteria and fungi. Series I and III showed antimicrobial activity against gram positive bacteria. All series demonstrated activity against fungi, however, they generally did not affect gram negative bacteria at the concentration range tested (2-64 micrograms/ml). Quaternisation procedure improved the bioactivity in compound IIIa for antibacterial activity and in compounds IIIa and IIIb for antifungal activity against Trichophyton rubrum and Mycosporium canis. There was no relationship between Hammett values of the aryl substituents and bioactivities in series III. The mono-Mannich bases of series I had better antimicrobial activities than bis-Mannich bases of series II. Compounds Ia, If, IIId had equal and compounds If and IIIf had higher antibacterial activities compared to the reference drug, streptomycin (CAS 57-92-1), against various gram positive bacteria. On the other hand, compounds Ia, IIIa, IIIc, IIIe, IIIf, and IIIg had equal and If, IIId, IIIf, IIIg had higher antifungal activity compared to the reference drug, amphotericin-B (CAS 1397-89-3), against various fungi. To conclude, the compounds of series III, having both marked antifungal and antibacterial activities, may serve as candidate compounds for further studies. Especially compound IIIf may serve as a model compound to develop new agents against dermatophytes.     

Toxicity of some bis Mannich bases and corresponding piperidinols in the brine shrimp (Artemia salina) bioassay

Some acetophenone-derived bis Mannich bases were synthesized: bis[beta-benzoylethyl]ethylamine hydrochloride (IIa), bis[beta-(p-methylbenzoyl)ethyl]ethylamine hydrochloride (IIb), bis[beta-(p-chlorobenzoyl)ethyl]ethy- lamine hydrochloride (IId), bis[(2-thienylcarbonyl)ethyl]ethylamine hydrochloride (IIe); some corresponding piperidinol derivatives: 3-benzoyl-1-ethyl-4-phenyl-4-piperidinol hydrochloride (IIIa), 1-ethyl-3-(p-methyl- benzoyl)-4-(p-methylphenyl)-4-piperidinol hydrochloride (IIIb), 1-ethyl-3-(p-methoxybenzoyl)-4-(p-methoxy- phenyl)-4-piperidinol hydrochloride (IIIc), 1-ethyl-3-(p-chlorobenzoyl)-4-(p-chlorophenyl)-4-piperidinol hydrochloride (IIId), 1-ethyl-4-(2-thienyl)-3-(2-thienylcarbonyl)-4-piperidinol hydrochloride (IIIe); and some representative quaternary piperidinols: 3-benzoyl-1-ethyl-4-hydroxy-1-methyl-4-phenylpiperidinium iodide (IIIf), 1-ethyl-4-hydroxy-1-methyl-3-(p-methylbenzoyl)-4-(p-methylphenyl)piperidinium iodide (IIIg). Toxicity was tested by the brine shrimp bioassay as an intermediate test before further in vivo animal experiments. Piperidine derivatives were found to be more potent than bis Mannich bases. Quaternary piperidine derivatives IIIf and IIIg and also non-quaternary piperidine derivatives IIIb, IIIe, IIIc and IIId were more toxic than 5-fluorouracil in brine shrimp bioassay. Except for IIe, bis Mannich bases were not effective. Quaternization and conversion of bis Mannich bases to corresponding piperidines improved the toxicity. The lipid solubility of the compounds may not affect the toxicity. From these findings the quaternary piperidine derivatives IIIf and IIIg could be used in further drug development and also for in vivo experiments.     

2-羟基-3-甲基-环戊-2-烯酮 Mannich 碱衍生物的合成及其抗癌活性

以２羟基３甲基环戊２烯酮为母体化合物设计合成了１０个双Ｍａｎｎｉｃｈ碱衍生物，４个单Ｍａｎｎｉｃｈ碱衍生物．体外细胞毒性试验和ＤＮＡ合成抑制试验结果表明：脂肪胺、杂环胺双Ｍａｎｎｉｃｈ碱活性较强，优于阳性对照药５Ｆｕ；二甲胺单Ｍａｎｎｉｃｈ碱活性较强，而芳胺类Ｍａｎｎｉｃｈ碱活性很弱，ＩＣ５０值大于５０ｍｇ／Ｌ．     

Studies on antifungal agents. 23. Novel substituted 3,5-diphenyl-3-(1H-imidazol-1-ylmethyl)- 2-alkylisoxazolidine derivatives

