Showing papers on "Piperidine published in 1978"

Structural Studies of Crystalline Enamines

Abstract: Crystal structure analyses of five crystalline enamines together with recently published structural data for two other enamines reveal varying degree of pyramidality at the enamine nitrogen atom. The pyramidality appears to be most pronounced in enamines from piperidine and morpholine, less so in enamines derived from prolinoid amines. A pyrolidine enamine obtained from a derivative of cyclohexane-1,4-dione seems to have a virtually planar enamine group. The implications of these findings for current stereochemical problems in enamine chemistry are discussed.

Base-specific reactions useful for DNA sequencing: methylene blue – sensitized photooxidation of guanine and osmium tetraoxide modification of thymine

Abstract: Exposure of DNA to methylene blue and visible or ultraviolet light causes guanine-specific modification, and subsequent treatment with piperidine leads to chain cleavage at each guanine residue. Treatment of DNA with osmium tetraoxide in dilute pyridine leads to thymidine-specific modification, and subsequent treatment with piperidine leads to chain cleavage at the modified thymidine residues. Both reactions can be used in conjunction with other base specific modifications described by Maxam and Gilbert (1) for the determination of the nucleotide sequence in DNA.

Antihyperglycemic N-alkyl-3,4,5-trihydroxy-2-piperidine methanol

Abstract: 2-Hydroxymethyl-3,4,5-trihydroxy-N-alkylpiperidines and their acid addition salts are antihyperglycemic agents. A typical example is 2-hydroxymethyl-3,4,5-trihydroxy-N-methylpiperidine.

The chemistry of nitroso compounds. Part 12. The mechanism of nitrosation and nitration of aqueous piperidine by gaseous dinitrogen tetraoxide and dinitrogen trioxide in aqueous alkaline solutions. Evidence for the existence of molecular isomers of dinitrogen tetraoxide and dinitrogen trioxide

Abstract: Detailed quantitative results are reported for the interaction of aqueous piperidine in aqueous 0.1M-NaOH at 25° with gaseous N2O4 and N2O3. Both reagents rapidly give substantial amounts of N-nitrosopiperidine, plus smaller amounts of N-nitropiperidine in the case of N2O4, in addition to hydrolysis products such as NO2–. All these reactions are considered to occur predominantly in the aqueous phase and to be complete in a few seconds. With excess amine, yields of N-nitrosopiperidine reach maximum values corresponding to 100% for N2O3 but only ca. 50% for N2O4. The yield of N-nitropiperidine from N2O4, however, shows no maximum even at the highest [Piperidine]. The dependence of product yields on initial [Piperidine] and [N2Ox] suggests that N-nitrosopiperidine formation follows Rate =kp[Piperidine][N2Ox]. The concurrent hydrolysis of N2O3 and N2O4 is not significantly catalysed by HO– and is considered to involve H2O only. On a molar basis, piperidine is more reactive than H2O towards nitrosation by N2O3 and N2O4 by factors of 3 300 and 2 000, respectively. The results are discussed in relation to the existence of two molecular isomers for both N2O3 and N2O4, and the mechanisms by which these entities react with amines. For N2O4, the more stable symmetrical O2N–NO2 is considered to form only N-nitropiperidine, probably via a four-centre transition state: N-nitrosopiperidine results from concurrent reaction by the less stable ON–ONO2 isomer formed in aqueous solution by dimerisation of NO2 from the gaseous phase. For N2O3(which is fully dissociated in the gaseous phase) recombination of NO with NO2 in aqueous solution produces the less stable, symmetrical ON–ONO rather than the more stable ON–NO2 isomer present in aqueous HNO2. The existence of two isomers explains the higher reactivity of gaseous N2O3 towards weakly basic amines. N-Nitrosopiperidine formation with gaseous N2O3 results predominantly from nucleophilic attack by the amine on the ON–ONO isomer. Analysis of the data suggests that the formation of both ON–ONO2 and ONONO from their radical components in solution may be the rate-limiting step for the reactions leading to N-nitrosopiperidine.

