Glycosylidene Carbenes, Part 30, Crystal Structure of a Glucose-DerivedN,N-Unsubstituted Alkoxydiaziridine

Blüchel, Christian; Linden, Anthony; Vasella, Andrea

doi:10.1002/1522-2675(20011114)84:11<3495::aid-hlca3495>3.0.co;2-n

Cited by 5 publications

(3 citation statements)

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“…In the solid state, the X-ray structure of only two N,N′-unsubstituted diaziridines has been described with CSD 19 refcodes: OCIWUS and RAJQID. The first one contains at positions 3 a spiro chiral glucose residue, 20 while the second one has an achiral 3,3-pentamethylene substituent. 21 In both cases, the NH protons are in a trans disposition and the hydrogen-bond network involves N-H‚‚‚N bonds forming chains in the case of OCIWUS 20 and more complex patterns in the case of RAJQID.…”

Section: Introductionmentioning

confidence: 99%

“…The first one contains at positions 3 a spiro chiral glucose residue, 20 while the second one has an achiral 3,3-pentamethylene substituent. 21 In both cases, the NH protons are in a trans disposition and the hydrogen-bond network involves N-H‚‚‚N bonds forming chains in the case of OCIWUS 20 and more complex patterns in the case of RAJQID. 21 In the present article, the chiral discrimination in diaziridine clusters, connected through hydrogen bonds (HBs), has been studied using density functional theory (DFT) methods.…”

Section: Introductionmentioning

confidence: 99%

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Chiral Recognition in Diaziridine Clusters and the Problem of Racemization Waves

2007

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Theoretical calculations (B3LYP/6-31+G**) of chiral clusters of diaziridines have been carried out. Five configurations of chiral and nonchiral clusters with up to eight monomers have been considered. The proton transfer within the neutral and protonated clusters has been studied as a possible source of racemization waves. The optical rotatory power (ORP) has been calculated for the neutral and protonated homochiral clusters. The results show that the clusters with alternated chiral molecules are the preferred ones and that the proton transfer proceeds with low energetic barriers in the protonated systems. The ORP results are very dependent on the shape of the clusters and the neutral or protonated state of them.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chiral Recognition in Diaziridine Clusters and the Problem of Racemization Waves

2007

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“…Both compounds 35 and 36 could be crystallized from the reaction mixtures. The glycosylidene diaziridines 35 could be also characterized through its crystallographic structure and displayed slightly shorter C-N bond lengths and slightly longer N-N bond length when compared to noncyclic C-N and N-N bond lengths[22].…”

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confidence: 99%

Anomeric Spiro-Annulated Glycopyranosides: An Overview of Synthetic Methodologies and Biological Applications

Pommier

Vidal

2019

Topics in Heterocyclic Chemistry

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Organic chemistry developed a series of synthetic strategies toward spiro-annulated carbohydrates as potential pharmaceutical drugs or developed new organic synthetic methodologies. The present chapter gives a general overview of the spiro-annulation of carbohydrates at the anomeric position. The main synthetic strategies can be summarized in five paths. Intramolecular cyclizations can be performed through two short tethers with their reactive ends generating the

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Glycosylidene Carbenes. Part 31

Bernet

Mangholz

Briner

et al. 2003

Helvetica Chimica Acta

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Dedicated to Professor Jack D. Dunitz on the occasion of his 80th birthdayThe diastereoselectivity of the addition of NH 3 and MeNH 2 to glyconolactone oxime sulfonates and the structures of the resulting N-unsubstituted and N-methylated glycosylidene diaziridines wereThe 15 N-labelled glucono-and galactono-1,5-lactone oxime mesylates 1* and 9* add NH 3 mostly axially (> 3 : 1; Scheme 4), while the 15 N-labelled mannono-1,5-lactone oxime sulfonate 19* adds NH 3 mostly equatorially (9 : 1; Scheme 7). The 15 N-labelled mannono-1,4-lactone oxime sulfonate 30* adds NH 3 mostly from the exo side (> 4 :1; Scheme 9). The configuration of the N-methylated pyranosylidene diaziridines 17, 18, 28, and 29 suggests that MeNH 2 adds to 1, 9, 19, and 23 mostly to exclusively from the equatorial direction (> 7 : 3; Schemes 5 and 8). The mannono-1,4-lactone oxime sulfonate 30 adds MeNH 2 mostly from the exo side (85 : 15; Scheme 10), while the ribo analogue 37 adds MeNH 2 mostly from the endo side (4 : 1; Scheme 10). Analysis of the preferred and of the reactive conformers of the tetrahedral intermediates suggests that the addition of the amine to lactone oxime sulfonates is kinetically controlled. The diastereoselectivity of the diaziridine formation is rationalized as the result of the competing influences of intramolecular H-bonding during addition of the amines, steric interactions (addition of MeNH 2 ), and the kinetic anomeric effect.The diaziridines obtained from 2,3,5-tri-O-benzyl-d-ribono-and -d-arabinono-1,4-lactone oxime methanesulfonate (42 and 48; Scheme 11) decomposed readily to mixtures of 1,4-dihydro-1,2,4,5-tetrazines, pentono-1,4-lactones, and pentonamides.The N-unsubstituted gluco-and galactopyranosylidene diaziridines 2, 4, 6, 8, and 10 are mixtures of two trans-substituted isomers (S/R ca. 19 :1, Scheme 2). The main, (S,S)-configured isomers S are stabilised by a weak intramolecular H-bond from the pseudoaxial NH to ROÀC(2). The diaziridines 12, derived from GlcNAc, cannot form such a H-bond; the (R,R)-isomer dominates (R/S 85 : 15; Scheme 3). The 2,3-di-O-benzyld-mannopyranosylidene diaziridines 20 and 22 adopt a 4 C 1 conformation, which does not allow an intramolecular H-bond; they are nearly 1 : 1 mixtures of R and S diastereoisomers, whereas the O H 5 conformation of the 2,3:5,6-di-O-isopropylidene-d-mannopyranosylidene diaziridines 24 is compatible with a weak H-bond from the equatorial NH to OÀC(2); the (R,R)-isomer is favoured (R/S ! 7 : 3; Scheme 6). The mannofuranosylidene diaziridine 31 completely prefers the (R,R)-configuration (Scheme 9).

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Glycosylidene Carbenes, Part 30, Crystal Structure of a Glucose-DerivedN,N-Unsubstituted Alkoxydiaziridine

Cited by 5 publications

References 18 publications

Chiral Recognition in Diaziridine Clusters and the Problem of Racemization Waves

Chiral Recognition in Diaziridine Clusters and the Problem of Racemization Waves

Anomeric Spiro-Annulated Glycopyranosides: An Overview of Synthetic Methodologies and Biological Applications

Glycosylidene Carbenes. Part 31

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