Showing papers on "Piperidine published in 1986"
TL;DR: Diketopiperazine formation rates under the usual conditions of a solid phase peptide synthesis cycle with Fmoc-amino acids have been studied on a p -alkoxybenzyl ester resin.
104 citations
102 citations
77 citations
TL;DR: The prediction that high pH in and of itself will not create strand breaks at sites of N7-alkylguanines is confirmed, and the tertiary amine, N-methylpiperidine, does not catalyze the formation of strand breaks in alkylated DNA.
69 citations
Patent•
24 Dec 1986TL;DR: In this article, a novel piperidine derivative as defined by the formula (I), including a salt thereof, wherein R1, X, A and R2 have the aforementioned meanings is disclosed.
Abstract: A novel piperidine derivative as defined by the formula (I), including a salt thereof, wherein R1, X, A and R2 have the aforementioned meanings. Further, pharmaceutical compositions containing the same and the use of the piperidine derivatives for the making of such compositions preventing dementias and sequelae of cerebrovascular disease is disclosed.
62 citations
TL;DR: In this article, it was shown that terminal alkynes with secondary amines (dimethylamine, diethylamine and piperidine, morpholine) and CO2 in the presence of mononuclear ruthenium catalysts, afford the vinyl carbamates R1CH CHOCONR2.
59 citations
TL;DR: Alumina supported copper was found to be most selective for the synthesis of cyclic amines from the corresponding amino-alcohols as mentioned in this paper, and cyclizations were performed in a continuous fixed-bed reactor at 200 − 210 °C in the presence of hydrogen.
37 citations
35 citations
TL;DR: In this paper, the absolute configuration of (−)-4-hydroxypent-2-enenitrile, predominantly obtained by the reaction of (R)- 1a with propanal, was determined to be R.
30 citations
Patent•
08 Aug 1986
TL;DR: In this paper, a process for the preparation of a compound of formula (I): where Ar is substituted aryl and R3 is hydrogen, alkyl or aralkyl.
Abstract: A process is disclosed for the preparation of a compound of formula (I): ##STR1## wherein Ar is aryl or substituted aryl and R3 is hydrogen, alkyl or aralkyl, which process comprises reducing a compound of formula (II): ##STR2## wherein Ar and R3 are as defined with respect to formula (I) and R4 is alkyl. Compounds of formula (I) are useful as chemical intermediates.
30 citations
Patent•
06 Aug 1986
TL;DR: In this article, a process for the preparation of a compound of formula (I): wherein Ar is aryl or substituted aryls and R³ is hydrogen, alkyl or aralkyl, which process comprises reducing a compoundof formula (II), wherein Ar and R ³ are as defined with respect to formula(I) and R Ω is alkyls Compounds of formula(II) are useful as chemical intermediates
Abstract: A process is disclosed for the preparation of a compound of formula (I): wherein Ar is aryl or substituted aryl and R³ is hydrogen, alkyl or aralkyl, which process comprises reducing a compound of formula (II): wherein Ar and R³ are as defined with respect to formula (I) and R⁴ is alkyl Compounds of formula (I) are useful as chemical intermediates
TL;DR: A series of piperidine derivatives with a 2-oxo-1, 2, 3, 4-tetrahydro-quinazoline ring at the 4-position produced relatively strong hypotension in the spontaneously hypertensive rat model.
Abstract: A series of piperidine derivatives with a 2-oxo-1, 2, 3, 4-tetrahydro-quinazoline or 2, 4-dioxo-1, 2, 3, 4-tetrahydroquinazoline ring at the 4-position were prepared and tested for antihypertensive activity. Among the compounds tested, 1-[2-hydroxy-2-(3, 4-methylenedioxyphenyl)ethyl]-4-(2, 4-dioxo-1, 2, 3, 4-tetrahydro-3-quinazolinyl)piperidine (20) and 1-[2-(4-chlorophenyl)-2-hydroxyethyl]-4-(2-oxo-1, 2, 3, 4-tetrahydro-3-quinazolinylmethyl)piperidine (30) produced relatively strong hypotension in the spontaneously hypertensive rat model.
TL;DR: The second-order rate coefficient is almost insensitive to the amine concentration in chloroform, acetonitrile, and nitromethane; for the other solvents this value of k3/k2 is greater than 102, indicating neat base catalysis.
Abstract: The kinetics of the reaction between 1-fluoro-2,4-dinitrobenzene and piperidine were studied in toluene, benzene, dioxane, trichloroethane, tetrahydrofuran, chlorobenzene, ethyl acetate, chloroform, dichloromethane, acetone, acetonitrile, and nitromethane. The second-order rate coefficient is almost insensitive to the amine concentration in chloroform, acetonitrile, and nitromethane; for the other solvents this value of k3/k2 is greater than 102, indicating neat base catalysis. The trend in k3/k2 does not follow the solvent basicity order; the solvents insensitive to base catalysis are those which exhibit hydrogen-bond donor (HBD) properties. These results are interpreted as an indication that in this reaction the detachment of the nucleofuge is the rate-limiting step in most of the aprotic solvents studied; those solvents which are HBD assist the departure of fluoride, and the formation of the intermediate is the rate-determining step. This conclusion was confirmed by kF/kCl determinations. A simple linear energy solvation correlation was found between the parameter ET(30) and kA obtained at [B] < 10–2M. For higher amine contents increasing deviations were found.
