3,4,6-Tri-O-acetyl-1,2-dideoxy-D-hex-1-enopyranose

Krajewski, J. W.; Urbańczyk‐Lipkowska, Zofia; Gluziński, P.; Bleidelis, J.; Ķemme, A.

doi:10.1107/s0567740879006075

Cited by 8 publications

(3 citation statements)

References 2 publications

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“…The substituents at the C3 and C4 sites occupy equatorial positions while that at atom C5 is bisectional. The crystal structure of the unsubstituted parent compound has been reported three times and also adopts a distorted half-boat conformation (Vangehr et al, 1979;Krajewski et al, 1979;Voelter et al, 1981).…”

Section: S2 Results and Discussionmentioning

confidence: 99%

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Crystal structure of [(2R,3R,4S)-3,4-bis(acetyloxy)-5-iodo-3,4-dihydro-2H-pyran-2-yl]methyl acetate

et al. 2015

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In the title compound, C12H15IO7, the 3,4-dihydro-2H-pyran ring is in a distorted half-boat conformation with the atom bearing the acetyloxy group adjacent to the C atom bearing the methylacetate group lying 0.633 (6) Å above the plane of the remaining ring atoms (r.m.s. deviation = 0.0907 Å). In the crystal, molecules are linked into a supramolecular chain along the a axis through two C—H⋯O interactions to the same acceptor carbonyl O atom; these chains pack with no specific intermolecular interactions between them.

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Section: S2 Results and Discussionmentioning

confidence: 99%

“…For the structure of the unsubstituted parent compound, determined three times, and having a distorted half-boat conformation, see: Vangehr et al (1979); Krajewski et al (1979); Voelter et al (1981 Symmetry codes: (i) x À 1; y; z; (ii) x À 1 2 ; Ày þ 3 2 ; Àz þ 1.…”

Section: Related Literaturementioning

confidence: 99%

Crystal structure of [(2R,3R,4S)-3,4-bis(acetyloxy)-5-iodo-3,4-dihydro-2H-pyran-2-yl]methyl acetate

et al. 2015

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“…Substituen t Effects on Hydrogen Bonding Basicity.-Su bs ti t ution at the imino nitrogen atom, where hydrogen bonding takes place (uide infra), changes the basicity of amidines. When R is benzyl [(11)-- (15)] the effects of meta or para substituents can be predicted from the CT" substituent constant [equations (1) and ( 2…”

Section: Resultsmentioning

confidence: 99%

Hydrogen bonding basicity of amidines

Raczyńska¹,

Laurence²,

Nicolet³

1988

J. Chem. Soc., Perkin Trans. 2

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The hydrogen bonding basicity of amidines (1)-( 20) has been measured by means of the frequency shift Av(0H) of methanol hydrogen bonded to amidines and of the formation constant K of their complexes with 4-fluorophenol. The electronic and steric effects of substituents on the imino nitrogen have been studied. Hydrogen bonding occurs at the imino nitrogen atom except for acetylformamidine (16) for which it occurs on the carbonyl group. For compounds 4-XC6H,N=CHNMe,, with X = NO, , COMe, or C=N, hydrogen bonding also takes place on the NO, , COMe, or CzN groups. From the logK/Av( OH) correlation, two subsets, phenylformamidines and alkylformamidines, can be distinguished for the family of formamidines. Forformamidines, Bronsted basicities correlate with Av(0H)as for the pyridines. Hydrogen bonding basicity of amidines has only been measuredfor 1,1,3,3-tetramethylguanidine (1)' and for seven N',N 'dimethyl-N2-phenylformamidines, para and/or meta substituted on the phenyl ring.2,3 We extend here these preliminary results to amidines (2j-(20). All the amidines have the same E stereochemical s t r u c t ~r e . ~-~ (19) ; R = Bu' (20)'; R = But We have measured: (a) Av(OH), a spectroscopic scale of hydrogen bonding basicity, from the frequency shift of the v(0H) vibrator of methanol in CCl, at 20°C; Av(0H) = v(OH, free) -v(OH, hydrogen bonded) and, (b) logK, a thermodynamic scale of hydrogen bonding basicity from the formation constant K of hydrogen bonded complexes of 4fluorophenol with amidines in CCl, at 25 "C. These quantities allow us (a) to study the influence of substitution on hydrogen bonding basicity, (b) to compare hydrogen bonding and Bronsted basicities, and (c) to investigate on which atom (imino nitrogen, amino nitrogen, or heteroatom in R) hydrogen bonding takes place.

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Reverse anomeric effect of the carbamoyl group of 2,6‐disubstituted 6‐carbamoyl‐5,6‐dihydro‐2H‐pyrans

Chmielewski

Jurczak

Priebe

et al. 1987

Magnetic Reson in Chemistry

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The 'H NMR spectra of 2,6-disubstituted 6-carbamoyl-5,6-dihydro-2H-pyrans and their 6-methoxycarbonyl analogs have been recorded. With the use of coupling constants between ring protons, the conformational preference of the carbamoyl group has been evaluated. The 'H6 6Hl conformational equilibria in the above compounds are discussed. It is found that the conformational tendency of the carbamoyl group to the equatorial disposition helps to determine the conformational equilibrium in the seven examples studied.

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3,4,6-Tri-O-acetyl-1,2-dideoxy-D-hex-1-enopyranose

Cited by 8 publications

References 2 publications

Crystal structure of [(2R,3R,4S)-3,4-bis(acetyloxy)-5-iodo-3,4-dihydro-2H-pyran-2-yl]methyl acetate

Crystal structure of [(2R,3R,4S)-3,4-bis(acetyloxy)-5-iodo-3,4-dihydro-2H-pyran-2-yl]methyl acetate

Hydrogen bonding basicity of amidines

Reverse anomeric effect of the carbamoyl group of 2,6‐disubstituted 6‐carbamoyl‐5,6‐dihydro‐2H‐pyrans

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