scholarly journals Stereoselectivities in Catalytic Hydrogenation of Several Branched-Chain 6-Deoxyhex-5-enopyranosides.A Synthesis of Branched-Chain Methyl 6-Deoxy-β-L-hexopyranoside

1992 ◽  
Vol 65 (1) ◽  
pp. 292-294 ◽  
Author(s):  
Ken-ichi Sato ◽  
Shogo Sakuma ◽  
Kazuo Takahashi ◽  
Hironobu Hashimoto
Keyword(s):  
Catalytic Hydrogenation ◽  
Branched Chain

New Route to Branched-chain Aminodeoxy Sugars by Reaction of Ketoses with Acetonitrile. Synthesis of Methyl 3-C-2′-Aminoethyl-2-deoxy-α-D-arabino-hexopyranoside

1974 ◽  
Vol 52 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Alex Rosenthal ◽  
G. Schöllnhammer
Keyword(s):  
Catalytic Hydrogenation ◽  
Liquid Ammonia ◽  
High Yield ◽  
Lithium Amide ◽  
Branched Chain

Addition of methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose (1) to acetonitrile in liquid ammonia at −50 to −60° in the presence of lithium amide gave, in high yield, crystalline methyl 4,6-O-benzylidene-3-C-cyanomethyl-2-deoxy-α-D-arabino-hexopyranoside (2) exclusively. The proof of structure 2 is described. Debenzylidenation of 2 afforded the branched-chain cyano glycoside 3. Compound 3 was converted into its 3,4,6-tri-O-acetate (8) and 4,6-di-O-p-nitrobenzoate (9) derivatives. Catalytic hydrogenation of 3 over rhodium on alumina yielded methyl 3-C-2′-aminoethyl-2-deoxy-α-D-arabino-hexopyranoside which was characterized as its N-2,4-dinitrophenyl derivative (7).

Catalytic Hydrogenation of Phosphate Enol Esters Present in Branched Chain Dienepyranosides in a Route to Thromboxane Analogs from D-Galactose

1999 ◽  
Vol 18 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Oscar Moradei ◽  
Cecile M. du Mortier ◽  
Alicia Fernández Cirelli ◽  
Joachim Thiem
Keyword(s):  
Catalytic Hydrogenation ◽  
Enol Esters ◽  
Branched Chain

Oxidation of carbohydrates with chromium trioxide in acetic acid. I. Glycosides

1970 ◽  
Vol 23 (6) ◽  
pp. 1209 ◽  
Author(s):  
SJ Angyal ◽  
K James
Keyword(s):  
Acetic Acid ◽  
Hydrogen Atom ◽  
Catalytic Hydrogenation ◽  
Chromium Trioxide ◽  
Keto Ester ◽  
Keto Esters ◽  
Branched Chain ◽  
Acetyl Migration

Fully acetylated methyl β-D-hexopyranosides are oxidized by chromium trioxide in acetic acid to acetylated methyl 5-hexulosonates. Catalytic hydrogenation of these keto esters leads into the L-series. The corresponding a-D-glycosides are not oxidized in the same way, with the exception of methyl tetra-O-acetyl-α-D-idopyranoside. Both α- and β-anomers of the acetylated fnranosides are oxidized to aoetylated methyl 4-hexulosonates. The octaacetates of α- and β-lactose are similarly oxidized, the ring of the galactose moiety being opened. The methyl pyranoside of a branched-chain sugar, with no hydrogen atom on C5, is oxidized to a 4-keto ester, acetyl migration occurring from O4 to O5.

Isoprene and Rubber. XXIV. The Reduction of Rubber with Hydriodic Acid

1931 ◽  
Vol 4 (3) ◽  
pp. 365-367
Author(s):  
H. Staudinger ◽  
James R. Senior
Keyword(s):  
Elevated Temperature ◽  
Catalytic Hydrogenation ◽  
Catalytic Reduction ◽  
Hydriodic Acid ◽  
Hydrogenation Product ◽  
Butadiene Rubber ◽  
Paraffin Hydrocarbon ◽  
Normal Paraffin ◽  
The Past ◽  
Branched Chain

