2-Acetamido-2-deoxy-<scp>D</scp>-<i>glycero</i>-<scp>D</scp>-<i>gulo</i>-heptose

Williams, D. T.; Perry, Malcolm B.

doi:10.1139/v69-742

Cited by 23 publications

(28 citation statements)

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“…A great variety of potential parameters are available in the literature to describe the interactions of C and H atoms. We have selected set IVa of Williams (1967) which has been used successfully for obtaining thermal crystallographic parameters in aromatic hydrocarbons (Filippini, Gramaccioli, Simonetta & Suffritti, 1973;Gramaccioli & Filippini, 1983). We have also tested Williams (1972) parameters and Mirskaya, Kozlova & Bereznitskaya (1974) parameters; even though both of them predicted an equilibrium configuration as close to the experimental one as the first set, calculated thermal parameters were slightly worse for the Williams (1972) set, and rather worse (some diagonal thermal parameters twice their experimental values) for the Mirskaya et al parameters, indicating that lattice-dynamics calculations are more critical with respect to potential parameters than packing calculations.…”

Section: Application To Phenothiazinementioning

confidence: 99%

Lattice dynamics and thermal crystallographic parameters in phenothiazine

Criado¹,

Conde²,

Márquez³

1984

Acta Cryst Sect A

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A computer program has been developed to study the lattice dynamics of molecular crystals in the harmonic approximation with the external Born-yon KS.rm~n formalism and an atom-atom potential function. Dispersion curves are obtained for monoclinic phenothiazine together with frequency distribution functions and external mode contribution to thermodynamic functions. Lattice dynamical T, L and S rigid-body tensors are obtained and individual thermal tensors are compared with experiment. The disagreement with respect to experimental results is of the same order as the disagreement with a Schomaker-Trueblood fit of experimental data.

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Section: Application To Phenothiazinementioning

confidence: 99%

Lattice dynamics and thermal crystallographic parameters in phenothiazine

Criado¹,

Conde²,

Márquez³

1984

Acta Cryst Sect A

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“…In the procedure of Nauchitel (hereafter called NM) the summation limit is 15 A, which yields 100% of the lattice energy. In the procedure of Williams (1967) and Govers (1975) (hereafter called WG) the summation limit is 6 A, yielding 80% of the lattice energy.…”

Section: Methodsmentioning

confidence: 99%

“…The latter values show clearly the improvement obtained when the 22 observational equations of a + fl-Se 8 were used [sets (IV) and (V)] instead of the 11 observational equations of either a-or fl-Se s only [sets (VI)-(IX)]. In all calculations a weight of IO00/AH s"b~ (= 29.5) has been assigned to the observational equations of type (5) and a weight of 1 to those of type (6) (Williams, 1967;Govers, 1975). The heats of sublimation of both modifications were calculated by means of the best sets of parameters derived.…”

Section: Derivation Of the Parametersmentioning

confidence: 99%

“…The parameters derived have to be used in combination with parameters for atom-atom interactions involving C, H, N and S atoms (Govers, 1975(Govers, , 1978b. 0567-7394/79/010236-05 $01.00 Therefore, we used the procedures of Williams (1967) and Nauchitel . Both procedures require the experimental values of the heats of sublimation and of the structural parameters of molecular crystals which contain a considerable number of Se atoms in the absence of intermolecular interactions other than van der Waals and/or electrostatic.…”

Section: Introductionmentioning

confidence: 99%

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Derivation of selenium–selenium nonbonded potential parameters for molecular crystals

Govers¹

1979

Acta Cryst Sect A

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Potential-function parameters for Se-Se non-bonded atom-atom pair interactions have been derived from the room-temperature heat of sublimation of a mixture of monoclinic a-and fl-Se s and from the crystal structures of these two modifications. The first procedure applied was that of Nauchitel ' & Mirskaya [Soy. Phys. Crystallogr. (1972), 16, 891-892]; the second was that of Williams [J. Chem. Phys. (1967), 47, 4680-4684]. In the latter procedure, the exponential parameter for the Se-Se repulsive term from the previous procedure was used and the coefficients of the attractive and repulsive terms were fitted to 22 observational equations by a weighted least-squares calculation. The second procedure proved to be more reliable than the first. Unlike the first procedure it yielded parameters with which a heat of sublimation of a-Se a could be calculated that was 0-8 kcal mol -~ higher than that of fl-Se a. At the same time, the calculated heats of sublimation of both modifications deviate by less than 2% from the experimental value of the monoclinic mixture. A low average value of 2.7% for the standard deviation of the parameters derived was obtained.