The synthesis and antifungal activity of a novel series of substituted 3,5-diphenyl-3-(1H-imidazol-1-ylmethyl)-2-alkylisoxazolidine derivatives (15-30) are described. The synthesis of the title compounds was accomplished via a 1,3-dipolar cycloaddition reaction of alpha-substituted ketonitrones with appropriate styrene precursors. The compounds when tested in vitro in solid agar cultures exerted a very potent antifungal activity against a wide variety of yeast and systemic mycoses and dermatophytes, especially Trichophyton and Microsporum sp., Epidermophyton floccosum and Candida stellatoidea. The in vitro activity against Aspergillus fumigatus and Candida albicans was moderate to potent. Overall, the two bis(4-chlorophenyl) analogues 18 and 19 were the most potent in vitro compounds, showing MIC values ranging between 0.2 and 7.0 microgram/mL, as compared to 0.2-20.0 micrograms/mL for ketoconazole, which was used as the positive standard in all assays. When tested in vivo in the rat vaginal candidiasis model, derivative 18, although showing significant antifungal activity when compared to controls, was less effective than ketoconazole. The title 3,5-substituted isoxazolidine compounds represent a novel class of potent antifungal agents.     

Synthesis and evaluation of anticonvulsant activities of some bis Mannich bases and corresponding piperidinols

Some acetophenone derived bis Mannich bases (B1-B5) and piperidinols (C1, C4), which are the structural isomers of B1 and B4, and also quaternary piperidine derivative C6 were synthesized and studied for anticonvulsant activity. Of the compounds, C6 was reported for the first time. Chemical structures of the compounds were confirmed by UV, IR, 1H-NMR, 13C-NMR, mass spectra and elemental analysis. Their anticonvulsant activities were determined by maximal electroshock (MES), subcutaneous metrazol (scMet) tests and rotarod test for neurological deficits. According to the activity studies, B2, B4, C1 and C4 derivatives were found to be protective against MES at 30 mg/kg and above. B1, B2, B3, B4, C4 and C6 derivatives were found to be protective against scMet. at different dose levels ranging from 30 to 300 mg/kg. Since no neurotoxicity was detected for the compounds B4 and C4, they seem to be candidate compounds for further synthesis and in vivo studies for their potential anticonvulsant activity.     

Synthesis of some Mannich bases with dimethylamine and their hydrazones and evaluation of their cytotoxicity against Jurkat cells

1-Aryl-3-dimethylamino-1-propanone hydrochlorides type mono Mannich bases, D series, and corresponding hydrazone derivatives, K series, were synthesized and their cytotoxicity was tested against Jurkat cells (transformed human T-lymphocytes). The aryl part was changed as phenyl in D1 and K1, 4-methylphenyl in D2 and K2, 4-methoxyphenyl in D3 and K3, 4-hydroxyphenyl in D4 and K4, 4-chlorophenyl in D5 and K5, 3-methoxyphenyl in D6 and K6, 4-fluorophenyl in D7 and K7, 4-bromophenyl in D8 and K8, 3-hydroxyphenyl in D9 and K9, and 2-acetylthiophene in D10 and K10. Of the compounds synthesized, K2, K3, K5, K6, K7, K8, K9, and K10 are reported for the first time. Cytotoxic activities of the D and K series were compared with each other to see alterations in bioactivity depending on the chemical structures in Jurkat cells. Cytotoxicities of the compounds synthesized were also compared with the reference compound, 5-fluorouracil (CAS 148-82-3). Mono Mannich bases, D1 (3.60 times), D2 (4.45 times), D3 (2.46 times), D4 (3.52 times), D5 (5.18 times), D6 (3.20 times), D7 (3.23 times), D8 (3.95 times), D9 (3.36 times) and D10 (3.99 times) had 2.46-5.18 times higher cytotoxic potency than the reference compound 5-fluorouracil against Jurkat cells, while hydrazones K1 (4.92 times), K2 (4.65 times), K3 (6.04 times), K4 (6.34 times), K5 (4.67 times), K6 (5.12 times), K7 (5.39 times), K8 (8.31 times), K9 (4.65 times) and K10 (8.65 times) had 4.65-8.65 times higher cytotoxic potency than the reference compound 5-fluorouracil against the same cell line. On the other hand, hydrazone compounds K1 (1.37 times), K3 (2.46 times), K4 (1.80 times), K6 (1.60 times), K7 (1.67 times), K8 (2.11 times), K9 (1.38 times), and K10 (2.17 times) had 1.37-2.46 times higher cytotoxic potency than their corresponding mono Mannich bases. The results of this study suggest that hydrazones were better compounds compared with the corresponding mono Mannich bases in terms of cytotoxicity, and they may serve as model compounds to develop new cytotoxic agents for further studies.     

