- Three-membered Heterocycles,10. - Phosphonohydrazidic Esters by Alkoxide-induced Rearrangement of N-Chlorophosphonic Diamides
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Phosphoric and phosphonic amides 8 are formed from phosphoric and phosphonic chlorides 6 and primary amines 7 in high yields. 2,5-Dimethyl-2,5-hexanediamine (7e) reacts with phenylphosphonic dichloride (6c) to give the perhydro-1,3,2-diazaphosphepine 8h.The amides 8 are converted almost quantitatively into the N-chlorophosphoric and N-chlorophosphonic amides 9 by means of tert-butyl hypochlorite.The N,N'-di-tert-alkyl-N-chlorophosphonic diamides 9 derived from methyl-, tert-butyl-, or phenylphosphonic acid react with methoxide or tertiary alkoxides to afford the phosphonohydrazidic esters 10-13.The methyl ester 10d is also formed from 1,2,3-tri-tert-butyldiazaphosphiridine 3-oxide (14) and methanol. 1H-, 13C-, and 31P-NMR spectra prove that the sharply melting phosphonohydrazidic esters 10-13 exist in solution as two diastereomers with ratios ranging from 9:1 to 6:4.The hydrazidic methyl ester 10d which was investigated as a representative example exhibits a temperature dependent 1H-NMR spectrum.Due to the presence of the tert-alkyl groups, inversion at the tertiary nitrogen atom is slow on each NMR time scale. The independence of the IR spectrum on the concentration shows that the predominant diastereomer of 10d is stabilized by an intramolecular hydrogen bond.The electron impact induced decomposition of the amides 8, N-chloroamides 9, and phosphonohydrazidic esters 10-13 ultimately produces cations which are derived from monomeric metaphosphoric or metaphosphonic acid. 6 N hydrochloric acid first splits off the P-N-tert-butyl group of the methyl ester 10d to give the intermediate 15 which can be isolated or which undergoes further hydrolysis to tert-butylphosphonic acid (17) and tert-butylhydrazine(19).The tert-butyl ester 11d yields the same final products in hot hydrochloric acid.At low temperatures and short reaction times, however, di-tert-butylhydrazine (18) is formed.
- Quast, Helmut,Heuschmann, Manfred,Abdel-Rahman, Mohamed O.
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p. 943 - 966
(2007/10/02)
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