scholarly journals Further studies on the glycerol teichoic acid of walls of Staphylococcus lactis I3. Location of the phosphodiester groups and their susceptibility to hydrolysis with alkali

1971 ◽  
Vol 125 (1) ◽  
pp. 353-359 ◽  
Author(s):  
A. R. Archibald ◽  
J. Baddiley ◽  
J. E. Heckels ◽  
S. Heptinstall
Keyword(s):  
Acid Hydrolysis ◽  
Teichoic Acid ◽  
Hydroxyl Group ◽  
High Yield ◽  
Selective Hydrolysis ◽  
Partial Acid Hydrolysis ◽  
Structural Types ◽  
Phosphodiester Group ◽  
Hydrolysis Of ◽  
Alcoholic Hydroxyl

1. The teichoic acid from walls of Staphylococcus lactis I3 is readily degraded in dilute alkali. 2. Degradation proceeds by selective hydrolysis of that phosphodiester group attached to an alcoholic hydroxyl group of the N-acetylglucosamine and gives a repeating unit in high yield. 3. Further studies on a different repeating unit isolated by partial acid hydrolysis have shown that the glycerol diphosphate is attached to the 4-hydroxyl group of the N-acetylglucosamine and not to the 3-hydroxyl group as was proposed earlier. 4. The susceptibility towards hydrolysis by alkali of other structural types of teichoic acid has been examined and found to vary markedly according to their structure.

Direct Preparation of 1,2:3,5-Di-O-cyclohexylidene-α-D-xylofuranose from Corncobs and Its Conversion to 1-O-Acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose

1994 ◽  
Vol 59 (8) ◽  
pp. 1884-1888 ◽  
Author(s):  
Mirjana Popsavin ◽  
Velimir Popsavin ◽  
Nada Vukojevic ◽  
Dušan Miljković
Keyword(s):  
Acid Hydrolysis ◽  
Hydroxyl Group ◽  
Partial Acid Hydrolysis ◽  
Novel Synthesis ◽  
Direct Preparation ◽  
Acid Methanolysis ◽  
Hydrolysis Of ◽  
Mild Acid

A novel synthesis of 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (I) has been described starting from 1,2:3,5-di-O-cyclohexylidene-α-D-xylofuranose (II), obtained directly from the crude xylose syrup originated from corncobs. Partial acid hydrolysis of II gave 1,2-O-cyclohexylidene-α-D-xylofuranose (III). Selective benzoylation of primary C-5 hydroxyl group of III followed by tosylation of C-3 hydroxyl group afforded IV in an overall yield of 67%. Mild acid methanolysis of IV gave the corresponding methyl xylofuranosides V which were further benzoylated to afford 2,5-di-O-benzoyl derivatives VI in 65% yield. Solvolysis of VI in 95% DMF gave a mixture of 2,5- and 3,5-di-O-benzoylribofuranosides VII, which were subsequently converted into the corresponding tribenzoates VIII. An acetolysis of VIII afforded I in an overall yield of 96% related to VI.

On the synthesis of 3,4-dihydroxyprolines. II. Synthesis, stereochemistry and reactivity of some 3,4-Epoxy-DL-proline derivatives

1975 ◽  
Vol 28 (11) ◽  
pp. 2479 ◽  
Author(s):  
CB Hudson ◽  
AV Robertson ◽  
WRJ Simpson
Keyword(s):  
Acid Hydrolysis ◽  
Methyl Esters ◽  
High Yield ◽  
Butyl Esters ◽  
Epoxy Acids ◽  
Trifluoroperacetic Acid ◽  
Catalytic Hydrogenolysis ◽  
Direct Separation ◽  
Proline Derivatives ◽  
Hydrolysis Of

N-Protected esters of 3,4-dehydro-DL-proline react with trifluoroperacetic acid to give, in high yield, approximately equal amounts of the corresponding stereoisomeric 3,4-epoxy-DL-proline derivatives, direct separation of which proved difficult. However individual members of the two families were obtained by discovery of selective transformations and fractionations. Relative configurations of the two 3,4-epoxy-N-tosylproline methyl esters were established by borohydride reduction to authentic 4-hydroxy-N-tosylprolinols. Epoxide reduction is regioselective. Extensive p.m.r. analyses then permitted stereochemical assignment of other derivatives. These epoxides are remarkably resistant to catalytic hydrogenolysis, and to hydration in acid or alkali. N-Substituted 3,4-epoxyproline methyl esters undergo ready β-elimination in alkali to yield the corresponding 4-hydroxy-2,3- dehydroproline esters and ultimately the N-substituted pyrrole-2- carboxylic acid or ester. Prolonged aqueous acid hydrolysis of 3,4- epoxy-N-tosylprolines, or of their methyl esters, gives mixtures of 3,4-dihydroxy-N-tosyl-DL-prolines in the 2,3-cis-3,4-trans and 2,3- trans-3,4-trans families. Their stereochemistry was allotted from p.m.r. of the diacetate methyl esters. During acid hydrolysis of 3,4- epoxy-N-tosylproline methyl esters, the ester of the trans stereoisomer hydrolyses selectively, and some epimerization of the cis stereoisomer occurs. Ester hydrolysis is much faster than epoxide hydration. Anhydrous acid cleavage of 3,4-epoxy-N-tosyl-DL-proline t-butyl esters to the epoxy acids is unusually slow.

