Halogenated alkaloids

XE-30 Polycyanomethyl siloxane 275 Drugs, Alkaloids, Halogenated Ampds... 

Although, in most cases, iodine is a fairly inert halogen (in contrast to bromine) and does not normally react with the substances that have been chromatographed there are, nevertheless, examples where chemical changes have been observed. Oxidations can evidently take place (e.g. aromatic hydrocarbons and isoquinoline alkaloids [252,253]) and additions and substitutions have also been observed. Pale zones then appear on a brown background. 

Halogen lamp la 22 Halogen oxyacids la 188,189 Haloperidol lb 268,354 Harmalin lb 188 Harpagophytum alkaloids lb 243 Harpagoside lb 243 Hecogenine la 71... 

A molecular dissection of the alkaloid vasicine (52) ultimately resulted in the expectorant and mucolytic agent bromhexine (54). The synthesis starts with displacement of halogen on 2-nitrobenzyl-bromide (53) by N-methyl cyclohexylamine, followed by Raney nickel and hydrazine reduction of the nitro group. Bromination in acetic acid then affords bromhexine. 

Cyclization arising from the intramolecular photoelimination of HC1, HBr, and HI has been extensively used in the synthesis of heterocycles and alkaloids. The mechanisms of these transformations have not in many cases been thoroughly investigated. Some undoubtedly are initiated by simple homolysis of the carbon-halogen bond whereas others involve photocycliza-tion and subsequent elimination of HX. 

Alcohols, alkaloids, aromatic hydrocarbons, flavors, fuels, halogenates, herbicides, pesticides, petroleum products, solvents, waxes, general purposes... 

Because 1,4-dichlorobenzene is a liver toxin, it probably can interact with other chemicals that are liver toxicants. These toxicants are many, and include ethanol, halogenated hydrocarbons (chloroform, carbon tetrachloride, etc ), benzene, and other haloalkanes and haloalkenes. In addition, 1,4-dichlorobenzene toxicity may also be exacerbated by concurrent exposure with acetaminophen, heavy metals (copper, iron, arsenic), aflatoxins, pyrrolizidine alkaloids (from some types of plants), high levels of vitamin A, and hepatitis viruses. Such interactions could either be additive or S5mergistic effects. 

The focus of this review is to discuss the role of Cinchona alkaloids as Brpnsted bases in organocatalytic asymmetric reactions. Cinchona alkaloids are Lewis basic when the quinuclidine nitrogen initiates a nucleophilic attack to the substrate in asymmetric reactions such as the Baylis-Hillman (Fig. 3), P-lactone synthesis, asymmetric a-halogenation, alkylations, carbocyanation of ketones, and Diels-Alder reactions 30-39] (Fig. 4). 

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. ... 

The chemistry of carbazoles was last reviewed in 1952 and 1954 following earlier accounts. More recently, Rodd s first edition coverage was updated and halogen derivatives of carbazoles were reviewed. Alkaloids... 

Although very few terrestrial plant alkaloids contain halogen, brominated alkaloids have been reported from the marine environment. From the Okinawan marine sponge Hymemacidon sp., several bromopyrrole alkaloids have been described, e.g., tauroacidins A and B, Fig. (35) [262], konbuacidin A, Fig. (36) [263] and spongiacidins A-D [264]. Several species of sponges contain hymenialdisine, Fig. (37), which has been shown as a potent inhibitor of nuclear factor kappa B and interleukin-8 production in vitro [265,266]. 

Volutamides A-E (143-147), halogenated alkaloids of amino acid origin, have been isolated from the Atlantic bryozoan Amathia convoluta. Several of the volutamides deter feeding by potential predators and are toxic toward larvae of the co-occurring hydroid Eudendrium carneum, suggesting that these metabolites form the basis of an effective chemical defense. [114]. 

Cytotoxic and antifungal pyrroloquinoline alkaloids have been isolated from the Caribbean deep water sponge Batzella sp. Isobatzelline A (166) is considerably more active than the halogen-free isobatzelline B (P-388 leukemia IC50 0.42 and 2.6 pg/ml, Candida albicans IC50 3.1 and 25 pg/ml, respectively) [127]. 

SALT. A compound formed by replacement of part or all of the hydrogen of an acid by one (or more) element(s) or radrcal(s) that are essentially inorganic. Alkaloids, amines, pyridines, and other basic organic substances may be regarded as substituted ammonias in this connection. The characteristic properties of salts are the ionic lattice in the solid state and the ability to dissociate completely in solution. The halogen derivatives of hydrocarbon radicals and esters are not regarded as salts in the strict definition of the term,... 

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