Synthesis and Structure of Novel Bromine-Containing Derivatives of 2-Hydroxybenzo[e][1,2]oxaphosphinine 2-Oxides

Bromination of 2-hydroxybenzo[e][1,2]oxaphosphinine 2-oxide derivatives afforded the first representatives of mono- and dibrominated products: 3-bromo-2-hydroxy-[1,3]dioxolo[4′,5′:4,5]benzo[1,2-e][1,2]oxaphosphinine 2-oxide, 3-bromo-6,8-di-tert-butyl-2-hydroxybenzo[e][1,2]oxaphosphinine 2-oxide, 3,6-dibromo-2-hydroxy-5,7,8-trimethylbenzo[e][1,2]oxaphosphinine 2-oxide, 3,6-dibromo-2-hydroxy-7-methoxybenzo[e][1,2]oxaphosphinine 2-oxide. Structure of all the synthesized compounds was confirmed by 1H, 13C, 31P NMR, IR spectroscopy, mass spectrometry (ESI-TOF), and elemental analysis data. Structure of 3,6-dibromo-2-hydroxy-5,7,8-trimethylbenzo[e][1,2]oxaphosphinine 2-oxide was additionally confirmed by single crystal X-ray crystallography.