Abstract In the past, the reduction of rubber has been of special interest since Harries was of the opinion, based on his ideas on the constitution of rubber, that hydrorubber might possibly be distilled without decomposition in vacua, and therefore that its preparation would be of importance in explaining the constitution of rubber. Staudinger and Fritschi obtained a hydrorubber by catalytic reduction, which they considered to be a high molecular paraffin hydrocarbon; in the distillation it cracked and yielded low molecular cleavage products. It was concluded from this that rubber must also be a high molecular hydrocarbon. Contrary to this opinion, there was the evidence that the hydrorubber had the same appearance as rubber and dissolved readily in solvents like ether, and therefore showed essential differences from high molecular paraffins of known constitution as, for example, dimyricyl. Since hydrorubber has a branched chain, it might be thought that it differed from dimyricyl on this account. It was surprising, however, that in the reduction of butadiene rubber the hydrogenation product obtained likewise does not possess the physical properties of a high molecular paraffin hydrocarbon, although here properties similar to those of high molecular paraffins are to be expected, since a normal paraffin chain should result from the reduction of butadiene rubber. These problems were sufficient inducement for preparing hydrorubber in still another way. Berthelot had already many years ago converted rubber with hydriodic acid at an elevated temperature into paraffin hydrocarbons, which distilled above 350° without decomposition. One might assume, therefore, that there is perhaps in this substance the true hydrogenation product of rubber which was sought by Harries, whereas in catalytic hydrogenation the rubber micelle assumed by Harries is not completely split up.

ChemInform Abstract: Catalytic Hydrogenation of Phosphate Enol Esters Present in Branched Chain Dienepyranosides in a Route to Thromboxane Analogues from D-Galactose.

ChemInform ◽  
2010 ◽  
Vol 30 (26) ◽  
pp. no-no
Author(s):  
Oscar Moradei ◽  
Cecile M. du Mortier ◽  
Alicia Fernandez Cirelli ◽  
Joachim Thiem
Keyword(s):  
Catalytic Hydrogenation ◽  
Enol Esters ◽  
Branched Chain

Branched-chain aminodeoxy sugars. Methyl 3-C-aminomethyl-2-deoxy-α-D-ribo-hexopyranoside and methyl 3-C-aminomethyl-2-deoxy-α-D-arabino hexopyranoside

1970 ◽  
Vol 48 (19) ◽  
pp. 3034-3038 ◽  
Author(s):  
Alex Rosenthal ◽  
Khong-Seng Ong
Keyword(s):  
Catalytic Hydrogenation ◽  
Sodium Methoxide ◽  
Acetyl Derivative ◽  
Molar Equivalent ◽  
Branched Chain

Addition of methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose (1) to excess nitromethane and 1 molar equivalent of sodium methoxide in methanol gave methyl 4,6-O-benzylidene-2-deoxy-3-C-nitromethyl-α-D-ribo-hexopyranoside (2) and the arabino stereoisomer 3 in 63 and 22% yields, respectively. The proof of structure of the branched-chain deoxy nitro sugars is described. Debenzylidenation of the nitro sugars afforded the partially blocked nitro sugars 4 and 5. Catalytic hydrogenation of the latter or of 2 and 3 yielded the branched-chain aminodeoxy sugars 7 and 9 (7 characterized as its N-acetyl derivative and 9 as its N-2,4-dinitrophenyl derivative).

The Weight Loss Effects of Branched Chain Amino Acids and Vitamin B6: A Randomized Controlled Trial on Obese and Overweight Women

2018 ◽  
Vol 88 (1-2) ◽  
pp. 80-89 ◽  
Author(s):  
Zahra Shakibay Novin ◽  
Saeed Ghavamzadeh ◽  
Alireza Mehdizadeh
Keyword(s):  
Amino Acids ◽  
Weight Loss ◽  
Body Composition ◽  
Vitamin B6 ◽  
Controlled Trial ◽  
Density Lipoprotein ◽  
Branched Chain Amino Acids ◽  
Model Assessment ◽  
Waist To Hip Ratio ◽  
Branched Chain

Abstract. Branched chain amino acids (BCAA), with vitamin B6 have been reported to improve fat metabolism and muscle synthesis. We hypothesized that supplementation with BCAA and vitamin B6 would result in more weight loss and improve body composition and blood markers related to cardiovascular diseases. Our aim was to determine whether the mentioned supplementation would affect weight loss, body composition, and cardiovascular risk factors during weight loss intervention. To this end, we performed a placebo-controlled randomized clinical trial in 42 overweight and obese women (BMI = 25–34.9 kg/m2). Taking a four-week moderate deficit calorie diet (–500 kcal/day), participants were randomized to receive BCAA (6 g/day) with vitamin B6 (40 mg/day) or placebo. Body composition variables measured with the use of bioelectrical impedance analysis, homeostatic model assessment, and plasma insulin, Low density lipoprotein, High density lipoprotein, Total Cholesterol, Triglyceride, and fasting blood sugar were measured. The result indicated that, weight loss was not significantly affected by BCAA and vitamin B6 supplementation (–2.43 ± 1.02 kg) or placebo (–1.64 ± 1.48 kg). However, significant time × treatment interactions in waist to hip ratio (P = 0.005), left leg lean (P = 0.004) and right leg lean (P = 0.023) were observed. Overall, supplementation with BCAA and vitamin B6 could preserve legs lean and also attenuated waist to hip ratio.

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