Siamin, ein neues isochinolon-derivat aus cassia siamea

Ahn, Byung Zun; Zymalkowski, F.

doi:10.1016/s0040-4039(00)92893-4

Cited by 15 publications

(6 citation statements)

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“…Therefore, the structure of siaminine A is suggested to be 4methyl-siamine (3,4-dimethyl-6, ß-dihydroxyisoquinoline-1-one, 2). The close similarity between the uv, ir, and nmr spectral data of siamine (1) (8,11) and siaminine A are also in good agreement with this structure.…”

supporting

confidence: 73%

New Isoquinolone Alkaloids from the Leaves of Cassia siamea

El–Sayyad¹,

Ross²,

Sayed³

1984

J. Nat. Prod.

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Piperidenol and monoterpene alkaloids have been isolated from Cassia species (1-7). This paper deals with the isolation and structure elucidation of two new alkaloids from the leaves of Cassia siamea Lam. Four fluorescing and DragendorfFs-positive spots were seen on a tic chromatogram of the concentrated and processed alkaloid extract of the leaves. Preparative tic resulted in the isolation of the four weakly-basic alkaloids that gave precipitates with Mayer's reagent. One of them, present only in small amounts, was identified by co-chromatography, mp, mmp, and ir spectra as the known isoquinolone siamine (1) (8).The other three alkaloids were named siaminine A, B, and C. They showed from five to seven maxima in the uv spectra in the range from 230 to 355 nm, indicating a complex pattern of a highly conjugated chromophore. The ir spectra showed intense peaks at 3000-3050 cm-1 assigned to the associated N-H stretching vibration of a lactam; while a peak at 1635 cm 1 was consistent with the presence of a -lactam carbonyl. The latter was clearly significant at miz 43 in the mass spectra. Another peak in the ir at 840 cm-1 was assigned to the NH group, which was confirmed by the presence of a broad singlet in the pmr at 11.2

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supporting

confidence: 73%

New Isoquinolone Alkaloids from the Leaves of Cassia siamea

El–Sayyad¹,

Ross²,

Sayed³

1984

J. Nat. Prod.

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“…has been isolated from the pods and branches of the plant might be responsible for the toxic effects on hogs [2]. Meanwhile from Cassia siamea the dimeric anthraquinones Cassiamin A, B, C [3, 41, Cassianin, Siameanin and Siameadin [5], the isoquinoline alkaloid Siamin [6] and the dioxaphenalene derivative barakol [7] have been isolated.…”

Section: Introductionmentioning

confidence: 99%

Chemical Constituents of Cassia siamea Lam., I

Wagner¹,

El–Sayyad²,

Seligmann³

et al. 1978

Planta Med

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“…Isoquinolones are among a small subgroup of heteroaromatic natural products isolated from plant sources . They are frequently substituted with a hydroxy or methoxy group at C-6 (and C-7) as in doryphornine, siamine, coryaldine, dorianine, thalflavine, and ruprechtstyril (Figure ).…”

Section: Introductionmentioning

confidence: 99%

“…20 It is interesting to mention that the substitution of the 6-methoxy ether group in naturally occurring alkaloids such as doryphornine by ethertethered azacyclic equivalents led to inhibitors of Rho kinase. 21 Increasing the sp 3 character of bioactive compounds often comprising stereogenic carbon atoms has proven beneficial for both their physical 22 and chemical properties. 22,23 There are, to the best of our knowledge, scant reports of isoquinolones that bear sp 3 carbon-linked acyclic aminoalkyl, or aza-and oxacyclic appendages at C-6 and C-7.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In the first of these, we were inspired by the scholarly contributions of Weix, 26 Gong, 27 and Molander 28 relying on well-precedented Ni-catalyzed reductive cross-coupling reactions involving alkyl (sp 3 ) and aryl or heteroaryl (sp 2 ) reacting partners. 29 In the second approach, we capitalized on the recent innovative methods of merged photocatalytic and Ni-catalyzed coupling reactions pioneered by MacMillan 30,31 to forge the same reaction between heteroaryl and a series of aza-and oxacyclic α-carboxylic acids toward C-6 and C-7 sp 3 /sp 2 substituted isoquinolones for the first time.…”

Section: ■ Introductionmentioning

confidence: 99%

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Ni-Catalyzed Reductive and Merged Photocatalytic Cross-Coupling Reactions toward sp³/sp²-Functionalized Isoquinolones: Creating Diversity at C-6 and C-7 to Address Bioactive Analogues

et al. 2020

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Naturally occurring isoquinolones have gained considerable attention over the years for their bioactive properties. While the late-stage introduction of various functionalities at certain positions, namely, C-3, C-4, and C-8, has been widely documented, the straightforward introduction of challenging sp 3 carbon-linked acyclic aminoalkyl or aza- and oxacyclic appendages at C-6 and C-7 remains largely underexplored. Interest in 6-substituted azacyclic analogues has recently garnered attention in connection with derivatives exhibiting anticancer activity. Reported here is the first application of the versatile and recently emerging field of Ni-catalyzed reductive cross-coupling reactions to the synthesis of 6- and 7- hetero(cyclo)alkyl-substituted isoquinolones. In a second and complementary approach, a new set of C-6- and C-7-substituted positional isomers of hetero(cyclo)alkyl appendages were obtained from the merging of photocatalytic and Ni-catalyzed coupling reactions. In both cases, 6- and 7-bromo isoquinolones served as dual-purpose reacting partners with readily available tosylates and carboxylic acids, respectively.

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Siamin, ein neues isochinolon-derivat aus cassia siamea

Cited by 15 publications

References 1 publication

New Isoquinolone Alkaloids from the Leaves of Cassia siamea

New Isoquinolone Alkaloids from the Leaves of Cassia siamea

Chemical Constituents of Cassia siamea Lam., I

Ni-Catalyzed Reductive and Merged Photocatalytic Cross-Coupling Reactions toward sp³/sp²-Functionalized Isoquinolones: Creating Diversity at C-6 and C-7 to Address Bioactive Analogues

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Siamin, ein neues isochinolon-derivat aus cassia siamea

Cited by 15 publications

References 1 publication

New Isoquinolone Alkaloids from the Leaves of Cassia siamea

New Isoquinolone Alkaloids from the Leaves of Cassia siamea

Chemical Constituents of Cassia siamea Lam., I

Ni-Catalyzed Reductive and Merged Photocatalytic Cross-Coupling Reactions toward sp3/sp2-Functionalized Isoquinolones: Creating Diversity at C-6 and C-7 to Address Bioactive Analogues

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Ni-Catalyzed Reductive and Merged Photocatalytic Cross-Coupling Reactions toward sp³/sp²-Functionalized Isoquinolones: Creating Diversity at C-6 and C-7 to Address Bioactive Analogues