Alkaloids of Veratrum eschscholizii Gray. II.<sup>1</sup> The Ester Alkaloids

Klohs, M. W.; Draper, M. D.; Keller, Fred S.; Köster, Sandra; Malesh, W.; Petracek, F. J.

doi:10.1021/ja01633a062

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“…However, countercurrent distribution involving a relatively small number of transfers in a chloroform-methanol-water system separated the resin sharply into twTo groups of substances, which then could be resolved easily by chromatography. Other examples (79,93) have also appeared of the use of countercurrent distribution in the isolation of this type of alkaloid.…”

Section: Factors Determining Choice Of Separation Toolmentioning

confidence: 99%

“…In spite of the fact that this was well demonstrated in the synthetic quinoline antimalarial field (38), it is only recently that wide use is being made of the method for alkaloids. Recent papers include alkaloids from Rauwolfia (46,79,93), veratrine (92), ergot (76), tropane alkaloids (12), heliotropium alkaloids (39), pilocereine and anhalonidine (44), cuauchichicine (42), and laurifoline (43).…”

Section: Alkaloidsmentioning

confidence: 99%

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Craig¹

1956

Anal. Chem.

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Section: Factors Determining Choice Of Separation Toolmentioning

confidence: 99%

Section: Alkaloidsmentioning

confidence: 99%

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Craig¹

1956

Anal. Chem.

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“…Protoverine 3,6,15-triisobutyrate 7-acetate {VII). Methanolysis of (V) (1)(2)(3)(4)(5)(6)(7)(8) g) by the procedure described for the preparation of (VI) yielded (VII) (760 mg) in the form of colourless needles.…”

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Veratrum Alkaloids--XLIV. Structure-Activity Relationships in a Series of Synthetic Hypotensive Esters of Protoverine

Kupchan¹,

Hensler²,

Weaver³

1961

J. Med. Chem.

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A study aimed at further elucidation of the relationship between hypotensive activity and structure among analogs of the protoveratrines is reported. A series of synthetic protoverine tetraesters, which differ from each other only in the nature of the acid residue affixed at 6 5 , have been prepared and subjected to preliminary phatmacological evaluation. The results indicate that alteration in the structure of the ester affixed at C16 in analogs of the protoveratrines profoundly affects hypotensive potency.wo recent developments have stimulated Tstudies involving the synthesis and pharmacological evaluation of analogs of the protoveratrines. On the chemical side, our elucidation of the complete structures and configurations of protoveratrine A (I) and protoveratrine B (11) (1) and several related hypotensive ester alkaloids (2, 3) made feasible the systematic alteration of the molecules. On the clinical side, recent work has demonstrated significant differences between protoveratrine A and protoveratrine B when the substances are administered orally, particularly with regard to hypotensive-emetic relationships (4-6). Since protoveratrines A and B differ only in the nature of the ester moiety a t C3, it was deemed desirable that new protoverine (111) (7) esters, which differ from the protoveratrines solely in the nature of the acid residues, should he prepared and subjected to pharmacological evaluation.In our previous studies the compounds examined were protoverine derivatives with varying substitution a t positions 3, 4, 6, 7, 14, 15, and 16 (8-10). The results supported the following generalizations (a) esterification a t position 16 with acetate or isobutyrate is accompanied by a profound loss in activity, (b) esterification a t positions 3 and 15 is required for high activity, chain acid may be disadvantageous, (g) oxidation of the alcohol group at position 16 to a ketone group is accompanied hy a loss in activity, (lz) acetonide formation a t positions 14 and 1.5 is accompanied by a profound loss in activity, (i) esterification a t position 3 may he disadvantageous, and ( j ) considerable alteration can be made in the structure of the ester affixed a t 3 without greatly altering hypotensive potency. In view of the aforementioned facts that minor differences in the ester affixed a t 3 significantly affect the hypotensive-emetic ratio of the protoveratrines and that changes in the structure of the ester at C3 do not greatly alter hypotensive potency, it was deemed desirable that additional compounds which differ from each other only in the nature of the ester a t C15 should be prepared and subjected to pharmacological evaluation. The present report details the synthesis and preliminary pharmacological evaluation of three new analogs of the protoveratrines In the new analogs, the isohutyrate residue, previously demonstrated to he an effective suhstitute for the naturally-occurring substituted a-niethylhutyrate residues (S), is affixed a t C3 Treatment of protoverine (111) with acetone and hydrochloric ac...

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Veratrum‐Alkaloide. 5. Mitteilung. Über die Konstitution der Decevinsäure

Gautschi

Jeger

Prelog

et al. 1954

Helvetica Chimica Acta

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En outre, dans les conditions experimentales utilisees au cours de ce travail, nous n'avons jamais remarque un apport d'argent par la solution. Si tel avait bte le cas, les zones marquant la limite entre deux dkveloppements ( fig. 7 a 9) n'auraient pas persist6 jusqu'lt la fin de la croissance du grain d'argent. D'autre part, nous n'avons jamais observe de dBp6t d'argent sur les fils mbtalliques servant d'electrodes.I1 serait prkmaturk, sur la base de ces constatations, d'btablir un mecanisme d'extrusion des grains pyramidaux. Nous nous proposons de poursuivre des recherche8 dans ce sens. SUMMARY.When we reduce a monocrystalline surface of silver bromide with an hydroquinone developer, the rate of growth of the siker grains depends, among other factors, on the surface orientation and on the distribution density of the grains.The rate of reaction rises when the grain surface is artificially increased by contact with a metallic wire, showing that the contact metal-solution is the determining factor. Besides we have verified that the silver grains are pushed out of the crystal when their size exceeds a certain dimension. Institut de Chimie, UniversitB de Neuchhtel. 265. Veratrum-Alkaloide. a e r die Konstitution der Decevinsaure von F. Gautechi, 0. Jeger, V. Prelog und R. B. Woodward. (13. X. 54.) Mitteilungl).Die sauerstoffreichen Veratrum-Ester-Alkaloide2), von welchen einige neuerdings therapeutische Verwendung bei der Bekiimpfung der Hypertension finden, wurden in letzter Zeit in versehiedenen Laboratorien intensiv chemisch bearbeitet. Es konnten dabei nicht

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Alkaloids of Veratrum eschscholizii Gray. II.¹ The Ester Alkaloids

Cited by 10 publications

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Veratrum Alkaloids--XLIV. Structure-Activity Relationships in a Series of Synthetic Hypotensive Esters of Protoverine

Veratrum‐Alkaloide. 5. Mitteilung. Über die Konstitution der Decevinsäure

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Alkaloids of Veratrum eschscholizii Gray. II.1 The Ester Alkaloids

Cited by 10 publications

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Veratrum Alkaloids--XLIV. Structure-Activity Relationships in a Series of Synthetic Hypotensive Esters of Protoverine

Veratrum‐Alkaloide. 5. Mitteilung. Über die Konstitution der Decevinsäure

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Alkaloids of Veratrum eschscholizii Gray. II.¹ The Ester Alkaloids