1-cinnamyl-4-(2-methoxyphenyl)piperazines: synthesis, binding properties, and docking to dopamine (D(2)) and serotonin (5-HT(1A)) receptors

Clinical properties of atypical antipsychotics are based on their interaction with D(2) dopamine receptor and serotonin 5-HT(1A) and 5-HT(2A) receptors. As a part of our research program on new antipsychotics, we synthesized various derivatives of 1-cinnamyl-4-(2-methoxyphenyl)piperazines, and evaluated their affinities for D(2), 5-HT(1A), 5-HT(2A), and adrenergic (alpha(1)) receptors using radioligand-binding assays. In addition, we performed docking analysis using models for the D(2) and 5-HT(1A) receptors. All compounds exhibited low to moderate affinity to 5-HT(1A) and 5-HT(2A) receptors, high affinity to the D(2 )receptor and large variability in affinities for the alpha(1) receptor. Docking analysis indicated that the binding to D(2) and 5-HT(1A) receptors is based on (i) interaction between protonated N1 of the piperazine ring and various aspartate residues, (ii) hydrogen bonds between various moieties of the ligand and the residues of threonine, serine, histidine or tryptophane, and (iii) edge-to-face interactions of the aromatic ring of the arylpiperazine moiety with phenylalanine or tyrosine residues. Docking data for the D(2) receptor can account for the binding properties obtained in binding assays, suggesting that the model is reliable and robust. However, docking data for the 5-HT(1A) receptor cannot account for actual binding properties, suggesting that further refinement of the model is required.     

A Search for New 5-HT1A/5-HT2A Receptor Ligands. In Vitro and in vivo Studies of 1-[ω-(4-Aryl-1-piperazinyl)alkyl]indolin-2(1H)-ones

A series of 1-[ω-(4-aryl-1-piperazinyl)alkyl]indolin-2(1H)-one derivatives 2–14 was synthesized in order to obtain ligands with a dual 5-HT_1A/5-HT_2A activity. The majority of those compounds ( 2–5, 7, 10–13 ) exhibited a high 5-HT_1A (K_i = 2 – 44 nM) and/or 5-HT_2A affinity (K_i = 51 and 39 for 5 and 7 , respectively). Induction of lower lip retraction (LLR) and behavioral syndrome and inhibition of these efects evoked by 8-hydroxy-2-(di-n-propyl-amino)tetralin (8-OH-DPAT) were used for determination the agonistic and antagonistic activity, respectively, at 5-HT_1A receptors. The 5-HT_2A antagonistic activity was assessed by the blocking effect on the head twitches induced by (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) in mice. Two of the tested compounds, 1-{3-[4-(3-chlorophenyl)-1-piperazinyl]propyl}-6-fluoroindolin-2(1H)-one ( 5 ) and 1-{3-[4-(2-methoxyphenyl)-1-piperazinyl]propyl}indolin-2(1H)-one ( 7 ), demonstrated a high 5-HT_1A/5-HT_2A affinity and an in vivo antagonistic activity towards both receptor subtypes.     

Synthesis and 5-HT2A radioligand receptor binding assays of DOMCl and DOMOM,two novel 5-HT2A receptor ligands

A synthesis of two new active substances, DOMCl (1-(4-chloromethyl-2, 5-dimethoxyphenyl)-2-propanamine; 2) and DOMOM (1-(2, 5-dimethoxy-4-methoxymethylphenyl)-2-propanamine; 3), was developed. Unexpectedly, the Blanc reaction permitted successful synthesis of 2, 5-dimethoxyphenylpropylamine derivatives having a substituted methyl group in position 4 since solvation of the reactant occurs during the reaction. Afterwards, their affinities towards the 5-HT(2A) receptor were examined in 5-HT(2A) radioligand receptor binding assays. The study of these substances is of considerable interest because they were predicted, by preliminary molecular modeling studies based on mescalin units, to be potential new hallucinogens that should be added to the list of substances prohibited by law. It was assumed that DOMCl would be 82 times more potent as a hallucinogen than mescalin, and DOMOM would be 94 times more potent. The 5-HT(2A) radioligand receptor binding studies showed that the affinities of DOMCl and DOMOM for the 5-HT(2A) receptor are less than expected but are nevertheless 1.6 and 8.7 times higher, respectively, than that of mescalin. Therefore, scheduling these substances as potential drugs of abuse might be considered.     