1-[(Heterocyclyl)-alkyl]-4-diarylmethoxy piperidine derivatives

Abstract: Novel 1-[(heterocyclyl)alkyl]-4-diarylmethoxy piperidine derivatives are disclosed having the formula ##STR1## where n is 2-6, Ar1 and Ar2 are aryl and B is a substituted benzimidazolyl radical. These compounds are useful for their antianaphylactic and antihistaminic properties. Specific claimed compounds are 1-{3-[4-(diphenylmethoxy)-1-piperidinyl]-propyl}-1,3-dihydro-2H-benzimidazol-2-one, 1-{2-[4-(diphenylmethoxy)-1-piperidinyl]ethyl}1-, 3-dihydro-2H-benzimidazol-2-one, and 1-{4-[4-(diphenylmethoxy)-1-piperidinyl]butyl}-1,3-dihydro-2H-benzimidazol-2-one.

Steric carbonyl protection metalation and cleavage of highly hindered ureas. Preliminary communication

Abstract: Ureas of type 3 with sterically protected carbonyl groups such as 4a-7a are prepared by successively adding 2 equivalents of a highly substituted sec. amine and an excess of dimethylamine to benzene or toluene solutions of phosgene. The piperidine derivatives 6a and 7a are metalated in high yields to 6b and 7b, respectively, with sec.-butyllithium/TMEDA in THF at 0° [see derivatives 6, 7, (c-i) in Table 1]. Methods of cleaving urethanes 2 (see 8 9) and ureas 3 are described, among which the retro-Mannich reaction, removing the piperidine ring from 7 under acidic hydrolysis conditions, appears to be promising also for other applications of sterically blocked carbonyl compounds in organic synthesis.

Synthese der vier stereoisomeren Dihydropalustraminsäuren. 13. Mitteilung über Schachtelhalmalkaloide

Abstract: Syntheses of the four stereoisomeric dihydropalustramic acids ([6-(1-hydroxypropyl)-2-piperidyl]acetic acids) (−)-Dihydropalustramic acid, a key product in the structure elucidation of the alkaloid palustrin, has been assigned the threo-cis structure 20 by comparison with the four stereoisomeric (±)-dihydropalustramic acids (threo-cis, threo-trans, erythro-cis, erythro-trans). The latter were synthesized by a new route to α, α′-di-substituted piperidines of this type. Ring closure to the piperidine ring with simultaneous stereospecific formation of the hydroxylated side chain has been achieved by reaction of the stereoisomeric methylesters of 7,8-epoxy-2-decenoic acids with benzylamine. Assignment of the configuration at the piperidine ring is based on careful comparison of the H-NMR. spectra of the N-benzylpiperidines and with the help of lanthanide shift reagents.

Spiro-4'-piperidine compounds and their pharmaceutical compositions

Abstract: Spiro amine derivatives having excellent antihypertensive activity and central nervous system depressant activity, and represented by the formula: ##STR1## and their preparation and use.

Carbon-13 nuclear magnetic resonance spectroscopy of methyl-substituted piperidines and their hydrochloride salts

Abstract: Carbon-13 chemical shifts and 1J(CH) coupling constants of piperidine, 4-t-butylpiperidine, five C-methyl substituted piperidines and of the corresponding N-methyl compounds have been measured. These NMR parameters have also been determined for the fourteen corresponding hydrochlorides. The N-methyl-C-methyl piperidinium salts showed two stereoisomers on the positive nitrogen atom. The effect of protonation is discussed in relation to charge and steric effects and the methyl substituent effects are compared with those of methyl-substituted cyclohexanes. Deviations from the general tendencies in the series are correlated with changes in ring conformations around the highly crowded substituted carbons.

Oligomerisation and telomerisation of buta-1,3-diene catalysed by bis-(η-cyclo-octa-1,5-diene)-palladium and -platinum

Abstract: The [Pd(cod)2]-catalysed reaction of buta-1,3-diene with secondary amines (morpholine, piperidine, diethylamine, or dimethylamine) affords octa-2,7-dienylamines, the highest yields being obtained with the cyclic amines. However, treatment of buta-1,3-diene with acetic acid-diethylamine in the presence of [Pd(cod)2](cod = cyclo-octa-1,5-diene) affords an improved yield of the diethylamine C8 adduct. The addition of 1 mol of PPh3 per mol of Pd has only a small effect on the above reactions. The addition of acetic acid to buta-1,3-diene is catalysed by [Pd(cod)2] to give octa-2,7-dienyl acetate and 1-vinylhex-5-enyl acetate in the ratio of 4 : 1. The [Pd(cod)2]-catalysed reaction of isoprene with morpholine affords as the major product the tail-to-tail amine adduct. The specificity of this reaction is improved by the addition of 1 mol of PPh3. The system [Pd(cod)2]–PPh3 catalyses the addition of acetaldehyde to buta-1,3-diene to form 2-methyl-3,6-divinyltetrahydropyran. With phenyl isocyanate, piperidones are formed. Reaction of buta-1,3-diene with morpholine in the presence of [Pt(cod)2] gives only octa-1,3,6-triene; however, addition of the co-catalyst Al(OPrt)3 or Al(OBut)3 leads to the formation of the octadienylamine adducts. Telomerisation of buta-1,3-diene with acetic acid catalysed by [Pt(cod)2] gives selectively octa-2,7-dienyl acetate. Possible mechanisms for these reactions are discussed.

