ChemInform Abstract: Indolo(2,3‐a)quinolizines and a Convenient Synthesis of Flavoserpentine.

Abstract

Reaction of tryptamine·HCl (I) with the acetals (II) gives rise to the salts (IIIa) (+ by‐product (IVa)) or (IIIb).

5,5’-Biindole

“…Thus, starting with tryptamine hydrochloride 6 and acetylacetaldehyde dimethyl acetal, Teuber et al obtained 3-acetyl-7,12-dihydro-2-methyl-6H-indolo[2,3-a]quinolizinium chloride 7, which after oxidation with o-chloranyl yielded the compound 8 with ring C of the tetracyclic system completely aromatized; treatment of 8 with base yielded the corresponding indoloquinolizine 9 (Scheme 2) [19,20]. Scheme 2.…”