5-substituted 3,4-dihydro-3-amino-2H-1-benzopyran derivatives: synthesis and interaction with serotoninergic receptors

A new series of 3,4-dihydro-3-amino-2H-1-benzopyran derivatives (1 and 2) bearing various substituents on the 5-position was successfully prepared via palladium-mediated cross-coupling reactions. Some of the new compounds showed high affinity for 5-HT1A and 5-HT7 receptors. The best affinity for the 5-HT1A and 5-HT7 receptors was obtained for 2b (Ki = 0.3 nM for 5-HT1A and 3.1 nM for 5-HT7). The anxiolytic activity of compound 2b was evaluated.     

2H-1-苯并吡喃衍生物的合成及其体外抗癌活性的初步评价

目的设计并合成2H-1-苯并吡喃衍生物化合库并对其体外抗癌活性进行评价。方法以2＇-羟基查耳酮为原料通过微波促进合成得到黄酮衍生物中间体，此中间体与POCl，反应得到4-氯-2H-色原烯-3-醛，通过微波辅助液相平行合成的方法，此醛与ROCONHNH2反应得到2H-1-苯并吡喃衍生物化合库。利用HL-60细胞系评价该化合物库的体外抗癌活性。结果与结论合成了含有32个化合物的2H-1-苯并吡喃衍生物库，体外活性评价表明。部分化合物对HL-60细胞的增殖有一定的抑制作用，其中。化合物9e在浓度为30μmol·L^-1的抑制率为70．8％。     

Synthesis and antihypertensive activity of substituted trans-4-amino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-ols

A series of novel substituted trans-4-amino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-ols was prepared and tested for antihypertensive activity in the conscious deoxycorticosterone acetate (DOCA)/saline treated hypertensive rat. Optimum blood pressure lowering activity requires 6-substitution by a strong electron-withdrawing group, together with a pyrrolidino or piperidino group at the 4 position. Exceptions to this were the 7-nitro-4-pyrrolidine analogue and the 6-nitro-3-chloropropylamine, which retained marked antihypertensive activity. All of these compounds were direct vasodilators and had comparable antihypertensive activity to hydralazine and to the calcium antagonist, nifedipine. The synthetic route to these compounds involves cyclization of of propargyl ethers to 2H-1-benzopyrans, followed by conversion via bromohydrins to 3,4-epoxides, which were ring opened with the appropriate amines. Meta-substituted propargyl ethers gave both 5- and 7-substituted benzopyrans on thermal cyclization, the former predominating. A new route to 2,2-dimethyl-7-nitrobenzopyran is described.     

Synthesis and antidepressant properties of novel 2-substituted 4,5-dihydro-1H-imidazole derivatives

A unique combination of alpha 2-adrenoreceptor antagonist and serotonin-selective reuptake inhibitory activities has been identified in a series of 2-substituted 4,5-dihydro-1H-imidazole derivatives. This combination of blocking activities has provided one of these derivatives, napamezole hydrochloride (2), with potential as an antidepressant. A discussion of the syntheses of these compounds includes a convenient method for the conversion of nitriles to imidazolines with ethylenediamine and trimethylaluminum.     

Synthesis and antihypertensive activity of 6,7-disubstituted trans-4-amino-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-ols

A series of novel 6,7-disubstituted trans-3,4-dihydro-2, 2-dimethyl-4-pyrrolidino-(or piperidino)-2H-1-benzopyran-3-ols was prepared and tested for antihypertensive activity in the conscious spontaneously hypertensive rat (SHR) and compared with certain of their monosubstituted analogues. The potent blood pressure lowering activity of the 6-monosubstituted compounds was enhanced by incorporation of an acetylamino or amino group at C(7) and that of the 7-nitro-substituted compound by incorporation of an amino (but not an acetylamino group) at C(6). The combination of 6-nitro or 6-cyano with 7-(acetylamino) or 7-amino groups and 6-amino with 7-nitro groups in trans-4-pyrrolidino- or -4-piperidino-2,2-dimethyl-2H-1-benzopyranols conferred superior antihypertensive activity to hydralazine and to the calcium antagonist, nifedipine, in SHR. The synthetic route to these compounds involves the conversion of 2H-1-benzopyrans to bromohydrins that were treated with pyrrolidine or piperidine. Preparation of the 6-cyano-7-amino analogue was accomplished when 6-cyano-7-[(trifluoroacetyl)amino]-2,2-dimethylbenzopyran was used as starting material.     