Phosphopeptides Obtained by Partial Acid Hydrolysis of α-Casein2

1957 ◽  
Vol 79 (10) ◽  
pp. 2559-2565 ◽  
Author(s):  
N. J. Hipp ◽  
M. L. Groves ◽  
T. L. McMeekin
Keyword(s):  
Acid Hydrolysis ◽  
Partial Acid Hydrolysis ◽  
Hydrolysis Of

Enolic Ortho Esters. I. Preparation and Birch Reduction of Some Coumarinoid Ortho Esters

1989 ◽  
Vol 42 (8) ◽  
pp. 1235 ◽  
Author(s):  
DJ Collins ◽  
LM Downes ◽  
AG Jhingran ◽  
SB Rutschmann ◽  
GJ Sharp
Keyword(s):  
Carbon Tetrachloride ◽  
Acid Hydrolysis ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
High Yield ◽  
Ortho Ester ◽  
Birch Reduction ◽  
High Yields ◽  
Ortho Esters ◽  
Hydrolysis Of

Phenolic ortho esters such as 4′,4′-dimethylspiro[2H-1-benzopyran-2,2′-[1,3]dioxolan] (7b) and 4′,4′-dimethyl-3,4-dihydrospiro[2H-1-benzopyran-2,2′-[1,3]dioxolan] (9c) were prepared in low yields by reaction of 2H-1-benzopyran-2-one (5) or 3,4-dihydro-2H-1-benzopyran-2-one (8a) with 2,2-dimethyloxiran in carbon tetrachloride in the presence of boron trifluoride etherate. 3,4-Dihydrospiro[2H-1-benzopyran-2,2′-[1,3] dioxoan ] (9a) and the corresponding 7-methoxy compound (9e) were obtained in high yield by reaction of (8a) or its 7-methoxy analogue (8b) with 1,2-bis(trimethylsily1oxy)ethane (10) in the presence of trimethylsilyl trifluoromethane-sulfonate . Birch reduction of phenolic ortho esters such as (9c) and (9e) afforded the enolic ortho esters 4′,4′-dimethyl-3,4,5,8-tetrahydrospiro[2H-1-benzopyran-2,2′-[1,3] dioxola n] (11a) and 7-methoxy-3,4,5,8-tetrahydrospiro[2H-1-benzopyran-2,2′-[1,3]dioxolan] (llc) in high yields. Birch reduction of 4′,4′,5′,5′-tetramethylspiro[2H-1-benzopyran-2,2′-[1,3]dioxolan] (7c) gave a 1 : 3 mixture of 4′,4′,5′,5′-tetramethyl-3,4-dihydrospiro[2H-1-benzopyran-2,2′-[l,3] dioxolan ] (9d) and the corresponding 3,4,5,8-tetrahydro compound (11b). Acid hydrolysis of the enolic ortho ester (11a) gave 67% of 2-hydroxy-2-methylpropyl 3-(2-oxocyclohex-3-enyl) propanoate (20).

O-Isopropylidene derivatives of D-allulose (D-psicose) and D-erythro-hexopyranos-2,3-diulose

1968 ◽  
Vol 46 (8) ◽  
pp. 765-770 ◽  
Author(s):  
G. M. Cree ◽  
A. S. Perlin
Keyword(s):  
Deuterium Oxide ◽  
Spectral Characteristics ◽  
High Yield ◽  
Partial Acid Hydrolysis ◽  
Hydride Reduction ◽  
Sodium Amalgam ◽  
Isopropylidene Derivatives ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Sole Product

Oxidation of 1,2: 4,5-di-O-isopropylidene-β-D-fructopyranose (2) with ruthenium tetroxide affords crystalline 1,2: 4,5-di-O-isopropylidene-β-D-erythro-hexopyranos-2,3-diulose (3) in high yield. The latter, on reduction with metal hydrides or on catalytic hydrogenation over platinum, yields 1,2: 4,5-di-O-isopropylidene-β-D-allulopyranose (4) as virtually the sole product. By contrast, sodium amalgam reduction of 3 yields only the D-fructose derivative (2), although in low yield. Also, metal hydride reduction of impure 3, obtained by oxidation of 2 with dimethyl sulfoxide – acetic anhydride, yields equal amounts of both isomers (2 and 4). The stereochemistry of these reductions is complicated by uncertainty as to the conformation of 4 (and possibly of 2), owing to anomalous proton magnetic resonance spectral characteristics observed.Ketone 3, which is unstable in the presence of deuteroxide ion, is smoothly deuterated at C-4 by exchange in hot deuterium oxide – pyridine.Mono-O-isopropylidene derivatives have been prepared by partial acid hydrolysis of 2 and 4.

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