Reaction of an anthracene-based cyclic phosphonate ester with trimethylsilyl bromide unexpectedly generating two phosphonates: syntheses, crystal structures and fluorescent properties

Abstract

Reaction of the cyclic phosphonate ester of anthracen-9-yl(5,5-dimethyl-2-oxo-2l 5 -1,3,2-dioxaphosphinan-2-yl)-methanol (1) with TMSBr unexpectedly generated phosphonates 2-(10-bromoanthracen-9-ylmethyl)-5,5-dimethyl-2l 5 -1,3,2-dioxa-phosphinan-2-one ( 2) and (10-bromoanthrancen-9-yl)methyl-phosphonate mono(3-bromo-2,29-dimethylpropyl) ester (3) through a series of bond cleavages and formations.Compound 3 could transform into 2 in CH 3 OH-H 2 O solution, but it is stable in dry CH 3 CN. The structures of 1-3 have been characterized by IR spectra, 1 H NMR spectra, and crystal structures. In contrast to 1, the dioxaphosphorinane ring is open in 3, but not changed in 2. In addition, both 2 and 3 contain a brominesubstituted anthracene group, and have no hydroxyl group as that in 1. For compounds 1-3, their crystal structures and fluorescent properties in CH 2 Cl 2 solution and in the solid state have been studied.

Green and Effective Preparation of α-Hydroxyphosphonates by Ecocatalysis

“…They are especially useful as biologically active compounds such as antibiotics (e.g., Valinophos I [ 13 ], and Fosfazinomycin A III [ 14 ]); enzyme inhibitors (e.g., renin inhibitors II [ 15 ], for potential treatment of hypertension and congestive heart failure or neuraminidase inhibitor [ 16 ], for treatment of influenza infection, commonly called “the flu”); antiparasitics (e.g., inhibitors of Plasmodium falciparum growth IV [ 17 ], useful in treatment of malaria that is caused by this parasite); and insecticides (e.g., trichlorfon V ) ( Figure 1 ). Additionally, α-hydroxyphosphonic acids and their esters are very useful scaffolds in organic synthesis often used to prepare more complex molecules [ 18 ], e.g., after O -allylation and subsequent RCM or isomerization/Claisen rearrangement [ 19 ], reaction with primary amines leading to α-aminophosphonates and phosphonic acids [ 20 ], phospha-Brook rearrangement [ 21 ], reduction [ 22 ], halogenation [ 23 ], and oxidation leading to ketophosphonates ( Figure 1 ) [ 24 ].…”

Metal-Free Arylation to Access Distinct Anthracenylphosphonates and Anticancer Activities for These and Allied Phosphonates

“…Further, synthesis of compound 2 b was reported along with unexpected ring‐cleaved product by reacting 2 a with Me 3 SiBr in MeCN (eq. 2) . Particularly, these two protocols are only known in the literature to produce such an important phosphonate, 2 b .…”