TL;DR: Aminolysis of α,β-epoxy sulfoxides with weak Lewis acid led to 2,3-disubstituted indoles as discussed by the authors, and treatment of α-arylamino ketones with weak lewis acid led with 2, 3-dissubstituting indoles.
Abstract: Aminolysis of α,β-epoxy sulfoxides, easily prepared from 1-chloroalkyl phenyl sulfoxides or chloromethyl phenyl sulfoxide and carbonyl compounds, with alkyl- or arylamines afforded α-amino ketones or α-amino aldehydes in good yields. Treatment of thus obtained α-arylamino ketones with weak Lewis acid led to 2,3-disubstituted indoles.
TL;DR: In this paper, the authors studied the aminolysis of aryl diphenylphosphinates and diamines in acetonitrile, showing that diamines > butylamine > sec-amines.
Abstract: The aminolysis of aryl diphenylphosphinates, p-nitrophenyl diphenylphosphinothionate, -phosphinothioate, and -phosphinodithioate by n-butylamine, by the secondary amines piperidine, pyrrolidine, morpholine, and dipropylamine, as well as by a series of diamines, has been studied in acetonitrile. The general reactivity order is diamines > butylamine > sec-amines. Butylaminolysis follows a two-term rate law, one first order in amine and the other second order in amine. The second order in amine term predominates. sec-Amines and diamines follow a rate law which is first order in amine only. Leaving group effects, solvent effects, and activation parameters support a pathway which involves rate-determining collapse of a zwitterionic pentacoordinate intermediate. In the case of butylamine this collapse is general base catalyzed and for the diamines the reaction is intramolecularly general base catalyzed.
TL;DR: The N-alkenyl imidates with benzeneselenenyl chloride and bromide in chloroform at ambient temperature afford pyrrolidine and piperidine derivatives having a phenylseleno moiety in good to excellent yields under neutral conditions as discussed by the authors.
Abstract: The reactions of N-alkenyl imidates with benzeneselenenyl chloride and bromide in chloroform at ambient temperature afford pyrrolidine and piperidine derivatives having a phenylseleno moiety in good to excellent yields under neutral conditions. The key step of this new reaction consists of an intramolecular carbon–nitrogen bond formation and a simultaneous carbon–oxygen bond fission.
TL;DR: The synthesis of 5,10-dideazaaminopterin by two independent routes is described in this paper, where the pteroate intermediate with glutamate yielded the target 5, 10-dinopterin.
TL;DR: In this article, a regiospecific synthesis of 2,6-disubstituted pyridines and 1,3-dissubstitized isoquinolines is described.
TL;DR: In this article, the first known chelates of γ-mercaptomethylpiperidines with planar S2PdX2 metal environments have been presented.
Abstract: The complexes [Pd(HL)X2][X = Cl (1a) or Br (1b)], [(PdLX)2][X = Cl (2a), Br (2b), or I (2c)], and [Pd3L4]Cl2·2H2O (3), where HL and L denote respectively 3-(mercaptomethyl)piperidine in its zwitterionic and anionic forms, have been prepared and characterized. Complex (3) has been shown crystallographically to contain centrosymmetrical trinuclear cations where terminal PdL2 units, containing cis-S2PdN2 square-planar metal environments, are bound also in a square-planar fashion to a central palladium atom through bridging mercapto groups. The three planar metal environments exhibit equivalent dihedral angles. Complexes (2) exhibit trans mercapto-bridged dimeric structures containing S2PdNX square-planar metal centres. Similar sulphur-bridged dimeric structures, with planar S2PdX2 metal environments, are proposed for complexes (1). Complexes (2) and (3) are among the first known chelates of γ-mercaptopiperidines.
TL;DR: In this paper, the reactivities of 3-acetyl-2H-1-benzo-pyran-2-one and 4-(2-arylvinyl)-3acetyl 2H 1-benzopyran 2-ones were compared in the condensation with aromatic aldehydes.
TL;DR: The ring of 1-mesyl (1c) and 1-(phenylcarbamoyl)-2-phenylaziridine (1d) is opened between N and C-2 (benzylic effect) by some nucleophiles in high yields as mentioned in this paper.
Abstract: Reactions with Aziridines, 38. On the Regioselectivity of the Nucleophilic Ring Opening of Activated 2-Phenylaziridines
The ring of 1-mesyl (1c) and 1-(phenylcarbamoyl)-2-phenylaziridine (1d) is opened between N and C-2 (benzylic effect) by some nucleophiles in high yields.
