Secobisbenzylisoquinoline alkaloids

A list of the secobisbenzylisoquinoline alkaloids with their species of origin is included in Table VIII. The secobisbenzylisoquinoline alkaloids have mainly been found among members of the family Berberidaceae, less frequently in the Annonaceae, and in only a single case in the Ranunculaceae. In Table IX some of the physical data and spectral features of secobisbenzylisoquinoline alkaloids are presented. 

In UV spectra of secobisbenzylisoquinoline alkaloids possessing a phenolic hydroxy group para to the aldehyde function, a marked bathochromic shift is observed upon addition of base. In IR spectra absorption of the lactam group appears at 1645-1640 cm-1, that of the aldehyde function in the range between 1720 and 1680 cm-1, and that of the ester group at 1710 cm-1. 

Some Physical and Spectral Characteristics of Secobisbenzylisoquinoline Alkaloids... 

On the basis of in vitro oxidation of simple benzylisoquinoline quaternary salts with Oz/Cu+, it was proposed that secobisbenzylisoquinoline alkaloids could be derived by singlet oxygen oxidation of bisbenzylisoquinolines, specifically, bal-... 

A second of the three subgroups is made up of three secobisbenzylisoquinoline alkaloids baluchisanamine (257) from Berberis baluchistanica (Berberidaceae), secohomoaromoline (432) from Anisocycla jollyana (Menispermaceae), and seco-obaberine (269) from Pseudoxandra aff. lucida (Annonaceae). Only the nature of the groups at C(12) and C(7 ) differ in these three compounds, with some being phenolic and some being methyl ethers. 

Calafatimine (189) is a nonphenolic N(2 ) imine alkaloid that has only been isolated from Berberis buxifolia (Berberidaceae). Curacautine (259) and talcamine (271) are two secobisbenzylisoquinoline alkaloids that have been isolated from the same plant and that contain ring B in a higher oxidation state are. The ring C constituent in the former is a formyl group, while in the latter it is a carboxymethyl. 

There are four alkaloids that constitute this small subgroup. The mono imine [N(2 )] alkaloids thalmethine (98) and O-methylthalmethine (96) have only been isolated from Thalictrum species (Ranunculaceae), with the former reported as a constituent of T. minus, while the latter has been found in T. minus, T. minus var. minus, and T. revolutum. These two alkaloids differ at C(12), where thalmethine is monophenolic. A third N(2 ) imine alkaloid is thalsivasine (380), a constituent of Thalictrum cultratum and Thalictrum minus var. minus. This alkaloid is monophenolic at C(7), instead of C(12). The final alkaloid of this small group is the secobisbenzylisoquinoline alkaloid revolutionone (266) which has only been isolated from Thalictrum revolutum (Ranunculaceae). The alkaloids of this small subgroup appear to be restricted in distribution to the genus Thalictrum. 

Products of such oxidative fission of bisbenzylisoquinolines with one, two and three diphenyl ether linkages have been found to be natural products forming a small sub-group of secobisbenzylisoquinoline alkaloids. Those so far identified are karakoramine (68), jhelumine (69, R=H), chenabine (69, R=Me), sindamine (70), punjabine (73, R =H, R =CH0) and gilgi-tine (73, R =H, R =C00Me), isolated from Berberis lycium (J.E. Leet et al.. Heterocycles, 1982, J9, 2355 1983, 425),... 

Leet JE, Hussain SF, Minard RD, Shamma M 1982 Sindamine, punjabine and gilgitine three new secobisbenzylisoquinoline alkaloids. Heterocycles 19 2355-2360... 

Leet JE, Hussain SF, Minard RD, Shamma M (1982) Sindamine, punjabine and gilgitine three new secobisbenzylisoquinoline alkaloids. Heterocycles 19 2355-2360 Leet JE, Fajardo V, Freyer AJ, Shamma M (1983) Some dimeric benzylisoquinoline alkaloids with an unusual oxygenation pattern. J Nat Prod 46 908-912 Liao W-T, Beal JL, Wu W-N, Doskotch RW (1978) Alkaloids of Thalictrum. XXVI. New hypotensive and other alkaloids from Thalictrum minus race B. J Nat Prod 41 257-270 Mukhamedova S, Maekh SKh, Yunusov SYu (1981) Alkaloids of Thalictrum sultanabadense. Khim Prir Soedin 250-251... 

There are three alkaloids in this group, two of which are the secobisbenzylisoquinolines auroramine (390) and maroumine (391). These two bases, that have only been found as metabolites of Gyrocarpus americanus (Hemandiaceae), differ only in the nature of their C(6 ) groups, with the former being a methoxy while the latter is a hydroxy. The remaining alkaloid is 1.2-dehydro-2-norlimacusine (291) from Caryomene olivascens (Menispermaceae). 

The only alkaloid of this group is secolucidine (393), which is a secobisbenzylisoquinoline that has only been found in Pseudoxandra sclerocarpa (Annonaceae). The precursor to this alkaloid could have been medelline (318) from Pseudoxandra aff. lucida (Annonaceae), found in another subgroup of this series. 

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