БЕНЗИЛОКСИАЦЕТАЛЬДЕГИД ДИМЕТИЛАЦЕТАЛЬ

Description

Benzyloxyacetaldehyde dimethylacetal is a protected form of benzyloxyacetaldehyde in which the aldehyde group is transferred to dimethylacetal to increase stability during storage and during multi-step synthesis. Formula C11H16O3, CAS number 127657-97-0, synonym ((2,2-dimethoxyethoxy)methyl)benzene.

Basic Attributes

• Chemical formula: C11H16O3
• Molecular weight: 196.24
• Exact weight: 196.109940
• BRN: 3261948
• DSSTox ID: DTXSID50427364
• PSA specifications: 27.7
• XLogP3: 1.4

Physico-chemical characteristics

• Appearance: colorless liquid
• Density: 1.035 g/cm3
• Boiling point: 80-82 °C at 0.5 mm Hg. Art.
• Refractive index: 1.4895
• Steam pressure: 0.0303 mm Hg. Art. at 25 °C

Scope of application

The compound serves as a protected synthon of the aldehyde group in organic synthesis: the dimethyl acetal protection prevents unwanted side reactions of the aldehyde (oxidation, condensation, polymerization) in previous stages of the synthesis, and the benzyl ether group masks the alcohol hydroxyl, which is subsequently released by hydrogenolysis. Such bifunctional protected synthons are used in the synthesis of carbohydrates, polyols and natural compounds, which require step-by-step disclosure of the aldehyde and hydroxyl functions at different stages of molecular assembly.

Safety Information

• Safety instructions: 24/25

Storage conditions

Store in a tightly closed container, in a cool place, protected from moisture and direct sunlight: the acetal group is hydrolytically unstable in an acidic environment and in the presence of water regenerates the original aldehyde. Steam pressure 0.0303 mm Hg. Art. at 25 °C indicates low volatility of the substance at room temperature, which simplifies handling of the reagent in laboratory conditions.

Comparison with unprotected analogues

Unprotected benzyloxyacetaldehyde, as a free aldehyde, is prone to self-condensation via an aldol reaction and to oxidation in air, which makes its storage and accurate dosing difficult. Conversion to dimethyl acetal solves both problems: the acetal is chemically inert to most nucleophiles and oxidizing agents at neutral pH and easily regenerates the original aldehyde by short-term acid hydrolysis immediately before use at the desired stage of synthesis, which makes such a protected form preferable for long-term storage in a reagent warehouse.

Role in polyol synthesis

The glycol aldehyde moiety, hidden under double protection in this molecule, after removing both protecting groups, gives a diol synthon, which is in demand in the construction of sugar fragments and polyhydroxylated natural compounds, where precise control of the sequence of opening of functional groups is critical for the stereoselectivity of the final synthesis.

When carrying out acetal hydrolysis, the pH and temperature of the medium are controlled to avoid side reactions of aldol condensation of the newly released aldehyde.