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The aim of this research was to discover α2-receptor antagonist subtypes that are more selective than known compounds. We focused on rigid molecules possessing a benzo-fused bicyclo[3.2.0]heptane skeleton. The synthetic route used relied upon the intramolecular [2+2] cycloaddition of styrylketene precursors. The cycloaddition was remarkably efficient and delivered multigram quantities of the cycloadduct 2. Studies of the removal of the ketone group in 2 revealed a facile opening of the four-membered ring. Upon thermal elimination of TCI-13-endo (TCI = thiocarbonylimidazole) and TCI-13-exo, different products were obtaineddepending on the stereochemistry of the OH function of the precursor. Distinct mechanisms were proposed to account for the divergent outcomes observed. Double bond reductions from either methylcyclobutene or methylenecyclobutane isomers were thoroughly investigated in order to optimize the stereocontrol at the C-1 position. Hydrogenation of the internal π-bond produced an endo-1-methylcyclobutane derivative with high diastereoselectivity, whereas the exo-1-methyl isomer was best isolated by chromatographic separation of the acid 37. Finally, the prototypic imidazolidines 1, unsubstituted and bearing a methyl group at C-1, were synthesized for biological evaluation.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

The aim of this work was to improve the oral bioavailability of a recently discovered, novel structural class of 5-HT1A receptor agonists: aryl-{[4-(6-R-pyridin-2-ylmethyl)-amino]-methyl}-piperidin-1 -yl-metha none. Incorporation of a fluorine atom in the beta-position to the amino function in the side chain led to analogues that exhibited, in general, enhanced and long-lasting 5-HT1A agonist activity in rats after oral administration. Location of the fluorine atom at the C-4 position of the piperidine ring was the most favorable, and among the various substituents tested, the ability of the fluorine was unique in improving the oral activity of this family of ligands. Thus, the derivatives 39, 46, and 61 bound with higher affinity and selectivity to 5-HT1A receptors (versus dopaminergic D2 and adrenergic alpha1 receptors) and displayed more potent 5-HT1A agonist activity in vitro and in vivo than their C-4 desfluoro analogues. To examine the relationship between the conformation of the pharmacophore and the level of agonistic activity of this type of ligand, we synthesized a series of 3-chloro-4-fluorophenyl-(4-fluoro-4{[(5-(H or CH3)-6-R-pyridin-2-ylmethyl)-amino]-methyl}-piperidin-1-yl-+ ++methanone derivatives and found that the combination of a 5-methyl and a 6-methylamino substituent on the pyridine ring synergistically affected their 5-HT1A agonist properties. Thus, the 3-chloro-4-fluorophenyl-(4-fluoro-4{[(5-methyl-6-methylamino-pyridin- 2-ylmethyl)-amino]-methyl}-piperidin-1-yl-methanone 40 behaved as a more potent 5-HT1A receptor agonist in vitro and in vivo than its 5-unsubstituted analogue 38. The antidepressant potential of the lead compounds 40, 45, and 54 was examined by means of the forced swimming test (FST) in rats. The results indicated that, after a single oral administration, these compounds inhibited immobility in the FST more potently and more extensively than the clinically used antidepressant imipramine. Thus, 40, 45, and 54 are potent, orally active 5-HT1A receptor agonists with marked antidepressant potential.

