piperidines and 2-methylpiperidine

A series of organically templated vanadium selenites has been prepared under mild hydrothermal conditions. Single crystals of [C5H14N2][(VO)3(SeO3)2(HSeO3)4], [C5H14N2][VO(SeO3)2], [(R)-C5H14N2][(VO)3(SeO3)2(HSeO3)4], and [(S)-C5H14N2][(VO)3(SeO3)2(HSeO3)4] were grown from VOSO4, SeO2, and 2-methylpiperazine. Controlling the initial pH of the reaction mixture allows for one to select between the compounds found in the VOSO4/SeO2/2-methylpiperazine system, as the solution pH directly affects the relative ratio of the HSeO3(-) and SeO3(2-) concentrations. Moreover, partial resolution of racemic 2-methylpiperazine is observed in [C5H14N2][(VO)3(SeO3)2(HSeO3)4], which is understood through the use of a one-dimensional Ising model. The use of enantiomerically pure 2-methylpiperazine results in fully ordered and fully resolved structures.

Topics: Hydrogen Bonding; Hydrogen-Ion Concentration; Models, Molecular; Molecular Structure; Organometallic Compounds; Piperidines; Selenious Acid; Spectroscopy, Fourier Transform Infrared; Vanadium Compounds; X-Ray Diffraction

We report a practical 2-hydroxy-3-mercapto-propionic acid (Hmp)/2-methylpiperidine (2-MP) based Fmoc chemistry procedure to prepare the C-terminal Hmp peptides, which serve as the precursors of C-terminal thioester peptides. The subsequent O to S acyl shift and thiol-exchange mediated thioester conversion of the crude precursor peptides can be accomplished smoothly under mild conditions to provide the desired thioester peptides with good yield and high quality. This is a highly adaptable approach, and we envision its broad application in the preparation of C-terminal thioester peptides.

Topics: Amino Acids; Fluorenes; Molecular Structure; Peptides; Piperidines; Sequence Analysis, Protein; Sulfhydryl Compounds

Double protection: Efficient Fmoc-based solid-phase synthesis (SPPS) of sulfotyrosine (sY) peptides is achieved by incorporating the sY residue(s) as a dichlorovinyl-protected (DCV) sulfodiester(s) and using 2-methylpiperidine for Fmoc removal. After removal of the other protecting groups, the DCV group could be cleaved by mild hydrogenolysis giving the sY peptides in good yield.

Topics: Amino Acid Sequence; Molecular Sequence Data; Peptides; Piperidines; Sulfides; Tyrosine

The experimental and theoretical vibrational spectra of 2 and 3-methylpiperidine (abbreviated as 2-MP and 3-MP) were studied. The FT-Infrared spectra of 2-MP and 3-MP molecules were recorded in the liquid phase. The structural and spectroscopic analysis of the title molecules were made by using density functional harmonic calculations. For the title molecules, only one form was found most stable structure by using B3LYP level with the 6-311G (d,p) basis set. Selected experimental bands were assigned and characterized based on the scaled theoretical wave numbers by their total energy distribution (TED).

Topics: Carbon; Computer Simulation; Hydrogen Bonding; Models, Molecular; Molecular Structure; Nitrogen; Piperidines; Quantum Theory; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Vibration

The effects of ethylketazocine (EKC) administered intraperitoneally and the nicotinic ligands (-)- and (+)-nicotine, (-)-cytisine, (-)-lobeline, and (+)-2-methylpiperidine administered into the 4th ventricle on the latency of the thermally evoked withdrawal reflex of the decerebrate rat were investigated. EKC administered intraperitoneally produced both hyperalgesia and analgesia. (-)-Nicotine administered into the 4th ventricle produced a biphasic dose related effect on the latency of the withdrawal reflex; low doses produced a dose related analgesia while higher doses produced hyperalgesia. (-)-Cytisine and (-)-lobeline administered into the 4th ventricle produced biphasic effects. (+)-2-Methylpiperidine administered into the 4th ventricle produced a significant degree of hyperalgesia. Both the analgesic and hyperalgesic effects of (-)-nicotine were antagonized by mecamylamine (1 mg/kg) and naltrexone (5 mg/kg). The hyperalgesic action of (+)-2-methylpiperidine was antagonized by naltrexone but not by mecamylamine. These observations suggest that there are both medullary opioidergic and nicotinic cholinergic mechanisms for modulating both analgesic and hyperalgesic processes and that nicotinic ligands have multiple mechanisms of action in the brain.

Topics: Analgesics, Opioid; Animals; Cyclazocine; Cystine; Decerebrate State; Endorphins; Ethylketocyclazocine; Female; Hyperalgesia; Hyperesthesia; Lobeline; Medulla Oblongata; Nicotine; Piperidines; Rats; Rats, Inbred Strains

Four distinguishable nicotinic binding sites have been identified as well as four nicotinic ligands with different specificities: (+/-)-2-methylpiperidine which binds to a very high affinity site (Site 1) and produces up-regulation of the high affinity site (Site 2); (-)-nicotine which binds to Site 1 and Site 2 as well as to a low affinity site (Site 4); (+)-nicotine which binds to Site 1, Site 4 and Site 3 which is also a high affinity site; and (-)-cytisine which binds to Sites 1 and 2. These drugs were injected into the 4th ventricle of 5 dogs in graded concentrations (12.5 to 400 micrograms) and their effects on the EEG, skin twitch reflex latency, heart rate, rectal temperature, pupillary diameter, blood pressure and the amplitude of the flexor reflex were measured. Drugs which act predominantly on Site 1 [(+/-)-2-methylpiperidine and (+)-nicotine] produced EEG synchronization and hyperalgesia while drugs which interact with Sites 2 and 4 produce EEG desynchronization, analgesia and tachycardia. These data indicate that nicotinic ligands which have different binding specificities have different actions in medullary function and support the hypothesis that the different binding sites have different pharmacologic significance.

Topics: Alkaloids; Animals; Azocines; Blood Pressure; Body Temperature; Decerebrate State; Dogs; Electroencephalography; Heart Rate; Injections, Intraventricular; Nicotine; Pain Measurement; Piperidines; Pupil; Quinolizines; Receptors, Nicotinic; Stereoisomerism

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.

Topics: Acetylcholine; Animals; Binding Sites; Brain; Female; Nicotine; Piperidines; Pyridines; Pyrrolidines; Rats; Structure-Activity Relationship

(+/-)-2-Methylpiperidine has a high degree of specificity in enhancing the binding of (-)-[3H]nicotine in the rat brain P2 preparation. (-)- and (+)-2-Methylpiperidine have been resolved. The (+) but not the (-) isomer increased the binding of (-)-[3H]nicotine. The two isomers were equally effective in inhibiting the binding of (-)-[3H]nicotine in high concentrations. These data provide additional support for a stereospecific nicotinic up-regulatory site.

Topics: Animals; Brain; Female; Nicotine; Piperidines; Rats; Rats, Inbred Strains; Stereoisomerism

Topics: Piperidines