Reaction of 1,6-anhydro-4-O-benzyl-2-deoxy-2-isothiocyanato-β-D-glucopyranose; Preparation of 2-amino-1,6-anhydro-2,3-dideoxy-2,3-dideoxy-β-D-ribo-hexopyranose

1985 ◽  
Vol 50 (9) ◽  
pp. 2000-2009 ◽  
Author(s):  
Tomáš Elbert ◽  
Miloslav Černý
Keyword(s):  
Acetic Anhydride ◽  
Raney Nickel ◽  
Carbon Disulfide ◽  
Trifluoroacetic Acid

1,6-Anhydro-4-O-benzyl-2-deoxy-2-isothiocyanato-β-D-glucopyranose (IV), prepared from 2-amino-1,6-anhydro-4-O-benzyl-2-deoxy-β-D-glucopyranose (I) by reaction with carbon disulfide followed by oxidation with iodine, was converted into the 3-O-p-toluenesulfonate VII. This was cyclized to give either the 2,3-epimino derivative X or the thiazoline XII. 2-Acetamido-3-S-acetyl-1,6-anhydro-4-O-benzyl-2-deoxy-3-thio-β-D-glucopyranose (XVI), obtained from compound XII, was desulfurized with Raney nickel to afford 2-acetamido-1,6-anhydro-2,3-dideoxy-β-D-ribo-hexopyranose (XVII). The isothiocyanato group was not affected upon acetylation of compound IV and acetolysis of the 1,6-anhydride bond with acetic anhydride and trifluoroacetic acid.

Properties relating to critical phenomena in the acetic anhydride – acetone – carbon disulfide system

1970 ◽  
Vol 48 (6) ◽  
pp. 904-909 ◽  
Author(s):  
A. N. Campbell ◽  
E. M. Kartzmark
Keyword(s):  
Acetic Anhydride ◽  
Carbon Disulfide ◽  
General Rule ◽  
Dielectric Constants ◽  
Excess Volumes ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Heats Of Mixing ◽  
Upper Critical Solution Temperature ◽  
Molar Polarization

The following physical properties of the acetic anhydride – acetone – carbon disulfide system have been investigated: congruent compositions, excess volumes, dielectric constants. For the system acetone – carbon disulfide, the excess volumes and the molar polarizations are much greater than those required by the mixture rule. From this we deduced that this system is very non-ideal and might, at a suitable temperature, form two layers; two liquid layers did indeed form at −73 °C, the upper critical solution temperature occurring somewhere between this temperature and 0 °C. We offer it as a general rule that, if the deviation from additivity of molar polarization is large and positive, two layers will form at a sufficiently low temperature, provided that solid phases do not intervene. This deduction becomes almost a certainty if large positive deviations from additivity of molar volume and large positive heats of mixing are also present.

Base-catalyzed Degradations of Carbohydrates. III. Formation of a Novel Perester from 1-O-Acetyl-3-deoxy-2,4,6-tri-O-methyl-α-D-erytho-hex-2-enopyranose

1973 ◽  
Vol 51 (3) ◽  
pp. 388-393 ◽  
Author(s):  
G. O. Aspinall ◽  
R. R. King ◽  
Zofia Pawlak
Keyword(s):  
Acetic Anhydride ◽  
Spectral Data ◽  
Trifluoroacetic Acid ◽  
Oxidative Degradation ◽  
Chemical Degradation ◽  
Reductive Decomposition

1-O-Acetyl-3-deoxy-2,4,6-tri-O-methyl-α-D-erythro-hex-2-enopyranose (1) reacts with m-chloroperbenzoic acid to give a novel perester, which has been assigned the structure 1,2-O-(1′-m-chloroperbenzoyl-oxyethylidene)-2-methoxy-4,6-di-O-methyl-α-D-glucopyranose (2), on the basis of spectral data and chemical degradation. The perester 2 and the derived acetate 3 undergo oxidative degradation on treatment with trifluoroacetic acid to give 3,5-di-O-methyl- (4) and 2-O-acetyl-3,5-di-O-methyl-D-arabinonolactone (5), respectively. Reductive decomposition of the acetylated perester 3 yields 1,3-di-O-acetyl-4,6-di-O-methyl-α-D-arabino-hexopyranosulose (6), which, on treatment with acetic anhydride in pyridine, gives successively 1,2,3-tri-O-acetyl-4,6-di-O-methyl-α-D-erythro-hex-2-enopyranose (7), 2-O-acetyl-1-deoxy-4,6-di-O-methyl-α-D-erythro-hex-1-enopyranose-3-ulose (8), and 5-acetoxy-2-(methoxy-methyl)-4H-pyran-4-one (9).

