Showing papers on "Piperidine published in 1985"

New antihistaminic N-heterocyclic 4-piperidinamines. 1. Synthesis and antihistaminic activity of N-(4-piperidinyl)-1H-benzimidazol-2-amines.

Abstract: The synthesis of a series N-(4-piperidinyl)-1H-benzimidazol-2-amines and the preliminary evaluation of their in vitro and in vivo antihistaminic activity are described. Cyclodesulfurization of (2-aminophenyl)thioureas with mercury(II) oxide resulted in 2-aminobenzimidazole intermediates, which were monoalkylated on the endo-nitrogen atom. After deprotection of the piperidine nitrogen atom with 48% aqueous hydrobromic acid solution, the title compounds were obtained by three different methods, viz. alkylation, reductive amination, or oxirane ring-opening reactions. The in vivo antihistaminic activity was evaluated by the compound 48/80 induced lethality test in rats and histamine-induced lethality test in guinea pigs after oral and/or subcutaneous administration. The duration of action, for a selected number of compounds, was studied in the guinea pig. The phenylethyl derivatives showed the most potent antihistamine properties after oral administration in both animal species.

Substrate specificity of the intestinal brush-border proline/sodium (IMINO) transporter.

Abstract: L-proline uptake via the intestinal brush-border IMINO carrier was tested for inhibition by 41 compounds which included sugars, N-methylated, alpha-, beta-, gamma- and epsilon- amino and imino acids, and heterocyclic analogs of pyrrolidine, piperidine and pyridine. Based on competitive inhibitor constants (apparent Ki' 's) we find that the IMINO carrier binding site interacts with molecules which possess a well-defined set of structural prerequisites. The ideal inhibitor must 1) be a heterocyclic nitrogen ring, 2) have a hydrophobic region, 3) be the L-stereoisomer of 4) an electronegative carbonyl group which is 5) separated by a one-carbon atom spacer from 6) an electropositive tetrahedral imino nitrogen with two H atoms. Finally, 7) the inhibitor conformation determined by dynamic ring puckering must position all these features within a critical domain. The two best inhibitors are L-pipecolate (apparent Ki' 0.2 mM) and L-proline (apparent Ki' 0.3 mM).

N-(amino)alkyl)-1-pyrrolidine, 1-piperidine and 1-homopiperidinecarboxamides (and thiocarboxamides) with sulfur linked substitution in the 2, 3 or 4-positions

Abstract: Novel pyrrolidine, piperidine and homopiperidinecarboxamide and thiocarboxamide compounds having the formula: ##STR1## wherein X is --S--, --S(O)-- or --S(O) 2 --; A is a loweralkalene chain and A 1 and A 2 are alkalene chains when p and d are one; R, R 1 and R 2 are hydrogen, loweralkyl, phenyl cycloalkyl or phenylalkyl and R 1 and R 2 may form a heterocyclic residue with the adjacent nitrogen atom; Q is a selected aromatic radical, and the pharmaceutically acceptable acid addition salts useful as cardiac antiarrhythmia agents are disclosed. Novel chemical intermediates, unsubstituted on pyrrolidine, piperidine and homopiperidine nitrogen but with --(A 2 ) p --X--(A 2 ) d --Q side chain are also disclosed.

Chapter 3 Pyridine and Piperidine Alkaloids

Abstract: Publisher Summary The designation of pyridine and piperidine alkaloids as a group introduces a level of arbitrariness. These compounds do not stem from a common biosynthetic precursor, they are not unique to a single taxonomic family, and even the structural characteristics that might seem to define the group are open to interpretation. However, the historical recognition of these alkaloids as a class, and the practice of reviewing them as such are sufficient reasons to continue these traditions. This chapter represents a survey of the relevant literature on pyridine and piperidine alkaloids. It includes alkaloids containing a piperidine-type nitrogen heterocycle (at any oxidation level) that is not fused to a carbocyclic system. Alkaloids in which the nitrogen-containing ring is fused to a second heterocycle, such as gentianine have in some cases been included, except where such fusion generates another readily identifiable heterocyclic moiety, such as the quinolizidine system. The alkaloids are grouped in sections, largely on the basis of their structural characteristics, although biogenetic or taxonomic considerations have also been taken into account in some instances.

