Azides: their preparation and synthetic uses

Scriven, E. F. V.; Turnbull, Kenneth

doi:10.1021/cr00084a001

Cited by 1,431 publications

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“…[10][11][12] The isocyanate intermediate can be isolated when the reaction is carried out in non-nucleophilic solvent or can be intercepted by water, amines or alcohols to give the corresponding, amines, ureas or carbamates.…”

Section: Resultsmentioning

confidence: 99%

The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

Pilli¹,

Rodrigues²

2009

J. Braz. Chem. Soc.

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Uma síntese total e eficiente da (+) e (-)-tripargina, alcalóide b-carbolínico isolado da pele da rã africana K. Senegalensis, foi realizada em 6 etapas e 38% de rendimento global, a partir da triptamina, tendo como base a construção do sistema b-carbolínico via reação de BischlerNapieralski e a redução enantiosseletiva do intermediário diidro-b-carbolínico via reação de transferência de hidrogênio assimétrica usando o protocolo de Noyori.A concise and efficient total synhesis of (+)-and (-)-trypargine (6 steps and 38% overall yield), a 1-substituted b-carboline guanidine alkaloid isolated from the skin of the African frog K. senegalensis, was developed based on the construction of the b-carboline moiety via BischlerNapieralski reaction and the enantioselective reduction of the dihydro-b-carboline intermediate via an asymmetric transfer hydrogenation reaction using Noyori´s protocol.Keywords: trypargine, tetrahydro b-carboline alkaloid, Bischler-Napieralski reaction, Noyori asymmetric transfer hydrogenation IntroductionThe b-carboline skeleton is widely distributed among natural products including yohimbine (yohimbine and alloyohimbine), corynantheidine (corynantheidine), Rauwolfia (reserpine) and Vinca (vincamine) alkaloids. 1 (-)-Trypargine (1) is a b-carboline alkaloid which has been isolated from the skin of the African racophorid frog, Kassina senegalensis, by Akizawa et al. 2 in 1982 and more recently has also been isolated in nearly racemic form from the methanol extract of the ground ascidian Eudistoma sp. 3 The absolute configuration of natural (-)-trypargine (1) was initially assigned via resolution of its racemate, prepared via the Pictet-Spengler reaction between tryptamine and 4-guanidino butyraldehyde ethyleneacetal, followed by optical rotatory dispersion and circular dichroism studies. 4 Ishikawa and co-workers 4,5 established its absolute configuration by total synthesis via the Pictet-Spengler reaction between (R)-N-benzyl tryptophan methyl ester and 2-ketoglutaric acid, followed by X-ray diffraction analysis of the corresponding methyl ester of the major diastereoisomer. Synthetic (-)-(S)-1-(3´-guanidinopropyl)-1,2,3,4-tetrahydro-bcarboline was shown to be identical to natural (-)-trypargine (1) thus establishing its absolute configuration.The presence of a b-carboline and a guanidine moieties in the structure of (-)-trypargine (1) has led to preliminary evaluation of its biological profile. Neither a full account of the biological properties nor its biosynthetic origin have been reported although one may envision trypargine (1) to be formed from tryptophan and the 2-keto carboxylic acid derived from arginine. It has been reported to be toxic to mice (LD 50 = 16.9 mg kg -1 , intravenous administration) although complete details of this study are lacking. 5,6 Ireland and co-workers 3 have failed to observe significant cytotoxicity in fractions containing trypargine alkaloids against human colon tumor cells. Additionally, (-)-trypargine (1) has been reported to block voltage gated sodium channe...

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Section: Resultsmentioning

confidence: 99%

The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

Pilli¹,

Rodrigues²

2009

J. Braz. Chem. Soc.

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“…The chemistry of azides has thus attracted the attention of many chemists, since many of these compounds play an important role in organic chemistry [13][14][15]. One of the more useful synthetic applications of azides is the preparation of 1,2,3-triazoles via 1,3-dipolar cycloaddition click reactions of azides with substituted acetylene compounds [16][17][18][19].…”

Section: -Chloromethylstyrene (Cms)mentioning

confidence: 99%

Modification of styrene polymer by attaching suitable groups as side chain

2009

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Chemical modification of inexpensive commercial polymers, such as styrene, is a safe methodology to obtain new copolymers. The 4-chloromethyl styrene (CMS) was copolymerized with styrene (in various mole ratios) by free radical polymerization method at 70 ºC using α,α-azobis(isobutyronitrile) (AIBN) as an initiator. The azide ion was covalently attached to the obtained copolymers with replacement of all the chlorine atoms in CMS units. The 1,3-dipolar click cycloaddition reaction between azido polymers and dimethyl acetylene dicarboxylate (DMAD) yielded polymers with 1,2,3-triazoles in side chain. The polymers, obtained in quantitative yields, were characterized by FT-IR and 1 H NMR spectroscopy; thermogravimetric analysis (TGA) and GPC studies. The thermogravimetric analysis (TGA) indicated that the thermal stability of copolymers increases with incorporation of 1,2,3-triazole groups in side chains of copolymers.

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“…To a flask containing 2,4,6-trichloro [1,3,5] triazine (0.369 g, 2 mmol ) in dry CH 3 CN (3-5 mL), was added n-Bu 4 NN 3 (0.576 g, 2 mmol) under stirring. Benzyl alcohol (0.108 g, 1 mmol,) was added and the mixture was refluxed.…”

Section: Typical Procedures For Conversion Of Alcohols To Azidesmentioning

confidence: 99%

A Novel and highly selective conversion of alcohols, thiols, and silyl ethers to azides using the 2,4,6-trichloro[1,3,5]triazine/n-Bu4NN3 system

Akhlaghinia¹,

Samiei²

2007

J. Braz. Chem. Soc.

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Alquil azidas são preparadas em bons a excelentes rendimentos, pelo tratamento de álcoois, tióis e trimetilsilil éteres com 2,4,6-tricloro[1,3,5]triazina/n-Bu 4 NN 3 em acetonitrila. Este método é altamente seletivo para conversão de álcoois primários a alquil azidas na presença de álcoois secundários e terciários, tióis e trimetilsilil éteres.Alkyl azides are prepared in good to excellent yields by treatment of alcohols, thiols and trimethylsilyl ethers with 2,4,6-trichloro[1,3,5]triazine/n-Bu 4 NN 3 in acetonitrile. This method is highly selective for conversion of primary alcohols to alkyl azides in the presence of secondary and tertiary alcohols, thiols and trimethysilyl ethers.

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Azides: their preparation and synthetic uses

Cited by 1,431 publications

References 0 publications

The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

Modification of styrene polymer by attaching suitable groups as side chain

A Novel and highly selective conversion of alcohols, thiols, and silyl ethers to azides using the 2,4,6-trichloro[1,3,5]triazine/n-Bu4NN3 system

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