Caffeine

Caffeine (1,3‑dimethylxanthine) is a naturally occurring xanthine alkaloid that acts primarily as a central nervous‑system stimulant. It is widely consumed in beverages and as a dietary supplement to promote alertness, improve mental performance, and reduce perceived fatigue.

• Molecular Formula: C₈H₁₀N₄O₂ (molar mass = 194.19 g mol⁻¹).
• IUPAC Name: 1,3,7‑trimethylpurine‑2,6‑dione.
• Structure: The structure consists of a fused heterocyclic purine core with three methyl groups at N‑1, N‑3, and N‑7, and carbonyl groups at C‑2 and C‑6, conferring a planar, aromatic configuration.
• Acidity/Basicity: It is a weak base (pKa ≈ 0.6 for the imidazole nitrogen).
• Solubility: Highly soluble in water (≈21 g L⁻¹ at 25 °C) and organic solvents (e.g., ethanol).
• Stability: The compound is stable at neutral pH but undergoes oxidation to theobromine and theophylline under oxidative conditions.

• Natural Sources: Caffeine is extracted from coffee beans (Coffea spp.), tea leaves (Camellia sinensis), cacao beans (Theobroma cacao), and guarana seeds (Paullinia cupana).
• Extraction Method: Commercially, it is obtained by solvent (water/ethanol) extraction followed by spray‑drying to produce a fine white powder.
• Synthetic Production: Synthetic caffeine via the Mannich reaction (using urea, chloroacetone, and methylating agents) produces a chemically identical product, often used for pharmaceutical grade consistency.
• Quality Considerations: Quality considerations include purity (>99 % for pharmaceutical‑grade), absence of heavy metals or pesticide residues, and certification (e.g., USP, NSF) to assure safety and potency in supplements.