A mild methylation of alcohols with diazomethane catalyzed by silica gel

Ohno, Kiyotaka; Nishiyama, Hisao; Nagase, Hiroshi

doi:10.1016/s0040-4039(01)86601-6

Cited by 72 publications

(27 citation statements)

References 11 publications

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“…It appears that 1,3,4,5,6-penta-O-acetyl-2-deoxy-2-(N-acetamido)-glucitol comes from undermethylation, as could be expected of this method [26,27]. 4-0-Methyl-1,3,5,6-tetra-O-acetyl-2-deoxy-2-(N-acetamido)-glucitol, coming from the reducing glucosamine, might represent an unsubstituted hydroxy group of the free lipid A, while 6-0-methyl-l,3,4,5-tetra-O-acety1-2-deoxy-2-( N-acetamid0)-glucitol coming from the non reducing glucosamine might represent an attachment site of 3-deoxy-~-manno-octu~osonate in LPS, as also reported in Salmonella [27,30].…”

Section: Localization Of Fatty Acidsmentioning

confidence: 53%

“…Unsubstituted hydroxy groups in free lipid A were identified by silica gel catalyzed methylation using diazomethane first reported by Ohno et al [26] recently worked out by Wollenweber et al, cited in [27].…”

Section: Methods Of Structural Analysismentioning

confidence: 97%

“…The optical configuration of the hydroxy fatty acids was identified as the R form by comparing the liberated methoxy fatty acids as L-phenylethyl amide derivatives and by comparing their tR values with the tR of authentic standards on an OV-1 column [26]. 'H-NMR and 13C-NMR did not show any N-acetyl groups in lipid A.…”

Section: Localization Of Fatty Acidsmentioning

confidence: 99%

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Structural studies on the non‐toxic lipid A from Rhodopseudomonas sphaeroides ATCC 17023

Salimath

Weckesser

Strittmatter

et al. 1983

European Journal of Biochemistry

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The lipid A isolated from Rhodopseudomonas sphaeroides ATCC 17023 has been investigated. A sequence of analyses indicated fl-D-glucosaminyl-I ,6-~-glucosamine as the sugar backbone carrying phosphate groups at C-I of the reducing glucosamine and C-4 of the non-reducing glucosamine. Both 3-(7-tetradecenoyl)oxytetradecanoic and 3-oxotetradecanoic acid are linked to the NH2 groups. Two residues of 3-hydroxydecanoic acid are linked to hydroxy groups at C-3 of both reducing and non-reducing glucosamine, and the hydroxy group of 3-hydroxydecanoic acid is free. In free lipid A, the hydroxy group at C-4 of the reducing glucosamine and at C-6 of the non-reducing glucosamine are unsubstituted. The latter probably arises from a 3-deoxy-~-manno-octulosonate linkage.The structural similarities and dissimilarities existing between lipid A of R. sphaeroides, which is non-toxic, and lipid A types such as those from Salmonella, which are toxic, are discussed. Of special interest are the naturally occurring lipid A types that have chemical compositions close to that of toxic Dedicated to Professor Dr Otto Westphal on the occasion of his 70th birthday (February 1, 1983).

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Section: Localization Of Fatty Acidsmentioning

confidence: 53%

Section: Methods Of Structural Analysismentioning

confidence: 97%

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Structural studies on the non‐toxic lipid A from Rhodopseudomonas sphaeroides ATCC 17023

Salimath

Weckesser

Strittmatter

et al. 1983

European Journal of Biochemistry

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“…The products were than analyzed by glc/ms. Furthermore, direct methylation of free lipid A was carried out with diazomethane in the presence of silica gel [16]. Briefly, diazomethane was added to free lipid A which was uniformly spread on activated silica gel at ice-bath temperature for 3 -4 h and then allowed to stand overnight.…”

Section: Combined Gas-liquid Chromatography/mass Spectrometrymentioning

confidence: 99%

“…The degradation pathway developed by Caroff and Szabo [16] was used to distinguish which of the two amino groups is substituted by this fatty acid. Reduced free lipid A was oxidized with sodium metaperiodate.…”

Section: Identification Of the Amide-linked Substituent Of The Reducimentioning

confidence: 99%

Structural studies on the phosphate‐free lipid A of Rhodomicrobium vannielii ATCC 17100

Holst

Borowiak

Weckesser

et al. 1983

European Journal of Biochemistry

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The structure of the free lipid A from Rhodomicrobium vannielii ATCC 17100 was elucidated. It consists of a central β‐1′,6‐linked glucosamine disaccharide which is not substituted by phosphate. About 30% of the disaccharide molecules are substituted with mannopyranose in β‐1,4′‐linkage to the non‐reducing glucosamine. The reducing glucosamine can be directly reduced with NaBH4, indicating either that this glucosamine is not substituted at C1 or its substituent has been removed during the preparation of free lipid A or is removed during reduction with NaBH4. The following formula shows the ‘backbone’ structure of the free lipid A from Rm. vannielii ATCC 17100: β‐Manp(1→4)‐β‐GlcpN(1→6)GlcpN. 3‐(R)‐Hydroxyhexadecanoic acid is linked to the amino group of the reducing glucosamine. The residue at the amino group of the non‐reducing glucosamine has not been identified. The hydroxyl groups of the central disaccharide are acylated with 3‐(tetradecanoyloxy)‐tetradecanoic acid, 3‐hydroxytetradecanoic acid, Δ14‐ docosenoic acid (Δ14‐C22:1) and acetyl groups. The hydroxyl groups of the mannose are not substituted.

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Diazomethane

Sammakia

2001

Encyclopedia of Reagents for Organic Synthesis

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A mild methylation of alcohols with diazomethane catalyzed by silica gel

Cited by 72 publications

References 11 publications

Structural studies on the non‐toxic lipid A from Rhodopseudomonas sphaeroides ATCC 17023

Structural studies on the non‐toxic lipid A from Rhodopseudomonas sphaeroides ATCC 17023

Structural studies on the phosphate‐free lipid A of Rhodomicrobium vannielii ATCC 17100

Diazomethane

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