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Piperidine is widely used to convert ketones to enamines. [23] Enamines derived from piperidine are substrates in the Stork enamine alkylation reaction. [24] Upon treatment with calcium hypochlorite, piperidine converts to N-chloropiperidine, a chloramine with the formula C 5 H 10 NCl.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
Due to its poor solubility in water, piperine is typically extracted from black pepper by using organic solvents like dichloromethane. [5] The amount of piperine varies from 1–2% in long pepper, to 5–10% in commercial white and black peppers.
The nearer two molecules are in this three-dimensional space, the more likely they are to dissolve into each other. To determine if the parameters of two molecules (usually a solvent and a polymer) are within range, a value called interaction radius ( R 0 {\displaystyle R_{\mathrm {0} }} ) is given to the substance being dissolved.
Note that the especially high molar values, as for paraffin, gasoline, water and ammonia, result from calculating specific heats in terms of moles of molecules. If specific heat is expressed per mole of atoms for these substances, none of the constant-volume values exceed, to any large extent, the theoretical Dulong–Petit limit of 25 J⋅mol ...
[35] [36] The suggestion by Körner and Dewar was later confirmed in an experiment where pyridine was reduced to piperidine with sodium in ethanol. [37] [38] In 1876, William Ramsay combined acetylene and hydrogen cyanide into pyridine in a red-hot iron-tube furnace. [39] This was the first synthesis of a heteroaromatic compound. [24] [40]
Dimethylpiperidines are derivatives of the heterocycle piperidine, wherein two hydrogen atoms are replaced by methyl groups. The 2,6-dimethylpiperidines are prepared by reduction of 2,6-dimethylpyridine (2,6-lutidine). The achiral isomer is the predominant isomer produced in this reaction.
Lobeline is a piperidine alkaloid found in a variety of plants, particularly those in the genus Lobelia, including Indian tobacco (Lobelia inflata), Devil's tobacco (Lobelia tupa), great lobelia (Lobelia siphilitica), Lobelia chinensis, and Hippobroma longiflora. In its pure form, it is a white amorphous powder which is freely soluble in water.