Since ferrocene is highly reactive (due to its two cyclopentadienyl rings), AlCl3 can be replaced with a more benign catalyst, phosphoric acid. This reaction will also use acetic anhydride in place of an alkyl halide. Figure 2 shows the mechanism for this
Introduction:- In organic chemistry the substitution reactions is the most important reactions, especially Nucleophilic aromatic substitution reactions where nucleophile attacks positive charge or partially positive charge As it does so, it replaces a weaker nucleophile which then becomes a leaving group. The remaining positive or partially positive atom becomes an electrophile. The general form of the reaction is: Nuc: + R-LG → R-Nuc + LG: The electron pair (:) from the nucleophile (Nuc :) attacks the substrate (R-LG) forming a new covalent bond Nuc-R-LG. The prior state of charge is restored when the leaving group (LG) departs with an electron pair. The principal product in this case is R-Nuc.
One particular catalytic mechanism that can enhance the rate of a reaction is known as general acid-base catalysis. This mechanism lowers the activation energy, transfers a proton as a donor or acceptor, and is one of the most common biochemical reactions in the human body.
Since alkenes are immiscible with concentrated HBr, tetrabutylammonium bromide is used as a phase-transfer catalyst. It forms a complex with HBr and extracts it from the aqueous phase into the organic phase where the alkene is. This dehydrates the acid, making it more reactive so that the addition reaction is possible. Rapid stirring is required in order to maximize the surface area
The Wittig reaction is valuable reaction. It has unique properties that allows for a carbon=carbon double bond to form from where a C=O double bond used to be located. Creating additional C=C double bonds is valuable due to its use in synthesis. The Wittig reaction will allow the synthesis of Stilbene (E and Z) from a Benzaldehyde (Ketcha, 141). One purpose of a Wittig reaction is the formation of alkenes from aldehydes or ketones employing a carbo-phosphorous ylide, which is stabilized vie resonance to allow for the carbon bonded to phosphorus to be deprotonate from by a base (Ketcha, 142).
ABSTRACT The Diels-Alder reaction has been an area of great research interest with regards to enhancing enantioselectivity in the reaction by use of various catalysts and reaction conditions. INTRODUCTION In organic chemistry, a Diels-Alder reaction refers to a 4, 2 cycloaddition between a diene consisting of alternating double bonds and a substituted alkene (the dienophile) resulting in a substituted cyclohexene system. The reaction is often used to reliably control regioselective and enantioselective aspects in organic synthesis. If specific conditions are applied, these reactions can be reversible, with the reverse reaction referred to as the retro-Diels-Alder reaction. Mechanism, Regioselectivity and Enantioselectivity of the Diels-Alder Reaction
This reaction was able to happen during designated lab time due to the fact that a phenol was used. Phenols or more reactive than unsubstitued benzene rings due to the presence of the alcohol on the benzene ring. The alcohol is considered an activating group due to the oxygen’s ability to donate its lone pairs into the benzene ring thus giving it more electrons and thus making it more nucleophilic and more likely to react with the introduced electrophilic species. As aforementioned, there are various products formed in this reaction the two major products formed though are the ortho and para products. It is debatable which product is more prominent due to steric reasons and the capability of each product to conduct in hydrogen bonding.
Also, statins are very effective because they bind tightly to the enzyme compared to the substrate to block the pathway of cholesterol synthesis. Another function is to upregulate LDL receptors which results in a reduction of plasma
The CO oxidation efficiency was confirmed as a function of the [Cu]/[Mn] ratio and the reaction time. The binary Cu-Mn oxides have a flexible metal valences (Cu1+/2+ and Mn3+/4+) which give increase to their specific properties and outstanding catalytic activities for CO oxidation. The enhanced catalytic performance can be explained by the improved lattice oxygen mobility, specific surface area, and pore volume into the Cu-Mn catalysts. The binary Cu-Mn mixed metal oxide has a good potential for practical applications to decrease CO in air
The two primary hydroxyl functionalities provide excellent reactivity during both the esterification process and the subsequent crosslinking reaction. Although the cyclohexyl ring is completely saturated, the presence of labile beta hydrogens lowers the exterior durability of polyesters based on this diol. Generally, this diol is used for its excellent contribution to hardness and backbone rigidity. Ni et al [54] and Awasthi and Agrawal [56] can be considered in both works, 1,4 cyclohexanedimethanol was used for the synthesis of hydroxylated