Chapter 6 The Benzylisoquinoline Alkaloids

Deulofeu, Venancio; Comin, J.; Vernengo, Marcelo J.

doi:10.1016/s1876-0813(08)60258-4

Cited by 4 publications

(6 citation statements)

References 179 publications

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“…Botanical Occurrence of the Protopines BERBERIDACEAE Berberís Protopine (1) FUMARIACEAE Corydalis Protopine (1) Allocryptopine (2) Cryptopine (3) Corycavine (13) Corycavidine (14)…”

Section: Dactylicapnosmentioning

confidence: 99%

The Protopine Alkaloids

Guinaudeau¹,

Shamma²

1982

J. Nat. Prod.

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Sixteen naturally occurring protopines are known. The prototype for these bases is the widely distributed alkaloid protopine (1) wrhose numbering system is indicated in expression 1. The listing for the occurrence of this alkaloid as well as of allocryptopine (2) emphasizes the more recent findings. For an older listing of the occurrence of protopine (1) and allocryptopine (2) in plants, the reader should refer to H.-G. Boit's Ergebnisse der Alkaloid-Chemie Bis 1960, Akademie Verlag, Berlin (1961), pp. 349-351. Protopines are optically inactive, except in the case of C-13 substitution. The absolute configuration of the 13-methylated base corycavine (13) has been recently determined by correlation with a 13-methylated berbine of established absolute configuration (37).The alkaloid oreophiline is not a protopine base as long believed, but is instead a berbine (81).Among the Rutaceae, the genera Fagara and Zanthoxylum are generally considered to be identical. Neverthless, in the present listing, they have been kept apart to reflect the botanical names cited in the literature. It will be noted also that pseudoprotopine (9) and fagarine II (10) are the only two protopines substituted at C-10,11 rather than at the more common C-9,10 sites. Significantly, both of these alkaloids are found only among the Rutaceae.Uv wave lengths are in nm, and ir frequencies in cm-1. The solvent is always given whenever it has been indicated in the original literature. nmr chemical shifts are in CDCh solution unless indicated otherwise. In instances where chemical shift assignments were changed from those made in the original literature, this has been indicated with a double asterisk (**) as a superscript immediately after the appropriate reference. The H-l absorption in the protopines is found further downfield than that due to H-4 because of deshielding by the carbonyl function (5). The C-5 methylene protons are found near 52.6 4 5

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“…Botanical Occurrence of the Protopines BERBERIDACEAE Berberís Protopine (1) FUMARIACEAE Corydalis Protopine (1) Allocryptopine (2) Cryptopine (3) Corycavine (13) Corycavidine (14)…”

Section: Dactylicapnosmentioning

confidence: 99%

The Protopine Alkaloids

Guinaudeau¹,

Shamma²

1982

J. Nat. Prod.

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“…The affinities of racemic norlaudanosine (1) and its N-methyl (laudanosine, 2), N-ethyl (3) and N-propyl (4) derivatives for α 1 -adrenergic receptors was assessed in binding studies in rat brain cortical homogenates using the subtype-nonselective radioligand Table 1. a All binding experiments were carried out 3-5 times in duplicate.…”

Section: Resultsmentioning

confidence: 99%

“…Laudanosine (2) is a minor benzyltetrahydroisoquinoline (BTHIQ) alkaloidal constituent of opium, 1 and a major metabolite of the clinically important skeletal muscle relaxant atracurium, 2 as well as of its pure stereoisomer cisatracurium, both of which are used in combination with general anesthetics. One of the many pharmacological actions of laudanosine that may be of clinical concern in anesthesia is the relaxation of smooth muscle, mainly via blockade of α 1 -adrenergic receptors.…”

Section: Introductionmentioning

confidence: 99%

“…1). As a considerable number of these sterically constrained berbines and aporphines have also been shown to exhibit α 1 -adrenergic receptor blocking activity, 6,7 we decided to compare the affinities of laudanosine (2), norlaudanosine (1) and its N-ethyl (3) and -propyl (4) derivatives with the published data for their extended and semifolded rigid analogues, tetrahydropalmatine (5) and glaucine (6), and with our own results for the flexible coclaurine and armepavine analogues. 4 Figure 1: Preferred conformations of norlaudanosine (1), laudanosine (2), N-ethyl-and -propyl-norlaudanosine (3 and 4, respectively), showing their steric relationships to tetrahydropalmatine (5) and glaucine (6).…”

Section: Introductionmentioning

confidence: 99%

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N-Substitution AND Á1-Adrenergic RECEPTOR AFFINITY OF LAUDANOSINE ANALOGUES

Iturriaga-Vásquez

Cassels

Ivorra

et al. 2006

J. Chil. Chem. Soc.

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Benzyltetrahydroisoquinoline (BTHIQ) molecules are able to adopt widely differing conformations that depend on the presence or absence of N-substituents. To assess the possible role of BTHIQ conformation on the affinity of these compounds for α 1 -adrenergic receptors, of interest for the management of hypertension, the racemic N-unsubstituted BTHIQ norlaudanosine and a series of N-alkylated derivatives were assessed for binding to rat brain cortical sites labelled with the radioligand [ 3 H]prazosin. The α 1 -adrenergic affinity in this series increased with the bulk of the substituent on the nitrogen atom, from the N-ethyl to the N-propyl analogue. Comparison of these results with published data for related BTHIQs and for the rigid mimics of the fully extended and semi-folded conformations of laudanosine, tetrahydropalmatine and glaucine, suggested that the α 1 -adrenergic receptor binding site is able to accommodate either conformation. The presence of a bulky substituent on the nitrogen atom seems to favor receptor binding independently of the favored conformation, and that the orientation in which BTHIQs are bound probably differs depending on the presence or absence of a hydroxyl group at a key position.

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“…These early researchers demonstrated that do pamine (DA) and its N-methyl congener, epinine, would condense with aldehydes under physiological conditions to form the corresponding TIQ alkaloids. In plants, reaction of the ketoacid with the amine and subsequent decarboxylation is found (12). In 1964, Holtz (13) et al demonstrated the formation of THP following incubation of dopamine with monoamine oxi dase.…”

Section: +6760mentioning

confidence: 99%