A search for novel, selective agonists with high intrinsic activity at the 5-HT1A subtype of serotonin (5-HT) receptors was undertaken. Mechanistic and thermodynamic considerations led to the design of 6-substituted-2-pyridinylmethylamine as a potential 5-HT1A pharmacophore. Various adducts derived from the 6-substituted-2-pyridinylmethylamine moiety were tested for their affinity at 5-HT1A, alpha1-adrenergic, and D2-dopaminergic receptors. Compounds with high affinity for 5-HT1A receptors (pKi/= 8) were examined for agonist properties by measuring their ability to inhibit forskolin-stimulated cAMP production in HA7 cells (i.e., HeLa cells permanently transfected with the h5-HT1A receptor gene and expressing the h5-HT1A receptor protein). Several compounds of the type aryl¿4-[(6-substituted-pyridin-2-ylmethylamino)methyl]piperidin -1-yl¿ methanone had nanomolar affinity for 5-HT1A binding sites and were more than 500-fold selective with respect to alpha1 and D2 sites. Importantly, their 5-HT1A agonist properties were demonstrated in HA7 cells where they behaved as potent inhibitors of cAMP accumulation. In particular, (3, 4-dichlorophenyl)¿4-[(6-oxazol-5-ylpyridin-2-ylmethylamin o)methyl]pip eridin-1-yl¿methanone (70) and (3, 4-dichlorophenyl)¿4-[(6-azetidinopyridin-2-ylmethylamino)met hyl]piper idin-1-yl¿methanone (36) appeared to be more potent than, and at least as efficacious as, the prototypical 5-HT1A agonist (+/-)-8-OH-DPAT. SAR studies revealed that the pyridine nitrogen atom and the nature and the position of the substituents on the pyridine ring were critically involved in the ability of the compounds to recognize and activate 5-HT1A receptors. Structural modifications of the nonpharmacophoric part of the molecule showed, however, that the entire structure was required for affinity at 5-HT1A binding sites.

The stereoselective synthesis of cis and trans 2-methyl-1-phenyl-3-azabicyclo[3.1.0]hexanes and 1,2-diphenyl-3-azabicyclo[3.1.0]hexanes from 2-oxo-1-phenyl-3-azabicyclo[3.1.0]hexane is described. The relative stereochemistry of the products was established by nuclear magnetic resonance and molecular modeling studies

The reaction of a number of γ-butyrolactones with azole anions is shown to give γ-substituted butanoic acids in moderate to good yields. The pyrrolyl and indolylbutanoic acids obtained underwent cyclization in a simple one-pot procedure employing ethyl chloroformate and boron trifluoride etherate. Some aspects of the chemistry of the resulting indolizin-8-ones are described.

The stereoselective synthesis of cis and trans 2-methyl-1-phenyl-3-azabicyclo[3.1.0]hexanes and 1,2-diphenyl-3-azabicyclo[3.1.0]hexanes from 2-oxo-1-phenyl-3-azabicyclo[3.1.0]hexane is described. The relative stereochemistry of the products was established by nuclear magnetic resonance and molecular modeling studies

The dehydrogenation of pyrrolidines by activated manganese dioxide provides a fairly general and mild method for the preparation of substituted pyrroles

A search for novel, selective agonists with high intrinsic activity at the 5-HT1A subtype of serotonin (5-HT) receptors was undertaken. Mechanistic and thermodynamic considerations led to the design of 6-substituted-2-pyridinylmethylamine as a potential 5-HT1A pharmacophore. Various adducts derived from the 6-substituted-2-pyridinylmethylamine moiety were tested for their affinity at 5-HT1A, α1-adrenergic, and D2-dopaminergic receptors. Compounds with high affinity for 5-HT1A receptors (pKi ≥ 8) were examined for agonist properties by measuring their ability to inhibit forskolin-stimulated cAMP production in HA7 cells (i.e., HeLa cells permanently transfected with the h5-HT1A receptor gene and expressing the h5-HT1A receptor protein). Several compounds of the type aryl{4-[(6-substituted-pyridin-2-ylmethylamino)methyl]piperidin-1-yl}methanone had nanomolar affinity for 5-HT1A binding sites and were more than 500-fold selective with respect to α1 and D2 sites. Importantly, their 5-HT1A agonist properties we...

The reaction of a number of γ-butyrolactones with azole anions is shown to give γ-substituted butanoic acids in moderate to good yields. The pyrrolyl and indolylbutanoic acids obtained underwent cyclization in a simple one-pot procedure employing ethyl chloroformate and boron trifluoride etherate. Some aspects of the chemistry of the resulting indolizin-8-ones are described.

