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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
10
|
| pubmed:dateCreated |
1985-6-27
|
| pubmed:abstractText |
(1R)-1-3H-labeled and (1S)-1-3H-labeled geranyl pyrophosphate and neryl pyrophosphate were prepared from the corresponding 1-3H-labeled aldehydes by a combination of enzymatic and synthetic procedures. Following admixture with the corresponding 2-14C-labeled internal standard, each substrate was converted to (+)-bornyl pyrophosphate and (-)-bornyl pyrophosphate by cell-free enzyme preparations from sage (Salvia officinalis) and tansy (Tanacetum vulgare), respectively. Each pyrophosphate ester was hydrolyzed, and the resulting borneol was oxidized to camphor. The stereochemistry of labeling at C-3 of the derived ketone was determined by base-catalyzed exchange, taking advantage of the known selective exchange of the exo-alpha-protons. By comparison of such exchange rates to those of product generated from (1RS)-2-14C,1-3H2-labeled substrate, it was demonstrated that geranyl pyrophosphate was cyclized to bornyl pyrophosphate with net retention of configuration at C-1 of the acyclic precursor, whereas neryl pyrophosphate was cyclized to product with inversion of configuration at C-1. The observed stereochemistry is consistent with a reaction mechanism whereby geranyl pyrophosphate is first stereospecifically isomerized to linalyl pyrophosphate which, following rotation about C-2-C-3 to the cisoid conformer, cyclizes from the anti-endo configuration. Neryl pyrophosphate cyclizes either directly or via the linalyl intermediate without the attendant rotation.
|
| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
May
|
| pubmed:issn |
0021-9258
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
25
|
| pubmed:volume |
260
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
5956-62
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading | |
| pubmed:year |
1985
|
| pubmed:articleTitle |
Stereochemistry at C-1 of geranyl pyrophosphate and neryl pyrophosphate in the cyclization to (+)- and (-)-bornyl pyrophosphate.
|
| pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, U.S. Gov't, P.H.S.
|