Kopsia griffithii

The basic fraction of the ethanolic leaf extract of the Malaysian plant Kopsia griffithii exhibits a strong antileishmania activity. One of the two novel alkaloids isolated from this plant in 1998 was the indolizidino[8,7-fo]indole harmicine [17]. Synthetic approaches to harmicine became attractive owing to its pharmacological potential [18,19]. We applied our three-step pyrrolidine annulation strategy to the synthesis of harmicine (Scheme 15.5) [19]. 

Peschiera buchtieni (Tabernaemontana buchtiem) (153). It has also been subsequently found in Kopsia griffithii from Malaysia (154,155). The spectral data indicated affinity with 4, 17-dihydro-17jS-tchibangensine, except for the presence of a methyl ester substituent at C(16). The configuration at C(16) was assigned as R based on eomparison of the hydrogen chemical shifts with those of 16(7 )- and 16(5)-isositsirikine. 

In a subsequent paper, Jacobsen and co-workers utilized hydroxylactams as precursors to a reactive A-acyhminium ion intermediate. Again, a wide variety of substrates were demonstrated using this methodology including the synthesis of (-i-)-harmicine 116 [36], an antiparasitic compound derived from the Malaysian plant Kopsia griffithii (Scheme 1.28) [38]. 

Klebsiella pneumoniae, 984, 989 Knockdown, 4070, 4077, 4078 Kopsia griffithii, 1288 Kucha, 956 Kudzu root, 1852 Kutkoside, 3048, 3050 Kynurenic acid, 3699, 3711... 

In the plant, the unstable dihydrorhazinilam 25 is most certainly the direct biogenetic precursor of rhazinilam, which is an isolation artefact. Indeed, 25 was isolated together with 3 from the Apocynaceae Leuconotis eugenifolia and Leuconotis griffithii [58,59] and Kopsia singapurensis [60]. The question whether (+)-l,2-didehydroaspidospermidine 46 is the actual biogenetic precursor of 25 is still open. 

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