Oxirane Derivatives of Aldoses

Williams, N. R.

doi:10.1016/s0065-2318(08)60427-8

Cited by 171 publications

(19 citation statements)

References 204 publications

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“…The starting material for the synthesis of altrose-based onium salts having the ammonium function in position 3 was the methyl 2,3-anhydro-4,6-O-benzylidene-a-D-mannopyranoside (5), which was synthesized starting from D-glucose in four steps, in our laboratory according to literature methods. [21] The ring opening of mannopyranoside 5 with amines, as expected, [22] resulted in 3-amino altropyranose derivatives. The reactions were performed with butylamine and morpholine, in boiling acetonitrile, in the presence of LiClO 4 , giving intermediates 6a and 6c in good yields (88% and 89%, respectively) after column chromatography (Scheme 2).…”

Section: Resultsmentioning

confidence: 56%

Synthesis and application of novel carbohydrate-based ammonium and triazolium salts

Nemcsok

Rapi

Bagi

et al. 2019

Synthetic Communications

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The synthesis of nine new carbohydrate-based quaternary ammonium salts and two new triazolium salts starting from D-glucose has been accomplished. Our synthesis utilized the regio-and stereoselective ring opening reaction of 2,3-anhydro sugars by nucleophilic reagents to afford the key intermediates. In these new types of phase transfer catalysts, the ammonium and triazolium functions are directly attached to the carbohydrate scaffold in different positions (2-, 3-, 6-positions of the sugar). The efficiency of the altrose-and glucose-based quaternary salts were tested in the alkylation of N-(diphenyl) methylene glycine tert-butyl ester with benzyl bromide. To our knowledge this is the first example when sugar-based quaternary ammonium or triazolium salts were used successfully as phase transfer catalysts. The enantiomeric recognition ability of the synthesized salts towards racemic Mosher's acid silver salt was also investigated by 19 F NMR spectroscopy.

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Section: Resultsmentioning

confidence: 56%

Synthesis and application of novel carbohydrate-based ammonium and triazolium salts

Nemcsok

Rapi

Bagi

et al. 2019

Synthetic Communications

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“…Factors governing the opening of such epoxides have been discussed by bVilliams. 15 Cleavage of the a-allo-epoxide (20) with lithium aluminium hydride in refluxing tetrahydrofuran, followed by methylation l7 of the resulting alcohol (21), gave a product that was undoubtedly methyl 5-0-benzyl-2,6-Assignment of the constitution of (22) followed from elemental analysis and lH n.m.r. spectroscopy [6 5.09 (1 H, quartet, Jl,z ca.…”

Section: Identification Of Variose As 26-dideoxy-3-0-methyl-~-r~bo-hmentioning

confidence: 99%

“…spectroscopy) from the pure methyl glycofuranoside isolated from glycosidation of D-cymarose (3). (15) and (16).-To a mixture of methyl 5-0-benzyl-6-deoxy-a-and -P-D-allofuranosides l3 (0.9 g) in pyridine (10 ml) was added acetic anhydride (2 ml), after which the reaction mixture was set aside overnight before it was diluted with chloroform. The solution was then washed successively with dilute hydrochloric acid, a solution of sodium hydrogencarbonate, and water.…”

Section: Identification Of Variose As 26-dideoxy-3-0-methyl-~-r~bo-hmentioning

confidence: 99%

“…Acetylation of a mixture of methyl 5-0-benzyl-6deoxy-a-and -p-D-allofuranosides (prepared l3 in six steps from L-rhamnose) gave, after chromatography on silica gel, the pure diacetates (15) and ( 16) in the ratio of roughly 2 : 1. 0-Deacetylation then gave the diols (9) and ( 10).…”

Section: Identification Of Variose As 26-dideoxy-3-0-methyl-~-r~bo-he...mentioning

confidence: 99%

“…Methyl 5-O-Benzyl-6-deoxy-P-~-allofuranoside (9) .-To a solution of the P-diacetate (15) (2.8 g) in methanol (60 ml) was added a small piece of sodium, after which the solution was set aside for 2 h a t room temperature. After removal of the solvent, the residue was taken up in chloroform (100 ml), which was washed with water (3 x 50 mi), dried (MgSO,) , and concentrated.…”

Section: Acomentioning

confidence: 99%

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Identification of variose as 2,6-dideoxy-3-O-methyl-D-ribo-hexose (D-cymarose)