D2 dopaminergic and 5-HT1A serotonergic activity of 2-(1-naphthyl)ethyl- and 2-(2-naphthyl)ethyl amines

Several tertiary 2-phenylethyl, 2-(1-naphthyl)ethyl and 2-(2-naphthyl)ethyl amines were synthesized and their binding affinities for dopamine D(1), D(2) and serotonin 5-HT(1A) receptors evaluated in radioligand binding assays. All compounds were inactive in D(1) dopamine radioligand binding assay. The 2-(1-naphthyl)ethyl analogues expressed a low but significant binding affinity for the D(2) and moderate one for the 5-HT(1A) receptor subtypes. Most of the remaining compounds expressed binding affinity at the 5-HT(1A) receptor subtype but were inactive in D(2) receptor binding assay. Based on these results and considering the chemical characteristics of the compounds synthesized and evaluated for dopaminergic and serotonergic activity throughout the present study it can be concluded that hydrophobic type of interaction (stacking or edge-to-face) plays a significant role in the formation of receptor-ligand complexes of 2-(1-naphthyl)ethyl amines. This structural motive can be applied to design and synthesize new, more potent dopaminergic/serotonergic ligands by slight chemical modifications.     

Conformational restriction in novel NAN-190 and MP3022 analogs and their 5-HT(1A) receptor activity

The newly synthesized analogs of NAN-190 containing m-Cl and m-CF(3) substituents in the arylpiperazine moiety and their conformationally restricted counterparts showed a very high 5-HT(1A )receptor affinity. In the LLR test, the flexible compounds 4a and 5a displayed features of a partial agonist and agonist, respectively. The conformational restriction in the tested structures caused alternations in the observed in vivo effects; compounds 4b and 5b were classified as an inactive agent and an antagonist of postsynaptic 5-HT(1A )receptors, respectively. Rigidification of MP3022 and its 5,6-dimethyl analog structures resulted in cis and trans stereoisomers 6b-9b with a 1- and 2-substituted benzotriazole moiety. In both series, in vitro experiments showed that the cis configurations of the compounds were better tolerated by 5-HT(1A) receptor sites than the trans ones. The conformational analysis revealed various spatial regions that can be explored by terminal benzotriazole fragments in those structures. Like the previously described cis-6b, the new ligand cis-7b, displayed features of a postsynaptic 5-HT(1A) receptor agonist, whereas cis-8b was characterized as a partial agonist of those receptor sites. It was suggested that the nonlinear geometry of the above agents has significant influence on the postsynaptic 5-HT(1A )receptor stimulation.     

2, 3-Bis(5-alkyl-2-thiono-1, 3, 5-thiadiazin-3-yl) propionic acid: one-pot domino synthesis and antimicrobial activity

In a search for promising antibacterial and antifungal compounds, two new series of 2, 3-bis(5-alkyl-2-thiono-1, 3, 5-thiadiazin-3-yl)propionic acid 1 and their corresponding N, N-dimethylpropionamide 6 have been synthesized. The reaction of 2, 3-diaminopropionate 3, carbon disulfide, formaldehyde, and the appropriate alkyl amines furnished the title compound 1. N, N-dimethylpropionamides 6 were obtained by the reaction of 1 with dimethyl amine in the presence of POCl(3). The newly prepared compounds were screened in vitro against certain strains of Gram-positive and Gram-negative bacteria and compared with nalidixic acid and ciprofloxacin. Moreover, the title compounds were tested for their antifungal activity in vitro against Candida albicans, phytopathogenic, Penicillum expansum and Trichoderma hazianum, and aflatoxin-producing Aspergillus flavus. These compounds exhibit varied activity against the tested pathogenic bacteria and remarkable inhibitory effects on growth or sporulation of some of the tested fungal species.     

