The Synthesis of (±)-Cordrastine. A New Route to the Phthalideisoquinoline System

Smula, V.; Cundasawmy, N. E.; Holland, Herbert L.; MacLean, David B.

doi:10.1139/v73-490

Cited by 22 publications

(11 citation statements)

References 9 publications

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“…(-)-CORDRASTINE II C"H,5NO,: 399.1682 erythro (1R,9S) MP: 90°( ether-petroleum ether) (29) [ ] : -10°( c 1.0, CHCl,) (29) UV: -168,270,0, (29) Rf: 0.09 (EtOAc) (29) Remaining physical properties resemble those of (=*=)cordrastine II Source: Synthetic (29) 13. (±)-CORDRASTINE II C"H,5N06 : 399.1682 erythro racemate (IRS, 9SR) MP: 119° ( 50,51) 117-118°(MeOH) (76) IR: (CHCl,) 1755 (76) NMR : 100 MHz (CDCl,) (76, 97) Remaining physical properties resemble those of (-)cordrastine II (excluding ORD, CD, [ot]n) Source: synthetic (76,97) There is only one report of the isolation of a cordrastinetype alkaloid from a plant (Corydalis aurea Willd.). The compound was only partially characterized, and no stereochemistry was assigned (9).…”

mentioning

confidence: 99%

The Phthalideisoquinoline Alkaloids

Bogáts¹,

Gula²,

Shamma³

1982

J. Nat. Prod.

153

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Classical type phthalideisoquinolines are derived biogenetically from tetrahydroprotoberberines, and the former in turn lead to the secophthalideisoquinolines. The secophthalideisoquinolines may come in different forms including enol lactones, keto lactones, keto acids and diketo acids. The most logical biogenetic sequence appears to be classical type phthalideisoquinoline-^classical type phthalideisoquinoline .Y-metho salt->secophthalide enol lactone->secophthalide keto acid->secophthalide diketo acid. Thus if one were to start with (-)-bicuculline (1), the sequence would be 1-»( -)-bicuculline .Y-metho salt (la)->the Z enol lactone aobamidine (32)->the keto acid adlumidiceine (36)->the diketo acid bicucullinine (42) (100). A seco diketo acid may then undergo oxidative cleavage to yield the alkaloid fumariflorine (51), or one of its analogs. Alkaloids of the fumariflorine type may thus represent a final stage in the catabolism of the phthalideisoquinolines (101). It is worth noting here that the presence of classical type phthalideisoquinoline .Y-metho salts has been detected in Fumaria parviflora Lam. ( 70).An enol lactone such as aobamidine (32) may undergo photoisomerization to a mixture of Z and E isomers, and in fact the E analog of aobamidine is known as a natural product under the name adlumidiceine enol lactone (33).It has recently been shown that secophthalideisoquinoline enol lactones readily react with ammonia to form hydroxy lactams (e.g. fumschleicherine (50) ). A secophthalide hydroxy lactam can then undergo facile dehydration to an enelactam. Four enelactams have been apparently isolated from natural sources, namely, fumaramine (45), fumaridine (46), fumaramidine (48), and narceine imide (49). Since ammonium hydroxide is usually used in the course of the isolation, it seems likely that these four compounds, together with fumschleicherine (50), are artifacts of isolation. Until and unless the presence of secophthalideisoquinoline hydroxy lactams and enelactams is conclusively demonstrated in the plant extracts prior to treatment with ammonia, it can be concluded that they are artifacts and not true alkaloids (100). Nevertheless, and for the sake of completeness, the hydroxy lactam fumschleicherine (50) and the four enelactams 45, 46, 48, and 49, have been included in the present listing.The secophthalideisoquinoline keto acid nornarceine (40) may also be another artifact. It is the only known seco base which does not incorporate a complete ,. -dimethylaminoethyl side chain. It was isolated only once, and that time from opium, and it may very well have arisen from the known in vitro N-demethylation of narceine (39) in acid solution (100).All uv data are in nm with log < values between parentheses. Ir frequencies are in cm-1.The nmr chemical shift values quoted are from the first reference cited. However, in case we have found it necessary to modify the original assignment, this has been indicated by a double asterisk (**) as a superscript immediately after the reference. Whenever possible, we have ...

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mentioning

confidence: 99%

The Phthalideisoquinoline Alkaloids

Bogáts¹,

Gula²,

Shamma³

1982

J. Nat. Prod.

153

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“…As anticipated, 8 was readily transformed to was characteristic of a spirobenzylisoquinoline the spirobenzylisoquinoline 9 by bromination (2,7,8). The resonances at 6 5.95 and 6.62 at C-2' followed by treatment of the bromide were assigned to the C-8 and C-5 hydrogens, with triethylamine (8).…”

Section: Och]mentioning

confidence: 64%

“…The resonances at 6 5.95 and 6.62 at C-2' followed by treatment of the bromide were assigned to the C-8 and C-5 hydrogens, with triethylamine (8). Compound 9 exhibited respectively, by comparison with the spectra of analogous alkaloids (2,7). The overall yield from phthalideisoquinoline to spirobenzylisoquinoline was 75%.…”

Section: Och]mentioning

confidence: 99%

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The conversion of phthalideisoquinolines into spirobenzylisoquinolines and rhoeadine precursors

Holland¹,

Curcumelli-Rodostamo²,

MacLean³

1976

Can. J. Chem.