Very high frequency proton NMR studies of the conformations of opiate agonists and antagonists

Abstract: The solution conformational properties of the opiate agonist-antagonist pairs morphine-nalorphine and oxymorphone-naloxone have been investigated by NMR spectroscopy of their salts and free bases in aqueous and non-aqueous solutions, respectively Nitrogen inversion in the piperidine ring takes place in these compounds However, the equilibrium ratios differ between pairs The conformations of the piperidine rings are chairs with differing degrees of distortion from ideality On the NMR time scale the dynamically averaged orientations of the N-allyl substituents in the antagonists differ from one another with respect to a fixed molecular coordinate system The C-14 hydroxy group in oxymorphone-naloxone appears to be solvated, and this has important conformational effects In these latter compounds a stereoelectronic effect takes place involving the C-6 carbonyl position (D ring), which results in differential labilization of the C-7 protons

Intercalation of polar organic compounds into Sn(HPO4)2•H2O

Abstract: Divers types d'amines, ainsi que le DMSO, sont inverses dans la structure lamellaire d'hydrate d'hydrogenophosphate d'etain

Deprotection of allylic esters and ethers

Abstract: A process is disclosed for the deprotection of allylic esters and ethers. The process comprises reacting an allyl ester of a carboxylic acid or an allyl ether of a phenol with pyrrolidine or piperidine and a catalytic amount of an organic-soluble palladium complex having a coordinating phosphine ligand to cleave the allyl moiety. The resultant carboxylic acid or phenol is then recovered.

Diels‐Alder‐Reaktionen mit aktivierten 4‐Methyl‐1,3‐pentadienen

Abstract: Diels-Alder Reactions with Activated 4-Methyl-1,3-pentadienes Ethyl 4-methyl-1,3-pentadienyl ether, trimethyl[(4-methyl-1,3-pentadienyl)oxy]silane, and 1-(4-methyl-1,3-pentadienyl)pyrrolidine and the corresponding piperidine analogue have been used in Diels-Alder reactions with acrylonitrile, ethyl acetylenedicarboxylate, maleic anhydride, and 2,6-dimethyl-p-benzoquinone.

Structure-activity relationships of some pyridine, piperidine, and pyrrolidine analogues for enhancing and inhibiting the binding of (+/-)-[3H]nicotine to the rat brain P2 preparation.

Abstract: Previous studies have shown that (+/-)-[3H]nicotine binds to multiple sites in the rat brain P2 preparation. Using a series of pyridine, piperidine and pyrrolidine analogues, the present studies identified drugs with specificity for a separate up-regulatory site that increases the density of nicotine binding at another site. Of these compounds, (+/-)-2-methylpiperidine was the most specific. Some compounds inhibited without enhancing (+/-)-[3H]nicotine binding, but none bound with the very high affinity exhibited by nicotine and none could be classified as specific in inhibiting binding at a specific site. Structural changes in the 1- and 2-positions of pyridine and piperidine appear to be important for conferring specificity for the up-regulatory site whereas 3-position changes may be important for binding specificity.

Pyryliumverbindungen. XXIX [1] Substituierte Benzophenone aus 2,4,6‐Triaryl‐pyryliumsalzen und Methyl(en)ketonen

Abstract: Pyrylium Compounds XXIX Substituted Benzophenones from 2,4,6-Triarylpyrylium Salts and Methyl(ene) Ketones In the presence of piperidine acetate (or similar salts of certain dialkylamines), 2,4,6-triarylpyrylium perchlorates 5 react with methyl(ene) ketones 6 to give benzophenones 7, the structure of which was proved by spectroscopic methods as well as by independent synthesis Besides acetone and other acyclic ketones (e g alkyl methyl ketones, phenylacetone, desoxybenzoin, dibenzyl ketone) cyclic ketones (e g cyclopentanone, cyclohexanone, cycloheptanone, acenaphthenone) can also be used as ketone component 6; acetophenones react differently leading to hydrocarbons of the 1,3,5-triarylbenzene type 15 The varying efficiency of the diverse amine salts and the mode of incorporation of the unsymmetrically substituted ketones suggest the intermediate formation of enamines 10 as crucial step of the ring transformations observed This assumption is supported by isolation of the iminium salt 18 on reacting 3,5-dimethyl-2,4,6-triphenylpyrylium perchlorate (16) with acetone/piperidine acetate

