Synonyma a chemické vlastnosti

Synonyma

• Beta-iminazolylethylamine
• "H substance" or "substance H"

Chemicky

• Organic nitrogenous compound
• Imidazole ring attached to an ethylamine chain
• Amino group of the side-chain is protonated [1]

• Histamine base
• Mineral oil mull
• Melts at 83–84 °C

• Hydrochloride and phosphorus salts
• Form white hygroscopic crystals
• Easily dissolved in water or ethanol
• But not in ether

• In aqueous solution
• Imidazole ring of histamine exists in two tautomeric forms
• Which of the two nitrogen atoms is protonated

• Nitrogen farther away from the side chain
• 'tele' nitrogen
• Is denoted by a lowercase tau sign
• Nitrogen closer to the side chain
• 'pros' nitrogen
• Denoted by the pi sign
• Tele tautomer, Ntau-H-histamine
• Preferred in solution as compared to the pros tautomer, Npí-H-histamine [1]

• Histamine has two basic centres
• Aliphatic amino group
• Nitrogen atom of the imidazole ring
• Aliphatic amino group
• Having a pKa around 9.4
• Will be protonated

• Second nitrogen of the imidazole ring
• PKa 5.8
• Will not be protonated

• histamine is normally protonated to a singly charged cation
• Histamine is a monoamine neurotransmitter [1]

Historie

• 1907 připraven chemiky Windausem a Vogtem
• 1910 byl v nepatrném množství izolován z námelového výtažku
• First described - British scientists Henry H. Dale and P.P. Laidlaw
• 1913 the name histamine was in use
• Histo- + amine, yielding "tissue amine" [1]