Studien zum Vorgang der Wasserstoffübertragung, 75 [1]. Elektrochemische Untersuchungen von S-und P-vergiftetem Raney-Nickel (Ra—Ni) und Versuche zu dessen Reaktivierung / Studies on the Occurrence of Hydrogen Transfer, 75 [1]. Electrochemical Investigation of Raney-Nickel (Ra—Ni) Poisoned with S and P and Experiments for the Reactivation

1985 ◽  
Vol 40 (6) ◽  
pp. 814-821
Author(s):  
Leopold Horner ◽  
Christoph Franz
Keyword(s):  
Raney Nickel ◽  
Carbon Disulfide ◽  
Hydrogen Transfer ◽  
Phosphorus Compounds ◽  
Trivalent Phosphorus ◽  
Electrochemical Investigation ◽  
Constant Ph ◽  
Ni Powder ◽  
Rest Potential ◽  
Competing Reactions

Abstract Ra-Ni with an artificial rest potential of -1000 mV (vs SCE) is shifted with different rates to more positive values after the addition of thioethers and carbon disulfide. Only with Na2S·9H2O a potential of -1100 mV (constant) is observed. Ra-Ni poisoned with sulfur is not reactivated neither cathodically nor anodically nor by the corrosive degradation at constant pH. Hydrogen structurally incorporated into the lattice of Ra-Ni (structural bonded hydrogen) is consumed by poisoning with thioethers and trivalent phosphorus compounds in a stoichiometric way. Ra-Ni-powder stepwise corrosively degradated up to 30% shows the same degree of desulfuri-zation as the original Ra-Ni. Desactivated Ra-Ni (loss of structural bonded hydrogen) is reacti-vated (56%) by cathodical treatment. In competing reactions the P-S, C-S, and C -P-bond in thiophosphinic esters, thioethers and trivalent P-compounds are hydrogenolyzed by Ra-Ni, the C-P-bond faster than the C-S-bond.

The Acetone – Acetic Anhydride – Carbon Disulfide System: Surface Tension, Viscosity, and Total and Partial Vapor Pressures

1971 ◽  
Vol 49 (13) ◽  
pp. 2183-2192 ◽  
Author(s):  
A. N. Campbell ◽  
E. M. Kartzmark ◽  
S. C. Anand
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Acetic Anhydride ◽  
Carbon Disulfide ◽  
Vapor Phase ◽  
The Other ◽  
Vapor Pressures ◽  
Free Energies ◽  
Vapor State ◽  
Straight Line

The surface tensions, viscosities, and vapor pressures, total and partial, have been determined as functions of concentration for the following systems: (a) acetone – acetic anhydride; (b) acetone – carbon disulfide; (c) acetic anhydride – carbon disulfide; and (d) pseudo-binary mixtures of (a) and (b), whose compositions lie on a straight line tangential to the plait point of the ternary system.The general behavior of ideal and non-ideal systems, in regard to surface tension and viscosity is discussed. For the system acetone – carbon disulfide, whose vapor phase can be considered ideal, the activities, activity coefficients, excess free energies, enthalpies and entropies of mixing have been obtained from the vapor pressures. The vapor phase of the other three systems contains acetic anhydride which is associated in the vapor state, and for these systems the experimental data are reported without further calculation.

Cyclization of cysteinylglycine sulfoxides under Pummerer reaction conditions

1979 ◽  
Vol 57 (18) ◽  
pp. 2412-2425 ◽  
Author(s):  
Saul Wolfe ◽  
Peter Michael Kazmaier ◽  
Hillar Auksi
Keyword(s):  
Acetic Anhydride ◽  
Trifluoroacetic Acid ◽  
Carboxyl Group ◽  
Reaction Conditions ◽  
Pummerer Reaction ◽  
Peptide Cyclization

A number of sulfoxides derived from 3-benzylthiopropionic acid, S-benzylcysteine, and S-phenylcystelne have been synthesized and exposed to typical Pummerer reaction conditions. Cyclization of the S-benzyl sulfoxides to six-membered or seven-membered heterocyclic rings (1,3-thiazin-4-ones and 1,3,6-oxathiazepines) is observed only in acetic anhydride solvent and only after conversion of the carboxyl group to an amide or peptide. Cyclization of S-phenylcysteinyl amides to β-lactams could not be achieved. The thiazolidine isomers of the six- and seven-membered rings have been synthesized and found not to be intermediates in the acetic anhydride reactions. The thiazolidines do rearrange to the six- and (or) seven-membered rings in anhydrous trifluoroacetic acid solvent. S-Benzylphthalimidocysteinylglycine sulfoxide, a 3:2 mixture of epimers at sulfur, affords a 3:2 mixture of isomeric thiazinones. A mechanism for these cyclizations is proposed, and it is suggested that the configuration at sulfur controls the configuration at the new asymmetric centre in the product.

Synthesis of 3-benzylxanthine and Lumazine Analogues

2005 ◽  
Vol 2005 (4) ◽  
pp. 262-266 ◽  
Author(s):  
El Sayed H. El Ashry ◽  
Shaker Youssif ◽  
Maged El Ahwany ◽  
Mohamed El Sanan
Keyword(s):  
Acetic Anhydride ◽  
Carbon Disulfide ◽  
Nitrous Acid ◽  
Acid Treatment ◽  
Aromatic Aldehydes ◽  
Diethyl Oxalate

Several xanthines (7–13) are prepared by the cyclisation of 1-benzyl-5,6-diaminouracil with single-carbon inserting agents such as aromatic aldehydes, formamides, acetic anhydride, carbon disulfide, and nitrous acid. Treatment of 6-amino-1-benzyl-5-nitrosouracil with anilinobenzylidene derivatives (14–18) affords 7-hydroxyxanthines (19–23). Cyclisation of the diaminouracil 3 with glyoxal, benzil, and diethyl oxalate leads to lumazines (25–28).

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