Pharmacological evaluation of halogenated and non-halogenated arylpiperazin-1-yl-ethyl-benzimidazoles as D(2) and 5-HT(2A) receptor ligands

Five groups of previously synthesized and initially screened non-substituted and 4-halogenated arylpiperazin-1-yl-ethyl-benzimidazoles were estimated for their in-vitro binding affinities at the rat D(2) , 5-HT(2A) , and α(1) -adrenergic receptors. Among all these compounds, 2-methoxyphenyl and 2-chlorophenyl piperazines demonstrate the highest affinities for the tested receptors. The effects of 4-halogenation of benzimidazoles reveal that substitution with bromine may greatly increase the affinity of the compounds for the studied receptors, while the effect of substitution with chlorine is less remarkable. Most of the tested components show 5-HT(2A)/D(2) pK(i) binding ratios slightly above or less than 1, while only 4-chloro-6-(2-{4-[3-(trifluoromethyl)phenyl]piperazin-1-yl}ethyl)-1H-benzimidazole expresses an appropriate higher binding ratio (1.14), which was indicated for atypical neuroleptics. This compound exhibits a non-cataleptic action in rats and prevents d-amphetamine-induced hyperlocomotion in mice, which suggest its atypical antipsychotic potency.     

5-HT1A和5-HT2A/2C受体在粉防己碱增强戊巴比妥钠睡眠中的介导作用

前期研究表明粉防己碱增强戊巴比妥钠诱导的催眠作用与5-HT系统相关。本研究采用戊巴比妥钠（45 mg/kg,i.p.）诱导的小鼠翻正反射消失和恢复实验方法,对粉防己碱与不同5-HT受体在增强戊巴比妥钠诱导睡眠中的相互作用进行了探讨。结果表明粉防己碱分别与选择性5-HT1A受体拈抗剂p-MPPI（1 mg/kg,i.p.）,选择性5-HT2A/2C受体拮抗剂ketanserin（1.5 mg/kg,i.p.）合用可以显著增强戊巴比妥钠诱导的催眠作用。选择性5-HT1A受体激动剂8-OH-DPAT（0.1 mg/kg,s.c.）或5-HT2A/2C受体激动剂DOI（0.2mg/kg,i.p.）能够显著减少戊巴比妥钠诱导的小鼠睡眠时间,而粉防己碱（60 mg/kg,i.g.）可以显著拮抗这种睡眠抑制作用。此结果提示,粉防己碱增强戊巴比妥钠诱导的催眠作用可能与5-HT1A受体和5-HT2A/2C受体有关。     

Synthesis and in vitro antimicrobial evaluation of 5-(1-methyl-5-nitro-2-imidazolyl)-4H-1,2,4-triazoles

The increasing clinical importance of drug-resistant pathogens has lent additional urgency to antimicrobial research. Various 5-(1-methyl-5-nitro-2-imidazolyl)-4H-1,2,4-triazoles (4a-6f) were synthesized and tested in vitro for their antibacterial and antifungal activities. Compounds 4a and 4b exhibited significant effects against Bacillus subtilis at MIC ranges of 0.5-1 microg/mL and moderate effects against Staphylococcus aureus.     

Comparison of antidepressant activity in 4- and 40-week-old male mice in the forced swimming test: involvement of 5-HT1A and 5-HT1B receptors in old mice

RATIONALE: A recent study suggested that selective serotonin reuptake inhibitors were inactive in 40-week-old male mice in the mouse forced swimming test, possibly because of alteration of 5-HT1 receptors. OBJECTIVES: The present study was aimed at investigating the action of various antidepressant drugs in 4- and 40-week-old male mice using the mouse forced swimming test and determining the involvement of 5-HT1A and 5-HT1B receptors mediating the effects. METHODS: Different classes of antidepressants [imipramine (tricyclic), maprotiline (noradrenline reuptake inhibitor), venlafaxine (mixed serotonin and noradrenaline reuptake inhibitors), fluvoxamine and sertraline (selective serotonin reuptake inhibitor)] were tested in the same randomised experimental session, alone and in combination with 5-HT1A and 5-HT1B receptor agonists [buspirone (partial 5-HT1A agonist), anpirtoline (5-HT1B agonist)] in the mouse forced swimming test. RESULTS: All antidepressants were found to be active in the mouse forced swimming test in 4-week-old mice and 40-week-old mice, with the exception of fluvoxamine in the 40-week-old mice. The anti-immobility effect after antidepressant administration was higher in 4-week-old male mice than in 40-week-old male mice. Venlafaxine is the most active antidepressant drug in 40-week-old mice. Prior administration of buspirone (0.06 mg/kg, i.p.) or anpirtoline (1 mg/kg, i.p.) enhanced the antidepressant-like effects in 4-week-old mice (except in the case of sertraline, 8 mg/kg). In elderly mice, only prior administration of buspirone enhanced the antidepressant-like effects of fluvoxamine. A neurochemical study showed that significantly higher serotonin and dopamine concentrations were found in 40-week-old control mice brains than 4-week-old control mice brains but that the noradrenaline concentration is higher in 4-week-old mice. CONCLUSION: Tricyclic, noradrenaline reuptake inhibitors and serotonin reuptake inhibitors are more active in 4-week-old mice than 40-week-old mice. Our results suggested that 5-HT1B receptors may be more altered than 5-HT1A receptors in 40-week-old mice.     

