41. Indole alkaloids are also present in fungi.42. In the synthesis of monoterpenoid indole alkaloids, secologanin plays the role of the aldehyde. 43. Tryptophan in the diet is metabolized by bacteria in the gastrointestinal tract to produce indole . 44. The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter serotonin. 45. Bergman and Venemalm developed a technique for lithiating the 2-position of unsubstituted indole . 46. Alan Katritzky also developed a technique for lithiating the 2-position of unsubstituted indole . 47. Leaf extracts and sap contain many insecticidal compounds such as the indole alkaloid aspidophytine. 48. "' Eburnamine "'is an indole alkaloid in the aspidosperma group. 49. It is resistant to most common antibiotics and cold temperatures and is oxidase and indole positive. 50. One nitrogen is part of a rigid ring system and is shielded by the C6 indole .
