Geranyl pyrophosphate hydrolysis

The product of this reaction is geranyl pyrophosphate Hydrolysis of the pyrophosphate ester group gives geramol a naturally occurring monoterpene found m rose oil... 

Prenyl transferase, which catalyses the addition of an allylic pyrophosphate to iso-pentenyl pyrophosphate, also catalyses the hydrolysis of geranyl pyrophosphate.104 Inorganic pyrophosphate stimulates this hydrolysis, and the C—O bond is broken in... 

Simple transformations (hydrolysis of the pyrophosphate group to a hydroxy group, elimination, oxidation, etc.) convert geranyl pyrophosphate to monoterpenes such as geraniol, myrcene, and citronellal. 

Novel findings are still to be had from even well-studied systems. Highly purified prenyltransferase from porcine liver that catalysed the formation of geranyl pyrophosphate [GPP, (3)] or farnesyl pyrophosphate (FPP) from IPP also feebly catalysed the hydrolysis of its allylic substrate. This hydrolysis is stimulated by... 

Most acyclic monoterpenes exhibit the head-to-tail arrangement of C units, and it is natural to suggest that geranyl pyrophosphate (GPP), the first Cio compound to arise from mevalonate (Fig. 1), is the precursor of such monoterpenes. Geraniol, which is rather widespread in the plant kingdom, undoubtedly arises in vivo by hydrolysis of the corresponding pyrophosphate. Linalool may also arise directly from GPP. Although such an enzy-... 

Biosynthesis. The starting compound is geranyl pyrophosphate (see Terpenes). Acyclic D. are formed by hydrolysis of the pyrophosphate residne (e.g. phytol). Geranylgeranylpyrophosphate is probably converted easily to geranyl linalool, which is then converted to bi- and tricyclic compoimds (Rg.). In a few of the cyclic D-, e. g. abietic acid, there is a migration of the substituents. The gibberellins are derived from the labda-diene type of D. 

M. are biosynthesized from geranyl pyrophosphate (see Terpenes) via its isomer neryl pyrophosphate (Fig.). Aliphatic M. arise by hydrolysis of the phosphate bond, or the elimination of pyrophosphate (synthesis of 3,7-dimethyloctane type). Cyclic M. usually arise by nucleophilic substitution at Cl of the neryl pyrophosphate with loss of pyrophosphate. Iridoid compounds arise from the reductive cyclization of neryl pyrophosphate. 

Allylic hydrolysis of geranyl pyrophosphate produces linalool (92). Like geraniol, linalool occurs widely in nature. The richest source is ho leaf, the oil of which can contain well over 90% linalool. Other rich sources include linaloe, rosewood, coriander, freesia, and honeysuckle. Its acetate is also frequently encountered and is a signi cant contributor to the odors of lavender and citrus leaf oils. 

Just as geraniol (63) is the precursor for all the monoterpenoids, famesol (111) is the precursor for all the sesquiterpenoids. Its pyrophosphate is synthesized in nature by the addition of isopentenyl pyrophosphate (66) to geranyl pyrophosphate (68) as shown in Figure 5.14 and hydrolysis of that gives famesol. Incipient heterolysis of the carbon-oxygen bond of the phosphate gives the nascent... 

Hydrolysis of geranyl pyrophosphate and farnesyl pyrophosphate produces the terpenes geraniol and farnesol, respectively (Fig. 12.74). 

Aqueous hydrolysis of geranyl and farnesyl pyrophosphates forms the monoterpene geraniol and the sesquiterpene famesol, respectively. 

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