2-氨基-5-溴-4-取代嘧啶类化合物的合成

目的合成2-氨基-5-溴-4-取代嘧啶类化合物。方法溴素在冰醋酸中溴化2-氨基-4-甲基嘧啶,得到2-氨基-5-溴-4-溴甲基嘧啶以及其他不同溴化程度的中间体,再以2-氨基-5-溴-4-溴甲基嘧啶为底物进行衍生得到一系列2-氨基-5-溴-4-取代嘧啶类化合物。结果与结论目标化合物的结构经1H-NMR、13C-NMR以及GC-MS确证。合成得到的12个化合物中有9个是未见报道的新化合物。     

Arylpiperazine derivatives of 3-propyl-beta-tetralonohydantoin as new 5-HT1A and 5-HT2A receptor ligands

A series of new analogues of 3-[3-(4-arylpiperazinyl)-propyl]-cyclo-hexane-1',5-spirohydantoin (2), with aromatic ring fused in amide moiety (4-9) were synthesized and evaluated for affinity at 5-HTIA and 5-HT2A receptors. The influence of the substitution mode in the phenyl ring of phenylpiperazine moiety on the affinity for both receptors has been discussed. The most potent 5-HTIA (9, Ki = 53 nM) and 5-HT2A (4, 6, 8 and 9; Ki = 14-76 nM) ligands were evaluated in in vivo tests. The obtained results indicate that all in vivo tested compounds showed pharmacological profile of 5-HT2A antagonists. Additionally, a m-CF3 derivative (9), behaved like a partial agonist (agonist of pre- and antagonist of postsynaptic) of 5-HTIA receptors and may offer a new lead for the development of potential psychotropic agents.     

Synthesis and biological evaluation of new 2-(4,5-dihydro-1H-imidazol-2-yl)-3,4-dihydro-2H-1,4-benzoxazine derivatives

2-(4,5-Dihydro-1H-imidazol-2-yl)-3,4-dihydro-2H-1,4-benzoxazine derivatives and tricyclic analogues with a fused additional ring on the nitrogen atom of the benzoxazine moiety have been prepared and evaluated for their cardiovascular effects as potential antihypertensive agents. The imidazoline ring was generated by reaction of the corresponding ethyl ester with ethylenediamine. Affinities for imidazoline binding sites (IBS) I(1) and I(2) and alpha(1) and alpha(2) adrenergic receptors were evaluated as well as the effects on mean arterial blood pressure (MAP) and heart rate (HR) of spontaneously hypertensive rats. With few exceptions the most active compounds on MAP were those with high affinities for IBS and alpha(2) receptor. Among these, compound 4h was the most interesting and is now, together with its enantiomers, under complementary pharmacological evaluation.     

Synthesis and bioevaluation of Schiff and Mannich bases of isatin derivatives with 4-amino-5-benzyl-2,4-dihydro-3H-1,2,4-triazole-3-thione

Isatin (2,3-dioxindole) and its derivatives show a wide range of biological activities. In the present study, a series of Schiff and Mannich bases of isatin derivatives were prepared using 4-amino-5-benzyl-2,4-dihydro-3H-1,2,4-triazole-3-thione. The structures of these derivatives were characterized by IR, ¹H NMR and elemental analysis. In vitro antimicrobial activities were evaluated by agar dilution method and the zone of inhibition values of these derivatives were compared with ciprofloxacin and fluconazole. Chloro and Bromo groups at fifth position of isatin broaden the spectrum of antibacterial activity against S. aures, P. aeruginoa, and E. coli, respectively. For the antifungal activity, the compound 6h showed equipotent activity against A. niger. The remaining majority of the compounds were found active in the biological screening. The efforts were also made to establish structure activity relationships among synthesized compounds.     

9-substituted 1,2,3,4-tetrahydro-beta-carbolin-1-ones, new 5-HT1A and 5-HT2A receptor ligands.

