New synthesis of royal jelly acid
A new synthesis of (E)-10-hydroxy-2-decenoic acid (royal jelly acid) is described, starting from 8-bromo-1-octanol via condensation of malonic acid with 8-hydroxyoctanal or 8-acetoxyoctanal.
Lithiated anions derived from (alkenyl)pentamethyl phosphoric triamides: Useful synthons for the stereoselective synthesis of 9-oxo- and 10-hydroxy-2(E)-decenoic acids, important components of queen substance and royal jelly of honeybee Apis mellifera
Lithiated anions derived from (alkenyl)pentamethyl phosphoric triamides as homoenolate equivalents are used in the reaction with halogenated acetal and ketal giving regioselectively the γ-alkylation adducts. Chemoselective acidic hydrolysis of the enephosphoramide moiety in the presence of acetal or ketal groups leads to expected carbonyl products, key intermediates in the synthesis of natural compounds. The synthetic potential of the presented strategy is illustrated by stereoselective synthesis of two pheromones namely, 9-oxo-2(E)-decenoic acid 1 from queen substance and 10-hydroxy-2(E)-decenoic acid 2 from royal jelly of honeybee Apis mellifera.
Synthesen in der Carotinoid-Reihe. 10. Mitteilung. Anwendung der Wittig-Reaktion zur Synthese von Estern des Bixins und Crocetins†
A simple and efficient synthesis of norbixin and crocetin diesters is described following the schemes C2 + C2o + C2,=C24 and C3 + C14 + C3 = C20 respectively. By means of the Wittig reaction crocetin di-aldehyde is condensed with a bromoacetic acid ester and a C14-dialdehyde with an α-bromopropionic acid ester. The intermediate tri- phenylphosphorane compounds are crystalline and easily isolated in a pure state.