Reductive cleavage of lignocarbohydrate complex by sodium metal in liquid ammonia

1973 ◽  
Vol 22 (12) ◽  
pp. 2748-2751 ◽  
Author(s):  
N. F. �fendieva ◽  
N. N. Shorygina ◽  
N. P. Krasovskaya
Keyword(s):  
Liquid Ammonia ◽  
Reductive Cleavage ◽  
Sodium Metal ◽  
Lignocarbohydrate Complex

Reductive cleavage with metal in liquid ammonia. II. Olefin formation in attempts at selective cleavage of methyl S-benzyl-4,6-O-benzylidene-3-O-methyl-2-thio-α-d-altropyranoside and its S-methyl analogue by sodium metal in liquid ammonia diluted with 1,2-dimethoxyethane

1967 ◽  
Vol 45 (5) ◽  
pp. 481-494 ◽  
Author(s):  
U. G. Nayak ◽  
M. Sharma ◽  
R. K. Brown
Keyword(s):  
Liquid Ammonia ◽  
Mixed Solvent ◽  
Reductive Cleavage ◽  
Metallic Sodium ◽  
Reaction Conditions ◽  
Sodium Metal ◽  
Alkaline Reaction

When methyl S-benzyl-4,6-O-benzylidene-3-O-methyl-2-thio-α-d-altropyranoside (VI) in liquid ammonia was treated with metallic sodium, a reductive cleavage occurred to give methyl 3-O-methyl-2-thio-α-d-altropyranoside in an 85% yield. In the solvent 1,2-dimethoxy-ethane, the reaction of sodium with VI gave little, if any, reductive cleavage. Instead, a base-catalyzed elimination of methanol took place to give the two olefins methyl,S-benzyl-4,6-O-benzylidene-2,3-didehydro-3-deoxy-2-thio-α-d-erythro-hexopyranoside (IX) and S-benzyl-4,6-O-benzylidene-l,2-didehydro-1-deoxy-3-O-methyl-2-thio-d-ribo-hexopyranose (X). Under the alkaline reaction conditions, IX isomerized partly to a third olefin, methyl.S-benzyl-4,6-O-benzylidene-3,4-didehydro-3-deoxy-2-thio-α-d-erythro(threo)-hexopyranoside (XI).In the mixed solvent liquid ammonia and 1,2-dimethoxyethane, sodium reacted with VI to give a 33% yield of the 2,3-olefin IX. Other products, no doubt present, were not isolated in this experiment.Three analogous olefins were obtained from the reaction of sodium or basic reagents with methyl 4,6-O-benzylidene-3-O,S-dimethyl-2-thio-α-d-altropyranoside (VIa) in 1,2-dimethoxyethane.

Reductive cleavage with metal in liquid ammonia. III. Olefin formation from the reaction of sodium metal with methyl 4,6-O-ethylidene-3-O,S-dimethyl-2-thio-α-d-altropyranoside dissolved in 1,2-dimethoxyethane

1967 ◽  
Vol 45 (15) ◽  
pp. 1767-1775 ◽  
Author(s):  
U. G. Nayak ◽  
M. Sharma ◽  
R. K. Brown
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Liquid Ammonia ◽  
Reductive Cleavage ◽  
Metallic Sodium ◽  
Sodium Metal ◽  
Infrared Data ◽  
Nuclear Magnetic

Methyl 4,6-O-ethylidene-3-O,S-dimethyl-2-thio-α-d-altropyranoside, when heated in refluxing 1,2-dimethoxyethane with an equimolar quantity of metallic sodium, gave approximately a 75% yield of a mixture of the three olefins, methyl 2,3-didehydro-3-deoxy-4,6-O-ethylidene-S-methyl-2-thio-α-d-altropyranoside (XI), l,2-didehydro-l-deoxy-4,6-O-ethylidene-3-O,S-dimethyl-2-thio-d-ribo-hexopyranose (XII), and methyl 3,4-didehydro-3-deoxy-4,6-O-ethylidene-S-methyl-2-thio-α-d-erythro(or threo)-hexopyranoside (XIII) (tentative). Only compounds XI and XII could be separated and characterized. The structural assignments were based on a comparison with authentic samples and on nuclear magnetic resonance and infrared data, as well as on a comparison with the characteristics of analogous 4,6-O-benzylidene compounds previously reported (2).

