One Phosphorus Atom

There have been no reports of dibenzo-l,2-azaphosphorines since Edmundson s review (79MI1). However, the naphthalene derivative (1) has been described but its further reactions were not detailed (80IJC(B)404). The tricycle (2) was prepared in low yield by sodium hydride induced cycliza-tion of (3) (79JHC897). 

There has been more work on monocyclic systems and a number of patents have been taken out on the amino-diacid 4 (75GEP2343147,75GEP2343195, 75GEP2417534 76GEP2456667). Uses proposed for the compound include detergent builder, hardening retardant for gypsum, reduction of calcification 

A similar compound (5) was prepared by cyclization of the aminophos-phonate 6 (78ZOB51). Unfortunately, the source of the starting material was 

Free radical cyclization of the allylphosphine 17 gave some 1,3-azaphos-phorinanes in admixture with other products (83PS73). 

A different approach involved treating (3-oxoalkyl)phenylphosphines with aldehydes and ammonia to give 18. The same phosphorus compounds also reacted with aldimines to give tetrahydro-l,3-azaphosphorines (73MI2). 

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In addition to the above acids and anions which contain only one phosphorus atom there are many other condensed phosphates(V)... 

Phosphorus Compounds. Acyclic phosphorus compounds containing only one phosphorus atom, as well as compounds in which only a single phosphorus atom is in each of several functional groups, are named as derivatives of the parent structures listed in Table 1.12. Often these... 

For the oxygen atoms in P4Oio that are bonded to only one phosphorus atom the predicted amount of ir-bond character, 1.02, leads to 1.45 A. for the P=0 distance. This is in only rough agreement with the observed distance, 1.39 0.02 A. 

The X-ray crystallographic analysis of the unsymmetrical BisP shows a strong distortion of the five-membered chelation ring as compared to that of symmetric BisP [32]. The large difference in the steric repulsions between the bulky substituent borne on one phosphorus atom and the neighboring atoms on the one hand and the other (different) bulky substituent borne on the other phosphorus atom and the same neighboring atoms on the other hand is believed to be responsible for better steric matching with some substrates. 

Compound 1 contains one phosphorus atom, so that the broad-band proton decoupled spectrum is extremely simple it consists of only one line at 8.5 ppm. This spectrum is shown in Fig. 22, together with the proton-coupled spectrum. 

It is by no means unusual to come across compounds which contain more than one phosphorus atom Fig. 23 shows the proton decoupled coupled phosphorus spectrum of compound 6, which contains three chemically different phosphorus nuclei. Phosphorus behaves in NMR just like the proton, so we shall expect to see three signals, split into multiplets if there is an observable coupling between the phosphorus nuclei. 

Since the coefficient of H,P04 is 1, there is one phosphorus atom on the left of the equation. Phosphorus appears in only one product, and so that product must have a coefficient of 1. The one Na,P04 has three Na atoms in it, and so there must be three Na atoms on the left the NaOH gets a coefficient of 3. There are three H atoms in H3P04 and three more in three NaOH, and so three water molecules are produced. The oxygen atoms are balanced, with seven on each side. We drop the coefficients of 1 to finish our equation. 

However, other reaction directions via the formation of the phosphorane structure with migration of the methyl anion from one phosphorus atom... 

For various reasons, the generalizations mentioned above must be regarded as strictly provisional. Analyses utilizing formic acid indicate the presence of more than one phosphorus atom per purine or pyrimidine residue. This discrepancy, it is pointed out, could equally well result from an apparent deficiency of bases, due to error in the analytical technique.160 It is also necessary to consider that some nucleic acids are now known to contain more bases than was previously realized. Thus, 5-(hydroxymethyl)-cytosine is present in various viruses,181-182 and 5-methylcytosine occurs in various animal and plant deoxyribonucleic acids but is absent from those of microbial origin.17-160-1M- 184- 186 Certain microbial deoxyribonucleic acids also contain 6-methylaminopurine.186a Various bacteriophage deoxyribonucleic acids have been found to contain a component which is believed to consist of a D-glucoside186b of 5 -(hydroxymethyl)cytidylic acid. 

Although this monograph is concerned primarily with compounds containing one phosphorus atom, some account has already been given of esters of pyrophosphoric acid (p. 103) attention must also be drawn to some recent important contributions to the organic chemistry of polyphosphorus compounds made by M. Tolkmith. He has prepared decamethyltriphosphor-amide1 (XX) by the action ... 

Nomenclature of Compounds containing one Phosphorus Atom. September 1952. London The Chemical Society. 

Figure 9. A view of the P4(NMe)/jS4 molecule with the two locations Si and S2 found for the sulfur atoms at 3 °C (11). This disorder is shown on one phosphorus atom only to avoid overcrowding.

The high stability of X -phosphorins and X -phosphorins suggests that additional aromatic ring systems can be prepared, having more than one phosphorus atom or heteroatoms other than phosphorus. 

A number of macrocycles containing only one phosphorus atom have been prepared, and they are usually referred to as phosphorus-containing crown ethers rather than as P macrocycles. The 18-crown, or [18]anePOs, was prepared by van Zon (equation 28).82 This cyclic phosphine is stable in air, even in solution (cf. Ph3P). However, when the non-macrocyclic substituent is Bul the phosphorus is oxidized in solution by air in the presence of alumina. This unwelcome discovery was made by van Zon when purifying the material by chromatography on an alumina column. 

The molecular formulae of the tri- and pent-oxides are respectively P406 and P4O10 as shown respectively by T. E. Thorpe and A. E. H. Tutton, and by W. A. Tilden and R. E. Barnett. It is assumed that the phosphorus in the trioxide is tervalent because hydrogen chloride converts the oxide into phosphorous chloride, Pd3, and phosphorous acid, P(OH)3 while phosphorus in the pentoxide is assumed to be quinquevalent because water converts the oxide into phosphoric acid, 0 P(0H)3. Since water converts phosphorus tetroxide, P204, into a mixture of phosphorous and phosphoric acids, it has been argued that one phosphorus atom is tervalent, and the other quinquevalent. In the alleged phosphorus tetritoxide, P40, of A. Michaelis, the phosphorus is assumed to be tervalent ... 

Chapter 2 by Laszlo Nyulaszi and Zoltan Benko deals with the chemistry and physical organic chemistry of aromatic phosphorus heterocycles and is divided into four subchapters dealing with three-, four-, five-, and six-membered rings, in which there may be more than one phosphorus atom. The chapter begins with a clear presentation of the electronic structure that phosphorus may achieve in molecules with CP bonds. For cyclopentadiene and phosphole eight aromaticity indices are collected. Almost all of them indicate that phosphole is more aromatic than cyclopentadiene. It is also shown that even small structural effects (substituent, bonding modes) can have a substantial impact on the chemistry of the reported systems. 

Phosphetane, arsetane, stibetane, or bismetane. Saturated four-membered rings containing one phosphorus atom are named as phosphetane. Arsetane, stibetane, and bismetane are arsenic, antimony, and bismuth analogues of phosphetane, respectively. 

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