Piperidine derivative complexes

A somewhat more complex scheme is required for the preparation of benzimidazolones in which one of the nitrogen atoms is substituted by a 4-pi peridyl group. The sequence starts with aromatic nucleophilic substitution on dichlorobenzene by protected amino-piperidine derivative to give Reduction of the... 

The ZwKKER reaction involving Co salts is frequently used for the detection of barbituric acid derivatives [31-35], but some purine, pyridine and piperidine derivatives and heterocyclic sulfonamides also yield colored derivatives. The Zwkker reaction is particularly sensitive when it is possible to form a tetrahedral complex [Co(Barb)2 Xj] (X = donor ligand, e.g. amine) [4]. 

The mercury(II) acetate oxidation of tertiary amines is frequently used to introduce unsaturation into piperidine derivatives. The iminium ion is believed to be an intermediate in this reaction. These ions can give the enamine or react further with nucleophiles to give more complex heterocycles (Scheme 4). 

A number of adducts of bis(acetylacetonato)nickel(lI) have been studied by H and 13C NMR spectroscopy.39739,407"423 In several cases, always when aromatic bases are involved, the shifts of both protons and carbons cannot be accounted for by cr- and r-delocalization mechanisms. Similar results have been found for non-aromatic amines such as piperidine derivatives, showing that in these complexes there are also alternating 13C contact shifts which have been accounted for by inclusion of spin polarization in the mechanism of electron spin transfer through the carbon skeleton with INDO-MO calculations.412... 

Not much is known of its chemistry. Positive tests for alkaloids have been obtained in several species S-hydroxytryptamine has been identified in Urlica the substance responsible for the burning sensation from the leaves of Laporlea is a complex octapeptidc piperidine derivatives are found in the family as well. 

Optically active (—)-sparteine, a piperidine-derived alkaloid complexed with palladium chloride 33, has been used in the enantioselective oxidation of benzyl alcohol derivatives <2005JA14817>. 4-Hydroxy-TEMPO 34 serves as an efficient catalyst for the continuous production of aldehydes from alcohols and bleach in a tube reactor (TEMPO = 2,2,6,6-tetramethyl-piperidine-l-oxyl) <20050PD577>. 

The chiral piperidinones 46 formed by the reaction between Danishefsky s diene and the glycosyl imines are valuable synthons for the synthesis of higher substituted piperidine derivatives. 2,6-Disubstituted piperidinones 49 are obtained by addition of organocuprates complexes with boron trifluoride [53]. The reaction pathway is illustrated in Scheme 30. 

D.W. Grattan, A.H. Reddoch, D.J. Carlsson, and D.M. Wiles, Polymer photostabilization by piperidine derivatives the role of nitroxide-hydroperoxide complexing, J. Polym. Sci. Polym. Lett. Ed. 1978, 16, 143-148. 

From [(cod)IrCl]2 the pincer complex 1 is prepared. It is stable to air and water, and shows catalytic activity for hydroamination (e.g., to form pyrrolidine and piperidine derivatives). ... 

Motivated by the fact that polyolefins are stabilized using piperidine derivatives that can leach with time, the copolymerization of a-olefins with polymerizable piperidine derivatives was investigated. Hindered vinyl piperidines (e.g., Pip-I) can complex with aluminum compounds and incorporate into copolymers with propylene using commercial TiCh/MgCF Ziegler—Natta catalysts. ... 

Some ion-vapor pairs were projected to form two kinds of complexes core where the ion binds the vapor molecule strongly (e.g., via H" " for reasonably protic species) and facade with essentially van der Waals bonding. Other ions and/or vapors that lack the functionality for strong binding form only facade complexes. This idea was illustrated for piperidine derivatives that often form H" "-bound dimers at the amine. For pentamethylpiperidine, steric hindrance precludes such core complexes and only facade ones are aUowed. In contrast, the hydroxyl... 

Carbohydrates are inexpensive and renewable natural products which contain numerous functional groups and chiral centers. Utilizing their pronounced complexing abilities and their content of chiral information, carbohydrates are applied as chiral auxiliaries in Diels-Alder and aza-Diels-Alder reactions. The method involves the use of Lewis acid catalysts with different complexing properties. Thus, dienes of low reactivity can be transformed to their cycloadducts with high asymmetric induction. The use of N-glycosyl imines as the dienophiles offers stereoselective access to enantiomerically pure piperidine derivatives, e.g. the alkaloids coniin and anabasin. 

As in the case of the piperidine derivatives, azepine drugs in complex with protein were searched for in the PDB using the MSD server. Since the number of hits was very low no resolution criteria was used for this search that yielded one each in azepin and benzothiazepine and five in fused-diazepine (Table 6). 

Aminoalkenes can undergo cyclization via intramolecular hydroamination in the presence of Ti complexes, yielding predominantly pyrrolidine and piperidine derivatives. Good results for forming pyrrolidine derivatives were generally obtained withTi(NMe2)4 [317] (Scheme 14.137). 

In spite of electron withdrawing action of four fluorine atoms, 4,5,6, 7-tetrafluoroindole 132 reacts with electrophiles under quite mild conditions to give products of substitution at the 3-position. For example, reaction of 132 with AT-(carbobenzyloxy)piperidin-4-one 168 in the presence of trimethylsilyl triflate and tiiethylsilane afforded the corresponding piperidine derivative 169 [62], Using sulfur ttioxide-pyridine complex indolyl sulfonic acid 170 was obtained, which was further converted into sulfonyl amide 172 by reaction with phosphoms(V) oxychloride, followed by treatment with derivative of piperazine [2a],... 

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