Synthesis
General procedure for the synthesis of 9-fluorenylmethylhydrazinyl formate from 9-fluorenylmethylhydrazinyl formate as chloroformic acid methyl ester (FmocCl): to a well-stirred solution of hydrazine hydrate (19 g, 386 mmol) dissolved in 150 mL of CH3CN/H2O (1:1, v/v) at 0 °C, FmocCl (10 g, 38.65 mmol) dissolved in a solution of 600 mL of CH3CN. The reaction mixture was then warmed to room temperature and stirring was continued for 12 hours. Upon completion of the reaction, the mixture was concentrated in vacuum to about 150 mL and filtered to give the white solid product 9-fluorenylmethylhydrazinyl formate. The product was washed sequentially with water and hexane, dried to constant weight, and finally obtained under vacuum as 9.74 g (99% yield) of a pure product with a melting point of 172-173 °C. The structure of the product was confirmed by 1H NMR and 13C NMR: 1H NMR (DMSO) δ 4.08 (brs, 2H), 4.21 (t, J = 7.2 Hz, 1H), 4.28 (d, J = 7.2 Hz, 2H), 7.32 (t, J = 7.4 Hz, 2H), 7.42 (t, J = 7.4 Hz, 2H), 7.69 ( d, J = 7.4 Hz, 2H), 7.89 (d, J = 7.4 Hz, 2H), 8.36 (brs, 1H); 13C NMR (DMSO) δ 47.7, 66.7, 121.1 (2C), 126.3 (2C), 128.1 (2C), 128.7 (2C), 141.7 (2C), 144.9 (2C), 159.2. 159.2.
References
[1] Journal of Organic Chemistry, 2012, vol. 77, # 12, p. 5271 - 5278
[2] Patent: US9115171, 2015, B2. Location in patent: Page/Page column 43
[3] Patent: EP2182974, 2015, B1. Location in patent: Paragraph 0093
[4] Patent: CN108178739, 2018, A. Location in patent: Paragraph 0032; 0033; 0034
[5] Tetrahedron, 2011, vol. 67, # 42, p. 8187 - 8194
