Dissolve 1g of CBD in 10ml 0.005molar H2SO4 in glacial acetic acid.
Let solution stand at room temperature.
After 3 hours CBD has been converted into 52% delta-9-THC and 2% delta-8-THC.
After 3 days a mixture of 15% delta-9-THC, 54% delta-8-THC, 10% delta-8-iso-THC and 10% CBD has formed.
Work up:
Pour into water (100ml or more) and add cautiously with stirring (foaming!) enough sodium bicarbonate (15g should do) to raise the pH above 7. Extract with petrol ether, wash with water, evaporate solvent to get mixture of starting CBD and predominantly delta-9- or delta-8-THC with some other byproducts depending on the reaction time.
Can chromatograph on silica gel with 1 to 2% ether in petrol ether for purification.
CBD can also be converted into delta-9-THC with anhydrous ZnCl2 at 150° without solvent (perform reaction best in vacuum as product is sensitive to oxidation):
Heat 0.5g CBD with 0.09g anhydrous ZnCl2 under vacuum with stirring.
After 2 hours 40 to 50% delta-9-THC have formed.
