Diphenyl phosphine oxides

Kvl.5 In human atria, the Kvl.5 presents the ultrarapid delayed rectifier that contributes to the repolarization in the early phase of cardiac action potential. Selective blockers of Kvl.5 channels could be potentially beneficial in the treatment of atrial fibrillation because blocking Kvl. 5 could delay repolarization and prolong refractoriness selectively in cardiac myocytes. Examples for Kvl.5 blockers include AVE0118, S9947, and analogs of diphenyl phosphine oxide (DPO). 

D. Miscellaneous.—A further study of the reactions of diphenyl-phosphine oxide with tetracyclone has confirmed that the reaction yields the oxide (30) under mild, basic conditions, and that the reaction is thermally reversible. The displacement of halogen from phosphorus by amino-compounds has been used in the synthesis of a number of aminofluoro-phosphine oxides (31), and of A-methyl-AA-bis(dichlorophosphinyl)-amine (32). ... 

The different products obtained from the analogous reaction of diphenyl-phosphine oxide are explained in terms of the hardness of nucleophilic centres involved. Similar reactions with 2-methyl-3,4,5-triphenylcyclo-pentadienone gave the phosphonate (39). Gallagher and Jenkins have... 

Similarly, monobasic forms of other trivalent phosphorus species have been used successfully in such conjugate addition processes, including monoesters of phosphonous acids375 425 426 and secondary phosphine oxides.427-429 The notable exception to the last of these species is the addition of the anion from diphenyl phosphine oxide to unsaturated aldehydes, which appears always to proceed by addition to the carbonyl carbon.427... 

Scheme 7.8 Formation of a7l(diphenyl)phosphine oxide from propargylic alcohol and diphenylphosphine oxide.

Cyclohexene annelation.1 Reaction of ketone enolates with 2 equiv. of this salt results in two sequential Michael reactions to give a cyclohex-enyl(triphenyl)phosphonium bromide, which can be hydrolyzed to a cyclohex-enyl(diphenyl)phosphine oxide.1... 

While studying the conversion of the adducts, obtained from aldehydes, it was discovered that upon thermolysis they lose diphenyl-phosphine oxide (Ph2P0H) to form a-aminomethyl ketones 7. The overall reaction thus results in a-aminomethylation of the parent al-... 

Diphenyl phosphine oxide (4), generated for the first time photochemically in yields up to 59%, adds in situ to various carbonyl compounds (e.g. formation of 5, 6 and 9 by 1.2- or 1.4-additions, respectively). 

WITTIG-HORNER REAGENTS Carbome-thoxyethyl(diphenyl)phosphine oxide. Die-thoxymethyldiphenyl phosphine oxide. Diethyl [(2-tetrahydropyranyloxy)-methyl -phosphonate. Methyl bis(trifluoroethyl)-phosphonoacetate. N-Morpholinodiphenyl-phosphine oxide. Triethylphosphonoace-tate. 

Carbomethoxyethyl(diphenyl)phosphine oxide, (C6H5)2PCH (1). The... 

WITTIG-HORNER REAGENTS Diethyl 2,2-dichloro-l-ethoxyvinyl phosphate. Diethyl methoxyefhoxymethylphos-phonate. Dimethyl 3-bromo-2-ethoxy-propenylphosphonate. Methoxymethyl-(diphenyl)phosphine oxide. 

Table 2. Allcnyl(diphenyl)phosphine Oxides from 1-(1-Alkynyl)cyclohexanols and Chlorodiphenylphosphine...

Warren and co-workers reported that DBU did not influence the formation of olefin from eryi/jro-(2-hydroxyl-l-methyl-2-phenylethyl)diphenyl-phosphine oxide (215) in dimethylformamide (84JCS(P 1)243). 

The total synthesis of amaryllidaceae alkaloid buflavin was achieved in the laboratory of A. Couture by utilizing a Horner-Wittig reaction between a biaryl aldehyde and a metalated carbamate. The diphenyl phosphine oxide carbamate was deprotonated with n-BuLi. To the resulting metalated carbamate was added the solution of the biaryl aldehyde in THF. The reaction afforded the corresponding (Z)- and ( )-enecarbamates in good yield and with high -selectivity. 

Simple, but potentially useful, alkoxymethyl(diphenyl)phosphine oxides (6) are produced in good yields from benzene. A series of diphenylphosphinoyl acetals (7) has been prepared, and their n.m.r. spectra have been described. ... 

Addition of chlorodiphenylphosphine to aldehydes in the presence of carboxylic acids or of aqueous acids has long been used as a preparative route to a-hydroxyalkyl-(diphenyl)phosphine oxides (15). A re-examination of this reaction, using benzalde-hyde and acetic acid, has revealed that although (15 R = Ph) is the initial product, the final products are the acetate (16) and the bis-ether (17). It seems that (17) was first isolated by Conant and his colleagues, but that the analytical methods of fifty years ago failed to distinguish (15) from (17). 

Other reactions of allyl- and vinyl-phosphine oxides include a detailed study of their intermolecular cyclization by a Friedel-Crafts-type procedure. In certain cases, the unsaturated oxides are generated in situ from /S-hydroxyalkyl(diphenyl)-phosphine oxides. Examples are given in Scheme 12 for the oxides (54)—(56). Control of double-bond position in the products of acid treatment of the oxides (57) has been achieved by using an organosilicon substituent. Thus simple alkyl... 

Structural and Physical Aspects. - The stability of the various conformers of the phosphines oxides (269)- 211) has received theoretical consideration. A new triclinic polymorph of triphenylphosphine sulfide has been structurally characterised, together with a related triclinic polymorph of triphenylphos-phine. Two reports of the solid state crystal structure of the phenolic phosphine oxide (272) have appeared. A crystallographic study has confirmed that the product of electrochemical oxidation of o-diphenylphosphinoben-zenethiol is the disulfide-bridged bis(phosphine oxide) (273). Solid-state structural studies of the dioxides (274), the (i )-(-I-)-isomer of (275), 1-hexynyl(diphenyl)phosphine oxide,tribenzylphosphine oxide, and tris(t-butyl)phosphine selenide," have also been reported. 

Regitz and Maas (1986, Table 14.5) give 23 further examples of diazomethyl alkylation with aldehydes and ketones. A potential difficulty may be the dimerization of diazocarbonyl and related compounds in the presence of alkali hydroxides, by which l,4-dihydro-l,2,4,5-tetrazines are formed (see the discussion in Sect. 9.2). We know, however, of only one case in which this reaction interfered (Disterdorf and Regitz, 1976 diazomethyl(diphenyl)phosphine oxide, (H5C6)2P(0) —CH=N2). 

For 1,3,5-trithiane, reactions of the substituents attached to the heterocyclic ring system have been published. 2-Chloro-l,3,5-trithiane 174 reacts with isopropyl diphenyl phosphine oxide to yield the corresponding phosphine oxides 175, which were easily converted into the thiophosphoryl analogs 176 upon treatment with phosphorus pentasulfide (Scheme 46) <1987PAC983>. While the position of the phosphoryl group in the 1,3,5-trithiane 175 is exclusively axial, the thiophosphoryl derivative exists in solution as a mixture of axial and equatorial conformers. Furthermore, 2,4,6-tri(2-chloroethyl)-1,3,5-trithiane reacts with sodium diphenylarsenide in liquid ammonia to yield... 

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