Mixed Dopaminergic/Serotonergic Properties of Several 2-Substituted 4-[2-(5-Benzimidazole)ethyl]-1-arylpiperazines

A series of substituted 4-[2-(5-benzimidazole)ethyl]-arylpiperazines was synthesized by introducing different substituents into position 2 of benzimidazole ring of 4-[2-(N,N-di-n-propyl-amino)ethyl]-1,2-diaminobenzenes. They were evaluated for in vitro binding affinity at the D₁ and D₂ dopamine and 5-HT_1A serotonin receptors using synaptosomal membranes of the bovine caudate nuclei and hippocampi, respectively. Tritiated SCH 23390 (D₁ receptor-selective), spiperone (D₂ receptor selective) and 8-OH-DPAT (5-HAT_1A receptor selective) were employed as the radioligands. Only compound 6 expressed a moderate binding affinity at the dopamine D₁ receptor, while the remaining ligands were inefficient or weak competitors of [³H]SCH 23390. Compound 12 was an absolutely inactive competitor of all three radioligands. Also, compound 7 was an inefficient displacer of [³H]-8-OH-DPAT. Compound 19 with a K_i value of 3.5 nM was the most potent competitor of [³H]spiperone and compound 13 (K_i = 3.3 nM) was the most efficient in displacing [³H]-8-OH-DPAT from the 5-HAT_1A serotonin receptor. Ligands 5, 6, 8–11 , and 13–20 expressed mixed dopaminergic/serotonergic activity in nanomolar range of concentrations with varying affinity ratios which strongly depended on the properties of the substituents introduced into position 2 of benzimidazole ring of the parent compounds.     

3-(ω-Aminoalkyl)-5,5-dialkyl(or spirocycloalkyl-1′,5-)hydantoins as New 5-HT1A and 5-HT2A Receptor Ligands

A series of new 3-(ω-aminoalkyl)-5,5-disubstituted hydantoins, containing 1-phenylpiperazine, 1-(o-methoxyphenyl)piperazine or 1,2,3,4-tetrahydroisoquinoline fragments, were synthesized by standard alkylation procedures and their 5-HT_1A and 5-HT_2A receptor affinities were determined. It has been shown that the investigated derivatives are recognized by 5-HT_1A and 5-HT_2A receptors due to the presence of a 1-arylpiperazine fragment; however, the terminal hydantoin moiety plays an important role in stabilization of the receptor-ligand complex. It has also been found that the two 1-phenylpiperazine derivatives 32 and 36 are new, selective 5-HT_2A receptor ligands (K_i = 34 and 37 nM, respectively), whereas the derivative of 1-(o-methoxyphenyl)piperazine ( 38 ) is a new, highly potent 5-HT_1A receptor ligand (K_i = 0.51 nM) with a moderate affinity for 5-HT_2A receptors (K_i = 213 nM).     