TL;DR: In this article, the oxidation of a number of secondary amines coordinated to ruthenium(II) was investigated, and preliminary results indicated that the 1-aza 1,3-diene (11) product would undergo a Diels-Alder reaction while attached to the metal centre.
Abstract: The oxidation of a number of secondary amines coordinated to ruthenium(II) was investigated. Pyrrolidine (1) and piperidine (5) formed the corresponding 1-imines [1-pyrroline (2) and 2,3,4,5- tetrahydropyridine (6)]; these complexes were stable, although spectral and electrochemical properties show there to be only minor π-back- bonding between the RuII metal centre and the imine ligands. The analogous β-unsaturated amines [3-pyrroline (3) and 1,2,3,6- tetrahydropyridine (7)] complexes also underwent oxidative dehydrogenation reactions, and in these cases produced the corresponding aromatic species [pyrrole (4) and pyridine (8), respectively]. Coordinated N-methylallylamine (9) was oxidized to a mixture of the two possible 1-imine species (10) and (11), and preliminary studies indicated that the 1-aza 1,3-diene (11) product would undergo a Diels-Alder reaction while attached to the metal centre.
Patent•
26 Feb 1986TL;DR: In this article, the authors describe compounds of the formula I with activity as calcium channel blockers and accordingly, are useful as agents for lowering blood pressure, and as agent for treating ischemia.
Abstract: Compounds of the formula ##STR1## wherein R 1 is phenyl substituted with 1 to 3 lower alkoxy groups or 1 to 3 halogens; R 2 is hydroxy, lower alkoxy, lower alkanoyloxy, lower cycloalkylcarbonyloxy; ##STR2## R 3 and R 4 are independently lower alkyl, phenyl lower alkyl or together form a piperidine or pyrrolidine ring; n is 2 to 4; m is 1 to 2; or pharmaceutically acceptable acid addition salts thereof are described. The compounds of formula I have activity as calcium channel blockers and accordingly, are useful as agents for lowering blood pressure, and as agents for treating ischemia.
Patent•
07 Nov 1986
TL;DR: Analogs of nipecotic acid are the novel compounds of the present invention as mentioned in this paper, which are GABA uptake inhibitors for use to treat epilepsy and thus, thus, pharmaceutical compositions for the treatment of epilepsy.
Abstract: Analogs of nipecotic acid are the novel compounds of the present invention. The analogs are GABA uptake inhibitors for use to treat epilepsy and, thus, the invention is also pharmaceutical compositions for the treatment of epilepsy.
TL;DR: In this article, the stereoselective preparation of the cis-isomer was achieved by the following two methods: first one involves selective transformation of ethyl 4-bromo-6,6, 6-trichloro-3,3-dimethylhexanoate (8a) with piperidine followed by the selective conversion of 8a to cis-2,2-dichloroencarcboxylate (cis-5a) without cis-trans isomerization.
Abstract: A synthesis of the title compounds 5 involves the reaction between 3-methyl-2-buten-1-ol and triethyl orthoacetate to produce ethyl 3,3-dimethyl-4-pentenoate, which is followed by the addition of various carbon tetrahalides to the double bond. The reaction of resulting adducts with a base affords 5 in high yields. Stereoselective preparation of the cis-isomer was achieved by the following two methods: First one involves selective transformation of ethyl 4-bromo-6,6,6-trichloro-3,3-dimethylhexanoate to ethyl 6,6,6-trichloro-3,3-dimethyl-4-hexenoate (8a) with piperidine followed by the selective conversion of 8a to cis-2,2-dichloroethenyl compound (cis-5a). Second one is based on the stereoselective cyclization of ethyl 4,6,6,6-tetrachloro-3,3-dimethylhexanoate (t-BuONa/solvent/HMPA) to ethyl cis-2,2-dimethyl-3-(2,2,2-trichloroethyl)cyclopropanecarboxylate which is transformed into cis-5a without cis-trans isomerization.
TL;DR: In this article, thermolysis of p-azidoacetophenone in piperidine gave 5-acetyl-2-piperidino-3H-azepine and an unusual product, 6acetyl2-2 piperidin-3-hexadecane-3h-enzine, and p-aminoacetphenone.
Abstract: Thermolysis of several p-substituted aryl azides (p-R-C6H4N3; R=COCH3, CO2CH3, COPh) in methanol gave 5-substituted 2-methoxy-3H-azepines in moderate yields. Thermolysis of m-substituted aryl azides (m-R-C6H4N3; R=COCH3, CO2CH3, COPh, NO2) gave 4-substituted 2-methoxy-3H-azepines and 6-substituted 2-methoxy-3H-azepines in good yields. In contrast, thermolysis of p-azidoacetophenone in piperidine gave 5-acetyl-2-piperidino-3H-azepine and an unusual product, 6-acetyl-2-piperidino-3H-azepine, and p-aminoacetophenone.