Synthesis and bioactivity of 4-methylthio-3-butenylisothiocyanate and raphanusanin, phototropism-regulating substances of radish hypocotyls

Total syntheses of 4-methylthio-3-butenylisothiocyanate (MTBI, 1) and raphanusanin (2), which are growth inhibitors involved in the phototropism radish (Raphanus sativus) hypocotyls, were achieved from commercially available thiolane four five steps, respectively. MTBI (1) was prepared via ring opening with sodium azide, double bond introduction by oxidation, isothiocyanation. Cyclization to (2) under mild conditions using sauer Al2O3. Synthetic showed potent bioactivity a unilateral administration test segment elongation hypocotyls.