Synthesis of novel biologically active methylene derivatives of sydnones

A series of mono and bis N-Mannich bases incorporating 3-(4-methylphenyl)-4-(substituted-1/4-ylmethyl)sydnone scaffolds were synthesized and tested for their antibacterial, antifungal, anticancer, and antiviral activities. Most of the compounds showed moderate-to-significant antibacterial and antifungal activities. The compounds did not show selective activity against HIV. Some of the compounds have been evaluated for anticancer activity, but they were found as poorly active. The structures of the synthesized compounds were elucidated by IR and NMR spectroscopy.     

Synthetic acetylenic antifungal agents.

Several monoamino bis(propynyloxy)benzenes were prepared by a Mannich reaction and tested for antifungal activity against Trichophyton schoenleini, T. mentagraphytes, T. tonsurans, Candida albicans, and Epidermophyton flocossum. In addition, the bis(propynyloxy)benzene intermediates were tested and comparisons were made with standing drugs. The intermediates were found to be the most active, although two Mannich bases possessed considerable activity.     

1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物的合成及抗真菌活性

根据氮唑类抗真菌化合物的构效关系和作用机理,设计合成了29个1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物,其中九个为首次报道。初步体外抑菌试验结果表明,大多数目标化合物对八种试验菌株都有不同程度的抗真菌活性。化合物14对白念珠菌的活性与克霉唑及益康唑相当,对其它七种试验菌株的活性明显强于克霉唑及益康唑。化合物4,12对白念珠菌活性差,对其它七种试验菌株的活性也强于克霉唑和益康唑。化合物5,6和23除对白念珠菌外,对其它七种试验菌株,也有较强活性。     

1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物的合成及抗真菌活性

根据氮唑类抗真菌化合物的构效关系和作用机理,设计合成了29个1-{2-[(4-取代苯基)甲氧基]-2-(取代苯基)乙基}-1H-氮唑类化合物,其中九个为首次报道。初步体外抑菌试验结果表明,大多数目标化合物对八种试验菌株都有不同程度的抗真菌活性。化合物14对白念珠菌的活性与克霉唑及益康唑相当,对其它七种试验菌株的活性明显强于克霉唑及益康唑。化合物4,12对白念珠菌活性差,对其它七种试验菌株的活性也强于克霉唑和益康唑。化合物5,6和23除对白念珠菌外,对其它七种试验菌株,也有较强活性。     

硫色满酮3位Mannich碱衍生物的合成及其抗真菌活性

目的 设计、合成硫色满酮3位Mannich碱类化合物，并对其抗真菌活性进行初步评价。方法 以对氟苯硫酚为原料，经多步反应合成目标化合物，并测定目标化合物的抗真菌活性。结果共合成了10个未见文献报道的新化合物，经红外光谱、核磁共振氟谱及元素分析确证了其结构。其中化合物3对大部分供试真菌活性强于或相当于对照品克霉唑。结论 硫色满目3位取代Mannich碱具有较强的抗真菌活性。     

Synthesis and antifungal activity of new derivatives of 5-(4-halobenzoyl)-4-amino-3-(2-dialkylaminoethylthio)thieno [2,3-c] and [3,2-d] isothiazole

A new series of 5-(4-halobenzoyl)-4-amino-3-(2-dialkylamino-ethylthio)thieno [2,3-c] and [3,2-d] isothiazole derivatives has been synthetized. The compounds were evaluated for antifungal activity on yeast and dermatophytes. The compound (VI b) resulted about thirty times less potent than miconazole on dermatophytes.     

4-色满酮Mannich碱类化合物的合成及其抗炎活性

目的设计合成一些4-色满酮Mannich类化合物,并且考察其抗炎活性.方法以取代的4-色满酮为原料,经过Mannich反应合成4-色满酮Mannich碱类化合物,并测定了目标化合物的抗炎活性.结果合成了17种4-色满酮Mannich碱类化合物,并经元素分析、红外光谱、核磁共振氢谱确证这些化合物的结构,药理活性筛选结果表明:大多数化合物具有显著的抗炎活性.     

N-quaternary derivatives of tilorone

Tilorone (free base) reacts with alkyl halides forming quaternary ammonium salts. Bis- as well as mono quaternary compounds (2 resp. 3) were synthesized. The tilorone-bis-methoiodide (2a) was converted to several carbonyl derivatives (4 and 5). All produced compounds did not show any cytostatic activity against the murine leukemias L 1210 and P 388 in vivo. Especially the bis-quaternary derivatives 2 were highly toxic in the mouse.