抄録
The structure of lyofoligenic acid (II), obtained by acid hydrolysis of lyofolic acid2) (I), was investigated in comparison with protolyofoligenic acid (III), which is the genuine aglycone of I and has already been chemically proved to possess the same carbon skeleton as cycloartenol5).(i) Acid c1eavage of the cyclopropane ring in III has been elucidated to give a 9(10→19)-abeo-lanost-5(10)-ene system (II) by preparing a cyclohexadienone derivative (VII).(ii) The conformation of 3α-OH in II and III was discussed on the basis of 1Hnuclear magnetic resonance (1H-NMR).(iii) Chemical behavior of the tertiary carboxylic function in II was examined and the 14α-COOH in II Was examined by using the shift reagent in the 1H-NMR analysis of XX and by 13C-NMR analysis of I, II, and III.(iv) The absolute configuration of hydroxyl groups at C-3 and C-24 was examined by applying the modified Horeau's method an XI and XIX, and both proved to be R. The structure II assigned to lyofoligenic acid is consistent with the result obtained by X-ray crystallographic study of XXII.
