A. macrophylla

Ba e M. This substance, which is present in traces in A. macrophylla, has only been obtained as a crystalline sulphate, m.p. about 257°, [ajo - 71-9° (H2O). 

Negative results were obtained for Aristolochia hurchellii, A. didyma, A. jaliscana, A. kankauensis, A. macrophylla, A. paulis-tana, Aristolochia spp. (3), A. triangularis, Asarum canadense, A. lemon ii, A. lailoense. 

The third group of Alstonia species contains neither the alstonine nor the echitamine series of alkaloids hence, the genus appears to be divided into three clearly defined sections as far as alkaloid content is concerned. A. macrophylla Wall, contains villalstonine (33, 35), macralstonine (33, 36), macralstonidine, a base M which was obtained in minute amounts only (33), and macrophylline (37). A. villosa Blume contains villalstonine and base V, insufficiently characterized (33) A. somersetensis F. M. Bailey contains villalstonine and macralstonidine (33). 

The alkaloid macrophylline,1 C45H54N4O5, mp 267°-268° (dec.), resembles macralstonine in both its mode of extraction and its physical properties (37), and was earlier assumed to be identical with it. Recently, however, the isolation of a base, mp 270°-272°, reported to be identical with macralstonine, has been described from A. macrophylla it is also... 

Certain Alstonia species of the family Apocynaceae contain bisindole alkaloids of interesting construction. These are (+)-villalstonine from Alstonia macro-phylla Wall., A. muelleriana, A. somersetensis F.M. Bailey and A. villosa Blume, (+ )-macralstonine from A. macrophylla Wall., and macralstonidine from A. macrophylla Wall, and A. somersetensis F.M. Bailey. A common unit of all three dimers is the monomeric indolic base macroline. 

Of the 12 alkaloids belonging to this group occurring in Sri Lankan flora, 11 were encountered in Alstonia macrophylla Wall, of the family Apocynaceae, and the remaining alkaloid was isolated from Taberrtaemon-tana divaricata (L.) Br. ex Roem et Schult. of the same family. Six of the alkaloids were found to be new. Vincamajine (101) and its new derivative, 19-hydroxyvincamajine (102), are two alkaloids of the ajmaline subgroup present in A. macrophylla (82). The structure of 102 was elucidated with the aid of IR, H NMR, and low-resolution MS data. A. macrophylla also... 

The Sri Lankan Alstonia macrophylla also contained a series of alkaloids belonging to the 4,21-seco-lO-deoxysarpagine or indolohomotropane subgroup. Talcarpine (109) (82,88), alstophylline (110), (82,88), and alstonerine [demethoxyalstophylline (111)] (79,82,88) are three known alkaloids isolated from A. macrophylla. Alstomacrocine (112), C21H28N2O2, on the other... 

In connection with the biogenetic origin of alstonisidine it is of interest to note that 0-benzoylvincamajine (42) has been shown to occur in the closely related A. macrophylla (42) and trimethoxybenzoyl-quebrachidine (44) in A. constricta (35). It is thus possible that alstonisidine arises by Mannich condensation of macroline (57) with quebrachidine to give an intermediate similar to 69, which is then converted into alstonisidine by closure of the amino ketal function (39). 

Alstophylline, C22H26N2O3, the tertiary base recently isolated from the bark of A. macrophylla, is a monomeric alkaloid of structure XXVIII 9). The presence in the molecule of the ]8-alkoxy-a,j8-unsaturated ketone grouping was deduced from the IR spectrum, which exhibits maxima at 1616 and 1640 cm similar to those exhibited by dimedone methyl ether (XXIX). This deduction is also consistent with the UV spectrum of alstophylline which closely resembles the summation spectrum of XXIX and 7-methoxy-9-methyl-l,2,3,4-tetrahydrocarb-azole (XXX). The NMR spectrum of alstophylline confirms this orientation of the methoxyl group. In the aromatic region (6.60-7.52 ppm) the integrated signals disclose the presence of four protons, i.e., three aromatic ones and the olefinic proton j8 to the carbonyl group. If the... 

Only two members of this group are known, both from Alstonia species. They are alkaloid C (XVII) from A. muelleriana Domin (A. villosa Benth.) whose structure was determined by X-ray methods (68) and alstophylline (XVIII) from A. macrophylla Wall, whose structure was deduced largely from mass spectral data (69). Alstophylline is also... 

The Malaysian A. macrophylla provided a new bisindole, perhentinine (337), addition to villalstonine (222). The H and NMR data indicated that the bisindole is constituted from the union of two macroline halves, viz., macroline and alstophylline, with the branching from the nucleophilic C(IO ) of alstophylline to C(21) of the macroline unit. 

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