Mössbauer spectroscopic studies of carbonyl haemochromes; correlations with reactivity

Abstract: Mossbauer spectra of several bis(piperidine) and carbonylpiperidine haemochromes suggest that replacement of the axial amine by carbon monoxide causes pronounced changes in the iron–porphyrin bonding, i.e. causes a substantial cis-effect.

Synthese und Eigenschaften von 3,7‐Diethoxy‐4H, 8H‐benzo[1,2‐c:4,5‐c′]diisoxazol‐4,8‐dion

Abstract: Die Reaktion von Natriumazid mit 2,5-Dichlor-3,6-dioxo-1,4-cyclohexadien-1,4-dicarbonsaurediethylester (1a) fuhrt zum 2,5-Diazido-Derivat 1b, das mit Anilin in das Dianilino-Derivat 1c und durch Thermolyse unter Eliminierung von 2 Mol N2 in die Titelverbindung 2a ubergefuhrt wurde. Diese liefert mit Piperidin 2b und mit Ammoniak 2c. Uber die Ergebnisse der Rontgenstrukturanalyse von 2a wird berichtet. Synthesis and Properties of 3,7-Diethoxy-4H,8H-benzo[1,2-c:4,5-c′]diisoxazole-4,8-dione Sodium azide reacts with diethyl 2,5-dichloro-3,6-dioxo-1,4-cyclohexadiene-1,4-dicarboxylate (1a) to give the 2,5-diazido derivative 1b. The reaction of 1b with aniline leads to the dianilino derivative 1c, whereas thermolysis of 1b leads to elimination of 2 mols of N2 and formation of the title compound 2a. With piperidine 2a yields 2b and with ammonia the derivative 2c. The results of an X-ray structure analysis of 2a are reported.

N-phenyl-N-(4-piperidinyl)amides

Abstract: Novel compounds of the series of N-phenyl-N-(4-piperidinyl)amides having a (4,5-dihydro-4-R-5-oxo-1H-tetrazol-1-yl)alkyl or (4,5-dihydro-4-R-5-thioxo-1H-tetrazol-1-yl)alkyl substituent group in the 1-position of the piperidine nucleus, said compounds being useful as analgesic agents.

Piperidylalkylindoles. 1. Hypotensive activity of 3-[2-(phenoxypiperidyl)ethyl]indoles.

Abstract: A series of 3-[2-(phenoxypiperidyl)-ethyl]indoles was synthesized and evaluated for hypotensive activity in the spontaneous hypertensive rat. Maximum hypotensive activity appeared when the phenoxy substituent was para substituted and occupied the 4 position of the piperidine ring.

Preparation of dialkyl carbonate

Abstract: PURPOSE: To prepare the title compound useful as a solvent of resins, and an alkylating agent, etc., rapidly, under mild conditions, in high yield, without producing by-products, by reacting an alkylene carbonate with an aliphatic alcohol in the presence of a complex catalyst composed of a specific acid and a base. CONSTITUTION: A dialkyl carbonate is prepared by reacting (A) an alkylene carbonate, pref. ethylene carbonate or propylene carbonate, with (B) an aliphatic alcohol, pref. 1W10C alcohol such as methanol, in the presence of (C) pref. 0.5W 20wt%, based on the raw materials, of a complex catalyst composed of (a) a Lewis acid and (b) pref. equi-molar amount, based on the Lewis acid, of a nitrogen- containing organic base such as 1W20C primary, secondary or tertiary aliphatic amine, piperidine, piperazine, etc., at 50W150°C. COPYRIGHT: (C)1980,JPO&Japio

