Alkaloid class member

Montanine alkaloids are members of the alkaloids of the plant family of Amarylli-daceae. They represent a relatively small class of compounds with the typical methanomorphanthridine skeleton exhibiting some anxiolytic, anti-depressive and anti-convulsive activities [135, 136]. The total syntheses of the natural (-)-mon-tanine enantiomers are only mentioned, not described, here (for these (—(-enantiomers see, e.g. literature cited in [137]). 

Because benzylisoquinolines have been available synthetically (in racemic form) for decades, there is quite a bit of chemistry known regarding their use as key intermediates in the synthesis of a number of more complex isoquinoline alkaloids. The asymmetric synthesis of benzylisoquinolines has been used to complete total synthesis of representative members of several of these alkaloid classes. As shown in Figure 6, the protoberberine alkaloid norcoralydine, the aporphine alkaloid ocoteine, the isopavine alkaloid reframoline and the morphinan 0-methylflavinantine have been made available in optically active form for the first time (except by isolation or resolution) using this approach. 

Nummularine-F (60) and zizyphine-G (61), elaborated by Z. nummularia and Z. oenoplia respectively, represent the only new additions to the 14-membered-ring alkaloid class which exhibit the p-hydroxystyrylamine and 3-hydroxyproline units as characteristic features. The known cyclopeptide mauritine-A, together with minor amounts of amphibines-A, -E, and -F, and mauritine-C have been isolated from Z. spinachristi of Nigerian origin. ... 

The Aspidosperma alkaloids are a group of more than 100 monomeric and dimeric monoterpene indole alkaloids with aspidospermidine (228) representing a key member of the class and sometimes considered to be the parent [68]. Numerous total syntheses of this pentacyclic compound have been reported. Our own contributions in the area were prompted by the discovery of a new method for preparing indoles via a palladium-catalysed Ullmann cross-coupling reaction that proceeds especially efficiently at close to room temperature [69] and which we felt could serve as the centrepiece in developing a new synthesis of compound 228 and, in the longer term, syntheses of dimeric members of the indole alkaloid class such as the clinically significant alkaloids vinblastine and vincristine. 

NACE appears to be ideally suited for online coupling with mass spectrometry due to high volatility and surface tension of most of the organic solvents used [ 114]. Carefully optimized NACE-MS method was applied to a very large number of alkaloids in different psychoactive plant extracts, as demonstrated by Posch et al. [115]. The method allowed the separation of structurally closely related substances, such as diastereomers and other isobaric compounds, as well as to separate members of different alkaloid classes including tropane alkaloids without modification of the procedure. 

Marine alkaloids (-f)-batzelladine A and ( )-batzel-ladine D. Nine novel tricyclic guanidine marine alkaloids were isolated as metabolites of the Crambe genus. Members of the batzelladine alkaloid class exhibit potential antiviral activity in the inhibition of HIV gp 120-Human CD4 binding, as well as potential immunosuppressive... 

For many years oral xanthines, shown in Table 2, were the preferred first-line treatment for asthma in the United States, and if the aerosol and oral formulations of P2" go sts are considered separately, as they are in Table 1, this was still the case in 1989. Within this class of compounds theophylline (8), or one of its various salt forms, such as aminophylline [317-34-0] (theophylline ethylenediamine 2 l), have been the predominant agents. Theophylline, 1,3-dimethylxanthine [58-55-9], is but one member of a class of naturally occurring alkaloids. Two more common alkaloids are theobromine (9), isomeric with theophylline and the principal alkaloid in cacao beans, and caffeine, (10), 1,3,7-Trimethylxanthine [58-08-2], found in coffee and tea. 

Steroid alkaloids have been isolated from four famihes of terrestrial plant sources (Soianaceae l iliaceae pOijnaceae and Buxaceae) two animal sources (Saiamandra and Phjllobates) and several marine sources. Steroid alkaloids can be classified based on stmcture and fall into a variety of categories. The spirosolanes contain a cholestane skeleton with a C20 spiroaminoketal moiety, as exemplified by the most abundant members of this class, veramine... 

