Microgram Synthesis and Characterization of Benzoylfentanyl and Benzoylbenzylfentanyl. Microgram Journal 2018; 15(1-4):1-8. January 01, 2018 Synthesis and Characterization of Benzoylfentanyl and Benzoylbenzylfentanyl. Microgram Journal 2018; 15(1-4):1-8. Download PDF Synthesis and Characterization of Benzoylfentanyl and Benzoylbenzylfentanyl. Microgram Journal 2018; 15(1-4):1-8.