1-Methylxanthine from Mexico
1-Methylxanthine is a purine alkaloid metabolite and research chemical with nitrogen-only heterocyclic structure under 2933. Covered by additional U.S. note 3 specifications. Used in biochemical research and pharmaceutical synthesis.
Duty Rate — Mexico → United States
100%
Rate breakdown
9903.04.6093.5%Pharmaceuticals Annex IV: patented pharma articles — 100% floor rate
9903.05.900%Articles already subject to Section 232 (steel/aluminum/copper + derivatives, autos + parts, wood, medium/heavy vehicles + parts, semiconductors, patented pharma) — U.S. note 52(f)
Import Tips
• Include NMR or mass spec data confirming structure matches reference standard
• Label as 'research chemical - not for human consumption' to avoid FDA drug scrutiny
• Verify no heavy metal contaminants per USP <232> limits for pharma intermediates