REDUCTIVE CLEAVAGE WITH METAL IN LIQUID AMMONIA: I. THE SELECTIVE CLEAVAGE OF THE BENZYLTHIO C—S BOND VERSUS THE BENZYLIDENEDIOXY C—O BOND IN METHYL S-BENZYL-4,6-O-BENZYLIDENE-2-THIO-α-D-ALTROPYRANOSIDES; THE INFLUENCE OF THE COSOLVENT 1,2-DIMETHOXYETHANE ON THE COURSE OF THE REACTION

1966 ◽  
Vol 44 (5) ◽  
pp. 591-602 ◽  
Author(s):  
U. G. Nayak ◽  
R. K. Brown
Keyword(s):  
Infrared Absorption ◽  
Liquid Ammonia ◽  
Reductive Cleavage ◽  
The Other ◽  
Metallic Sodium ◽  
Absorption Bands ◽  
Strong Band ◽  
The One ◽  
Infrared Absorption Bands ◽  
Phenyl Moiety

The improved solubility of methyl S-benzyl-4,6-O-benzylidene-2-thio-α-D-altropyranoside (1) in liquid ammonia diluted with 1,2-dimethoxyethane has permitted the selective cleavage by metallic sodium or lithium of the C—S bond to give methyl 4,6-O-benzylidene-2-thio-α-D-altropyranoside in 70–75% yield. On the other hand, the slight solubility of I in liquid ammonia alone results only in the completely hydrogenolyzed material, methyl 2-thio-α-D-altropyranoside, along with unchanged I.Generally, in liquid ammonia alone, reductive cleavage is rapid (15–20 min) and the benzylidene and benzyl groups are converted largely into toluene accompanied by a small amount of bibenzyl. In liquid ammonia – 1,2-dimethoxyethane mixtures the reaction is much slower (≥ 1.5 h); under these conditions the benzylidene and benzyl groups are converted to a larger extent into bibenzyl, the rest becoming toluene.The two strong infrared absorption bands (in Nujol) in the region of 766 to 778 cm−1 and 706 to 718 cm−1 have been assigned to the phenyl moiety of the benzylidene group, and the one strong band in the region of 702 cm−1 to the phenyl moiety of the S-benzyl group.

3-deoxygenation of methyl α--glucopyranosides by treatment of their 3--(,-dimethylsulfamoyl) derivatives with sodium metal in liquid ammonia

1978 ◽  
Vol 19 (36) ◽  
pp. 3365-3368 ◽  
Author(s):  
Tsutomu Tsuchiya ◽  
Isamu Watanabe ◽  
Masao Yoshida ◽  
Fujio Nakamura ◽  
Takayuki Usui ◽  
...  
Keyword(s):  
Liquid Ammonia ◽  
Sodium Metal

Stepwise synthesis of selenium coronands containing an odd number of selenium atoms: 1,5,9-triselenacyclododecane and 1,5,9,13,17-pentaselenacycloeicosane

1995 ◽  
Vol 73 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Ivan Cordova-Reyes ◽  
Elizabeth VandenHoven ◽  
Ali Mohammed ◽  
B. Mario Pinto
Keyword(s):  
Liquid Ammonia ◽  
Metal Reduction ◽  
Selenium Atom ◽  
Stepwise Synthesis ◽  
Sodium Metal

The stepwise synthesis of two new selenium coronands containing an odd number of selenium atoms, starting from the fragments HO-(CH2)3-Cl, HO-(CH2)3-Br, HO-(CH2)3-SeCN, and NCSe-(CH2)3-SeCN, is described. The key diol containing one selenium atom, 4-selenaheptan-1,7-diol 4, was obtained in 97% yield from the reaction of 3-bromo-1-propanol 3 and the selonolate anion derived from 3-selenocyanato-1-propanol 2 by sodium metal reduction in liquid ammonia. The ditosylate 5, obtained from 4, was then treated with the bisselenolate anion derived from 1,3-bisselenocyanatopropane 6 to give the target selenium coronand, 1,5,9-triselenacyclododecane [12Se3] 7, in 96% yield. The ditosylate 5 was treated with two equivalents of the selenolate anion derived from 2 to give a second key acyclic diol 8 now containing three selenium atoms. The ditosylate 9, obtained from 8, was then treated with the bisselenolate anion derived from 6 to afford the second target coronand, 1,5,9,13,17-pentaselenacycloeicosane [20Se5] 11 in 44% yield. Keywords: selenium coronands, stepwise synthesis, macrocycles, heterocycles.

Reductive cleavage by sodium in liquid ammonia of the lignin of cotton-plant stems

1976 ◽  
Vol 12 (5) ◽  
pp. 574-576
Author(s):  
S. A. Saidalimov ◽  
L. S. Smirnova ◽  
Kh. A. Abduazimov
Keyword(s):  
Cotton Plant ◽  
Liquid Ammonia ◽  
Reductive Cleavage

scholarly journals Anionic Oligomerization of Styrenein Liquid Ammonia Catalized by Sodium Metal

1964 ◽  
Vol 67 (6) ◽  
pp. 939-944
Author(s):  
Eishun Tsuchida ◽  
Isao Shinohara ◽  
Shu Kambara ◽  
Takao Kawamura ◽  
Akikazu Takahashi
Keyword(s):  
Liquid Ammonia ◽  
Sodium Metal
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