WAY 405, a new silent 5-HT (1A) receptor antagonist with low affinity for vascular alpha (1)-adrenoceptors

1 The effect of WAY 405 ((R)-N-(2-methyl-(4-indolyl-1-piperazinyl)ethyl)-N-(2-pyridinyl) cyclohexane carboxamide), a putative 5-HT(1A) receptor antagonist, on cardiovascular function was studied. 2 In anaesthetized rats, the i.v. injection of WAY 405 did not significantly modify basal heart rate nor blood pressure at doses of 1, 3, 10 and 30 microg kg(-1); while the antagonist dose dependently antagonized the 5-HT(1A) receptor agonist, 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin)-induced hypotension and bradycardia. 3 WAY 405 antagonized noradrenaline-induced contraction in isolated arteries, with pK(B) values of 6.6+/-0.1, 6.5+/-0.1 and 6.5+/-0.1, for rat tail artery (alpha(1A)-adrenoceptors), rabbit aorta (alpha(1B)-adrenoceptors), and rat aorta (alpha(1D)-adrenoceptors) respectively. 4 The results show that in the control of blood pressure the new compound, WAY 405, behaves as a silent 5-HT(1A) receptor antagonist in the anaesthetized rat, also having low affinity for vascular alpha(1)-adrenoceptors.     

N-(双膦羧次甲基)-6-(5-氟-2,4-二氧代-3,4-二氢-2H-嘧啶-1-基)-6-氧代-己酰胺的合成及其初步的骨靶向性研究

目的合成N-（双膦羧次甲基）-6（5-氟-2，4-二氧代3，4-二氢-2H-嘧啶-1-基）-6-氧代-己酰胺，并进行初步体外骨靶向性实验。方法以5-氟尿嘧啶为原料，经硅烷化、缩合、氢解3步合成6-（5-氟-2，4-二氧代-3，4-二氢-2H-嘧啶-1-基）-6-氧代-己酸（2），用二氯亚砜氯化后再与含氨基的偕二膦酸酯偶联，最后再用溴代三甲基硅烷特异性解离掉膦酸酯得到目标化合物L，并采用羟磷灰石晶体吸附实验考察目标物的骨靶向性。结果合成了目标物L，并利用^-1H—NMR、IR和MS进行了结构确证。结论体外骨靶向性实验结果显示目标物L有较好的骨靶向性。     

Invesgations [correction investigations] on the influence of halide substituents on the estrogen receptor interaction of 2, 4, 5-tris(4-hydroxyphenyl)imidazoles

Previously, we reported on the synthesis and estrogen receptor (ER) interaction of imidazoles, which had to be 1-alkyl-4, 5-bis(2-halo-4-hydroxyphenyl) substituted for a high relative binding affinity (RBA >1 %). This led to the assumption that a shielding of the polar heterocyclic system is a prerequisite for ER binding. In continuation of this study we synthesized 2, 4, 5-tris(4-hydroxyphenyl)imidazoles with Cl-or F-atoms in the ortho-positions of the aromatic rings and evaluated whether they mediate sufficient hydrophobicity for ER interaction. 2-(2, 6-Dichloro-3/4-hydroxyphenyl)-4, 5-bis(2-halo-4-hydroxyphenyl)imidazoles were synthesized by reaction of the respective methoxy-substituted benzil with either the 2, 6-dichloro-4-methoxy-or the 2, 6-dichloro-3-methoxybenzaldehyde in ammonium acetate solution. The required ether cleavage was performed subsequently with BBr(3). In the competition experiment with [(3)H]estradiol the imidazoles with the a C2-standing (2, 6-dichloro-4-hydroxyphenyl) ring showed an RBA >0.02 %, but did not activate the luciferase gene in estrogen receptor positive MCF-7-2a breast cancer cells stably transfected with the plasmid ERE(wtc)luc. In the test for antagonistic potency only the 2-(2, 6-dichloro-4-hydroxyphenyl)-4, 5-bis(4-hydroxyphenyl)imidazole 3 antagonized the effects of 1 nM estradiol slightly. From these data, it can be concluded that a C2-standing 2, 6-dichloro-4-hydroxyphenyl ring is not appropriate to optimize the ER interaction of 4, 5-(4-hydroxyphenyl)imidazoles.     

Structure/activity investigations of 5-substituted 3-methylisoxazole[5, 4-d]1, 2, 3-triazin-4-one derivatives

The series of 5-substituted 3-methylisoxazole[5, 4-d]1, 2, 3-triazin-4-one derivatives was obtained by diazotization of 5-amino-3-methylisoxazol-4-carboxylic acid hydrazide. The immunological activity of these compounds was investigated experimentally in several in vitro and in vivo assays in mice and human models. In the next step, quantum-chemical investigations were performed using density functional theory with the B3LYP hybrid exchange-correlation energy functional and 6-31G(d, p) basis set. The Polarizable Continuum (SCRF/PCM) solvent model was also taken into account in order to show solvent influence on electron density and electrostatic potential around the exemplary molecules. Correlations between molecular structure and biological properties were found using a stepwise selection of scales for the multiple linear regression (MLR).     

