Saturday, February 19, 2011

Phloroglucinol

Phloroglucinol
Identifiers
CAS number 108-73-6 YesY
PubChem 359
RTECS number UX1050000
Properties
Molecular formula C6H6O3
Molar mass 126.11 g/mol
Exact mass 126.031694
Appearance white solid
Melting point 218-220 °C
Solubility in water 1 g/100 mL
Hazards
EU classification Harmful (Xn)
 YesY(what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
Phloroglucinol is a benzenetriol. It is an organic compound that is used in the synthesis of pharmaceuticals and explosives. This molecule exists in two forms, or tautomers, 1,3,5-trihydroxybenzene, which has phenol-like, and 1,3,5-cyclohexanetrione (phloroglucin), which has ketone-like character. These two tautomers are in equilibrium. Phloroglucinol is a useful intermediate because it is polyfunctional.
Tautomeric equilibrium
From water, phloroglucinol crystallizes as the dihydrate, which has a melting point of 116-117 °C, but the anhydrous form melts much higher, at 218-220 °C. It does not boil intact, but it does sublime.

Contents

  • 1 Isolation, synthesis, and reactions
  • 2 Natural occurrence
  • 3 Metabolism
  • 4 Applications

Isolation, synthesis, and reactions

Phloroglucinol was originally isolated from bark of fruit trees. It is synthesized via a number of processes, but representative is the following route from trinitrobenzene:[1]
Phlorosynth.png
The synthesis is noteworthy because ordinary aniline derivatives are unreactive toward hydroxide. Because the triaminobenzene also exists as its imine tautomer, it is susceptible to hydrolysis.
The compound behaves like a ketone in its reaction with hydroxylamine, forming the tris(oxime). But it behaves also like a triphenol (Ka1 = 3.56 × 10−9, Ka2 1.32×10−9), as the three hydroxyl groups can be methylated to give 1,3,5-trimethoxybenzene.[1]

Natural occurrence

Phloroglucinols occur naturally in certain plant species. For example, they (and sometimes their acyl dervatives) are present in the fronds of the coastal woodfern, Dryopteris arguta.[2] Brown algae also produce phloroglucinol derivatives[3][4] known as phlorotannins.[5]

Metabolism

Phloretin hydrolase uses phloretin and water to produce phloretate and phloroglucinol.

Applications

Phloroglucinol is mainly used as a coupling agent in printing. It links diazo dyes to give a fast black.
It is useful for the industrial synthesis of pharmaceuticals[6] and explosives.[7] It is also used as a treatment for gallstones, spasmodic pain and other related gastrointestinal disorders.[8][9][10] It has a non-specific spasmolytic action on the vessels, bronchi, intestine, ureters and gall bladder, and is used for treating disorders of these organs.

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