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“…Reaction of furanose 6 with nitromethane gave nitrosugar 31 (21). Acetylation of 31 could only be carried out using acidic conditions, giving the unstable triacetate 32, which spontaneously decomposed to give a 1: 1 mixture of 32 and 33 during work-up.…”

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confidence: 99%

Oxidation products of arachidonic acid. IV. Model studies on the attachaient of the C(13)—C(20) side-chain in the synthesis of tetrahydrofurans and pyrans 1,2, and 3

Just¹,

Crosilla²

1980

Can. J. Chem.

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GEORGE JUST and DANILO CROSILLA. Can. J. Chem. 58, 2349Chem. 58, (1980 The synthesis of methyl 15-hydroxy-8(R)-methoxy-11(R)-p-nitrobenzoyloxy-9(S),12(R)-oxy-eicosa-13-ynoate, an arachidonic acid metabolite derivative, is described. As well, methods for the attachment of the C ( 1 3 j C ( 2 0 ) prostaglandin side-chain to furanosides were studied and the results are described. The reduction of the C-15 keto group on a model compound was performed and was found to have the same behavior as in the prostaglandins.A partial structure proof of Pace-Asciak's compound, 9,12-oxy-8,11,15-trihydroxy-13-enoic acid is given.GEORGE JUST et DANILO CROSILLA. Can. J. Chem. 58,2349Chem. 58, (1980. On decrit la synthkse de I'hydroxy-15 methoxy-8(R) p-nitrobenzoyloxy-ll(R) oxy-9(S), 12(R) eicosyne-13 oate de mtthyle, un derive metabolique de I'acide arachidonique. On a egalement etudie les methodes de fixation des carbones en position 13 i 20 de la chaine laterale de la prostaglandine aux furannosides et on decrit les resultats. On a realist la reduction du groupe cetonique en position 15 sur un compose type et on a trouve qu'il se comporte comme celui des prostaglandines. On donne une preuve partielle de structure du compose de Pace-Asciak, I'acide oxy-9,12 trihydroxy-8,11,15 kne-13 oique.[Traduit par le journal]In connection with the synthesis of oxidation products of arachidonic acid of type 1, 2, and 3, isolated by Pace-Asciak and Wolfe (1) and Axelrod and co-workers (2), we had to work out procedures for attaching the C(13)-C (20) side-chain to furanose derivatives (for rationale of the choice of stereochemistry of the model compounds, see refs. 1,3). In this paper, we wish to describe some model studies on this attachment and the synthesis of a derivative of type 1 having an acetylenic bond at A13, which strongly supports the structure assigned to 1.As a model, we used 1,2-0-isopropylidene-3,5,6-tri-0-methyl-a-D-glucofuranose (5); which is easily obtained by methylation (4) of the commercially available glucofuranose 4. Hydrolysis of 5 with hydrochloric acid, followed by acetylation with p-nitrobenzoyl chloride in pyridine (5) gave 7 as a mixture of anomers. Treatment with hydrogen bromide in benzene at 0°C (6) transformed 7 to bromides 8, which, when submitted to the action of mercuric cyanide in nitromethane (6), gave the Pcyanide 9 as one isomer only, as established by nmr which showed the C(l) hydrogen as a broad singlet (J,,, 2 0-1) indicating a HI,,-dihedral angle of approximately 90°C. Alkaline hydrolysis gave the cyano alcohol

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2-Acetamido-2-deoxy-D-glycero-D-gulo-heptose

Abstract: 3,4,5,6,7-Pentaacetoxy-D-gluco-1-nitro-1-heptene with methanolic ammonia afforded crystalline 2-acetamido-1,2-dideoxy-1-nitro-D-glycero-D-gulo-heptitol which was converted via a modified Nef reaction to 2-acetamido-2-deoxy-D-glycero-D-gulo-heptose.

Cited by 23 publications

References 0 publications

Lattice dynamics and thermal crystallographic parameters in phenothiazine

Lattice dynamics and thermal crystallographic parameters in phenothiazine

Derivation of selenium–selenium nonbonded potential parameters for molecular crystals

Oxidation products of arachidonic acid. IV. Model studies on the attachaient of the C(13)—C(20) side-chain in the synthesis of tetrahydrofurans and pyrans 1,2, and 3

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