Synthesis of Kojidextrins and Their Protein Conjugates. Incidence of Steric Mismatch in Oligosaccharide Synthesis

Pozsgay, Vince; Dubois, Éric; Pannell, Lewis K.

doi:10.1021/jo962300y

Cited by 45 publications

(12 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…N ‐(3,4,6‐Tri‐ O ‐acetyl‐2‐ O ‐allyl‐β ‐ D ‐glucopyranosyl)piperidine (21): 18 Alcohol 20 14 (18.67 g, 50 mmol) and Ag 2 O (12.75 g, 1.1 equiv.) were mixed in anhydrous DMF (50 mL) and stirred under N 2 .…”

Section: Methodsmentioning

confidence: 99%

“…[ α ] D = + 17.7 ( c = 1.0 CHCl 3 ) [ref. [ α ] D = + 18 ( c = 1.3 CHCl 3 )] 18 . 1 H NMR (500 MHz, CDCl 3 ): δ = 1.46–1.59 [m, 6 H, N(CH 2 C H 2 ) 2 C H 2 ], 2.01 [s, 3 H, C(O)CH 3 ], 2.04 [s, 3 H, C(O)CH 3 ], 2.06 [s, 3 H, C(O)CH 3 ], 2.60–2.63 [m, 2 H, N(C H 2 CH 2 ) 2 CH 2 ], 2.85–2.89 [m, 2 H, N(C H 2 CH 2 ) 2 CH 2 ], 3.51–3.57 (m, 2 H, H‐2 and H‐5), 3.94 (d, J = 9.5 Hz, 1 H, H‐1), 4.05–4.09 (m, 2 H, H‐6 and O‐C H 2 ‐CH=CH 2 ), 4.21 (dd, J = 12.0 5.0 Hz, 1 H, H‐6′), 4.34 (dd, J = 12.5 5.0 Hz, 1 H, O‐C H 2 ‐CH=CH 2 ), 4.89 (t, J = 9.5 Hz, 1 H, H‐4), 5.10 (t, J = 9.5 Hz, 1 H, H‐3), 5.15 (dd, J = 10.5 0.5 Hz, 1 H, CH=C H 2 ), 5.22 (dd, J = 17.5 1.5 Hz, 1 H, CH=C H 2 ), 5.79–5.86 (m, 1 H, C H =CH 2 ) ppm.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Neighbouring Group Participation During Glycosylation: Do 2‐Substituted Ethyl Ethers Participate?

et al. 2014

View full text Add to dashboard Cite

The development of new protecting groups that undergo neighbouring group participation (NGP) via six‐membered ring intermediates to promote the formation of α‐1,2‐cis glycosidic linkages complements the established use of 5‐ring NGP in terms of stereochemical outcome. A selection of glycosyl donors was synthesised that possessed novel 2‐iodo‐ and 2‐(phenylseleno)ethyl ether protecting groups in an attempt to promote highly α‐selective glycosylation by 6‐ring NGP. Although the fully armed donors produced α‐glucosides as the predominant reaction products, low‐temperature NMR studies did not show NGP by the observation of cyclised reaction intermediates. The corresponding disarmed glycosyl donors were unexpectedly less stereoselective. NMR spectroscopy revealed that the 2‐iodoethyl ether did not participate in any of the glycosylation processes; however, the 2‐(phenylseleno)ethyl ether did participate, and β‐configured cyclic intermediates were observed. The fact that considerable amounts of β‐glycoside product were formed in these latter cases indicated that the predominant reaction pathway to product did not occur through the observed cyclic species. Clearly, a fine balance exists during glycosylation reactions, and the reaction pathway to product depends on a variety of factors. Notably, the formation of cyclised intermediates by 6‐ring NGP is not on its own sufficient to ensure high levels of α‐stereoselectivity.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Neighbouring Group Participation During Glycosylation: Do 2‐Substituted Ethyl Ethers Participate?

et al. 2014

View full text Add to dashboard Cite

show abstract

“…According to the extensive study performed by R. Schibli et al , we decided to introduce a bromobutyl chain linker in C2 position by a two‐step procedure. The first step involved the anomeric C protection with piperidine and selective hydrolysis of C2 to afford compound 1 by precipitation . The following step consisted in a nucleophilic substitution with 1,4‐dibromo butyl to obtain compound 2 in moderate yield .…”

Section: Resultsmentioning

confidence: 99%

Preparation and preliminary bioevaluation of a ^99mTc(CO)₃‐glucose derivative prepared by a click chemistry route

