Scheme 2

Synthetic procedures of methyl (Z)-Δ^βγ-matrinic crotonate and (Z)-Δ^βγ-matrinic crotonol derivatives. Reagents and conditions: (a) 6 N HCl, reflux, 9 h; (b) 2 N MeOH/HCl, reflux, 2 h; (c) RX, K₂CO₃, MeCN, r.t., overnight; (d) LiAlH₄, THF, r.t., 30 min; (e) Boc₂O, K₂CO₃, CH₂Cl₂, r.t., overnight; (f) 2 N HCl/Et₂O, 30 min, (g) TBSCl, CH₂Cl₂, imidazole, r.t., overnight; (h) 3-NO₂PhCH₂Br, TEA, CH₂Cl₂, r.t., 4 h; (i) 2 N HCl