Thalictrum rochebrunianum

The roots of Thalictrum rochebrunianum Franc, and Sav. (Ranunculaceae) yielded dihydrothalictrinine (142), mp 194-197°C, C38H3gN209, [a]j=,2 -125° (c 0.13, MeOH) (81). The NMR spectrum resembles that of thalictrinine (143, Section II,C,114), but shows broadening of the protons on the monosubstituted benzyl ring. The IR spectrum lacks the carbonyl and shows a hydroxy absorption at 3280 cm-1. Sodium borohydride reduction of thalictrinine gave dihydrothalictrinine as the sole product in high yield. From consideration of steric factors, 142 was suggested as the structure of dihydrothalictrinine (12,81). 

Thalictrum rochebrunianum produced northalibrine (239), amorphous, C37H42N206, [a]D +47° (c 0.2, CHC13), MS m/e 206 (base, cleavage at a) and 178 (23%, cleavage at b). On N-methylation, northalibrine gave thalibrine (225, Section II,C, 111). From the mass spectrum, the phenolic function and the secondary nitrogen of northalibrine are located in the same isoquinoline... 

AT-Northalibrunine (243), C38H42N208, needles, mp 158-16TC, [a]D +79° (c 0.16, MeOH), HRMS m/e 654.2954 (base, M + ) (81), was first observed as the major isomer from reduction of thalibrunimine (27) (13). In 1976, N -northalibrunine was isolated from Thalictrum rochebrunianum however, no evidence confirming the substitution pattern of the bottom ring was offered at that time, and an incorrect structure was postulated (116). The structures of... 

Thalibrine (225, see Section II,C,72), from Thalictrum rochebrunianum, amorphous, [a]D +110° (c 0.135, CHC13), has UV max 284 nm (e 8000), IR (KBr) 3400 cm -1 (nonbonded phenol). Methylation (CH2N2) of thalibrine gave 224, having opposite rotation but otherwise identical to O-methyldauricine, thus... 

Thalibrunine and thalibrunimine have been isolated from Thalictrum rochebrunianum together with the new bases norhernandezine, IV -northalibrunine, oxothalibrunimine, thalictrine, and dihydrothalictrine.51 These bases have been related as follows. Thalibrunine has been assigned the revised structure of 2 -hydroxy-hernandezine (26) on the basis of the oxidation of its O-acetyl derivative with ceric ammonium nitrate to the dialdehyde (27) and with... 

All of the alkaloids of this group are unusual in that they bear 10,12,13- trioxygenation in Ring C of their molecule. Six of the seven alkaloids are 10-hydroxy, 12-methoxy compounds, while one is a 10,12-dimethoxy compound. In addition, all seven of the alkaloids have only been isolated from one plant, Thalictrum rochebrunianum (Ranunculaceae), and thus these compounds are of very restricted distribution. 

Hernandezine (XCVI) (mp 192°-193°, when recrystallized from hexane) occurs in Thalictrum hernandezii Tausch (74), Th. fendleri (Auth. ), and Th. rochebrunianum Franch. and Sav. (75). 

The only two alkaloids of this very small subgroup are thalsimidine (85), which has only been isolated from Thalictrum simplex (Ranunculaceae), and thalsimine (86), an alkaloid that has been isolated from three species of Thalictrum (T rochebrunianum, T. rugosum, and T simplex). Thalsimine (86) is actually a 1 1 mixture of the two conformers of S-O-methylthalsimidine. 

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