Lactone I is an important intermediate in the synthesis of compounds with therapeutic properties. In order to prepare new derivatives, reactivity of I has been studied. Cis and trans conformations of both 2,3-diphenyl-1-oxabicyclo [3,1,0] hexanes VIIIa and VIIIb were assigned by 1 H N.M.R spectroscopy using NOE DIFF experiments, and molecular modelling.

The dehydrogenation of pyrrolidines by activated manganese dioxide provides a fairly general and mild method for the preparation of substituted pyrroles

A series of 1-aryl-2-(aminomethyl)cyclopropanecarboxylic acid derivatives were synthesized and evaluated as potential antidepressants. Compounds with the Z configuration were synthesized from 1-aryl-2-oxo-3-oxabicyclo[3.1.0]hexane and those with the E configuration from (E)-1-phenyl-2-(hydroxymethyl)cyclopropanecarboxylic acid. The compounds were evaluated in animal tests designed to reveal potential antidepressant activity and the existence of undesirable side effects. Several derivatives were more active than imipramine and desipramine. On the basis of its activity in pharmacological animal tests of antidepressant activity and its potential lack of side effects, 1-phenyl-1-[(diethylamino)carbonyl]-2- (aminomethyl)cyclopropane hydrochloride, midalcipran (INN), was selected for further development. This compound is currently in phase III clinical evaluation.

Itaconic acid-4-14C has been prepared by condensation of sodium cyanide 14C with ethyl α-bromomethyl acrylate and hydrolysis of the intermediate ethyl α-(cyanomethyl) acrylate. Itaconic anhydride-4-14C has been used in Friedel-Crafts reactions with respectively biphenyl, 2-chlorobiphenyl, 4-chlorobiphenyl for the preparation of 4-biphenyl-4-oxo-2-methylene butyric acid-4-14C and the corresponding-2′chloro and 4′-chloro substituted derivatives.

(Theoretical conformational analysis and anti-depressive effectiveness of new bifunctional cyclopropanic derivatives: Midalcipran and relatives) The conformational analysis of Midalcipran, a novel anti-depressor agent, was achieved through a concerted use of the CNDO/2 quantum technique and of some new specific software for micro-computers, such as APPLE ///, which are able to design and sort preferred conformations. The anti-depressive activity is then attributed to the existence in the molecule of a “double-locked” rigid lactamic pattern highly suitable for receptor recognition.

(14C) semicarbazide hydrochloride was obtained from (14C) urea and hydrazine hydrate. It was condensed with 1,2-di- (4-methoxy phenyl)-ethane-1,2-dione giving rise to 5, 6-di-(4-methoxyphenyl)-3-oxo-(3-14C)-1,2,4-triazine. The latter, after condensation with bromomethyl cyclopropane gave (3-14C) ST 1118 : 2-(cyclopropylmethyl)-5,6-di-(4-methoxyphenyl)-3-oxo-(3-14C)-1,2,4- triazine. The overall yield based on urea was 37.2%. After silicagel column chromatography and crystallisation the radiochemical purity was 99.5% - Specific activity : 5.8 mCi/mMole.

A series of 1-aryl-2-(aminomethyl)cyclopropanecarboxylic acid derivatives were synthesized and evaluated as potential antidepressants. Compounds with the Z configuration were synthesized from 1-aryl-2-oxo-3-oxabicyclo[3.1.0]hexane and those with the E configuration from (E)-1-phenyl-2-(hydroxymethyl)cyclopropanecarboxylic acid. The compounds were evaluated in animal tests designed to reveal potential antidepressant activity and the existence of undesirable side effects. Several derivatives were more active than imipramine and desipramine. On the basis of its activity in pharmacological animal tests of antidepressant activity and its potential lack of side effects, 1-phenyl-1-[(diethylamino)carbonyl]-2- (aminomethyl)cyclopropane hydrochloride, midalcipran (INN), was selected for further development. This compound is currently in phase III clinical evaluation.

Aktivierte Methylenverbindungen (I) ergeben nach Metallierung mit Natriumamid in der Umsetzung mit Epichlorhydrin (II) Hydroxymethylcyclopropane (III).