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

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.

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.

scholarly journals ECONOMIC EFFICIENCY OF RESOURCE-SAVING TECHNOLOGIES AND COTTON YIELD OF ANDIJАN-36 VARIETY

2019 ◽  
pp. 189-193
Author(s):  
Mamura Sadirdin kizi Atabayeva ◽  
Mukimjon Yakubjonovich Juraev ◽  
Ikboljon Kobiljon ugli Nosirov
Keyword(s):  
Cotton Plant ◽  
Liquid Ammonia ◽  
New Combination ◽  
Cotton Yield ◽  
Resource Saving ◽  
Double Row ◽  
Single Row ◽  
Growing Period ◽  
Net Profit ◽  
Combination Technology

With the use of resource-saving agro-technology and processing with a new combination aggregate in autumn, cotton yield of 37.9-40.4 c/ha was obtained from the variants where the 50% annual rate of 200 kg/ha norm of nitrogen was applied in the form of liquid ammonia under the ridges and the remaining 50% of liquid ammonia was used during the growing period of cotton plant in the form of ammonium salt petre by stratification. In these variants cotton seeds were sown in single-row and double-row methods. They produced additional yield of 4.1-5.9 c/ha compared to the control variants and the highest economic efficacy was achieved. Net profit from these variants constituted 2079,1-2793.7 thousand sums, profitability rate was 52.3-68.4%, in comparison with control variants, the net profit was 1127,7-1569,3 thousand sums more while the profitability rate was 29,1%. - 38.8% higher. KEYWORDS: Soil, cotton plant, single-row and double-row, cotton productivity, new combination technology, Andijan-36 variety, liquid ammonia, net profit.

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).

A kinetic study of the reductive cleavage of diphenyl ether by sodium in liquid ammonia

1989 ◽  
Vol 54 (1) ◽  
pp. 261-262 ◽  
Author(s):  
Robert R. Dewald ◽  
Nora J. Conlon ◽  
Woo M. Song
Keyword(s):  
Kinetic Study ◽  
Liquid Ammonia ◽  
Diphenyl Ether ◽  
Reductive Cleavage
Sign in / Sign up

Export Citation Format

Share Document