2-Azido-1,3-dimethylimidazolinium Salts: Efficient Diazo-Transfer Reagents for 1,3-Dicarbonyl Compounds

Kitamura, Masaya; Tashiro, Norifumi; Miyagawa, Satoshi; Okauchi, Tatsuo

doi:10.1055/s-0030-1258457

Cited by 52 publications

(52 citation statements)

References 6 publications

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“…[10] Seeking a route that did not require a large excess of azide, we reasoned that 2-azido-1,3dimethylimidazolinium hexafluorophosphate (1, ADMP), [11,12] could be used as both activating agent for the anomeric hydroxy group and as the source of azide. ADMP was prepared by conversion of the hexafluorophosphate salt of DMC to ADMP by reaction with sodium azide, as reported by Kitamura et al [13] The reaction of ADMP with glucose 2 in a mixture of D 2 O and MeCN [14] (4:1), with an excess of Et 3 N, gave the desired b-azide 3 in 93 % yield (Scheme 1). However, when the reaction was applied to GlcNAc (4) a mixture of the b-azide 5 and oxazoline 6 was formed.…”

Section: Methodsmentioning

confidence: 99%

Protecting‐Group‐Free One‐Pot Synthesis of Glycoconjugates Directly from Reducing Sugars

et al. 2014

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The conversion of sugars into glycomimetics typically involves multiple protecting-group manipulations. The development of methodology allowing the direct aqueous conversion of free sugars into glycosides, and mimics of oligosaccharides and glycoconjugates in a high-yielding and stereoselective process is highly desirable. The combined use of 2-azido-1,3-dimethylimidazolinium hexafluorophosphate and the Cu-catalyzed Huisgen cycloaddition allowed the synthesis of a range of glycoconjugates in a one-step reaction directly from reducing sugars under aqueous conditions. The reaction, which is completely stereoselective, may be applied to the convergent synthesis of triazole-linked glycosides, oligosaccharides, and glycopeptides. The procedure provides a method for the one-pot aqueous ligation of oligosaccharides and peptides bearing alkyne side chains.

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Section: Methodsmentioning

confidence: 99%

Protecting‐Group‐Free One‐Pot Synthesis of Glycoconjugates Directly from Reducing Sugars

et al. 2014

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“…[29,35] 2-Methylisothiouronium iodide [36] [36] (2) To a stirring solution of 2-methylisothiouronium iodide 25 (9.820 g, 45.03 mmol) in sat. NaHCO3 (50 mL) and CH2Cl2 (105 mL) was added Boc2O (19.668 g, 90.12 mmol) using CH2Cl2 (3 × 25 mL).…”

Section: Methodsmentioning

confidence: 99%

Facile Synthesis of Guanidine Functionalised Building Blocks

2015

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Three useful developments in the preparation of guanidines are presented herein; i) a collection of bis(Boc)aminoalkylguanidines (n = 2, 3, 4 and 6), known to be prone to cyclisation, have been synthesised and isolated (without chromatography) as shelf stable sulfonate salts in good yield (up to 94%); ii) a selection of guanidines tethered to a range of other functional groups (including alkyne, alkene, alcohol and azide) have been prepared in good yields with no requirement for a purification step; and iii) an inexpensive, high-yielding (93%) and facile synthesis of N,Nʹ-bis(Boc)guanidine (a key precursor for N,Nʹ-bis(Boc)-Nʺ-triflylguanidine) is described in which the need for chromatographic purification is again obviated.

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“…We subsequently synthesized various 2‐azido‐1,3‐dimethylimidazolinium salts 1 having different counter anions, and the corresponding hexafluorophosphate derivative (2‐azido‐1,3‐dimethylimidazolinium hexafluorophosphate, ADMP 1 b ) was found to isolate as a crystalline phase . ADMP 1 b was prepared from DMC 4 a as shown in Scheme .…”

Section: Preparation and Structure Of Azidoimidazolinium Saltsmentioning

confidence: 99%

Azidoimidazolinium Salts: Safe and Efficient Diazo‐transfer Reagents and Unique Azido‐donors

Kitamura¹

2016

The Chemical Record

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2-Azido-1,3-dimethylimidazolinium chloride (ADMC) and its corresponding hexafluorophosphate (ADMP) were found to be efficient diazo-transfer reagents to various organic compounds. ADMC was prepared by the reaction of 2-chloro-1,3-dimethylimidazolinium chloride (DMC) and sodium azide. ADMP was isolated as a crystal having good thermal stability and low explosibility. ADMC and ADMP reacted with 1,3-dicarbonyl compounds under mild basic conditions to give 2-diazo-1,3-dicarbonyl compounds in high yields, which were easily isolated in virtue of the high water solubility of the by-products. ADMP showed high diazo-transfer ability to primary amines even in the absence of metal salt such as Cu(II). Using this diazotization approach, various alkyl/aryl azides were directly obtained from their corresponding primary amines in high yields. Furthermore, naphthols reacted with ADMC to give the corresponding diazonaphthoquinones in good to high yields. In addition, 2-azido-1,3-dimethylimidazolinium salts were employed as azide-transfer and migratory amidation reagents.

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2-Azido-1,3-dimethylimidazolinium Salts: Efficient Diazo-Transfer Reagents for 1,3-Dicarbonyl Compounds

Cited by 52 publications

References 6 publications

Protecting‐Group‐Free One‐Pot Synthesis of Glycoconjugates Directly from Reducing Sugars

Protecting‐Group‐Free One‐Pot Synthesis of Glycoconjugates Directly from Reducing Sugars

Facile Synthesis of Guanidine Functionalised Building Blocks

Azidoimidazolinium Salts: Safe and Efficient Diazo‐transfer Reagents and Unique Azido‐donors

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