Three series of new 9-substituted 1,2,3,4-tetrahydro-beta-carbolin-1-ones with 2-, 3- and 4-membered alkyl chain (1, 2 and 3, respectively) were synthesized, and the effect of some structural modifications on their 5-HT1A and 5-HT2A receptor affinities and functional in vivo properties was discussed. Radioligand binding measurements showed that the majority of compounds had a distinct affinity for 5-HT1A (1b, 2a, 2b, 2c, 3b; Ki = 0.3-64 nM) and 5-HT2A receptors (1b, 2b, 2c, 3b; Ki = 0.9-80 nM). The most potent 5-HT1A (1b, 2a, 2b, 3b) and 5-HT2A (1b, 2b, 3b) ligands were evaluated in in vivo tests. The obtained results indicate that 1,2,3,4-tetrahydro-beta-carbolin-1-ones containing 1-(o-methoxyphenyl)piperazine (1-3b) show pharmacological profile of 5-HT1A postsynaptic antagonists (with very weak agonistic component) and 5-HT2A antagonists, compound with 1,2,3,4-tetrahydroisoquinoline (2a) is a pure 5-HT1A postsynaptic antagonist. Summing up, the connection of 1,2,3,4-tetrahydro-beta-carbolin-1-one moiety through the 2-4-membered alkyl spacer with 1-(o-methoxyphenyl)-piperazine, which is present in a variety of 5-HT1A ligands, allowed us to obtain the compounds with high and equal affinity for 5-HT1A/5-HT2A receptors and the expected functional properties, i.e. distinct antagonistic and weak agonistic activity at 5-HT1A postsynaptic receptors and antagonistic at 5-HT2A ones.     

Synthesis of 3-(3,4-dimethoxyphenyl)-1 H-1,2,4-triazole-5-thiol and 2-amino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazole derivatives exhibiting anti-inflammatory activity

New 1-acylderivatives of 5-alkylthio-3-(3,4-dimethoxyphenyl)-4H-1,2,4-triazole (5c-f, 6d-f) were synthesized by the acylation of 5-alkylthio-3-(3,4-dimethoxyphenyl)-4H-1,2,4-triazoles (3, 4) with acyl chlorides. The compounds 3, 4 were obtained by the alkylation of 3-(3,4-dimethoxyphenyl)-1H-1,2,4-triazole-5-thiol (2) sodium salt with alkyl iodides. Compound 2 and 2-amino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazole (8) were prepared by the treatment of 3,4-dimethoxybenzoylthiosemicarbazide (1) with sodium hydroxide or acetyl chloride (and then sodium hydroxide), respectively. Related 2-acylamino-5-(3,4-dimethoxyphenyl)-1,3,4-thiadiazoles (7c, e, f) were synthesized by the acylation of compound 8 with acyl chlorides. 3-(3,4-Dimethoxyphenyl)-4-phenyl-4,5-dihydro-1H-1,2,4-triazole-5-thione (9) was N-acylated with acyl chlorides or S-methylated with iodomethane to give 1-acyl-3-(3,4-dimethoxyphenyl)-4-phenyl-4,5-dihydro-1H- 1,2,4-triazole-5-thiones (10a, b) or 3-(3,4-dimethoxyphenyl)-5-methylthio-4-phenyl-4H-1,2,4-triazole (11) respectively. The synthesized compounds 6d, 7a, c, 10a, b, 11 exhibit anti-inflammatory activity.     

Synthesis of a new class of 2,3-dihydro-2-oxo-1H-benzimidazole-1-carboxylic acid derivatives as highly potent 5-HT3 receptor antagonists.

A series of 2,3-dihydro-2-oxo-1H-benzimidazole-1-carboxylic acid esters and amides containing a basic azacyclo- or azabicycloalkyl moiety has been synthesized and evaluated for 5-HT3 antagonistic activity in a radioligand binding assay ([3H]ICS 205930) and in the 5-HT-induced von Bezold-Jarisch reflex in the rat. It was found that endo-substituted azabicycloalkyl derivatives (e.g. 7a, 12a, 12b) were much more active than the corresponding exo analogues (e.g. 7b, 12h, 12i) or azacycloalkyl compounds. Amidic derivatives 12a, 12b, 12c, 12e, 13b, and 13c proved to be about 10 times more active than the corresponding ester derivatives 7a, 11a, 7c, 7d, 8a, and 8b. In particular, compound 12a (DA 6215) showed a Ki = 3.8 nM in the binding test and an ED50 = 1 nM/kg iv in the von Bezold-Jarisch reflex assay, an activity comparable to that of the reference compound 2 (ICS 205930, Ki = 2 nM, ED50 = 2.1 nM/kg). IR spectroscopy studies in the solid state and in CHCl3 solution revealed the existence of an intramolecular hydrogen bond in 13b, taken as a model compound for this class of substances. A molecular modeling study showed that 12a, in its internal hydrogen-bound conformation, well matches a recently proposed pharmacophoric model for 5-HT3 antagonist activity.     

