The synthesis and conformational analysis of the sterically congested bis(phosphite) ligand {2-{1-{3,5-tBu2-2-[2,2‘-CHCH3(4,6-tBu2C6H2O)2PO]C6H2}Et}-4,6-tBu2C6H2O}(PhO)2P (5) are reported. X-ray cr...

Atomic Proximity Due to Molecular Congestion: Rational Design of Bis(phosphite) Ligands by Restriction of Molecular Motion(1).

In this article, the syntheses and thermal properties of several alkyne- and phosphorus-containing materials are discussed. The materials were synthesized using substituted phenolic molecules which were added to phosphorus oxychloride. The materials synthesized include phosphine oxides, phosphates, diphosphates, and oligophosphates. The thermal properties of the synthesized materials were studied using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). In general, the DSC and TGA data showed that synthesized materials containing alkynes and phosphorus had good-to-excellent thermal stability with high-onset decomposition temperatures. Materials with a high alkyne-to-phosphorus ratio showed the highest char yields. DSC data showed crosslinking events for the alkynes and the phosphorus moieties. DSC also showed that the alkynes crosslinked at lower temperatures than the phosphates. Based on the TGA and DSC data of the alkyne-containing phosphorus materials, alkynes generally appeared to be better char-inducing groups than was phosphorus. The materials were blended into polycarbonate and tested for ignition resistance using the UL-94 flame test. In two cases, these halogen-free compounds, with their dual alkyne/phosphorous crosslinking mechanisms, are condensed-phase flame retardants that can be easily blended into polycarbonate at 10 wt % loadings to afford blends that give a UL-94 V-0 rating. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 707–718, 1999

Synthesis and testing of nonhalogenated alkyne/phosphorus‐containing polymer additives: Potent condensed‐phase flame retardants

The synthesis of novel 6-substituted-2,10-dichloro-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-oxides is described along with IR, 1H, 13C, and 31P NMR spectral data. Phosphorus couplings of 5 J PH, 2 J POC and 3 J POCC were determined. An appraisal of the data in total did not allow unequivocal differentiation between a boat-boat, boat-chair, distorted boat, or twist boat conformation for the eight-membered ring of the dioxaphosphocin 6-oxides. A few members of this family were evaluated for toxicity in the insect P. americana.

SYNTHESIS, 1H, 13C, 31P NMR ANALYSIS, AND INSECTICIDAL ACTIVITY OF MEMBERS CONTAINING EXTERNAL P—O OR P—N BONDS IN 6-SUBSTITUTED-2,10-DICHLORO-12H-DIBENZO[d,g][1,3,2]DIOXAPHOSPHOCIN 6-OXIDES

The conformation of the eight-membered membered 12H-dibenzo[d,g][1,3,2]dioxasilocin ring system was investigated both in the solid-state by X-ray crystallography and in solution by NOE experiments. Ab initio Hartree−Fock calculations were performed to locate all stationary points for the unsubstituted 12H-dibenzo[d,g][1,3,2]dioxasilocin ring system. The MM2* force field was parametrized to reproduce our ab initio results, and these data were compared to the experimental data. The transition states for conformational interchange were identified. The pseudoequatorial preference for a methyl substituent on either the C(12) carbon atom or silicon is greater than the difference in energy between a boat-chair and twist-boat conformation in 2,4,8,10-tetra-tert-butyl-substituted 12H-dibenzo[d,g][1,3,2]dioxasilocins. The conformations observed in the solid-state X-ray crystal structures of 12H-dibenzo[d,g][1,3,2]dioxasilocins are sensitive to crystal-packing forces and may be different from that in solution.

Steric Consequences on the Conformation of Medium-Sized Rings: Solution NMR, Solid-State Crystallographic, ab Initio Molecular Orbital Calculations, and Molecular Mechanics Studies on Substituted Eight-Membered Organosilicon Ring Systems1

Syntheses of 2-aryloxy/2-chloro ethoxy-2,3-dihydro-5-benzoyl-1H-1,3,2-benzodiaza-phosphole 2-oxides 3a–h were accomplished by reactions of equimolar quantities of 3,4-diaminobenzophenone (1) with various aryl/chloroethoxy phosphorodichloridates 2a–g and 2h in the presence of triethylamine at 50–60°C. Compounds 3i–k were prepared by reacting 3,4-diaminobenzophenone (1) with aryl thiophosphorodichloridates 2i–k under similar conditions. They were characterized by IR, 1H, 13C, and 31P NMR spectral data. Some of these products possessed siginificant antimicrobial activity © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:340–345, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10044

Synthesis of 2‐substituted‐2,3‐dihydro‐5‐benzoyl‐1H‐1,3,2‐benzodiazaphosphole 2‐oxides/sulfides

A new family of phosphorus heterocycles, namely 8-substituted-16H-dinaphtho[2, 1-d: 1′,2′-g]1, 3, 2- dioxaphosphocin 8-oxides, has been obtained via a synthesis from reaction of bis(2-hydroxy-1-naphthyl)methane with a series of aryl phosphorodichloridates in dry benzene in the presence of triethylamine. NMR analysis of a solution of the title compounds revealed essentially no coupling between the bridged methylene protons and the P atom which suggested the dioxaphosphocin ring may exist in a boat conformation in solution. An X-ray diffraction analysis of a crystal of 8-(2′,3′-dimethylphenoxy)- 16H-dinaphtho[2,1-d:1′,2′-g]1,3,2-dioxaphosphocin 8-oxide does indicate that in the solid state the dioxaphosphocin ring is in a distorted and extended boat-like conformation with the P[dbnd]O and bridged CH2 groups directed away from each other. Electron impact mass spectral analysis confirmed the structures of the esters and showed M+, (M — R)+, and (M – OR)+ ions containing the dioxaphosphocin ring system.

SYNTHESIS OF 8-SUBSTITUTED-16H-DINAPHTHO [2,1-d:1′,2′-g] 1, 3, 2-DIOXAPHOSPHOCIN 8-OXIDES

Synthesis of 8-Substituted-16H-dinaphtho(2,1-d:1′,2′-g)1,3,2- dioxaphosphocin 8-Oxides.

Synthesis, NMR (1H, 13C, and 31P), Mass Spectral Studies and Biological Activity of 2-Aryloxy/Alkyl-6-methyl-1,3,2-dioxaphosphorino [5,4-b]pyridine-2-oxides.

M. S. Reddy

Papers

SYNTHESIS OF 8-SUBSTITUTED-16H-DINAPHTHO [2,1-d:1′,2′-g] 1, 3, 2-DIOXAPHOSPHOCIN 8-OXIDES

Synthesis of 8-Substituted-16H-dinaphtho(2,1-d:1′,2′-g)1,3,2- dioxaphosphocin 8-Oxides.

Synthesis, NMR (1H, 13C, and 31P), Mass Spectral Studies and Biological Activity of 2-Aryloxy/Alkyl-6-methyl-1,3,2-dioxaphosphorino [5,4-b]pyridine-2-oxides.