Studies on the Alkylation and Chlorination of Fluorenes: Preparation of 9-(2-Hydroxyethyl)fluorene and 2,7-Dichloro-9-(2-hydroxyethyl)fluorene
作者:John Perumattam、Charley Shao、William L. Confer
DOI:10.1055/s-1994-25668
日期:——
Efficient large-scale syntheses of 9-(2-hydroxyethyl)fluorene (1) and its 2,7-dichloro derivative 2 are described. Major differences exist in the reactivity of fluorene and its 2,7-dichloro derivative toward 9-alkylation. These differences are attributed to the difference in acidity of the protons in the 9-position of these compounds. Also 2,7-dichlorination of fluorene and its derivatives was satisfactorily achieved by treatment with NCS and conc. HCl in acetonitrile under carefully controlled conditions. Specifically, a highly concentrated solution of substrates and elevated temperatures were required for facile 2,7-dichlorination.
描述了9-(2-羟乙基)氟烯(1)及其2,7-二氯衍生物2的大规模高效合成。氟烯及其2,7-二氯衍生物在9-烷基化反应中的反应性存在主要差异。这些差异归因于这些化合物的9位质子的酸性差异。此外,通过在精确控制的条件下,用NCS和浓盐酸在乙腈中处理,实现了氟烯及其衍生物的2,7-二氯化反应,结果令人满意。具体而言,需要高浓度的底物溶液和高温才能促进2,7-二氯化。