Alkaloids phthalide-isoquinoline

Phthalide isoquinoline alkaloids Hydrastine. narceine, narcotine... 

J.D. Phillipson, Phytochemistry, 1977, j 6, 2009). Hypecorin-ine (236, X=0) has been reduced by lithium aluminium hydride to a mixture of bicuculline diol (247, R =0H, R =H) and adlu-mine diol (247, R =H, R =0H), obtained by the reduction of the diastereoisomeric phthalide-isoquinoline alkaloids bicuculline and adlumine (see section 12) with the same reagent (Nonaka and Nishioka, loc.dt.). Hypecorinine has been synthesised from dehydrobicucul1ine by reduction with lithium aluminium hydride and re-oxidation with mercury (II) acetate (B.C. Nall-iah and MacLean, Canad.J.Chem., 1978, 56, 1378). 

Novel syntheses of the phthalide-isoquinoline alkaloids have been achieved as follows. Condensation of the Reissert compound (289, R R =CH2) with methyl opianate (290) in the presence of sodium hydride gave the isoquinoline (291), which is hydrolysed, reduced and then A -methylated to racemic a and g hydrastine. The isomeric cordrastines are prepared in the same way from the compound (289, R =R =Me) (P. Kerekes, et al., Acta Acad.Sci.Hung., 1978, 97, 353 1980, 105, 283). Hydra-... 

Preformed cyclic /V,A-dialkyliminium salts i.e. where a ring Joins the a-caibon and positively charged nitrogen) have been used in enolate condensation reactions. The number of examples, however, is rather limited, probably because of complications arising through abstraction of enolizable protons. A -Dehy-droindolizidinium salt (69) represents one of the few examples of an enolizable, cyclic A, -dialkylimi-nium salt known to react with an enolate (equation 8). The use of a soft zinc enolate in this reaction may be crucial. The relative stereochemistry of the resulting 3-amino ester (70) is undefined. /V-Alkyl-3,4-dihydroisoquinolinium salts e.g. 71), a class of nonenolizable, cyclic iminium salts, have had extensive applications in the total synthesis of protoberberine and phthalide isoquinoline alkaloids. A review by Pai and coworkers has covered much of this work. In a more recent application by Yamazaki and co-... 

A route for the synthesis of phthalide-isoquinoline alkaloids from Reissert compounds has been reported. The Reissert compound (111) reacts with methyl opianate in the presence of sodium hydride to give the isoquinoline (112), hydrolysis of which yields dehydrohydrastine (113) this can be reduced in... 

A patent that covers the equilibration of narcotine and hydrastine to the a- and /3-forms, with racemization, by ultraviolet light has been published." The circular dichroism of the phthalide-isoquinoline alkaloids has been studied and correlations have been made between the stability of the a- and /8-forms and the intensity of the Cotton effect." The effects of solvents on the parameters of the n.m.r spectra of a- and /3-hydrastines, adlumine, and corlumine have been studied." ... 

Narciuidine see Amaryllidaceae alkaloids. Narcotine see phthalide isoquinoline alkaloids. 

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