N-Phenylmaleimide from Canada
N-Phenylmaleimide is a cyclic imide with carboxyimide-function, but classified here under imine derivatives per Chapter Note 3 (last in numerical order) in HTS 2925.29.90.00. Key Diels-Alder dienophile.
Duty Rate — Canada → United States
100%
Rate breakdown
9903.04.6096.3%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
• Submit X-ray crystal structure confirming planar imide ring system
• Declare melting point (88-92°C) and purity by HPLC (>99%)
• Include polymerization inhibitor (hydroquinone) concentration