4-Methoxybenzylamine NEW

4-Methoxybenzylamine (often abbreviated as PMB-NH₂ or p-Anisylamine) is an organic compound with the chemical formula CH₃OC₆H₄CH₂NH₂. Here's a breakdown of its key aspects:

Chemical Structure:

• It consists of a benzylamine core (C₆H₅CH₂NH₂).

• A methoxy group (-OCH₃) is attached to the benzene ring at the para position (opposite to the -CH₂NH₂ group). Hence the name *4*-methoxybenzylamine or *p*-methoxybenzylamine.

• Structure: CH₃O-C₆H₄-CH₂-NH₂ (where the benzene ring connects OCH₃ and CH₂NH₂ at positions 1 and 4).

  Physical Properties:

• Appearance: Typically a colorless to pale yellow liquid.

• Odor: Characteristic amine odor.

• Boiling Point: Around 220-230 °C (428-446 °F).

• Density: ~1.06 g/cm³.

• Solubility: Soluble in common organic solvents (ethanol, ether, dichloromethane, acetone). Slightly soluble in water, but dissolves readily in acidic water (forming water-soluble salts).

• Basicity: It's a primary aliphatic amine (the -NH₂ group is attached to an alkyl chain, -CH₂-, not directly to the aromatic ring), making it moderately basic (pKa of conjugate acid ~9.5).

  Other Names:

• p-Methoxybenzylamine (PMBA)

• (4-Methoxyphenyl)methanamine

• p-Anisylamine

• 4-Anisylamine

  Primary Uses:

• Carboxylic Acids: Forms stable esters (PMB esters) that can be cleaved selectively under mild acidic conditions (like dichloroacetic acid (DCA) or trifluoroacetic acid (TFA)) or oxidative conditions (DDQ, CAN).

• Alcohols & Phenols: Forms stable ethers (PMB ethers) cleavable under similar acidic or oxidative conditions.

• Amines: Can be used to protect amines as carbamates (PMB carbamates), cleavable oxidatively.

• Organic Synthesis Building Block: Its most significant role is as a versatile precursor or intermediate in synthesizing more complex molecules.

• Protecting Group: The 4-Methoxybenzyl (PMB) group, derived from PMB-NH₂ (often via PMB-Cl or PMB-OH), is widely used as a protecting group in organic synthesis, particularly for:

• Pharmaceutical Intermediates: Used in the synthesis of various drugs, including migraine medications (e.g., Sumatriptan, Almotriptan, Eletriptan), antibacterial agents, and other bioactive molecules.

• Agrochemical Intermediates: Used in the synthesis of certain pesticides and herbicides.

• Corrosion Inhibitors: Used in some formulations.

• Chemical Research: A common reagent in research labs for developing new synthetic methods or studying reaction mechanisms.

  Safety and Handling:

• Corrosive: Causes severe skin burns and eye damage.

• Toxic: Harmful if swallowed, in contact with skin, or inhaled.

• Flammable: Combustible liquid.

• Environmental Hazard: Toxic to aquatic life.

• Handling: Requires strict precautions: Use in a well-ventilated fume hood, wear appropriate PPE (gloves, goggles, lab coat), avoid contact with skin/eyes, avoid breathing vapors/mist. Store in a cool, dry, well-ventilated place away from oxidizers and acids.

In Summary: 4-Methoxybenzylamine is a commercially important aromatic amine primarily valued as a key building block and the source of the PMB protecting group in organic synthesis, especially for pharmaceuticals. Its reactivity stems from the primary amine group (-NH₂) and the electron-donating methoxy group on the aromatic ring. Handle it with care due to its corrosive and toxic nature.