C-Alkaloids

C-Alkaloid UB forms a picrate, CjgH2303N2, CgHjO N, m.p. 238-240°, which gives an intense, but unstable, carrtiine colour with ceric sulphate in strong sulphuric acid and is convertible into a crystalline iodide. 

C-Alkaloid X obtained in minute quantity as a crystalline chloride, which with nitric acid gives an intense red colour with a violet fluorescence, and orange slowly becoming red, with ceric sulphate in sulphuric acid. 

In this study the alkaloids were separated by centrifugally accelerated radial TLC (Chromatotron) using Al O plates (E. Merck Art 1092), and further cleaned on preparative TLC plates. The stmctures were determined by ID and 2D NMR experiments including H- H COSY, HMQC, HMBC and NOESY. The new compounds were cochleareine (9) C and the other acoleareine (10) C alkaloids. 

Unique alkaloids and peptides were also isolated from Caribbean species (Chart 7.3.A/P), along with guanidine C alkaloids similar to those firom the Indo-Pacific. 

Spiraea salicifolia L. S. salicifolia L. var. grosseserrata Liou Liou fil. S. salicifolia L. var. oligodonta Yu Xiu Xian Jiu (Bridal wreath) (whole plant) Flavonoids, carotenoids, vitamin C, alkaloids, seed oil.33 Diuretic, treat cough, pain, monthly period, constipation. 

N.A. Physalin, vitamin C, alkaloids, flavonoids, sterols." Diuretic, treat kidney and urinary disorder. 

N.A. Physalis franchetti L. P. pube scene L. Flavonoids, plant sterols, vitamins A and C, alkaloids.100-310 A diuretic for urinary and arthritic problems including kidney and bladder stones, fluid retention, and gout. 

The mass spectra of deuterated C30 alkaloids, obtained as a result of reduction of hemiaminals with NaBD4, confirmed the fragmentation pathway leading to the mlz 178 ion (72). As shown in Scheme 16, deuteration at C-6 results in an increase of the mlz 178 ion by one mass unit. On the other hand, deuteration at C-6 does not increase the mass of the ion. In spectra of dideuterated compounds an mlz 179 ion appears, i.e., increased by one mass unit. On the basis of the above data it was concluded that the characteristic fragment (mlz 178 ion) of the C alkaloids derives from the AB quinolizidine ring. 

Of the numerous alkaloidal constituents ( 60) of the stem bark of Strychnos dolichothyrsa, six have so far been identified, including five bis-strychninoid ones 102 these are bisnordihydrotoxiferine, bisnor-C-curarine, bisnordihydrotoxi-ferine mono- and di-Xb-oxides, and (tentatively) bisnor-c-alkaloid D. 

C-Alkaloid E C4oH44N403+ + 0.36 III ether Blue/Chrome green 16, 35... 

C-Alkaloid H, picrate mp 189°-192°, was isolated (16) from a calabash and its structure has been shown to be the the hybrid one of 18-hydroxydihydrotoxiferine I (LXXV). This follows from its preparation... 

The formation of C-alkaloid D from C-dihydrotoxiferine I by aerial oxidation in dilute aqueous mineral acid has already been mentioned. This is one of several important reactions which show that many of the calabash curare and Strychnos alkaloids can be grouped together in so-called families containing mutually related alkaloids. Thus, C-dihydrotoxiferine I is converted into C-curarine by irradiation of the solid alkaloid in the presence of oxygen (110) similar irradiation of a solution of the alkaloid in the presence of eosin gives C-calebassine (110). C-Calebassine is also formed from C-dihydrotoxiferine I by the action of hot acetic acid in pyridine in the presence of oxygen (111). The production of C-fluorocurarine from C-calebassine and from C-curarine has already been noted. These reactions are summarized in Scheme 2. 

A similar scheme can be written for alkaloids related to toxiferine I, the corresponding fundamental changes involved being strictly analogous (see Scheme 3). C-Alkaloid E in the toxiferine I family corresponds to C-curarine in the C-dihydrotoxiferine I family similarly, C-alkaloid A corresponds to C-calebassine, and caracurine II methochloride to C-alkaloid D. The interconversions of the tertiary alkaloids related to toxiferine I have already been discussed. 

The toxiferine-like hybrid, C-alkaloid H (LXXV), is converted into C-alkaloid F by aerial oxidation in the presence of pivalic acid and pyridine irradiation of solid C-alkaloid H in the presence of oxygen gives a product identical with natural C-alkaloid G. The properties of these transformation products confirm that C-alkaloids F and G stand in the C-alkaloid H family, as do C-calebassine and C-curarine in the C-dihydrotoxiferine I family. The tertiary alkaloid caracurine VI is the nor base corresponding to C-alkaloid H. 

The quaternary C-alkaloid D was first isolated (16) from a sample of calabash curare and was later encountered (24) as one of the products formed when C-dihydrotoxiferine I is treated with dilute acid in the presence of oxygen. Because of its low mobility on paper chromatograms, it was considered to be a dimeric alkaloid, and the formula C4oH48N4Or was proposed (116) on the basis of analyses of the several crystalline salts afforded by this alkaloid. Despite its bisquaternary nature, C-alkaloid D has a low curarizing activity, and in this respect it is similar to caracurine V dimethochloride mentioned earlier. C-Alkaloid D chloride shows [a]D — 51° (in 1 1 aqueous acetone). 

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