Demethylvasconine (85) (9-methoxy-5-methyl-phenanthridin-8-olate) presented in Scheme 31 was found in Crinum kirkii (95P1291) (Amaryllidaceae). Although published as cation, no information about the anion of this alkaloid is given. Its relationship to other alkaloids of this class, however, makes a betainic structure more than likely and this is confirmed by a comparison of the NMR data of 85 with the cationic and betainic alkaloids presented in Table III. This betaine is isoconjugate with the 2-methylphenanthrene anion and thus defined the alkaloid as a member of class 1 (odd alternant hydrocarbon anions). Whereas substitution of the isoconjugate phenanthridinium moiety at the 1-position with an anionic fragment results in zwitterions (cf. Section III.D), the phenanthridinium-2-olate is a mesomeric betaine. 

Benzo[c]phenanthridine alkaloids are widespread in Papaveraceae, Fumariaceae, and Rutaceae. Fagaridine (118), the structure of which had to be revised, is a derivative of the unknown 5-methyl-benzo[c]phenan-thridine-8-olate (119) which is isoconjugate with the 2-methyl-chrysene anion (Scheme 43). Thus, Fagaridine is a member of class 1 of conjugated heterocyclic mesomeric betaines, which are isoconjugate with odd alternant hydrocarbon anions. 

Further members of this class of alkaloids are the araguspongines K (10) and L (11), isolated from the marine sponge Xestospongia exigua collected at Bayadha, on the Saudi Arabian Red Sea coast [16]. After evaporation of the EtOH extract, it was partitioned between hexanes and MeCN. The polar fraction was subjected to a series of chromatographic separations by column chromatography on silica gel. The structures of both alkaloids 10 and... 

Although several synthetic approaches have been developed toward the total synthesis of polycyclic diamine sponge alkaloids, only a few members of this class have been synthesized. 

Since Huisgen s definition of the general concepts of 1,3-dipolar cycloaddition, this class of reaction has been used extensively in organic synthesis. Nitro compounds can participate in 1,3-dipolar cycloaddition as sources of 1,3-dipoles such as nitronates or nitroxides. Because the reaction of nitrones can be compared with that of nitronates, recent development of nitrones in organic synthesis is briefly summarized. 1,3-Dipolar cycloadditions to a double bond or a triple bond lead to five-membered heterocyclic compounds (Scheme 8.12). There are many excellent reviews on 1,3-dipolar cycloaddition, in particular, the monograph by Torssell covers this topic comprehensively. This chapter describes only recent progress in this field. Many papers have appeared after the comprehensive monograph by Torssell. Here, the natural product synthesis and asymmetric 1,3-dipolar cycloaddition are emphasized.630 Synthesis of pyrrolidine and -izidine alkaloids based on cycloaddition reactions are also discussed in this chapter. 

Tetracyclic /3-carboline alkaloids, known as canthines, have a peri-fused indolo[3,2,Tnaphthyridine structure. Over 40 members of this class of compound have been isolated, and they are of interest on account of their broad range of pharmacological effects (antimicrobial, cytotoxic, antibacterial, anticancer). 

As a whole, the Lycopodium alkaloids consist of over 270 members, and the number of natural products in this family continues to grow [1], The natural products are divided into four structural classes, three of which are represented by the parent... 

Since 1966, several carbazole alkaloids which are oxygenated at the C-iing were isolated from different natural sources. Glycozoline (86) was the first member of this class of alkaloids and was obtained from the stem bark of G. pentaphylla (95,96). In 1991, glycozoline (86) was also isolated by McChesney and El-Feraly from the roots of C. lansium (23). In Taiwan, the roots of this ornamental tree are used in traditional medicine for the treatment of bronchitis and malaria (23). In 1999, Chakravarty et al. isolated glycozoline (86) from the roots of G. arborea (62). 

Pyranoid monoterpenoid alkaloids have been reviewed, " and halogenated members of this class, (84) and (85), have already been discussed in the halogenated monoterpenoids section. " " The monoterpenoid ether (245) is reported from Artemisia tridentata-, from reported mass spectral data it may well be identical with the previously reported (and uncited) arthole (Vol. 7, p. 20), the characterization of which is still not published. Loliolide (246) is claimed to be an in vivo carotenoid degradation product in Canscora decussata additional spectral data have been published. ... 

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