Yuzurimine

Yuzurimine-C formed the methiodide (151) on heating with methyl iodide in acetone, which, on treatment with aqueous alkaline solution, readily formed the keto-amine (152). This confirmed the location of the tertiary hydroxy-group a to the nitrogen atom. Oxidation of (149) with sodium metaperiodate gave the keto-lactam (153), which was reduced to (154) by catalytic hydrogenation. Partial reduction of 

Yamamura, M. Toda, and Y. Hirata, Bull. Chem. Soc. Japan, 1976, 49, 839. 

Steroidal Alkaloids of the Apocynaceae and Buxaceae and Related Compounds 

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Numerous UCNMR investigations on alkaloids have been reported in the literature [598, 599]. In Table 5.13 the 13C chemical shifts and structures of representative alkaloids of different types are collected Pyrrolidine, piperidine and pyridine [600-602], tropane [600, 603-605], izidine [606-612], indole [600, 603, 613-633], isoquinoline [599, 630, 634-647], quinolinic [648-656], imidazole [657], yuzurimine alkaloids [658], alkaloids with exocyclic nitrogen [659, 660], diterpenoid [661-663], steroid [664-666] and peptide alkaloids [667-671], The complete signal assignment for the alkaloids given in Table 5.13 was achieved using the correlations between 13C NMR spectral parameters and structural properties and the 13C chemical shift values of model compounds described in Chapters 3 and 4 of this monograph. 

From a structural viewpoint, these alkaloids are mainly divided into five types of nitrogen heterocyclic skeletons represented by daphniphylline (I), secodaphniphylline (28), daphnilactone-A (34), daphnil-actone-B (36), and yuzurimine (43). In this chapter, all of these alkaloids will be described including their spectral and chemical properties. Biogenesis of these bases with complex structure is quite interesting... 

Biogenetically, daphnilactone-B (36) is regarded as a plausible intermediate between daphniphylline-type and yuzurimine-type alkaloids. Thus, daphnilactone-B (36) was converted to a daphniphylline-type compound (38, mp 166-168° C22H3302N) via a bromocyanamide [39, mp (dec) 210°] and a debromocyanamide (40, mp 208-212°), as shown in Scheme V. The structure of this daphniphylline-type compound 38 was confirmed by its mass, IR, and NMR spectra coupled with von Braun degradation of 38 leading to the formation of a new... 

Yuzurimine [43 [a]D + 8.3° (in CHClg)] is one of the major alkaloids isolated from the bark and leaves of D. macropodum. The spectral data... 

Yuzurimine-B (52) is a minor alkaloid crystallized as the hydrochloride which has a secondary methyl group [81.22 (3H, d, J = 6.0... 

Reduction of yuzurimine (43) with active zinc powder in AcOH (90-95°, 2 hr) or with NBH gave deoxyyuzurimine (55, mp 132-134°). 

Further hydrolysis of the compound 55 with 7% HCl-MeOH followed by treatment with MsCl-pyridine and then with LiCl in dimethyl-formamide (DMF) (90-100°, 18 hr) afforded a monomesylate [56, mp 253-254° (as hydrochloride)] via deacetyldeoxyyuzurimine (57) and dimesylate (58). In the NMR spectrum of 56, a broad singlet resulting from two olefinic protons was observed at 5.93. Finally, catalytic hydrogenation of this compound over Pt02 gave yuzurimine-B mesylate (54) which was directly obtained from yuzurimine-B on mesylation with MsCl-pyridine. 

A list of the Daphniphyllum alkaloids is given in Table I. In addition to two alkaloids of undetermined structure, neodaphniphylline (28) and neoyuzurimine, both of which have been isolated in very small quantities (Vol. X, p. 556, and Vol. XII, p. 472), three more structurally unknown alkaloids (alkaloids Ax and A2, and yuzurimine-D) have been obtained from the bark and leaves of D. macropodum (14, 21). In particular, the carbon skeletons of the alkaloids Aj and A2 seem to be considerably different from those of the other alkaloids cited in parts A-E, on the basis of their spectral data. 

As reported by Yagi (3) a small amount of yuzurimine (43) acts as a weak depressant for the central nervous system. With larger quantities it was proved that this alkaloid had an efficient effect on muscle relaxation and sedation. 

On the basis of these data coupled with co-occurrence of yuzurimine-B (52), the structures of daphnijsmine and deaeetyldaphnijsmine are represented by 96 and 97, respectively. 

The Alkaloids of Daphniphyllum humile Deoxy-yuzurimine and Isodaphnilact-one-B.-Yamamura and Terada55 have isolated two new alkaloids from the leaves of D. humile M. Deoxy-yuzurimine (150), C27H37NO6, m.pt. 132 °C, was found to be identical with the previously reported product56 of the reduction of yuzurimine... 

Alkaloids of Daphniphyllum humile Deoxy-yuzurimine and Isodaphnilactone-B 243... 

Yuzurimine C, a minor squalene-derived alkaloid from Daphniphyllum mac-ropodum,n has been assigned the structure (5). A search for further compounds to support the postulated biogenetic pathway from squalene to the Daphniphyllum alkaloids has resulted in the isolation of daphniteijsmanine (6) from D. teijsmanii.12 It is structurally very similar to secodaphniphylline. Treatment of the mesylate (8) of the sodium borohydride reduction product of N-acetylsecodaphniphylline (7) with acetic acid afforded N-acetyldaphniteijsmanine acetate (see Chapter 6, p. 214). Further chemical interrelations in this series have been described.13... 

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