Fernández

Crócamo

Incerti

et al. 2012

Labelled Comp Radiopharmac

View full text Add to dashboard Cite

Development of a 99mTc-labelled glucose derivative as a single-photon emission computed tomography analogue to [ 18 F]-2-fluoro-2-deoxy-D-glucose (FDG) is considered of great interest. Herein, we present the synthesis and preliminary bioevaluation of a 99m Tc(CO) 3 -glucose derivative. Derivatization of glucose at C2 was achieved using the so-called 'click chemistry', forming a histidine-like, 1,4-disubstituted triazole adequate as donor atom system for Tc(I)-tricarbonyl complexes. Synthesis of the intermediate azide derivative was achieved by conventional organic chemistry. Because of the efficiency and selectivity of this cycloaddition, labelling was performed in 'one pot', adding the tricarbonyl precursor fac-[ 99m Tc(CO) 3 (H 2 O) 3 ] + to the same vial where the click reaction has taken place without any further purification. A single product with radiochemical purity higher than 90% was obtained. It was stable for at least 4 h in reaction milieu and exhibited high hidrophilicity (log P of À1.2) and low binding to plasma proteins (5 AE 1%). Biodistribution in C57BL/6 mice bearing induced Lewis murine lung carcinoma is characterized by low blood and liver uptake and rapid urinary excretion. 99m Tc complex showed moderate tumour uptake but significant retention until 2 h post-injection. Soft tissue clearance was fast leading to significantly higher uptake in tumour in comparison to muscle (p = 0.05) at all time points. Overall, biodistribution of our compound was very similar to that of [ 18 F]-FDG. However, tumour uptake was significantly higher for [ 18 F]-FDG, probably because of high hidrophilicity of our derivative that may hinder cell penetration. Similarity to biodistribution of FDG is a promising outcome, and modifications of the chelator and linker might improve biological results.

show abstract

“…15, 18 We have not found 20 a significant difference in immunogenicity of conjugates from the hexasaccharide fragment of Vibrio cholerae O:1, serotype Ogawa that were made by squaric acid chemistry involving either 1,2-diaminoethane or hydrazine hydrate. This finding, showing that both types of squaric acid derivatives can be useful in conjugate vaccine development, creates a need to evaluate their conjugation properties in more detail.…”

Section: Introductionmentioning

confidence: 88%

Preparation of glycoconjugates by dialkyl squarate chemistry revisited

Hou

Saksena

Kòváč

2008

Carbohydrate Research

View full text Add to dashboard Cite

The methyl 6-hydroxyhexanoyl glycoside of lactose was treated with each of 1,2-diaminoethane or hydrazine hydrate, and the corresponding amino amide 4 and acyl hydrazide 13, were treated with each of squaric acid dimethyl, diethyl, dibutyl, and didecyl esters. The monoesters were conjugated to bovine serum albumin (BSA) at different concentrations of hapten using 0.05 and 0.5 M pH 9 borate buffer. Maximum loading was achieved faster, and the conjugation efficiency was higher, when the conjugation was conducted at higher concentrations of both hapten and buffer. Conjugations involving haptens 14-17 prepared from hydrazide 13 were generally slower and less efficient than those with compounds 5-8, which were made from amino amide 4. Maintaining pH 9 during conjugation was found to be the most important factor in ensuring that the conjugation was a fast, highly efficient and reproducible process. When the pH of the conjugation mixture fell during the reaction, resulting in decreased reaction rate or even termination of the conjugation process, the normal course of the conjugation process could be restored by addition of buffer salts. Hydrolysis studies with monoesters formed from amino amide 4 under conjugation conditions showed that the decyl ester 8 was the most stable and that the methyl compound 5 was the one most readily hydrolyzed. The stability of monoesters prepared form hydrazide 13 were similar and comparable to the decyl ester prepared from 4. No definite advantage was found for the use any of the four dialkyl squarate reagents (methyl-, ethyl-, butyl-, and decyl-) for conversion of carbohydrate derivatives to species amenable for conjugation. Nevertheless, dimethyl squarate seemed to be the most convenient reagent because it is a crystalline, easy to handle, and commercially available material with very good reactivity.

show abstract

Synthesis of Kojidextrins and Their Protein Conjugates. Incidence of Steric Mismatch in Oligosaccharide Synthesis

Cited by 45 publications

References 43 publications

Neighbouring Group Participation During Glycosylation: Do 2‐Substituted Ethyl Ethers Participate?

Neighbouring Group Participation During Glycosylation: Do 2‐Substituted Ethyl Ethers Participate?

Preparation and preliminary bioevaluation of a ^99mTc(CO)₃‐glucose derivative prepared by a click chemistry route

Preparation of glycoconjugates by dialkyl squarate chemistry revisited

Contact Info

Product

Resources

About

Synthesis of Kojidextrins and Their Protein Conjugates. Incidence of Steric Mismatch in Oligosaccharide Synthesis

Cited by 45 publications

References 43 publications

Neighbouring Group Participation During Glycosylation: Do 2‐Substituted Ethyl Ethers Participate?

Neighbouring Group Participation During Glycosylation: Do 2‐Substituted Ethyl Ethers Participate?

Preparation and preliminary bioevaluation of a 99mTc(CO)3‐glucose derivative prepared by a click chemistry route

Preparation of glycoconjugates by dialkyl squarate chemistry revisited

Contact Info

Product

Resources

About

Preparation and preliminary bioevaluation of a ^99mTc(CO)₃‐glucose derivative prepared by a click chemistry route