N-methyl Piperidine Research Articles

ChemInform Abstract: STRUCTURAL EFFECTS IN THE INTERMOLECULAR EXCIPLEX FORMATION OF 2‐METHYLNAPHTHALENE AND TERTIARY AMINES

The quenching rate constant of 2-methylnaphthalene (2 MN) with triethylamine (TEA) and N-methylpiperidine (NMP) in a polar protic solvent is found to be less than diffusion controlled. In a non polar solvent the exciplex stabilisation and entropy of formation indicate a tighter bound complex for the 2 MN-TEA system than for 2 MN-NMP. Both observations are interpreted as arising from geometric restrictions in the approach of the amine to the excited 2-methylnaphthalene.

Structural effects in the intermolecular exciplex formation of 2‐methylnaphthalene and tertiary amines

AbstractThe quenching rate constant of 2‐methylnaphthalene (2 MN) with triethylamine (TEA) and N‐methylpiperidine (NMP) in a polar protic solvent is found to be less than diffusion controlled. In a non polar solvent the exciplex stabilisation and entropy of formation indicate a tighter bound complex for the 2 MN‐TEA system than for 2 MN‐NMP. Both observations are interpreted as arising from geometric restrictions in the approach of the amine to the excited 2‐methylnaphthalene.

The temperature dependence of saturated amine fluorescence

The temperature dependence of fluorescence intensity of several saturated amines was studied. For “flexible” amines such as triethylamine (TEA), dimethylethylamine (DMEA), triethylemine, tri- n-octylamine (TOA), and N-methylpiperidine (NMP), it was found that I f increased as the temperature was increased. For example, in DMEA, I f increases by a factor of ca. 77 between −100 and 100°C. These results are interpreted in terms of an activated configurational change from the initially-formed (nonfluorescent) state to a relaxed (fluorescent) state in these compounds. Activation energies for these conversions range from about 1.8 kcal/mole for TOA to about 4.3 kcal/mole for TEA. Rigid, bicyclic amines having bridgehead N-atoms such as 1-azabicyclo [2.2.2] octane (ABCO) and its [3.3.3] analog were found to have temperature independent fluorescence intensities. These results were assumed to reflect the difference in energetics between the initially-formed and relaxed states relative to the “flexible” amines.

An introduction to principles of veterinary clinical pharmacology: general principles.

Abstract Extract A drug is a chemical substance that acts in a biological system to preferentially give a beneficial pharmacological or chemotherapeutic effect. The effects of drugs are well documented and drugs are sometimes classified on the basis of their principal effect. With certain exceptions most drugs are thought to produce their effects by combining with enzymes, cell membranes, or other specialized functional components of cells. The effects of a drug in a biological system must be regarded as ultimate consequences of physico-chemical interaction between the drug and functionally important molecules in the living organism, that is, receptor sites (Goldstein et al, 1968 Goldstein, A., Aronow, L. and Kaiman, S. M. 1968. Principles of Drug Action: The Basis of Pharmacology, 1–30. New York: Harper and Row. [Google Scholar]). Morphine and its surrogates, for example, produce their major effects on the central nervous system and the bowel. Structurally, the narcotic analgesics may be thought of as N-methyl piperidine compounds with bulky ring substituents. Receptor attachment (Beckett and Casy, 1954 Beckett, A. H. and Casy, A. F. 1954. Synthetic analgesics: stereochemical considerations. J. Pharm. Pharmac., 6: 986–1001. [Google Scholar]) and analgesic activity (Gero, 1954 Gero, A. 1954. Science, 119: 112–114. Cited by Cutting, W. C. (1969), in Handbook of Pharmacology, 4th ed. p. 631. Appleton-Century-Crofts, New York. [Google Scholar]) are related to the γ-phenyl-N-methyl piperidine moiety of morphine, methadone, pethidine and their derivatives. The attachment of drug to receptors usually involves ionic and other relatively weak, reversible bonds. Occasionally, firm covalent bonds are involved and the, drug effect is only slowly reversible. An example of drug-receptor interaction through formation of a covalent bond is the long-lasting inhibition of the Cholinesterase enzymes by organic phosphates and carbamates.