Effect of catalyst and solvent on the stereochemistry of Diels-Alder reactions between cyclopentadiene and 3-Phenylsulfinylprop-2-enoic acids and methyl esters

1984 ◽  
Vol 37 (8) ◽  
pp. 1677 ◽  
Author(s):  
SM Proust ◽  
DD Ridley
Keyword(s):  
Methyl Ester ◽  
Silica Gel ◽  
Reaction Rate ◽  
Methyl Esters ◽  
Diels Alder ◽  
Enoic Acid ◽  
Stannic Chloride ◽  
Spectroscopic Methods

In Diels-Alder reactions between cyclopentadiene and the isomeric 3-phenylsulfinylprop-2-enoic acids and methyl esters, greatest stereoselectivity (94% d.e.) results when methyl (2)-3-phenylsulfinylprop-2-enoate (7) and benzene solvent are used. The major diastereoisomer, methyl (2-endo,3-endo,S-syn)-3-phenylsulfinylnorborn-5-ene-2-carboxylate (8), also predominates when silica gel or aluminiumchloride catalysts are used, but is formed in lesser amount to the anti-epimer (9) in the presence of stannic chloride. Stereoselectivity of the reaction is decreased as reaction rate accelerates. Mixturesof all four possible diastereoisomers are formed in reactions with (E)-3-phenylsulfinylprop-2-enoic acid (15) and its methyl ester (16), and the ratios of products vary with catalyst and solvent. The stereochemistry at sulfur in these adducts has been correlated unambiguously by chemical and spectroscopic methods.

Diels-Alder Reactions With Unsaturated Sulfoxides. Reactions of (Z)-3-Phenylsulfinylprop-2-Enoic Acid and Methyl-Ester With Furan, 1,3-Diphenylisobenzofuran and Anthracene

1986 ◽  
Vol 39 (4) ◽  
pp. 575 ◽  
Author(s):  
K Picker ◽  
SM Proust ◽  
DD Ridley
Keyword(s):  
Methyl Ester ◽  
High Temperatures ◽  
Low Temperatures ◽  
Diels Alder ◽  
Enoic Acid ◽  
Reaction Conditions ◽  
Thermal Reactions ◽  
Cis And Trans

Methyl (Z)-3-phenylsulfinylprop-2-enoate undergoes Diels -Alder reactions with furan, 1,3-diphenylisobenzofuran and anthracene but chemical and stereochemical courses of the reactions are very dependent upon reaction conditions. Thus, with furan, cis,endo - and cis,exo - adducts are formed exclusively; with 1,3-diphenylisobenzofuran cis,endo - and cis,exo -adducts are formed at low temperatures, whilst the corresponding trans-adducts are formed upon heating; with anthracene where high temperatures are required for condensation cis- and trans-adducts arise together with products from further thermal reactions.

scholarly journals Kinetika Reaksi Transesterifikasi Minyak Biji Ketapang (Terminalia Catappa L) Pada Proses Produksi Metil Ester

2020 ◽  
Vol 15 (1) ◽  
pp. 77
Author(s):  
Harun Al Rasyid ◽  
Rahmad Nasir
Keyword(s):  
Methyl Ester ◽  
Reaction Rate ◽  
Seed Oil ◽  
Methyl Esters ◽  
Transesterification Reaction ◽  
Molar Ratio ◽  
Time Interval ◽  
Terminalia Catappa ◽  
Kinetics Of ◽  
The Ideal

Study on the kinetics of the transesterification reaction of ketapang seeds oil (Terminalia catappa l) of methyl ester production processusing sokletation extraction have been carried out. The ketapang seeds oil had been dissolved and then the several gram of sample were solektated using petroleum benzene solvent. Extraction followed by distillation to obtain pure ketapang oil.The catalyst used in the manufacture of biodiesel is the KOH with catalyst concentration 0.5% b/b KOH / ketapang seed oil.The solvent used was methanol with molar ratio of ketapang seed oil was 6:1.The kinetics of the transesterification reaction studied by taking 50 ml samples of the three-neck flask with a time interval (10, 20, 30, 40, 50 and 60 min) at a temperature of 30 ° C and a stirring speed of 2140 rpm.Sample is poured in the bottles that had been poured of 50 ml of water and allowed to stand in a refrigerator at a temperature of 20° C for 24 hours.Methyl esters are then separated from the glycerol and water using a separating funnel and wash using a NaSO4 in order to in the water which still contained the methyl ester.Pure methyl esters then were analyzed by GCMS to determine the content of methyl ester and HNMR to calculate the kinetics transesterification reaction of ketapang seed oil to a temperature of 30 o C.The results showed that the ideal time to process for production of methyl ester for temperature 30o C is 60 min with the kinetics of the reaction on orde 2 that are the highest graphics and the equation transesterification reaction rate ketapang seed oil into methyl ester is 

Activity of Plasmin and Streptokinase-Activator on Substituted Arginine and Lysine Esters