Brimacombe¹,

Al-Hasan²,

Mengech³

1980

J. Chem. Soc., Perkin Trans. 1

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Variose, a sugar component of the antibiotic variamycin, has been identified as 2,6-dideoxy-3-0-methyl-~-ribohexose (i.e. D-CymarOSe). This assignment is based on the conversion of D-cymarose into, inter a h , methyl 2,6dideoxy-3-0-methyl-a-~-ribo-hexofuranoside (6) and then into the 5-benzoate ( 8 ) , which proved to be identical with methyl varioside benzoate. The a-cymarofuranoside (6) was also prepared by a less direct route that involved reaction of methyl 5 -0bentyl-6-deoxy-a-~-allofuranoside (1 0) with NN-dimethyl-a-chlorobenzylideneammonium chloride (1 1 ) to give methyl 2-0-benzoyl-5-0benzyl-3-chloro-3,6-dideoxy-a-~-glucofuranoside(1 9). Reductive cleavage of the a-ah-epoxide (20) derived from (1 9), followed by methylation and debenzylation, gave the desired product.

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Epoxide Migration (Payne Rearrangement) and Related Reactions

Hanson

2002

Organic Reactions

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Under a variety of basic conditions, 2,3‐epoxy alcohols rearrange with inversion at C‐2. The reaction, originally referred to in the literature as the β‐oxanol rearrangement, is now exclusively referred to as epoxide migration or Payne rearrangement. Epoxide migration is reversible, often leading to a mixture of epoxy alcohol isomers. Furthermore, in the presence of hydroxide or other nucleophiles, in situ opening of the equilibrating species may be observed. When such opening is desired, epoxide migration becomes a powerful method for the introduction of functionality into a substrate containing a 2,3‐epoxy alcohol moiety. However, when opening is not desired, epoxide migration can become a significant problem. The epoxide migration process lends itself to other synthetically useful manipulations. For example, the anionic equilibrating species may also be trapped with electrophiles such as alkyl and silyl halides, alkyl sulfonates, and epoxides. Electrophilic trapping may be inter‐ or intramolecular, and has been used as a means of delivering functionality to either C‐2 or C‐3 selectively. The intent of this chapter is to provide a comprehensive review of epoxide migration, including factors influencing the equilibrium position, conditions leading to in situ epoxide opening, and examples of electrophilic trapping. The reaction is discussed in relation to its utility as a synthetic method as well as its prevention as an unwanted side reaction. Related rearrangements in which either the epoxide or hydroxy oxygen has been replaced with nitrogen or sulfur have also been studied. These reactions, referred to in the literature as aza‐Payne and thia‐Payne rearrangements, respectively, are comprehensively included in this chapter as well. For the purposes of this discussion, the term “forward” aza‐Payne rearrangement refers to the direction of reaction leading from oxirane to aziridine. Similarly, “forward” thia‐Payne rearrangement refers to the direction of reaction leading from oxirane to thiirane. In the case of aza‐Payne rearrangements, both forward and reverse reactions have been effected, and in this chapter the term “reverse” aza‐Payne rearrangement refers to reactions leading from aziridine to oxirane. Epoxides have long been considered important in the chemistry of carbohydrates, and epoxide migration in the context of carbohydrate chemistry has been discussed in several reviews. In addition, particularly since discovery of the catalytic asymmetric epoxidation of allylic alcohols and the rise in importance of enantiomerically enriched acyclic epoxy alcohols, epoxide migration with in situ opening in acyclic systems has been much studied. The tabular survey summarizes the literature of epoxide migration and related reactions, including equilibration, in situ opening and trapping, aza‐Payne rearrangements, and thia‐Payne rearrangements, from 1931 to 1999. Reports referring to reactions involving addition at C‐1 or C‐3 without inversion of stereochemistry at C‐2 as “Payne rearrangements” are not covered in this review.

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Oxirane Derivatives of Aldoses

Cited by 171 publications

References 204 publications

Synthesis and application of novel carbohydrate-based ammonium and triazolium salts

Synthesis and application of novel carbohydrate-based ammonium and triazolium salts

Identification of variose as 2,6-dideoxy-3-O-methyl-D-ribo-hexose (D-cymarose)

Epoxide Migration (Payne Rearrangement) and Related Reactions

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