Simple Syntheses of 3-Substituted Indoles and their Application for High Yield <sup>14</sup>C-Labelling

Schallenberg, J.; Meyer, Eckart

doi:10.1515/znb-1983-0120

Cited by 16 publications

(7 citation statements)

References 11 publications

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“…Brassinin was first synthesized from 3-aminomethylindole by reaction with carbon disulfide in the presence of triethylamine followed by treatment with iodomethane in pyridine (8). Syntheses of the key intermediate, 3aminomethylindole, from indole-3-carboxaldehyde oxime, 3-cyanoindole or indole-3-carboxaldehyde (21,22), have been described as being poorly reproducible and giving low yields (21,23,24). The published synthesis of 3aminomethylindole (21,22) worked rather poorly on scale-up.…”

Section: Methodsmentioning

confidence: 99%

“…Syntheses of the key intermediate, 3aminomethylindole, from indole-3-carboxaldehyde oxime, 3-cyanoindole or indole-3-carboxaldehyde (21,22), have been described as being poorly reproducible and giving low yields (21,23,24). The published synthesis of 3aminomethylindole (21,22) worked rather poorly on scale-up. Therefore, we developed a high-yield, simple one-pot synthesis starting from commercially available indole-3-carboxaldehyde for brassinin (1) or 2-methylindole-3-…”

Section: Methodsmentioning

confidence: 99%

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Cancer chemopreventive activity of brassinin, a phytoalexin from cabbage

et al. 1995

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Brassinin [3-(S-methyldithiocarbamoyl)aminomethyl indole], a phytoalexin first identified as a constituent of cabbage, was synthesized and evaluated for cancer chemopreventive activity. Dose-dependent inhibition of 7,12-dimethylbenz[a]anthracene (DMBA)-induced preneoplastic lesion formation was observed with mouse mammary glands in organ culture, as was dose-dependent inhibition of DMBA-induced mouse skin tumors that were promoted by treatment with 12-O-tetradecanoylphorbol-13-acetate. Cyclobrassinin is a biologically derived product of the oxidative cyclization of brassinin, and was as active as the parent compound in inhibiting the formation of preneoplastic mammary lesions in culture; however, 2-methylbrassinin was not significantly active in this process. Therefore, oxidative cyclization may be an effective metabolic activation step. As judged by these tumor inhibition studies in conjunction with potential to induce phase II enzymes in mice or cell culture, brassinin may be effective as a chemopreventive agent during both the initiation and promotion phases of carcinogenesis. This is the first report documenting the chemopreventive potential of structurally novel indole-based phytoalexins that are naturally occurring in cruciferous vegetables, and the synthetic route described herein has proven amenable for scale-up production. The bifunctional structural nature of brassinin, bearing both an indole nucleus and a dithiocarbamoyl-aminomethyl moiety, is notably similar to the individual structural elements of other known chemopreventive agents such as indole-3-carbinol or benzylisothiocyanate. The favorable biological activity demonstrated by the compound may originate from the presence of these two moieties.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Cancer chemopreventive activity of brassinin, a phytoalexin from cabbage

et al. 1995

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“…For the fifth leaf of Arimar and Proctor, NMT activity towards both AMI and MAMI increased as growth temperature was increased between 15°C/10°C and 35°C/30°C (Fig. 3); NMT activities at these extremes differed by a factor of about 8 for Arimar, about 20 for Proctor. In contrast, NMT activities in the second leaf remained low at all temperatures, consistent with the failure of the second leaf to accumulate alkaloids in comparable experiments (1 1).…”

Section: Resultsmentioning

confidence: 98%

“…Tryptamine HCI (NBC) and tyramine (Sigma) were recrystallized from 96% ethanol and checked for purity by paper chromatography in the 'Isobuf'f system (1 1). AMI was synthesized according to Putochin (19) and Schallenberg and Meyer (20). MAMI H3BO3/l M Na2CO3 buffer (pH 10).…”

Section: Methodsmentioning

confidence: 99%

“…Alkaloids were extracted into 2 ml of CHC13, 1 ml of which was taken for scintillation counting. The remaining 1 20 mm Tris/HCI, 0.9% NaCl, 0.01% NaN3 (pH 7.4) (BSA-Trissaline) to block unreacted protein binding sites. Blots were then incubated for 1 h at 37C or overnight at 4°C in 1% BSA-Trissaline to which either 1:100 preimmune serum or 1:5000 antiserum had been added.…”

Section: Methodsmentioning

confidence: 99%

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Induction of a Specific N-Methyltransferase Enzyme by Long-Term Heat Stress during Barley Leaf Growth

Leland¹,

Hanson²

1985

Plant Physiol.

