Alchemy was the precursor to modern chemistry. Alchemists were therefore chemists, pharmacologists, and physicians. Alchemy flourished in the Islamic world during the Middle Ages, and then in Europe from the 13th to the 18th centuries. We know the names of some of the better known alchemists thanks to the numerous alchemical manuscript and books that survived. It must be kept in mind however that the vast majority of ancient alchemists, being self-taught, and more bent on experimenting than writing, have left no trace in history.

Middle East
Geber / Abu Musa Jabir ibn Hayyan (721-815)
Abu Bakr Mohammad Ibn Zakariya al-Razi (864-930)
Avicenna - Abu Ali al-Husain ibn Abdallah ibn Sina (985-1037)

Classical and Roman Empire
Hermes Trismegistus
Albertus Magnus (1193-1280)
Roger Bacon (1220- 1292)
Arnaldus Villanovanus (1240-1311)
Nicolas Flamel (1330-1418)
Basil Valentine (1394-1450)
Georg Agricola (1494-1555)
Paracelsus (1493-1541]
Valentin Weigel (1533-1588)
Tycho Brahe (1546-1601)
John Dee (1527-1608)
Edward Kelley (1555-1595)
Jacob Bohmen (1575 - 1624)
Heinrich Khunrath (1560-1605)
Michal Sedziwoj (1566-1636)
Jan Baptista van Helmont (1577-1644)
Robert Boyle (1626-1691)
John Mayow (1641-1679)
Isaac Newton (1642 -1727)
Count Alessandro de Cagliostro (1743-1795)
Count St. Germain (18th Century)
Demosthenes - The Alchemist God
Alexandre Saint-Yves d'Alveydre The Archeometre (1842-1909)
Fulcanelli

Other Alchemists Wikipedia