Alkaloid lamine

Dipsacus asper Wall. Xu Duan (Teazel) (root) Essential oil, alkaloid lamine.50 Increase the leukocyte count, prevent spontaneous abortion. 

Alizarin-l-methyl ether Alkaloid lamine Alkaloids... 

An even more direct approach to carbazole-3,4-quinone alkaloids is provided by the palladium(II)-mediated oxidative coupling of ort/zo-quinones with ary-lamines, which gives access to this class of natural products in a three-step route [137]. 

Interestingly, all other diols, tried as a protecting group on the acetal, led to lower diastereoselectivity of the addition. This synthetic strategy was used in the synthesis of indolizidine alkaloids,279 bis(l-arylethyl)amines,280 a protease inhibitor.281 The addition reaction of 1,2-bisimines, easily available from glyoxal and chiral cr-phenylethy-lamine, gives under optimized conditions a diastereomerically pure product, that was converted to a chiral 1,2-diamine. Interestingly, decrease of the temperature below the optimum (50 °C) leads to a sharp drop of the stereoselectivity (Scheme 96).282... 

Snieckus et al. (158,159) demonstrated the usefulness of photocycliza-tion of the o-halogenophenethylenamide 341 in alkaloid synthesis. The bromoenamide 341 was irradiated with 2537-nm light in benzene -triethy-lamine solution to give the seven-membered product 342 in 20-21.5% yield. This (342) was then converted to the Schopf-Schweickert amine 343 on reduction (755) 343 has a structure closely related to the skeleton of the rhoeadine group of alkaloids (Scheme 121). 

A second alkaloid without the oxazolidine ring, but with the carbino-lamine system is cycloneosamandaridine (XXVII). The IR-spectrum evidences a five-membered lactone ring (band at 1780 cm i) as well as the carbinolamine group (bands at 1050/1180 cm i). The IR-spectrum of the X-acetyl compound no longer shows these hands at 1050-1180 cm i, hut an additional carbonyl frequency at 1735 cm i for an aldehyde group. The mass spectrum confirms the molecular formula as well as structure XXVII(id). 

Figure 23.7 Separation of opium alkaloids with supercritical mobile phase [reproduced with permission from J.L. Janicot, M. Caude and R. Rosset, J. Chromatogr., 437,351 (1988)]. Conditions column, 12 cm x 4 mm i.d. stationary phase, Spherisorb NH2, 3pm mobile phase, carbon dioxide-methanol-triethy-lamine-water (87.62 11.80 0.36 0.22),8 ml min pressure, 220 bar temperature, 40.7 C UV detector, 280 nm. Peaks 1= narcotine 2 —thebaine 3 = codeine 4 = cryptopine 5 = morphine.

The regioselective ET-sensitized addition of primary amines has been cleverly employed by Yasuda and co-woikers in the synthesis of isoquinolines and related alkaloids. For example, the DCNB-sensitized photoamination of stilbene with 2-hy-doxypropylamine in an acetonitrile-water solution yields the adduct 98, which is converted to the benzylisoquinoline 99 upon treatment with CFjSOjH, The P-hydroxyl group of ethano-lamine can be replaced with acetal or vinyl groups which also can serve as precursors of the carbocation required for the acid-catalyzed ring-forming reaction. Analogous reaction sequences have been used to convert phenanthrene to aporphines. ... 

The eudistomins are a class of polycyclic alkaloids that contain a unique 1,3,7-oxathiazepine ring system as well as an iV,iV,0-trisubstituted hydrojq lamine substructure (Scheme 15.7). These natural products were isolated by Rinehart et al from the colonial tunicate Eudistoma olivaceum in 1984, and they exhibited strong antiviral activity against the Herpes sinplex... 

Wilson, B.J. (2003) Anionic ortfto-Fries rearrangement of n-carbamoyl diary-lamines, synthesis of the acridone alkaloid junosidine. M.Sc. Thesis. Queen s University, Kingston, Canada. 

These alkaloids are formed through the reaction of phenyletl lamine and formaldehyde, followed by cyclisation (see Scheme 20). The occurrence and properties of these alkaloids were reviewed by Menachery (d7). 

The utility of the above-mentioned class of catalytic transformations has been demonstrated in the context of preparation of enantiomerically enriched coniine, the neurotoxin found in the hemlock plant. Thus, Mo-catalyzed RCM of benzy-lamine 1 in the presence of 10 mol% of chiral [Mo]-catalyst ([Mo]-II) gives rise to the formation of unsaturated piperidine 2 in 93.5/6.5 er and 83% yield (Scheme 12.1). A two-step sequence furnishes the poisonous alkaloid. 

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