Interaction of 1,2,4-substituted piperazines, new serotonin receptor ligands, with 5-HT1A and 5-HT2A receptors

In the present paper, we describe affinities to 5-HT1A and 5-HT2A receptors of several new 1,2,4-trisubstituted piperazine derivatives. The affinities were compared with those described earlier for 1,4-disubstituted piperazines and the influence of the third (methyl) substituent on the affinity to both receptors is discussed. The difference between two- and three-substituted derivatives was rationalised in terms of molecular modelling of the respective ligand-receptor complexes. Additionally, the functional activity of some 1,2,4-trisubstituted piperazines for 5-HT1A receptor was examined in behavioural and biochemical models. The obtained results have shown that some trisubstituted compounds exhibited a higher affinity to 5-HT2A receptors than their respective disubstituted analogues (with the affinity to 5-HT1A receptors remaining the same or somewhat improving). The molecular dynamics simulations suggested that the presence of the third substituent in the piperazine ring of those compounds may induce stabilising effect on the ligand-receptor complexes. The results of the in vivo studies have shown that some of the examined trisubstituted piperazines (10-13, 16, 17) exhibited properties of postsynaptic 5-HT1A partial agonists. Moreover, compounds 13 and 16 exhibited features of 5-HT1A presynaptic agonists in in vitro test, and compound 16 also in in vivo tests.     

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.     

Synthesis and dopaminergic activity of 3-substituted 1-(aminomethyl)-3,4-dihydro-5,6-dihydroxy-1H-2-benzopyrans: characterization of an auxiliary binding region in the D1 receptor.

The synthesis and dopaminergic activity of a series of C3 and nitrogen-substituted 1-(aminomethyl)-3,4-dihydro-5,6-dihydroxy-1H-2-benzopyrans (isochromans) is described. The synthesis of the compounds was stereospecific for the 1,3 cis isomer, and the enantioselective synthesis of both enantiomers of one of the analogues (20) was achieved. It was determined that all of the dopaminergic activity resides in the [1R,3S] isomer. Generally, substitution at the C3 position provided compounds with very high potency (less than 10 nm EC50) and selectivity for the D1 receptor, with a wide range of intrinsic activities (60-160%). Analogues containing C3 substituents including aryl, arylalkyl, and cyclic and acyclic alkyl groups showed a marked enhancement of dopaminergic activity compared to the unsubstituted compound. As a class, the drugs were orally active in the rat rotation model with a very long duration of action.     

PD128907中间体3-氨基-6-甲氧基-3,4-二氢-2H-苯并吡喃-4-酮盐酸盐的合成

目的：合成多巴胺D3受体选择性激动剂PD128907中间体3-氨基-6-甲氧基-3,4-二氢-2H-苯并吡喃-4-酮盐酸盐.方法：以对甲氧基苯酚为起始原料,经加成、酸解、环合、成肟、酯化和Neber重排6步反应制备了3-氨基-6-甲氧基-3,4-二氢-2H-苯并吡喃-4-酮.结果：以总收率43.4%合成了多巴胺D3受体选择性激动剂PD128907中间体,结构经核磁氢谱、质谱和红外光谱确证.结论：该法原料价廉易得,反应条件温和,收率较高.     

1,9-Alkano-bridged 2,3,4,5-tetrahydro-1H-3-benzazepines with affinity for the alpha 2-adrenoceptor and the 5-HT1A receptor

A number of 1,9-alkano-bridged 2,3,4,5-tetrahydro-1H-3-benzazepines were prepared and evaluated for 5-HT1A receptor and alpha 2-adrenoceptor affinity by using radioligand receptor binding techniques. Several compounds displayed 5-HT1A receptor affinity comparable to, or greater than, the known 5-HT1A ligand buspirone. The highest affinity 5-HT1A receptor ligands were N-alkyl-, N-allyl-5-chloro-, and 5-methoxy-1,2,3,4,8,9,10,10a-octahydronaphth[1,8-cd]azapines (4c, 4m, 4n), which had pKi values of 7.9-8.1. The S enantiomer of 4c had a higher affinity for the 5-HT1A receptor than the corresponding R isomer (pKi of 8.2 for (S)-4c vs 7.7 for (R)-4c). These compounds had a relatively low affinity for the alpha 2-adrenoceptor (pKi of 7 or less). On the other hand, the closely related 5-chloro-2-methyl-2,3,4,8,9,9a-hexahydro-1H-indeno[1,7-cd]azepine (3b) had high affinity for both the alpha 2-adrenoceptor (pKi = 8.1) and 5-HT1A receptor (pKi = 7.6). These results indicate that the two receptors may share common recognition sites.