Methanol → 3,7-Dimethyl-2,4,6,8-nonatetraenoic acid ethyl ester

Temperatur

-40 °C

A solution of [[2-(nonyloxy)phenyl]methyl]triphenylphosphonium bromide (150 g) in tetrahydrofuran (1100 mL) was cooled to -50° C. to yield a fine suspension of the solid salt. To this mixture was added a solution of n-butyllithium in hexane (180 mL, a 1.6 molar) to yield a solution of the ylide. The mixture was then stirred a further15 min at -40° C., cooled to -70° and treated with 7-formyl-3-methyl-2,4,6-octatrienoic acid ethyl ester (65 g) dissolved in tetrahydrofuran (250 mL). Addition of hexane and aqueous methanol (40%) to the reaction mixture follwed by concentration of the hexane extract yielded ALL(E)-9-[2-nonyloxy)phenyl]-3,7-dimethyl-2,4,6,8-nonatetraenoic acid ethyl ester (64 g, 58% yield), mp 52-53° C. This ester was then hydrolized by forming a solution of this ester (70 g) in ethanol (1000 mL). This solution was treated with aqueous potassium hydroxide (80 g in 400 mL water) and heated at reflux for 1 h. Water and aqueous mineral acid was then added and the solids were extracted into chloroform. Concentration of this organic extract and crystallization of the residue from an ethyl acetate hexane mixture yielded All(E)-9-[2-(nonyloxy)phenyl]-3,7-dimethyl-2,4,6,8-nonatetraenoic acid (38 g), mp 102-103° C.

1. customto yield
2. additiona fine suspension of the solid salt
3. customa 1.6 molar) to yield a solution of the ylide
4. temperaturecooled to -70°
5. extractionextract

ORD-Eintrag

ord-85baa331c3ab49d799da414c6aa6f669

Quelldatensatz

uspto-grants-1989_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04883613