Phosphorus-nitrogen heterocycles

The third chapter Recent Developments in the Chemistry of N-Heterocyclic Phosphines presents a survey on five- and six-membered phosphorus-nitrogen heterocyclic compounds whose rings combine a phosphazene or phosphazane unit... 

Structure 1 Generic representation of the structures of basic types of binary phosphorus-nitrogen heterocycles cyclophosphazanes (I), cyclophosphazenes (II), cyclic phosphoranes (III)... 

Structure 2 Parent representatives of phosphorus-nitrogen heterocycles covered in this chapter... 

Phosphoryl chloride reacts successively with aniline and ammonia to produce PO(NHPh)(NH2)2, which on heating loses ammonia with formation of condensed amidophosphates. A new phosphorus-nitrogen heterocycle... 

R 245 A. Mazzah, H.W. Roesky and R. De Jaeger, Metal-Phosphorus-Nitrogen Heterocycles, Metallacyclophosphazenes and Imidodiphosp-hato Metal Complexes , p. 883... 

Redmore, D., Phosphorus derivatives of nitrogen heterocycles. 2. Pyridine-phosphonic acid derivatives, /. Org. Chem., 35, 4114, 1970. 

Similarly the combination of R2PN and NSCl units affords heterocycles containing phosphorus, nitrogen and three coordinate sulfur (e.g. and 5) which may be considered as hybrids of the well known ring systems (R2PN)3 and (NSC1)3. 

Zwitterionic four-membered PN2Nb heterocycles were obtained in the reaction of ij5-phosphorus-nitrogen ylides with NbCl5 according to equation (40). 496... 

Further phosphorus-nitrogen systems are considered under Heterocycles (Section 56.1.4.8) and have been surveyed.9-15,14680- ... 

In neutral medium the deuterium solvent isotope effect, (A h2o/ D2o) in the hydrolysis of diaryldiacyloxyspirosulphuranes483, 404-407 has been found to be 1.66. In acidic medium the ratio of catalytic rate constants has been found to be 0.56. Heterocondensed imidazoles 408, are produced in the reaction of N-benzylamides, 409, of nitrogen heterocyclic carboxylic acids with phosphorus pentachloride. Deuterium labelling experiments have been carried out to understand the mechanism of this reaction involving a nitrile ylide species484. 

PNMR spectroscopy and generates heterocycles that are hybrids of r-electron-rich (S-N) and tt-electron-precise ring systems (cyclophosphazenes, see Phosphorus-Nitrogen Compounds). 

Mercapto or methylthio nitrogen heterocycles are either obtained by direct treatment of hydroxy-nitrogen heterocycles with reagents such as phosphorus pentasulfide or Lawesson reagent (78BSB223 79T2433), or by treatment of activated intermediates such as chloro-nitrogen heterocycles with mercaptide anions as well as by total synthesis. 

Hydrogenolysis of metal carbonyls, such as Mnj(CO)jg [250 atm (25 MPa), 200°C] or COjCCOg [250 atm (25 MPa), 110°C], leads to metal-metal bond cleavage, forming HMn(CO)j or HCo(CO) The conversion of CoJiCO to HCo(CO) is the rate-determining step in Co-catalyzed hydroformylations at high P and T. Tertiary amines, nitrogen heterocycles, tertiary phosphorus bases or halide ions enhance the rate of HCo(CO) formation e.g., pyridine can increase the rate of HCo(CO).j formation 300-fold at 40°C. 

New information on the three-membered phosphorus(v) heterocycles which are often postulated as reactive intermediates comes from a study of the reactions of phosphonic diamides R P(0)(NHR )2. On treatment with t-butyl hypochlorite these are converted into the mono-N-chloro-amides, which with base lose hydrogen chloride, forming the diazaphosphoridine oxide (53). The structure is supported by spectroscopic data and by the quantitative formation of the hydra-zide (54) on reaction with methanol. New phosphorus(v)-nitrogen-phosphorus(in) systems (55) have been synthesized by transamination reactions between... 

Full X-ray structures for two phosphorus-nitrogen-containing heterocycles (69)380 (70) have been published, the P—N bond length in the former... 

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