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Previous work showed that the indole alkaloid gramine accumulates in the upper leaves (e.g. the fifth) of barley as a response to high growth temperatures. The biosynthesis of gramine proceeds from tryptophan to 3-aminomethylindole (AMI); sequential N-methylations of AMI then yield N-methyl-3-aminomethylindole (MAMI) and gramine.To determine whether high-temperature stress increases the activity of gramine pathway enzymes, leaf tissue from plants grown at various temperatures was assayed for N-methyltransferase (NMT) activity using AMI and MAMI as substrates in both in vivo and in vitro assays. NMT activity in expanding fifth leaves was increased 8-to 20-fold by growth at high temperatures (35°C day/30°C night) compared to cool temperatures (15°C/10°C). Several days of high temperature were required for full induction of NMT activity. No induction of NMT activity occurred in leaves which had completed expansion in cool conditions before exposure to high temperature.To investigate NMT induction at the protein level, NMT activity was purified to homogeneity and used to produce polyclonal antibodies. Throughout enzyme purification, relative NMT activities towards AMI and MAMI remained constant, consistent with a single NMT enzyme. Immunoblot analysis showed that a large increase in NMT polypeptide coincided with induction of NMT activity by heat stress. Our results point to a type of high-temperature regulation of gene expression that is quite distinct from heat shock.Gramine is a simple indole alkaloid found in the shoots of many barley (Hordeum vulgare L.) cultivars and wild barley lines (3,12). Gramine biosynthesis involves the steps shown in Scheme 1. The indole nucleus and the methylene side chain oftryptophan are incorporated into the first stable intermediate ofthe pathway, AMI3 (7,9). AMI is then methylated at the amino nitrogen to form the secondary amine, MAMI, which is in turn N-methylated to produce the tertiary amine, gramine (7,18,22). Indirect evidence indicates that these methylations are catalyzed by an NMT enzyme (or enzymes) specific to the gramine pathway (1 1), for which SAM acts as the methyl donor (18). Although degradative pathways for gramine are known (6), gramine catabolism is very slow (1 1) so that accumulation is controlled mainly by ' Research conducted under contract DE-AC02-76ERO-1 338 from the United States Department of Energy. Michigan Agricultural Experimental Station Journal Article 11630. 2Present address: Funk Seeds International,

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Optimisation, Scope and Limitations of Enantioselective Aldol Reactions of an S-Ketene Silyl Acetal with Aliphatic Aldehydes under (R)-BINOL-Titanium(IV) Catalysis Conditions

et al. 2002

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The Mukaiyama aldol reaction between the functionalised aldehydes 5 and the S‐ketene silyl acetal 2 catalysed by 1,1′‐binaphthyl‐derived chiral titanium(IV) complex 4 afforded the corresponding aldol products 6 in good yields and with good to excellent enantioselectivities. The chemical yield could further be enhanced, without loss of stereoselection, by addition of phenol and/or molecular sieves. The presented aldol reactions with aluminium, boron and ytterbium‐BINOL catalysts demonstrate that only low chiral induction can be achieved. Aldol product 6a was converted into an α‐lipoic acid precursor 8, thus providing a formal synthesis of this biologically active compound. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

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Simple Syntheses of 3-Substituted Indoles and their Application for High Yield ¹⁴C-Labelling

Cited by 16 publications

References 11 publications

Cancer chemopreventive activity of brassinin, a phytoalexin from cabbage

Cancer chemopreventive activity of brassinin, a phytoalexin from cabbage

Induction of a Specific N-Methyltransferase Enzyme by Long-Term Heat Stress during Barley Leaf Growth

Optimisation, Scope and Limitations of Enantioselective Aldol Reactions of an S-Ketene Silyl Acetal with Aliphatic Aldehydes under (R)-BINOL-Titanium(IV) Catalysis Conditions

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Simple Syntheses of 3-Substituted Indoles and their Application for High Yield 14C-Labelling

Cited by 16 publications

References 11 publications

Cancer chemopreventive activity of brassinin, a phytoalexin from cabbage

Cancer chemopreventive activity of brassinin, a phytoalexin from cabbage

Induction of a Specific N-Methyltransferase Enzyme by Long-Term Heat Stress during Barley Leaf Growth

Optimisation, Scope and Limitations of Enantioselective Aldol Reactions of an S-Ketene Silyl Acetal with Aliphatic Aldehydes under (R)-BINOL-Titanium(IV) Catalysis Conditions

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Simple Syntheses of 3-Substituted Indoles and their Application for High Yield ¹⁴C-Labelling