ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Straightforward synthesis of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivatives containing P–N bonds

Marco Bortoluzzi, Lodovico Agostinis, Stefan Ghincolov, Valentina Ferraro, Giacomo Marra, and Jesús Castro

Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Mestre, Italy

E-mail: markos@unive.it

Received: 22 June 2023  Accepted: 4 August 2023

Abstract:

The H-phosphinate 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), a commercial compound of interest for its flame retardant properties, was successfully converted to related phosphonamidates following a recently patented one-pot method based on the oxidation of the species in the presence of a suitable aliphatic or aromatic amine under mild conditions. In this way, the compounds 6-morpholinodibenzo[c,e][1,2]oxaphosphinine 6-oxide, 6-(4-acetylpiperazino)dibenzo[c,e][1,2]oxaphosphinine 6-oxide, 6-p-tolylaminodibenzo[c,e][1,2]oxaphosphinine 6-oxide and 6-(methyl(phenyl)amino)dibenzo[c,e][1,2]oxaphosphinine 6-oxide, where the P–H bond is formally replaced by P–N bonds, were isolated in good yields and with high purities. The characterization data were supported by the single-crystal X-ray structure determination of 6-morpholinodibenzo[c,e][1,2]oxaphosphinine 6-oxide and 6-(methyl(phenyl)amino)dibenzo[c,e][1,2]oxaphosphinine 6-oxide.

Graphical abstract

Keywords: H-phosphinates; DOPO; Phosphonamidates; P–N bond formation; Flame retardants

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03028-3

Chemical Papers 77 (12) 7999–8006 (2023)