2-Amino-3-cyano-4-(5-arylisoxazol-3-yl)-4H-chromenes: synthesis and in vitro cytotoxic activity

A new series of 4-aryl-4H-chromenes bearing a 5-arylisoxazol-3-yl moiety at the C-4 position were prepared as potential anticancer agents. The in vitro cytotoxic activity of the synthesized compounds was investigated against a panel of tumor cell lines including MCF-7 (breast cancer), KB (nasopharyngeal epidermoid carcinoma), Hep-G2 (liver carcinoma), MDA-MB-231 (breast cancer), and SKNMC (human neuroblastoma) using the MTT colorimetric assay. Doxorubicin, a well-known anticancer drug, was used as positive standard drug. Among the synthesized compounds, the 5-(3-methylphenyl)isoxazol-3-yl analog (7j) showed the most potent cytotoxic activity against all five human tumor cell lines.     

Synthesis and in vitro antibacterial evaluation of novel imidazo[2',1':5,1]-1,2,4-triazolo[4,3-c]-quinazoline derivatives of 5-thioxo-1, 2, 4-triazole, 4-oxothiazolidine, and their open-chain counterparts

Two novel series of imidazo[2', 1':5, 1]-1, 2, 4-triazolo[4, 3-c]quinazolines bearing 5-thioxo-1, 2, 4-triazoles, 6a-f, and 4-oxothiazolidines, 7a-f, were synthesized from corresponding thiosemicarbazide derivatives, 5a-f. The stepwise methodology applied to the preparation of compounds 5a-f was initiated with reaction of the parent 3-amino-1, 2, 4-triazolo[4, 3-c]quinazolines, 2, with ethyl 2-chloroacetoacetate resulting in annelation of the imidazole ring to give esters, 3a-c. However, hydrazinolysis of these ester derivatives gave the corresponding acid hydrazides, 4a-c, which on reaction with the appropriate alkyl isothiocyanate yielded compounds 5a-f. In turn, compounds 5, were cyclized with potassium hydroxide or with ethyl bromoacetate to give the corresponding thioxotriazoles 6 and oxothiazolidines 7, respectively. All synthesized compounds were screened for their in vitro antibacterial activity against various Gram-positive and Gram-negative bacteria. Some test compounds were found to possess potent antibacterial activities. Compound, 7f, exhibited much higher potency than the reference standard ciprofloxacin, against both types of bacteria, particularly, Gram-positive organisms.     

6-(1-溴乙基)-4-氯-5-氟嘧啶合成新方法

以氟乙酸乙酯为起始原料,改进抗真菌药物伏立康唑中间体6-(1-溴乙基)-4-氯-5-氟嘧啶的合成方法.该方法简化了生产工艺,降低了反应成本,反应条件温和,适合工业化生产,总收率为41.7%.     

New amides of 5-(4-chlorobenzoyl)aminoorotic acid: their synthesis and biological activity

The synthesis and in-vitro biological evaluation of the amide series 4 of 5-(4-chlorobenzoyl)aminoorotic acid 2 are presented. The biological properties of a few 5-(4-chlorobenzoyl)amino-2,6-dihydroxy-N-substituted-4-pyrimidinecarboxamide derivatives 4 tested here were compared with those of the isosteric isothiazole derivative MR-2/94 (5-(4-chlorobenzoyl)amino-N-(4-chlorophenyl)-3-methyl-4-isothiazolecarboxamide), which possesses a strong immunosuppressive and anti-inflammatory activity [1, 2], It must be suggested that replacement of the isothiazole by a pyrimidine core ring system resulted in considerable lowering of the anti-inflammatory and immunotropic actions of the obtained amides. Physicochemical properties of 2-(4-chlorophenyl)-6,8-dihydroxy-4H-pyrimido[5,4-d]-1,3-oxazin-4-on 3 are also briefly described.