Exercício de Química Sintética e Organica Mista (744)

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(d) The distribution of the 14C label in �-carotene becomes evident once its isoprene units are
identified.
26.16 The carbon chain of prostacyclin is derived from acetate by way of a C20 fatty acid. Trace a contin-
uous chain of 20 carbons beginning with the carboxyl group. Even-numbered carbons are labeled
with 14C when prostacyclin is biosynthesized from 14CH3CO2H.
26.17 The isoprene units in the designated compounds are shown by disconnections in the structural
formulas.
(a) Ascaridole:
(b) Dendrolasin:
(c) �-Bisabolene
(d) �-Santonin
CH3
CH3
O
O
CH3
O
or
O
or
O
O
O
O
Prostacyclin
HO OH
COOH
CH3
O
* * **
*
*
*
*
*
*
�-Carotene
* *
**
* *
*
* * * *
*
*
* *
*
*
*
* *
*
**
*
LIPIDS 739