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Treatment of hydrastine with p-nitrophenylchloroformate in the presence of diethylisopropylamine resulted in opening of the isoquinoline ring with the formation of an ene-lactone carbamate. The latter compound rearranged upon treatment with methanolic sodium methoxide to an indan-1,3-dione carbamate which gave, on basic hydrolysis, the corresponding amine. This was ring closed to a spirobenzylisoquinoline. In addition, acid-catalysed dehydration of the amino indandione led to the formation of two isomeric benzazepines, synthetic precursors of the rhoeadine alkaloids. The predominately formed isomer has a substitution pattern identical with that of the rhoeadines.

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“…When an ethanol/ether solution of the oil was seeded with an authentic sample of cordrastine 11, crystals were deposited, mp 119-120°C (lit. (17,18) mp 117-119°C.…”

Section: Cordrastines 3 a And 3bmentioning

confidence: 99%

Synthesis of phthalideisoquinolines by direct coupling of phthalide anions with 3,4-dihydroisoquinolinium salts

Marsden¹,

MacLean²

1984

Can. J. Chem.

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, 306 (1984). The condensation of phthalide anions, derived from phthalide itself and from its 6,7-and 5,6-dimethoxy derivatives, with 6,7-dimethoxy-2-methyl-3.4-dihydroisoquinoine is described. The reaction products obtained in ca. 40% yield are easily separable mixtures of substituted (*)-erythro and (*)-threo-phthalidetetrahydroisoquinolines. The reaction is potentially useful for synthesis of naturally occurring akaloids of this family. RICHARD MARSDEN et DAVID B. MACLEAN. Can. J. Chem. 62, 306 (1984). On dtcrit la condensation des anions phtalides, provenant du phtalide lui-meme et de ses dtrivts dimtthoxy-6,7 et dimtthoxy-5,6 sur la dimtthoxy-6,7 mtthyl-2 dihydro-3,4 isoquinoltine. Les produits de la reaction obtenus avec un rendement d'environ de 40% sont des mtlanges facilement stparables de (+) trythro et de (*) thrto phtalidetttrahydroisoquinoltines substitutes. La reaction est potentiellement utile pour la synthkse des alcaloi'des naturels de cette famille.[Traduit par le journal]Perkin and Robinson (1) reported in 191 1 the first successful synthesis of a phthalideisoquinoline alkaloid, although in low yield, by treating cotarnine with meconin in boiling alcohol. Many synthetic approaches to these alkaloids have appeared in the intervening years, which are summarized in several reviews (2-6) and in a recent paper (7). Several reports describing new and efficient syntheses of these alkaloids based on the PerkinRobinson approach have recently appeared. In 1979 a preliminary account appeared of the reaction between 3-halophthalides and 2-methyl-3,4-dihydroisoquinolinium salts in the presence of Zn metal or Zn-Cu couple (8) and a full account of this reaction was published in 1981 (7). The validity of this approach to phthalideisoquinoline alkaloid synthesis has recently been confirmed by Shono et al. (9) who carried out the same reaction in a different solvent system. The electrochemical i coupling of bromophthalides and 3,4-dihydroisoquinolinium salts has also been reported (10). In another approach Prager et al. (I 1) have shown that 2-methylisoquinolinium salts condense with ~hthalides in the Dresence of sodium methoxide yielding adducts that may be reduced catalytically with hydrogen or with sodium cyanoborohydride to the 2-methylphthalidetetrahydroisoquinoline system present in the naturally occurring alkaloids. Prager et al.( 1 1) noted that they were unable to carry out a similar addition to 3,4-dihydroisoquinolinium salts. In this laboratory we had encountered similar difficulties in the past. Now, however, by preparation of the phthalide anions at low temperature using LDA, we are able to report the direct coupling of phthalide anions with 3,4-dihydroisoquinolinium salts. Phthalide anions have been prepared and used successfu!ly by Broom and Sammes (12) as Michael donors. Sammes' group has also shown that they add to acyclic imines forming isoquinolones (13) and we have shown that they add to 3,4-dihydroisoquinolines (cyclic imines), forming in one step the berberine ring system (14). Their add...

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The Synthesis of (±)-Cordrastine. A New Route to the Phthalideisoquinoline System

Cited by 22 publications

References 9 publications

The Phthalideisoquinoline Alkaloids

The Phthalideisoquinoline Alkaloids

The conversion of phthalideisoquinolines into spirobenzylisoquinolines and rhoeadine precursors

Synthesis of phthalideisoquinolines by direct coupling of phthalide anions with 3,4-dihydroisoquinolinium salts

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