Colorimetric Estimation of Dialkyl Phosphites in Presence of Trialkyl Phosphites, Phosphates, and Phosphonates

1956 ◽  
Vol 28 (12) ◽  
pp. 1968-1970
Author(s):  
Samuel. Sass ◽  
James. Cassidy
Keyword(s):  
Trialkyl Phosphites ◽  
Dialkyl Phosphites ◽  
Colorimetric Estimation

scholarly journals Organophosphorus Chemistry, 18

1990 ◽  
Vol 45 (7) ◽  
pp. 1027-1031 ◽  
Author(s):  
W. M. Abdou ◽  
H. A. Abd El Monem ◽  
M. R. Mahran
Keyword(s):  
New Products ◽  
The Other ◽  
Spectroscopic Measurements ◽  
Other Hand ◽  
Trialkyl Phosphites ◽  
Dialkyl Phosphites ◽  
Organophosphorus Chemistry

Trialkyl phosphites (2a—c) react with 1,8-naphthosultam (6) to give the respective N-alkylated products 7 a—c. Compounds 7a—c were also prepared by the action of dialkyl phosphites on 6 in the presence of p-TsOH. Moreover, 7 a could be obtained by treating 6 with DMMP (8). On the other hand, chlorinated phosphorus reagents (11) condense with 6 to give products of type 12. Structures of the new products were assigned according to consistent analytical and spectroscopic measurements.

Friedel-Crafts Alkylation of Aromatic Compounds with Phosphorus Esters

1972 ◽  
Vol 27 (11) ◽  
pp. 1339-1348 ◽  
Author(s):  
G. Sosnovsky ◽  
M. W. Shende
Keyword(s):  
Aluminum Chloride ◽  
Aromatic Compounds ◽  
Heterogeneous Reaction ◽  
Isomer Distribution ◽  
Aromatic Substrates ◽  
Trialkyl Phosphates ◽  
Strong Lewis Acid ◽  
Trialkyl Phosphites ◽  
Dialkyl Phosphites ◽  
Heterogeneous Reaction Conditions

The alkylations of aromatic compounds with trialkyl phosphites (1), dialkyl phosphites (2), and trialkyl phosphates (3) in the presence of aluminum chloride were studied involving several raction variables, such as time, ratio of reactants, nature of catalyst and solvent, and combinations thereof. Extensive disproportionation and isomerization were observed in the reaction with monosubstituted alkylbenzenes under heterogeneous reaction conditions obtained by the use of an excess of aromatic substrates. A combination of aluminum chloride—nitromethane complex and dichloromethane as solvent was used to eliminate these undesirable effects and to give homogeneous and practically non-isomerizing conditions. The scope of the reaction was studied with a number of aromatic substrates, and their relative reactivities were compared to that of benzene in competitive isopropylations with triisopropyl phosphite. The relative rates and isomer distributions showed low substrate and low positional selectivities and poor agreement with Brown’s selectivity relationship. The substrate selectivity was somewhat higher and the positional selectivities were somewhat lower than those obtained in competitive isopropylation reactions with other isopropylating agents. The selectivity factor, Sf, and partial rate factors were calculated. An electrophilic alkylation mechanism is proposed on the basis of (1) the relative rates of isopropylation, (2) the isomer distribution of dialkylated aromatics, and (3) the necessity of a strong Lewis acid in these reactions.

DIAMAGNETIC SUSCEPTIBILITIES OF SOME COMPOUNDS CONTAINING OXYGEN LINKED TO NITROGEN OR PHOSPHORUS

1964 ◽  
Vol 42 (8) ◽  
pp. 1817-1821 ◽  
Author(s):  
M. W. Lister ◽  
R. Marson
Keyword(s):  
Amine Oxide ◽  
Phosphine Oxides ◽  
Trialkyl Phosphates ◽  
Trialkyl Phosphites ◽  
Dialkyl Phosphites ◽  
Carboxylic Esters ◽  
Usual Formula ◽  
Extra Oxygen ◽  
Oxygen Atoms

The diamagnetic susceptibilities of a number of compounds containing oxygen linked to nitrogen or phosphorus have been measured. The results are interpreted in terms of the apparent contribution of the oxygen atoms to the susceptibility in these and other series of compounds, and are compared with other evidence on the nature of the bonds to oxygen. The results support the usual formula of an amine oxide as R3N → O, but phosphine oxides behave as would be expected for R3P = O. Phosphorus oxyhalides have molar susceptibilities about 4.6 (in units of −10−6 e.m.u.) larger than the corresponding trihalides, a difference close to that for singly bound oxygen in ethers or alcohols. Each oxygen contributes 4.4 in trialkyl phosphites, as might be expected for P(OR)3; but the value in dialkyl phosphites is 4.9 per oxygen, thereby showing behavior similar to that of carboxylic esters. The extra oxygen in trialkyl phosphates as compared with trialkyl phosphites contributes 9.4, a surprisingly large amount.

Synthesis of Phosphonates, Phosphinates and Tertiary Phosphine Oxides by Pd- or Ni-Catalyzed Microwave-Assisted P–C Coupling Reactions without the Addition of Conventional Ligands

2021 ◽  
Vol 25 ◽  
Author(s):  
Réka Henyecz ◽  
György Keglevich
Keyword(s):  
Tautomeric Form ◽  
Catalyst Precursor ◽  
Coupling Reactions ◽  
Optimum Conditions ◽  
Pd Catalysts ◽  
Catalyst Complex ◽  
Two Factors ◽  
Dialkyl Phosphites ◽  
Catalyst Systems ◽  
P Ligands

Abstract: Microwave (MW)-assistance may be a powerful tool also in the Hirao P–C coupling reactions of vinyl/aryl halides with dialkyl phosphites in the presence of Pd-catalysts/P-ligands elaborated forty years ago. This review surveys the development of this reaction by showing the expansion of the reagents and catalysts, as well as the information accumulated. The stress was laid on the “green” aspects, the simplification of the catalyst systems, and the reliable mechanistic details in order to be able to establish the optimum conditions. The best protocol involves the use of some excess of the >P(O)H reagent to ensure the PdII→Pd0 reduction and, via its trivalent tautomeric form (>POH) also the P-ligand. The overall rate is the result of two factors, the activity of the catalyst complex formed, and the reactivity of the reactants in the P–C coupling reactions. Both components are influenced by the nature of the aryl substituents in Ar2P(O)H. NiII salts may also be used as the catalyst precursor, however, despite the PdII→Pd0→PdII route, in this case, a NiII→NiIV→NiII sequence was proved.

scholarly journals COLORIMETRIC ESTIMATION OF GUANIDINE-LIKE SUBSTANCES IN THE URINE

1937 ◽  
Vol 118 (1) ◽  
pp. 137-145
Author(s):  
Jerome E. Andes ◽  
Victor C. Myers
Keyword(s):  
Colorimetric Estimation

scholarly journals THE COLORIMETRIC ESTIMATION OF CYSTINE AND GLUTATHIONE

1927 ◽  
Vol 72 (1) ◽  
pp. 177-183
Author(s):  
George Hunter ◽  
Blythe Alfred Eagles
Keyword(s):  
Colorimetric Estimation
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