LSD or Lysergic acid diethylamide, is a hallucinogenic drug that is synthesized from lysergic acid, which is a naturally occurring substance in a fungus called Claviceps purpurea, commonly known as ergot. Here's the basic synthesis of LSD:

1. Extraction and purification of ergot alkaloids: The ergot fungus is harvested and the ergot alkaloids are extracted and purified. These alkaloids are later used as the starting materials for LSD synthesis.

2. Synthesis of lysergic acid: The purified ergot alkaloids are chemically modified to synthesize lysergic acid.

3. Synthesis of LSD: Lysergic acid is chemically modified with the addition of diethylamine to form lysergic acid diethylamide (LSD). This step requires careful control of reaction conditions such as temperature, pH, and reagent amounts, as any variation could result in a different chemical compound.

4. Purification of LSD: The LSD product is purified through various methods like recrystallization or column chromatography to obtain the final pure product.

Due to its complex synthesis and potent psychoactive effects, LSD is a Schedule I controlled substance in the United States, meaning it is illegal to manufacture, distribute or possess without a license or prescription.