scholarly journals Synthesis of olivomycose (2,6-dideoxy-3-C-methyl-L-arabino-hexose)

1969 ◽  
Vol 47 (23) ◽  
pp. 4467-4471 ◽  
Author(s):  
E. H. Williams ◽  
W. A. Szarek ◽  
J. K. N. Jones
Keyword(s):  
Wittig Reaction ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Ruthenium Tetroxide ◽  
Lithium Aluminium ◽  
Acid Catalyzed ◽  
Hydrolysis Of

Oxidation of methyl 4,6–O-benzylidene-2-deoxy-α-L-arabino-hexopyranoside (1) with ruthenium tetroxide gave the 3-ketone 2 in high yield. A Wittig reaction between methylenetriphenylphosphorane and compound 2 gave methyl 4,6-O-benzylidene-2,3-dideoxy-3-C-methylene-α-L-erythro-hexopyranoside (3), which was hydrated by the oxymercuration–demercuration procedure to afford methyl 4,6-O-benzylidene-2-deoxy-3-C-methyl-α-L-arabino-hexopyranoside (4). The reaction of compound 4 with N-bromosuccinimide gave methyl 4-O-benzoyl-6-bromo-2,6-dideoxy-3-C-methyl-α-L-arabino-hexopyranoside (5) in high yield. Treatment of compound 5 with lithium aluminium hydride followed by acid-catalyzed hydrolysis of the resultant product, gave L-olivomycose (6).

The synthesis of Cyclododecane-r-1,c-5,c-9-triamine and r-1,c-5,c-9-Tris(2,3-dimethoxybenzamido)cyclododecane

1975 ◽  
Vol 28 (3) ◽  
pp. 673 ◽  
Author(s):  
DJ Collins ◽  
C Lewis ◽  
JM Swan
Keyword(s):  
Aqueous Solution ◽  
Acid Hydrolysis ◽  
Sulphuric Acid ◽  
Sodium Carbonate ◽  
Sodium Azide ◽  
Room Temperature ◽  
Dimethyl Formamide ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Hydrolysis Of

Treatment of cyclododecane-r-1,c-5,c-9-triyl tris(p-toluenesulphonate) with sodium azide in dimethyl-formamide at 100� for 6 h gave the corresponding cis,cis-triazide which upon hydrogenation or reduction with lithium aluminium hydride gave cyclododecane-r-1,c-5,c-9-triamine, isolated as the tris-salicylidene derivative. Acid hydrolysis of this, removal of the salicylaldehyde, and treatment of the aqueous solution with sodium carbonate and 2,3-dimethoxybenzoyl chloride gave r-1,c-5,c- 9-tris(2,3-dimethoxybenzamido)cyclododecane. ��� Treatment of (E,E,E)-cyclododeca-1,5,9-triene with an excess of acetonitrile and sulphuric acid at room temperature for three days gave 18% of (E,E)-1-acetamidocyclododeca-4,8-diene; no di- or tri-amides were isolated.

4,5-Seco-4,6-cyclosteroids. I. Structure and properties of the diol from reductive rearrangement of 6β-Bromo-4β,5-epoxy-5β-cholestan-3β-ol

1969 ◽  
Vol 22 (3) ◽  
pp. 607
Author(s):  
DJ Collins ◽  
JJ Hobbs ◽  
RJ Rawson
Keyword(s):  
Physical Properties ◽  
Transformation Products ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Structure And Properties ◽  
Lithium Aluminium

Treatment of 6β-bromo-4β,5-epoxy-5β-cholestan-3β-ol (IV) with lithium aluminium hydride in tetrahydrofuran at reflux for 16 hr gave a high yield of a new diol, C27H48O2, formulated as 4,5-seco-4,6-cyolo-6β- cholestane-3β,5α-diol (VIIa). This assignment follows from mechanistic considerations, and the chemical and physical properties of the dial and its transformation products. ��� Stepwise removal of the oxygen functions gave the new hydrocarbon 4,5-seco-4,6-cyclo-6β-cholestane (XIXg).

Flavan derivatives. XXIII. Preparation and synthetic applications of Flav-3-enes

1968 ◽  
Vol 21 (9) ◽  
pp. 2247 ◽  
Author(s):  
JW Clark-Lewis ◽  
RW Jemison
Keyword(s):  
Sodium Borohydride ◽  
Acidic Medium ◽  
Catalytic Reduction ◽  
Heterocyclic Ring ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Lower Field ◽  
Field Characteristic ◽  
Lithium Aluminium ◽  
New Synthesis

