SYNTHESIS : A solution of 6.7 g KOH in 100 mL H2O, under an inert atmosphere and magnetically stirred, was brought to 75 °C, and 10 g ergotamine tartrate (ET) added. The reaction mixture turned yellow as the ergotamine went into solution over the course of 1 h. The stirring was continued for an additional 3 h. The reaction mixture was cooled to about 10 °C with an external ice bath, and acidified to a pH of about 3.0 by the dropwise addition of 2.5 N H2SO4. White solids started to appear early in the neutralization; approximately 60 mL of sulfuric acid was required. The reaction mixture was cooled overnight, the solids removed by filtration, and the filter cake washed with 10 mL Et2O. The dry solids were transferred to a beaker, suspended in 50 mL 15 % ammonia in anhydrous ethanol, stirred for 1 h, and separated by decantation. This extraction was repeated, and the original decantation and the second extract combined and filtered to remove a few hundred milligrams of unwanted solids. The clear filtrate was stripped of solvent under vacuum, the residual solids dissolved in 50 mL of 1% aqueous ammonia, and this solution was acidified as before with 2.5 N H2SO4. The precipitated solids were removed by filtration and washed with Et2O until free of color. After drying under vacuum to a constant weight, there was obtained 3.5 g of d-lysergic acid hydrate, which should be stored in a dark, sealed container.
A suspension of 3.15 g d-lysergic acid hydrate 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 can be recrystallized from benzene to give white crystals with a melting point of 87-92 °C. IR (in cm-1): 750, 776, 850, 937 and 996, with the carbonyl at 1631. The mass spectrum of the free base has a strong parent peak at mass 323, with sizable fragments at masses of 181, 196, 207 and 221.
This base was dissolved in warm, dry MeOH, using 4 mL per g of product. There was then added dry d-tartaric acid (0.232 g per g of LSD base), and the clear warm solution treated with Et2O dropwise until the cloudiness did not dispel on continued stirring. 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 a mp 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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LSD-25
