Hexamethylphosphorous amide

HMPT = hexamethylphosphoric triamide (more correct than hexamethylphosphor-amide HMPA). 

In contrast to uridine,389 cytidine does not yield a 5 -chloro-5 -deoxy derivative on reaction with N,N-dimethyl(chlorometh-animinium) chloride instead 2,2 -anhydrocytidine is formed.395 However, thionyl chloride or bromide in hexamethylphosphor-amide at room temperature achieves this selective replacement of the primary hydroxyl group of halogen in cytidine, and also in adenosine, in respective yields of 80 and 75% for the chloro compounds, and 55 and 30% for the bromo analogs.396... 

Concentrated solutions of supporting electrolytes in hexamethylphosphor-amide (HMPA) become very viscous, which causes a twofold increase in resistance over solutions in acetonitrile and dimethylformamide. The increased viscosity may be due to the greater solvation of the cations by the more basic HMPA. 

Reagents. Para-Bis-A polymerization-quality bisphenol-A (Dow Chemical Co.) was recrystallized once from toluene. Pfaltz and Bauer s 4,4 -dichlorodiphenylsulfone was recrystallized three times from ethanol. Reagent phenol (Baker) and 4,4 -biphenol (Eastman s white label) were used as received. Spectroquality methyl sulfoxide, dimethyl acetamide, and dimethylformamide (Matheson, Coleman, and Bell) were used as solvents. 3,5,3, 5 -Tetramethyldiphenoquinone and hexamethylphosphor-amide (Aldrich) were used as received. 

O) 1—benzoyl fluoride 2—nitromethane 3—nitrobenzene 4—benzo-nitrile S—acetonitrile 6—propanediol-1, 2-carbonate 7—ethylene sulfite 8—Water 9—trimethyl phosphate 10—dimethylformamide 11—N, N-di-methylaoetamide 12—dimethyl sulfoxide 13—hexamethylphosphoric amide. 

Pig. 3. Molar conductivities of Sn(CH3)3l (c = 7 x 10" mole/liter) dissolved in nitrobenzene on addition of increasing amounts of various electron pair donor (EPD) solvents. HMPA, hexamethylphosphoric amide DMSO, dimethyl sulfoxide DMF, dimethylformamide TBP, tributyl phosphate THF, tetrahydrofuran AN, acetonitrile. 

EPD solvents do not correctly reflect the ionizing properties of these solvents due to the differences in dielectric constants. Although Sn(CH3)3l is considerably ionized in pure tributylphosphate, the solutions are essentially nonconducting because of the very low dielectric constant e = 6.8 of this medium (see Section IV). Puoss-Krauss analysis of conductance data for Sn(CH3)3l in strong EPD solvents, such as dimethylformamide (DME), dimethyl sulfoxide (DMSO), pyridine, and hexamethylphosphoric amide (HMPA), reveal that the substrate is completely ionized and consequently behaves as a 1 1 electrolyte (33). 

HMPA, hexamethylphosphoric amide, DMSO, dimethyl sulfoxide DMF, dimethylformamide TMP, trimothyl phosphate PDC, propanediol-1,2-carbon-ate. 

Hexadienyl Hexamethylphosphor amide Hexamethylphorous triamide Isopropyl Infrared... 

PyBOP (1 H-benzotriazol-l-yloscy)tripyrrolidino phosphonium hescafluorophosphate HMPA hexamethylphosphor amide rt reflux temperature... 

Once 42 forms, treatment first with Ph3P and then with hexamethylphosphor-amide (HMPA) results in the formation of alkylidene 43 (phosphines are good ligands for electron-deficient Zr(IV) complexes such as 42). First the phosphine binds to Zr, and then HMPA (a highly polar molecule and a Lewis base) attacks A1 (equation 10.14).33 Fragmentation results in formation of the alkylidene and an HMPA-A1 complex. 

Isotactic polystyrene was epimerized to various extents by reaction with KOtBu in hexamethylphosphor-amide solution at 100°. The 13C-NMR spectra of the epimerized samples and of polystyrene in 9 1 trichlorobenzene nitrobenzene-d6 solution at 150° were recorded and analyzed using stereosequence distributions that were calculated for the samples by Monte Carlo simulation of the epimerization process. 

REDUCTION OF ALKYL HALIDES AND TOSYLATES WITH SODIUM CYANOBOROHYDRIDE IN HEXAMETHYLPHOSPHOR-AMIDE (HMPA) A. 1-IODO-DECANE TO n-DECANE B. I-DODECYL TOSYLATE TO n-DODECANE.53,107... 

Mg[CpFe(CO)2]2, Mg[Co(CO)3L]2, and Tl[Co(CO)4] in THF and similar solvents 13). Similarly, the anion [Cr2(CO)10]2-, which contains only terminal carbonyls, forms contact ion pairs with Na+ in THF (17,18). In strong donor solvents such as dimethyl sulfoxide or hexamethylphosphor-amide, the contact ion pair is broken up. As will be described in Section II,B,2, contact ion pairs are seen also in polynuclear carbonyls containing bridging carbonyls, in which case the cation has an affinity for the bridging CO ligand. 

A mixture of N-p-tolyldiphenylacetamide and hexamethylcyclotrisilazane heated 4 hrs. at 240 diphenylacetonitrile. Y 73%. - The dioice of silazanes, chloro-silanes, or alkoxysilanes allows the reaction to be run under mildly basic, acidic, or neutral conditions. If the former reagents are used, the reaction may be followed by NH3- or HCl-liberation respectively. The products can be easily isolated by distillation if volatile or by filtration if solid. F. e., also from unsubst. amides and aldoximes, and f. silicon compds. as reagents, s. W. E. Dennis, J. Org. Chem. 35, 3253 (1970) nitriles from unsubst. amides with hexamethylphosphor-amide s. R. S. Monson and D. N. Priest, Can. J. Chem. 49, 2897 (1971). 

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