2'-Hydroxychalcones and α-alkoxy-2'-hydroxychalcones are converted by sodium borohydride in isopropanol into flav-3-enes and 3-alkoxyflav-3-enes in the convenient new synthesis which makes these flavenes readily available. Catalytic reduction of the flavenes gives the corresponding flavans or 3-alkoxyflavans in high yield, and the latter are obtained mainly in the 2,s-cis-form. The flavenes immediately give flavs lium cations in the cold when treated with acids in air, and oxidation of 5,7,3',4'-tetramethoxyflav-3-ene with benzoquinone in an acidic medium gave the flavylium salt, isolated as the ferrichloride. Reduction of 5,7,3',4'-tetramethoxy-flavylium chloride with lithium aluminium hydride gave 5,7,3',4'-tetramethoxy-flav-2-ene identical with the flavene obtained from (-)-epicatechin tetramethyl ether, and confirms an earlier investigation by Gramshaw, Johnson, and King. In its N.M.R. spectrum the heterocyclic-ring protons of this flav-2-ene give an ABX multiplet which is easily distinguished from the ABX multiplet at much lower field characteristic of flav-3-enes.

4,5-Seco-4,6-cyclosteroids. III. Observations on the course of reductive rearrangement of 6β-Bromo-4β,5-epoxy-5β-cholestan-3β-ol

1969 ◽  
Vol 22 (4) ◽  
pp. 807 ◽  
Author(s):  
DJ Collins ◽  
JJ Hobbs ◽  
RJ Rawson
Keyword(s):  
Hydrogen Bromide ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Experimental Conditions ◽  
Lithium Aluminium ◽  
Reaction Proceeds ◽  
Derivatives Of

It has been shown that reductive rearrangement of 6β-bromo-4β,5-epoxy- 5β-cholestan-3β-ol (I) to 4,5-seco-4,6-cycle-6β-cholestane-3β,5α-diol (IXa) with lithium aluminium hydride in tetrahydrofuran proceeds via 6β-bromo-5β-cholestane-3β,5-diol (IIa). Relevant reactions of the latter and the corresponding 3-ketone are discussed. ��� Similar conversion of the 3-epimer of (I) into 4,5-seco-4,6-cyclo- 6β-cholestane-3α,5α-diol (XIIIa) in high yield indicates that reductive rearrangement of the 6β-bromo-5β-hydroxy moiety proceeds without participation of the 3-aluminate complex. Some derivatives of (XIIIa) are described. ��� Experimental conditions required for the conversion of (I) into (IXa) are defined. ��� Combined evidence indicates that the reaction proceeds in a concerted manner by essentially base-catalysed, 1,3-elimination of hydrogen bromide from diol (IIa) with 4,5-bond migration to give the formal intermediate 3β-hydroxy-4,5-seco-4,6-cyclo-6β-cholestan-5-one (VI), further reduced to (IXa).

Synthesis of mono- and di-functional benzyl and phenethyl derivatives containing silicon

1967 ◽  
Vol 45 (17) ◽  
pp. 1957-1961 ◽  
Author(s):  
Avner Rotman ◽  
David Gertner ◽  
Albert Zilkha
Keyword(s):  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Hydrolysis Of

Dimethylbis(p-tolyl)silane was converted into the mono- or di-benzyl bromides by reaction with appropriate equivalents of N-bromosuccinimide; these were then converted into the nitriles, which were hydrolyzed to the corresponding phenylacetic acids or reduced to the phenethylamines. The mono- and di-phenethyl alcohols were prepared by reduction of the corresponding acids with lithium aluminium hydride. The dialdehyde, dimethylbis(p-formylphenyl)silane, was prepared by hydrolysis of dimethylbis(p-dibromomethylphenyl)silane.

scholarly journals Acid-Catalyzed Conversion of Cellulose Into Levulinic Acid With Biphasic Solvent System

2021 ◽  
Vol 12 ◽  
Author(s):  
Changyue Ma ◽  
Bo Cai ◽  
Le Zhang ◽  
Junfeng Feng ◽  
Hui Pan
Keyword(s):  
Levulinic Acid ◽  
Value Added ◽  
Acid Catalyst ◽  
Solvent System ◽  
High Yield ◽  
Catalyst Loading ◽  
Amberlyst 15 ◽  
Hydrolysis Of Cellulose ◽  
Acid Catalyzed ◽  
Hydrolysis Of

In this work, acid-catalyzed conversion of cellulose into levulinic acid in a biphasic solvent system was developed. Compared to a series of catalysts investigated in this study, the Amberlyst-15 as a more efficient acid catalyst was used in the hydrolysis of cellulose and further dehydration of derived intermediates into levulinic acid. Besides, the mechanism of biphasic solvent system in the conversion of cellulose was studied in detail, and the results showed biphasic solvent system can promote the conversion of cellulose and suppress the polymerization of the by-products (such as lactic acid).The reaction conditions, such as temperature, time, and catalyst loading were changed to investigate the effect on the yield of levulinic acid. The results indicated that an appealing LA yield of 59.24% was achieved at 200°C and 180 min with a 2:1 ratio of Amberlyst-15 catalyst and cellulose in GVL/H2O under N2 pressure. The influence of different amounts of NaCl addition to this reaction was also investigated. This study provides an economical and environmental-friendly method for the acid-catalyzed conversion of cellulose and high yield of the value-added chemical.

