hydroxypethidine

The story

1. Proto-Indo-European*wed-
2. Proto-Indo-European*wódr̥
3. Proto-Hellenic*údōr
4. Ancient Greekῡ̆̔́δωρ (hū̆́dōr)
5. Ancient Greekὑδρο- (hudro-)
6. Frenchhydro-
7. Proto-Indo-European*ǵenh₁-
8. Proto-Indo-European*ǵénh₁os
9. Proto-Hellenic*génos
10. Ancient Greekγένος (génos)
11. Frenchhydrogène
12. Englishhydrogen
13. Proto-Indo-European*h₂eḱ-der.?
14. Ancient Greekὀξύς (oxús)
15. Ancient Greekγένος (génos)
16. Frenchoxygène
17. Englishoxygen
18. Proto-Indo-European*swel-der.?
19. Ancient Greekῡ̔́λη (hū́lē)
20. Englishhydroxyl
21. Englishhydroxy-
22. Ancient Greekπέπερῐ (péperĭ)
23. Latinpiper
24. Englishpiperidine
25. Proto-Indo-European*h₂eydʰ-
26. Proto-Hellenic*áitʰō
27. Ancient Greekαἴθω (aíthō)
28. Ancient Greekᾱ̓ήρ (āḗr)influ.?
29. Ancient Greekαἰθήρ (aithḗr)
30. Latinaethēr
31. GermanÄther
32. GermanEther
33. Ancient Greekῡ̔́λη (hū́lē)
34. GermanEthy
35. Englishethyl
36. Englishpethidine
37. English todayhydroxypethidine

From hydroxy- + pethidine.