α-Secondary dialkylallylamines from aminonitriles via the Bruylants reaction

Abstract: Synthese d'alkyl-1 alcene-2yl dialkylamines a partir de dialkylamines (A) et d'alcene-2als (via l'action de bromures d'alkylmagnesium sur les dialkylamino-2 alcene-3 nitriles) ou a partir de A et d'alcanals (via l'action de bromures d'alcene-1yl magnesium sur des dialkylamino-2 alcanenitriles). Regio- et stereoselectivites

Piperidine derivatives, their production and use as stabilizers

Abstract: The present invention relates to a piperidine derivative represented by the general formula (I), ##STR1## wherein R 1 and R 2 independently represent a hydrogen atom or a C 1 -C 3 alkyl or C 2 -C 20 acyl group, R 3 represents a hydrogen atom or a C 1 -C 20 alkyl, C 6 -C 20 aryl, C 7 -C 20 aralkyl or C 2 -C 20 acyl group, and l represents 1 to 3, and a stabilizer for organic substances containing said piperidine derivative as an effective ingredient.

A new general synthesis of 2-(N-mono- and N-di-substituted amino)thiazoles

Abstract: Although α-mercapto ketones react with cyanamides to give substituted 2-aminothiazoles the yields are satisfactory in only the simplest cases. However, a range of 2-aminothiazoles with substitutents on the ring or the exo-nitrogen atom was obtained efficiently by the following one-pot procedure: a solution of an α-mercapto ketone anion was generated by treating an O-ethyl S-2-oxoethyl dithiocarbonate with piperidine at 20 °C, a cyanamide was added, and the solution was heated for 3–6 h.

Unusually facile aminolysis of β-ketoesters

Abstract: The unusually facile aminolysis of β-ketoesters does not proceed via simple amine nucleophilic attack on the ester carbonyl.

Addition and cycloaddition reactions of β-chloroazo-olefins

Abstract: 2-Chloro-1-(2,4-dinitrophenylazo)ethene (1a) has been isolated, and the corresponding alkoxy-carbonylazo compounds (1b) and (1c) have been generated in solution, as the first examples of azo-olefins bearing single β-halogeno substituents. The compounds (1a) and (1b) undergo [4 + 2] cycloaddition to indene and to ethyl vinyl ether with high endo stereoselectivity. Furan and cyclopentadiene give the cycloadducts (6) and (7), respectively, with (1a). Nucleophilic addition–elimination reactions are observed with piperidine, indole, thiophenol, and carbanions. In most of these reactions the primary products are subject to further nucleophilic attack: thus, the hydrazones (11) formed by addition of carbanions are converted into aminopyrroles (12) by further reaction with the carbanions and dehydration.

1 H and 13C nuclear magnetic resonance identification of the products of the reaction of NN-dialkylformamide dimethyl acetals with secondary amines

Abstract: Eight reactions of NN-dialkylformamide dimethyl acetals with secondary amines have been followed by means of 1H n.m.r. The reaction products were not only other amide acetals but also ester aminals and orthoamides. Therefore secondary amines exchanged the amine moiety and the methoxy group of the amide acetal. The relative concentrations of products at equilibrium have been estimated. The 13C chemical shifts for substrates and some products have been reported.

Novel piperidine derivative

Abstract: NEW MATERIAL:The compound of formula I [R is univalent group such as benzene, pyridine, imidazole, piperidine, morpholine, uracil, dihydrouracil, naph thalene, theophylline, indole, etc.; alk is lower alkylene, -COCH2, group of formu la II, formula III, CO, etc.; X is CO, C(OH)H, etc.; Ar is univalent group induced from (substituted) benzene] and its pharmacologically permissible acid addition salt. EXAMPLE:1-(2-Piperidinyl-1)-ethyl-4-(p-fluorobenzoyl)piperidine dihydrochloride. USE:Medicine having antiserotonin activity and useful for the remedy of various diseases to which the isolation of serotonin is important. PREPARATION:The compound of formula I wherein alk is lower alkyl, X is CO and Ar is substituted benzene residue can be produced e.g. by refluxing the bromoalkyl compound of formula IV and benzoylpiperidine of formula V in an organic solvent such as butanol in the presence of a base such as NaHCO3.