1966 ◽  
Vol 16 (01/02) ◽  
pp. 018-031 ◽  
Author(s):  
S Sherry ◽  
Norma Alkjaersig ◽  
A. P Fletcher
Keyword(s):  
Molecular Structure ◽  
Methyl Ester ◽  
Comparative Studies ◽  
Esterase Activity ◽  
Methyl Esters ◽  
Hydrolytic Activity ◽  
The Other ◽  
Other Hand

SummaryComparative studies have been made of the esterase activity of plasmin and the streptokinase-activator of plasminogen on a variety of substituted arginine and lysine esters. Human plasmin preparations derived by different methods of activation (spontaneous in glycerol, trypsin, streptokinase (SK) and urokinase) are similar in their esterase activity; this suggests that the molecular structure required for such esterase activity is similar for all of these human plasmins. Bovine plasmin, on the other hand, differs from human plasmin in its activity on several of the substrates studied (e.g., the methyl esters of benzoyl arginine and tosyl, acetyl and carbobenzoxy lysine), a finding which supports the view that molecular differences exist between the two animal plasmins. The streptokinase-activator hydrolyzes both arginine and lysine esters but the ratios of hydrolytic activity are distinct from those of plasmin and of other activators of plasminogen. The use of benzoyl arginine methyl ester as a substrate for the measurement of the esterase activity of the streptokinase-activator is described.

scholarly journals Evaluation of 3-Methylbutanoic Acid Methyl Ester as a Factor Influencing Flavor Cleanness in Arabica Specialty Coffee

2021 ◽  
Vol 11 (12) ◽  
pp. 5413
Author(s):  
Keiko Iwasa ◽  
Harumichi Seta ◽  
Yoshihide Matsuo ◽  
Koichi Nakahara
Keyword(s):  
Methyl Ester ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Chemical Compounds ◽  
Gas Chromatography Mass Spectrometry ◽  
Arabica Coffee ◽  
Acid Methyl ◽  
Coffee Brew ◽  
Coffee Beans ◽  
Specialty Coffee

This paper reports on the chemical compounds in arabica coffee beans with a high Specialty Coffee Association (SCA) cupping score, especially those in specialty coffee beans. We investigated the relationship between the chemical compounds and cupping scores by considering 16 types of Coffea arabica (arabica coffee) beans from Guatemala (SCA cupping score of 76.5–89.0 points). Non-targeted gas chromatography-mass spectrometry-based chemometric profiling indicated that specialty beans with a high cupping score contained considerable amounts of methyl-esterified compounds (MECs), including 3-methylbutanoic acid methyl ester (3-MBM), and other fatty acid methyl esters. The effect of MECs on flavor quality was verified by spiking the coffee brew with 3-MBM, which was the top-ranked component, as obtained through a regression model associated with cupping scores. Notably, 3-MBM was responsible for the fresh-fruity aroma and cleanness of the coffee brew. Although cleanness is a significant factor for specialty beans, the identification of compounds that contribute to cleanness has not been reported in previous research. The chemometric profiling approach coupled with spiking test validation will improve the identification and characterization of 3-MBM commonly found in arabica specialty beans. Therefore, 3-MBM, either alone or together with MECs, can be used as a marker in coffee production.

scholarly journals 30-Normedicagenic Acid Glycosides from Chenopodium Foliosum

2012 ◽  
Vol 7 (11) ◽  
pp. 1934578X1200701
Author(s):  
Paraskev T. Nedialkov ◽  
Zlatina Kokanova-Nedialkova ◽  
Daniel Bücherl ◽  
Georgi Momekov ◽  
Jörg Heilmann ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Cell Lines ◽  
Interleukin 2 ◽  
Leukemic Cell ◽  
2D Nmr ◽  
Spectroscopic Methods ◽  
Dioic Acid ◽  
Leukemic Cell Lines ◽  
Aerial Parts

Two new glycosides of 30-normedicagenic acid, namely 3- O-[ β-D-glucuronopyranosyl methyl ester]-2 β,3 β-dihydroxy-30-noroleane-12,20(29)-diene-23,28-dioic acid 28- O-β-D-glucopyranosyl ester, and 3- O-β-D-glucopyranosyl-2 β,3 β-dihydroxy-30-noroleane-12,20(29)-diene-23,28-dioic acid, together with the known 3- O-β-glucopyranosyl-2 β,3 β-dihydroxy-30-noroleane-12,20(29)-diene-23,28-dioic acid 28- O-β-glucopyranosyl ester, and 3- O-β-glucuronopyranosyl-2 β,3 β-dihydroxy-30-noroleane-12,20(29)-diene-23,28-dioic acid 28- O-β-glucopyranosyl ester were isolated from the aerial parts of Chenopodium foliosum Asch. The structures of the compounds were determined by means of spectroscopic methods (1D and 2D NMR, UV, IR) and HRMS-ESI. The compounds were tested for cytotoxicity on three leukemic cell lines (BV-173, SKW-3, HL-60). In addition, the saponins showed moderate stimulatory effects on interleukin-2 production in PHA/PMA stimulated Jurkat E6.1 cells.

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