scholarly journals Facile synthesis of benzothiadiazine 1,1-dioxides, a precursor of RSV inhibitors, by tandem amidation/intramolecular aza-Wittig reaction

2013 ◽  
Vol 9 ◽  
pp. 503-509 ◽  
Author(s):  
Krishna C Majumdar ◽  
Sintu Ganai
Keyword(s):  
High Purity ◽  
Wittig Reaction ◽  
Facile Synthesis ◽  
The Core ◽  
Amide Derivatives ◽  
Acid Catalyzed ◽  
Hydrolysis Of

Reaction of o-azidobenzenesulfonamides with ethyl carbonochloridate afforded the corresponding amide derivatives, which gave 3-ethoxy-1,2,4-benzothiadiazine 1,1-dioxides through an intramolecular aza-Wittig reaction. The reaction was found to be general through the synthesis of a number of benzothiadiazine 1,1-dioxides. Acid-catalyzed hydrolysis of 3-ethoxy-1,2,4-benzothiadiazine 1,1-dioxides furnished the 2-substituted benzothiadiazine-3-one 1,1-dioxides in good yields and high purity, which is the core moiety of RSV inhibitors.

Chemistry of the Podocarpaceae. XXII. Aspects of the chemistry of Totara-8,11,13-trien-13-ol

1969 ◽  
Vol 22 (9) ◽  
pp. 1975 ◽  
Author(s):  
RC Cambie ◽  
DR Crump ◽  
RN Duve
Keyword(s):  
Sulphuric Acid ◽  
Methyl Ether ◽  
Major Product ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Birch Reduction ◽  
Transannular Cyclization ◽  
Lithium Aluminium ◽  
Fragmentation Reactions

Attempts have been made to effect fragmentation reactions with bromo- tetralone systems related to 6α-bromo-13-hydroxytotara-8,11,13-trien-7- one (VII), a compound which affords a secoditerpenoid (IX) when treated with DMSO-NaHCO3. On treatment with sulphuric acid in acetone, the mono- epoxide derivative (XXVIII) of the methyl ether of the secoditerpenoid undergoes a novel aromatization to a naphthalenic aldehyde (XXXI) by successive transannular cyclization and fragmentation reactions. ��� A 7β-hydroxy configuration has been confirmed for the major product from reduction of 13-acetoxytotara-8,11,13-trien-7-one (VIII) with lithium aluminium hydride. 13-Methoxytotara-8,11,13-triene (II) has been deisopropylated and then subjected to Birch reduction in an attempt to effect a high yield conversion into (+)-podocarp-8(14)-en- 13-one (XXXVII), a potentially useful intermediate for synthesis.

Optimization of dilute acid-catalyzed hydrolysis of oil palm empty fruit bunch for high yield production of xylose

2012 ◽  
Vol 181-182 ◽  
pp. 636-642 ◽  
Author(s):  
Dongxu Zhang ◽  
Yee Ling Ong ◽  
Zhi Li ◽  
Jin Chuan Wu
Keyword(s):  
Oil Palm ◽  
High Yield ◽  
Empty Fruit Bunch ◽  
Dilute Acid ◽  
Yield Production ◽  
Acid Catalyzed ◽  
Hydrolysis Of ◽  
High Yield Production

Addition of pseudohalogens to unsaturated carbohydrates. III. Synthesis of 3-deoxy-3-C-nitromethyl-D-allose, a branched-chain nitro sugar

1969 ◽  
Vol 47 (23) ◽  
pp. 4473-4476 ◽  
Author(s):  
W. A. Szarek ◽  
J. S. Jewell ◽  
I. Szczerek ◽  
J. K. N. Jones
Keyword(s):  
Sodium Borohydride ◽  
Wittig Reaction ◽  
Furanose Form ◽  
Acid Catalyzed ◽  
Branched Chain ◽  
Hydrolysis Of

Addition of nitryl iodide to 3-deoxy-1,2:5,6-di-O-isopropylidene-3-methylene-α-D-ribo-hexofuranose (2), followed by treatment of the product with sodium borohydride, gave crystalline 3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-nitromethyl-α-D-allofuranose (3); the branched-chain unsaturated sugar (2) was prepared by way of a Wittig reaction with 1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose (1). Acid-catalyzed hydrolysis of 3 afforded 3-deoxy-3-C-nitromethyl-D-allose, which exists predominantly in the β-D-furanose form (4).

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