THE REACTIVITY OF CELLULOSE: III. THE NITRATION OF COTTON LINTERS ALTERNATELY WETTED WITH WATER AT VARIOUS TEMPERATURES AND DRIED, AND THE PROBABLE DISTRIBUTION OF THE NITRATE GROUPS

1959 ◽  
Vol 37 (2) ◽  
pp. 444-453 ◽  
Author(s):  
T. P. Yin ◽  
R. K. Brown
Keyword(s):  
Lead Tetraacetate ◽  
Hydroxyl Groups ◽  
Secondary Hydroxyl ◽  
Cotton Linters ◽  
Probable Distribution

Cotton linters alternately wetted at 0° or 25° and dried show progressively greater ease of nitration paralleling the number of wetting–drying cycles. The reverse is found to be true for linters wetted at 50°, 75°, or 100°. Analysis of the data obtained from lead tetraacetate oxidation of the nitrates favors the depressive concept of nitration and indicates that the observed changes in reactivity occasioned by the wetting–drying treatments are largely due to greater alterations in the accessibility of the primary rather than the secondary hydroxyl groups.

Regioselectivity among six secondary hydroxyl groups: selective acylation of the least reactive hydroxyl groups of inositol

2012 ◽  
Vol 48 (18) ◽  
pp. 2448 ◽  
Author(s):  
Amol M. Vibhute ◽  
Adiyala Vidyasagar ◽  
Saritha Sarala ◽  
Kana M. Sureshan
Keyword(s):  
Hydroxyl Groups ◽  
Secondary Hydroxyl ◽  
Selective Acylation

scholarly journals THE LOCATION OF THE XANTHATE GROUPS IN PARTLY SUBSTITUTED CELLULOSE XANTHATES

1957 ◽  
Vol 35 (12) ◽  
pp. 1522-1533 ◽  
Author(s):  
E. P. Swan ◽  
C. B. Purves
Keyword(s):  
Cellulose Acetate ◽  
Chlorine Dioxide ◽  
Methyl Esters ◽  
Lead Tetraacetate ◽  
Degree Of Substitution ◽  
Hydroxyl Groups ◽  
Primary Position ◽  
Standard Methods ◽  
The Third ◽  
Almost All

Cellulose sodium xanthates of degree of substitution (D.S.) 0.4 to 0.66 were methylated to xanthate S-methyl esters which were then acetylated completely, the final xanthate D.S. remaining close to the original value. Dexanthation with aqueous chlorine dioxide near pH 4.5 and −5° removed almost all of the S-methyl xanthate groups, but the loss of a few acetyl groups from, and the retention of 1 to 2% of sulphur in, the resulting cellulose acetate could not be avoided. The original xanthate groups were presumably represented in this acetate as unsubstituted hydroxyl groups, and these were located by standard methods involving tosylation–iodination, tritylation, and oxidations with lead tetraacetate. Xanthate groups appeared to occupy the third and sixth, but not the second, position in the cellulose, and 53 to 61% of the substituent was in the sixth or primary position; one sample of viscose was "ripened" before the cellulose sodium xanthate was isolated, and the value was 81%. The results were of a preliminary nature, because severe technical difficulties reduced their reliability.

Conversion of hydroxyl groups into bromo groups in carbohydrates with inversion of configuration

1981 ◽  
Vol 59 (2) ◽  
pp. 339-343 ◽  
Author(s):  
Björn Classon ◽  
Per J. Garegg ◽  
Bertil Samuelsson
Keyword(s):  
Elevated Temperature ◽  
Hydroxyl Groups ◽  
Secondary Hydroxyl ◽  
Reaction Proceeds ◽  
One Step ◽  
High Yields

A novel reagent system is described for the efficient, one-step transformation of hydroxyl groups in carbohydrates to bromodeoxy groups. The reaction proceeds with inversion of configuration. The reagent system consists of triphenylphosphine, tribromoimidazole, and imidazole in toluene at elevated temperature. The carbohydrate need not be soluble in toluene. The examples given include substitution of isolated primary and secondary hydroxyl groups in otherwise protected carbohydrates as well as disubstitution involving one primary and one secondary position in hexopyranosides. High yields are obtained in the replacement of hydroxyl by bromine in the 2-position of 3,4,6-protected methyl α-D-gluco- and -mannopyranosides.

Regioselective monophosphorylation of glycols containing primary and secondary hydroxyl groups

2000 ◽  
Vol 10 (1) ◽  
pp. 3-4 ◽  
Author(s):  
Edward E. Nifantiev ◽  
Mikhail K. Gratchev ◽  
Stephen F. Martin
Keyword(s):  
Hydroxyl Groups ◽  
Secondary Hydroxyl

Selective Benzoylation of Methyl 6-Deoxy-α- and β-D-glucopyranosides

1973 ◽  
Vol 51 (19) ◽  
pp. 3272-3276 ◽  
Author(s):  
Yôtaro Kondo ◽  
Kiyoshi Miyahara ◽  
Naoki Kashimura
Keyword(s):  
Major Product ◽  
Hydroxyl Groups ◽  
Secondary Hydroxyl

Selective dimolar benzoylation of methyl 6-deoxy-α- and β-D-glucopyranosides yielded the 2,3-di-O-benzoate of the respective glucopyranoside as the major product in 61 and 29% yields. The orders of the reactivity of the secondary hydroxyl groups in α- and β-anomers were different, i.e., the order was 2-OH > 3-OH > 4-OH for the former and 3-OH > 2-OH > 4-OH for the latter.

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