Antihypertensive 7-trifluoromethyl-4-aminoquinolones

Abstract: Antihypertensive compounds of the formula II ##STR1## wherein D is a piperidino or 1,2,5,6-tetrahydropyridino ring; wherein X is chloro or trifluoromethyl; wherein R 1 is hydrogen or hydroxy when the D ring is piperidino, or nothing when the D ring is 1,2,5,6-tetrahydropyridino; and, wherein the moiety Ar is 2-oxo-1-benzimidazolinyl, phenyl, or phenyl substituted by one or two halo, trifluoromethyl, or alkyl, alkoxy, in which the carbon moieties are of 1 to 3 carbon atoms, inclusive, and halo is chloro, bromo, or fluoro, are produced by reacting 4-[[7-(chloro) or (trifluoromethyl)-4-quinolinyl]-amino]benzoic acid with thionyl chloride or a carbonyl diimidazole and subsequent reaction with the selected substituted piperidine or 1,2,5,6-tetrahydropyridine. The pharmacologically acceptable acid addition salts of II can also be used as antihypertensives.

Optical Activation of 2-Phenylpropionaldehyde via Some 2-Substituted Pyrrolidine Enamines

Abstract: Optical activation of 2-phenylpropionaldehyde (PPA) via enamines using L-proline derivatives as amine components was studied. S(+)-PPA was obtained when R(−)-2-methylpyrrolidine and S(−)-2-ethoxycarbonylpyrrolidine were used, while R(−)-PPA was obtained when S(−)-prolinamide, N-(L-prolyl)pyrrolidine, N-(L-prolyl)piperidine, S(+)-2-(1-pyrrolidinylmethyl)pyrrolidine, and S(+)-2-(piperidinomethyl)pyrrolidine were used. This suggests that there are two mechanisms for optical activation.

Aminopiperidines, their production and the pharmaceutical compositions incorporating them

Abstract: This invention relates to 4-aminopiperidines and more precisely to 4-aminopiperidines the nitrogen atom of the piperidine ring is substituted with an aryl lower alkyl side-chain. This invention also relates to processes for producing the same. This invention further extends to pharmaceutical compositions and to the method of using the same.

Swelling behavior of cotton fibers in morpholine and piperidine

Abstract: Solution properties (conductivity and refractometry) of aqueous solutions of morpholine and piperidine as well as their aqueous mixtures with model compounds (glucose, cellobiose, xylose, and cellobiose octaacetate) in varying molar ratios were studied. The possible mechanism of the unique swelling action of morpholine on cotton cellulose and the total inaction of piperidine was investigated. It was shown that the solubility parameter (δ) may not fully indicate the swelling ability of a reagent, but the H-bonding portion (δH) and polar part (δp) of δ are of importance. Morpholine possesses a higher value of δH + δp than does piperidine; hence it is a powerful swelling agent for cellulose. It produces over 200% swelling at the interfibrillar level and has the ability to decrystallize cellulose under certain favorable conditions.

Polyalkylated 4-aminopiperidine derivatives

Abstract: New polyalkylated 4-aminopiperidine derivatives contain in their molecule two or three piperidine rings, each having two alkyl substituents at both the 2- and the 6- positions, optionally having substituents at the 1- and 3- positions and having an amino substituent at the 4- position. The piperidine rings are joined together by attachment of the 4-amino substituents through, where there are two piperidine rings, a polyalkylene, polyether or polyester chain, or through, where there are three piperidine rings, an isocyanurate or glycerol system. These compounds and their acid addition salts are useful as stabilizers for synthetic polymers.

Preparation and I. R. studies of Ethyl(n-Propyl)Tin Dichloride and its Adducts with Nitrogen Donors

Abstract: Preparation of ethyl(n-propyl)tin dichloride by the redistribution-reaction method has been reported. It has been found to form 1:2 adducts with phenyl hydrazine, aniline, piperidine, n-propyl- and n-butylamines while with benzyl amine only 1:1 adduct is obtained. IR spectra of EtPRnSnCl2 and its complexes have been discussed. Athyl(n-Propyl)-Zinndichlorid und seine Addukte mit Stickstoff-Donatoren Athyl(n-Propyl)-Zinndichlorid wurde nach der Methode der Umverteilung dargestellt. Mit Phenylhydrazin, Anilin, Piperidin, n-Propylamin und n-Butylamin bildet es 1:2-Addukte, mit Benzylamin nur ein 1:1-Addukt. Die IR-Spektren der Verbindung und der Komplexe werden mitgeteilt.