Studies on the Syntheses of Royal Jelly Acid, Queen Substance and Their Related Compounds

Abstract

The syntheses of royal jelly acid (10-hydroxy-trans-2-decenoic acid), queen substance (9- oxo-trans-2-decenoic acid) and their related compounds have been examined systematically by the standard methods using general reagents (Scheme 1). Dehydrogenation of 1, 5-pentanediol [ 1], 1, 6-hexanediol[ 2 ], 1, 8-octanediol C 3 j, 1, 10- decanediol [ 4 ] and their monoacetates [ 5 ], -[ 8 led to 5-hydroxypentanal ], 6-hydroxyhexanal [10], 8-hydroxyoctanal [11], 10-hydroxydecanal [12] and their monoacetates [13] [16], respectively (Table 1). w-Hydroxy- and w-acetoxy-trans-2-alkenoic acids [17] [24] were derived from hydroxy and acetoxy aldehydes [9][16] by the condensation with malonic acid in pyridine (Table 2).
Thus royal jelly acid [19] and its related compounds [17][24] were easily synthesized by two steps in good yield.
w-Hydroxy-trans-2-alkenoic acid methyl esters [25][28] were prepared by esterification of [17]-[24]. w-Bromo-trans-2-alkenoic acid methyl esters [29][32] were obtained by the bromination of [25][28] with PBr3. w-Acetyl-trans-2-alkenoic acids [33][36] were easily derived from [25] [28] by the condensation with ethyl acetoacetate.
Thus queen substance and its related compounds [33][36] were synthesized by the standard method.