? 2,2-dimethyl-1,3-dioxane-4,6-dione: definition and explanations

The 2,2-dimethyl-1,3-dioxane-4,6-dione Where acid (An acid is a chemical compound generally defined by its reactions…) Meldrum a organic compound (A chemical compound is called an organic compound when it contains at least one carbon atom…) molecular formula C₆H₈He₄. This compound was first developed in 1908 Andrew Norman Meldrum (in) with his reaction condensation (Condensation is the name given to the physical phenomenon related to the change of state of matter that…) who’smalonic acid (Malonic acid is an aliphatic dicarboxylic acid: HOOC-CH2-COOH. It…) andacetone (In chemistry, acetone, (official IUPAC name propanone, also…) one mixed (A mixture is a combination of two or more solid, liquid, or gaseous substances…) ofacetic anhydride (Acetic anhydride or ethanoic anhydride is an acid anhydride…) and D’sulfuric acid (Sulphuric acid (formerly called vitriol or oil of vitriol) is a compound…). Meldrum misidentified the structure of this compound as a beta-lactone with one group carboxyl (In organic chemistry, a carboxyl group is a functional group consisting of an atom) for free. The correct structure was described in 1948 by David Davidson et al.

As an alternative to its original preparation, Meldrum’s acid can be synthesized with malonic acid, isopropenyl acetate and sulfuric acid. catalyst (In chemistry, a catalyst is a substance that increases the speed of a chemical reaction;…). 2,2-dimethyl-1,3-dioxane-4,6-dione is quite acidic with a pKa of 4.97. This acidity is so high that it was long considered an anomaly because it is eight times higher than the acidity of dimethyl malonate, whose pKa is closely related.water (Water is a ubiquitous chemical compound on Earth, essential for everyone…) does around (Autour is the name given by French bird nomenclature (update)…) 13. In 2004, Tomohiko Ohwada et al. made numerous calculations and revealed the secret of this acidity. Ohwada points out that the structure was formed as a result of minimizationenergy (Energy in common sense refers to anything that allows you to do work, energize, etc.) of adaptation (In chemistry, the conformation of a molecule is the spatial arrangement of its constituent atoms…) place the orbitals σ_VSH CH bonds (H in alpha of carbonyl groups). geometry (Geometry is the branch of mathematics that studies the shapes of space…) suitable for matching with an antibonding orbital π * _VSHe so thatground condition (In quantum physics, the ground states of a system are more…) Corresponds to extremely strong destabilization of CH bonds.

Due to this high acidity, 2,2-dimethyl-1,3-dioxane-4,6-dione, like malonic acid, can serve as a reagent. Knoevenagel condensation (in).

2,2-dimethyl-1,3-dioxane-4,6-dione is the basis of the general synthesis of beta-ketoesters. The reaction of Meldrum’s acid with acyl chloride (chloridecarboxylic acid (The term carboxylic acid refers to a molecule containing a carboxyl group…), RCOCl) in dichloromethane/pyridine gives the corresponding 5-acyl-2,2-dimethyl-1,3-dioxane-4,6-dione. When the latter is withdrawn with an alcohol aliphatic (In organic chemistry, a molecule is said to be aliphatic when it has carbon chain(s)…)R’OH, RCOCH ketoester₂COOR’ results, often in overall yields better than 80%, and even with inhibiting reagents such as tert-butanol. This type is useful for ketoesters synthesis pyrrole (A pyrrole or azole with the structural formula C4H5N is a simple heterocyclic compound and…) by Knorr (in) :

Knorr synthesis