Lysergic acid diethylamide (LSD) is a compound that has been the subject of much interest, research, and controversy over the years. Its synthesis has evolved, and two the most popular methodologies have emerged. This article provides an overview of the LSD synthesis pathways from Lysergic Acid Hydrate and Lysergic Acid.
Equipment and glassware:
Lysergic acid 2.80 g is added to a methylene chloride (DCM; CH2Cl2) 100 ml with a constant stirring. N,N-Diethylmethylamine 1.81 g is added to the reaction mixture and the solution is stirred for 5 min. Then PyBOP 5.70 g is added, and the solution is stirred for an additional 5 min. Then, diethylamine 0.84 g is added and the reaction is stirred at room temperature for 60 min.
The reaction mixture is quenched with concentrated ammonium hydroxide (NH4OH) 100 ml 7.5 M. Layers are separated, the aqueous phase is extracted with 3x30 ml DCM. Organic layers are combined and evaporated in a rotovap machine at 35 °C under high vacuum.
The residue is dissolved in sodium bicarbonate (cold saturated aq solution) NaHCO3 40 ml and extracted with 3x20 ml EtOAc. Organic layers are combined and washed with deionized H2O, brine, and dried over MgSO4. Solution is filtered and evaporated in a rotovap machine at 40 °C under vacuum to a constant weight. A yield is 3.13 g before chromatography purification (optional), 93% purity.
Lysergic Acid Diethylamide (LSD) Free-base
A suspension of 3.15 g d-lysergic acid hydrate (2) and 7.1 g of diethylamine in 150 mL CHCl3 was brought to reflux with stirring. With the external heating removed, there was added 3.4 g POCl3 over the course of 2 min, at a rate sufficient to maintain refluxing conditions. The mixture was held at reflux for an additional 5 min, at which point everything had gone into solution. After returning to room temperature, the solution was added to 200 mL of 1 N NH4OH. The phases were separated, the organic phase dried over anhydrous MgSO4, filtered, and the solvent removed under vacuum. The residue was chromatographed over alumina with elution employing a 3:1 C6H6/CHCl3 mixture, and the collected fraction stripped of solvent under hard vacuum to a constant weight. This free-base solid (3) can be recrystallized from benzene to give white crystals with a melting point of 87-92 °C.
Lysergic Acid Diethylamide (LSD) Tartrate
This base was dissolved in warm, dry MeOH, using 4 mL per 1 g of product. There was then added dry d-tartaric acid (0.232 g per 1 g of LSD base), and the clear warm solution treated with Et2O dropwise until the cloudiness did not dispel on continued stirring (use 100 mL RBF in this case). This opaqueness set to a fine crystalline suspension (this is achieved more quickly with seeding) and the solution allowed to crystallize overnight in the refrigerator. Ambient light should be severely restricted during these procedures. The product was removed by filtration, washed sparingly with cold methanol, with a cold 1:1 MeOH/Et2O mixture, and then dried to constant weight. The white crystalline product was lysergic acid diethylamide tartrate with two molecules of methanol of crystallization, with an m.p. of about 200 °C with decomposition, and weighed 3.11 g (66%).
Repeated recrystallizations from methanol produced a product that became progressively less soluble, and eventually virtually insoluble, as the purity increased. A totally pure salt, when dry and when shaken in the dark, will emit small flashes of white light.
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