Alkaloid Studies. LVI.¹ The Constitution of Vallesiachotamine²

Abstract

preparation of glycol 16. Hydrolysis of the intermediate osmate ester furnished 577 mg of crude material, which gave 243 mg of homogeneous, but amorphous, glycol on chromatography over Florisil. The glycol thus produced was dissolved in 5 ml of dry benzene and was treated directly with a solution of 384 mg of lead tetraacetate in 7 ml of anhydrous benzene. After 15 min at room temperature, the reaction mixture was worked up as previously described, yielding 214 mg of crystalline residue: A : : :3.67, 5.80, and 5.94 1.1.Attempts to purify a small sample of the keto aldehyde 36 by chromatography (alumina) and subsequent crystallization from methylene chloride-petroleum ether gave an isomer, mp 21 5-216", A, " : 2.81, 3.65, and 5.83 p, for which structure 37 is suggested.Anal. Calcd for G4H2604: C, 76.17; H, 6.92. Found: C, 76.23; H, 7.05.In view of this difficulty the remainder of the crude keto aldehyde above was reduced directly with lithium aluminum hydride in ether as described for the reduction of keto ester 33. Chromatography of the reduction product (Florisil) and crystallization from ethyl acetate-petroleum ether yielded a sample of glycol 34, mp 210.5-211.5", that was indistinguishable from the specimen derived from keto ester 33.Abstract: Through a combination of chemical and spectroscopic techniques (notably nuclear magnetic resonance and mass spectrometry) it has been possible to show that vallesiachotamine, an alkaloid isolated from the Peruvian Apocynaceae Vallesia dichotoma Ruiz et Pav, possesses structure I. A likely biogenetic route to this unusual structure is discussed.xtensive studies"6 in our laboratory on the con-

Monoamine oxidase inhibition by monoterpene indole alkaloids and fractions obtained from Psychotria suterella and Psychotria laciniata

“…The UV spectra displayed by the peaks referents to these compounds are consistent with βC, THβC 4 and vallesiachotamine-like nuclei 29 . The presence of the alkaloids 1 and 2 in SAE and LAE was further confirmed by coinjection, in HPLC-PDA, with the pure compounds isolated from P. suterella 4 .…”

“…Fragments for the loss of CH 3 , CH 3 O and CHO were also observed. The major fragments at m/z 291, 279, 221 and 263 are diagnostic for the alkaloids 3 and 4 29,31,32 . Three main fractions corresponding to mixtures of 3 and 4 in different proportions were obtained from CPTLC.…”

Phytochemical study and anti-inflammatory effect of Psychotria stenocalyx (Rubiaceae)

“…The HPLC chromatogram at 280 nm showed the presence of nine major compounds, of which seven were identified ( Fig). The UV spectra displayed by the peaks for these compounds are consistent with β-carboline (1, 2 and 4), tetrahidro-β-carboline (3) (Passos et al, 2013a) and vallesiachotamine-like nuclei (5-7) (Djerassi et al, 1966).…”

Phytochemical, pharmacological and ethnobotanical studies of Rhazya stricta Decne.

“…Stemmadenine, an antimicrobial alkaloid isolated from Melodinus australis (Apocynaceae; Linde, 1965) has also been isolated from R. stricta (Table 1). Similarly, vallesiachotamine was first isolated from Vallesia dichotoma (Djerassi et al, 1966). All other plants, including R. stricta, from which these alkaloids were reported belong to the family Apocynaceae, suggesting that these alkaloids are family-specific indole alkaloids.…”