Imidazole-4-Carboxylic Acid from China
Imidazole-4-carboxylic acid is a key intermediate for pharmaceutical synthesis, featuring the unfused imidazole ring required by heading 2933. As an aromatic heterocyclic compound listed in additional U.S. note 3, it imports under HTS 2933.29.35.00.
Duty Rate — China → United States
125%
Rate breakdown
9903.88.0325%Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
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 synthesis route and impurity profile for downstream pharma validation
• Ensure proper pH adjustment documentation for carboxylic acid handling
• Label with GHS hazard statements for corrosive organic acid properties