SALVINORIN A synthesis

Yield:83729-01-5 0.5%

Reaction Conditions:

with dmap in dichloromethane at 20;

Steps:

1
Dried Salvia divinorum leaves (1.5 kg), obtained commercially from Ethnogens.com, were ground to a fine powder and percolated with acetone (5 x EPO 4 L). The acetone extract was concentrated under reduced pressure to afford a crude green gum (93 g), which was subjected to column chromatography on silica gel with elution in n-hexanes containing increasing amounts EtOAc. Fractions eluting in 20% n -hexanes/ EtOAc contained salvinorm A (TLC) and other minor diterpenes and some pigmented material. These fractions were pooled and concentrated in vacuo to give a green gum (24 g). A mixture of the crude green gum, acetic anhydride (50 mL, 530 mmol) and DMAP (0.2 g) in CH₂Cl₂ (250 mL) was stirred at RT overnight. The CH₂Cl₂ solution was washed sequentially with IN HCl (2 x 500 mL), 2N NaOH (10OmL), and H₂O (2 x 100 mL). The CH₂Cl₂ solution was dried (Na₂SO₄) and the solvent was removed under reduced pressure to afford a yellow-green gum (23 g). The resulting gum was subjected to column chromatography on silica gel. Elution was performed in 1000 mL aliquots of a mixture of n-hexanes/ EtOAc in increments of 10% EtOAc with the final elution in neat EtOAc. Fractions eluting in 30% n- hexanes/ EtOAc and subsequent fractions were pooled and the solvent was removed under reduced pressure affording salvinorm A (1 7.5 g, 0.5%) as a green powder, mp 235-238 °C (Lit.¹'² 240-242 °C).

References:

UNIVERSITY OF IOWA RESEARCH FOUNDATION;BOHN, Laura, M.;PRISINZANO, Thomas, E. WO2006/138589, 2006, A2 Location in patent:Page/Page column 33-34

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