28 (±)-トドマツ酸とその類縁体の合成

抄録

Juvabione (Ib=methyl todomatuate) and dehydrojuvabione (IIIb) show strong juvenile hormone activity in the bug, Pyrrhocoris apterus L. (±)-Juvabione (Ib), its stereoisomer (XXIb) and a mixture of (±)-dehydrojuvabione (IIIb) and its stereoisomer (XLIIb) were synthesized in the following manner. (±)-JUVABIONE An acid (IX) was prepared from anisole (V). This was converted to the corresponding dimethylamide (XI). Reduction of (XI) gave an aldehyde (XII) which was treated with isobutyl magnesium bromide to afford (XIII). Birch reduction of (XIII) followed by acid hydrolysis gave (XV). The unsaturated ketone (XV) was reduced to give (XVI) which in turn was acetylated to afford (XVII). The corresponding cyanohydrin (XVIII) was dehydrated to give (XIX). This was hydrolyzed and oxidized to give a mixture of (Ia) and (XXIa) which was separated into (Ia) and (XXIa) via semicarbazones (XXII, crystal; XXIII, oil). The acids were esterified to give (±)-juvabione (Ib) and its stereoisomer (XXIb), respectively. (±)-DEHYDROJUVABIONE A β-keto ester (XXXI), prepared from (X) via (XXIX) and (XXX), was hydrogenated to give (XXXII). This was treated with methyl magnesium iodide to give a diol (XXXIII). Birch reduction of this diol gave (XXXIV). This was treated with acid to give (XXXV) which in turn was hydrogenated and acetylated to give (XXXVII). Addition of hydrogen cyanide to (XXXVII) followed by dehydration gave an unsaturated nitrile (XXXIX). This was hydrolyzed, oxidized and dehydrated to give a mixture of (IIIa) and (XLIIa).This was esterified to give a mixture of (±)-dehydrojuvabione (IIIb) and its stereoisomer (XLIIb).