Hexamethylphosphoric acid triamide

Another hydro-de-diazoniation method in which the solvent is the reagent is that of dediazoniation in hexamethylphosphoric acid triamide (HMPT) it was discovered by Newman and Hung (1974). The mechanism is discussed in some detail in Section 8.9. We do not recommend it for synthetic purposes, however, as (solid) arenediazonium mercuric bromide complexes are used in all but one case. The authors mention only briefly that 4-toluenediazonium tetrafluorophosphate can also be used. 

Hexamethylphosphoric acid triamide l-t-Butylamino-3-(2-methyl-indole-4-yloxy)-2-propanol Benzoic acid anhydride Tartaric acid... 

M-hexane or hexyl hexaisobutyl alumoxane high-impact polystyrene hexamethylphosphoric acid triamide versatic acid... 

Heating 3-methylene-2,3-dihydrotellurophene at 50° for one hour with a mixture of potassium /er/.-butoxide, hexamethylphosphoric acid triamide, and THF produced 3-methyl tellurophene1. 

Heating 2-carboxytellurophene with hexamethylphosphoric acid triamide at 180° yielded N,N-dimethylaminocarbonyltellurophene3. 

There exists also a synthesis of cyclopentadecanone (VII/81) and ( )-mus-cone, based on a three-carbon annulation of cyclic ketones followed by the regioselective radical cleavage of the zero bridge of the so formed bicyclic system [44], The synthesis of cyclopentadecanone is summarized in Scheme VII/16. The cyclization of VII/78 to the bicyclic alcohol VII/79 proceeds best (94 % yield) with samarium diiodide in the presence of hexamethylphosphoric acid triamide and tetrahydrofuran [45], The oxidative cleavage of VII/79 to the ring expanded product VII/80, was performed by treatment with mercury(II)-oxide and iodine in benzene, followed by irradiation with a 100 Watt high pressure mercury arc. Tributyltinhydride made the de-iodination possible. 

The reaction of HFA with tris(dimethylamino)phosphane leads mainly to the formation of tris(dimethylamino)difluorophosphorane and a smaller amount of hexamethylphosphoric acid triamide, although indirect evidence for the formation of 1,3,2-dioxaphospholanes (Section III,A,4) has been found (277). 

All pentavalent P=0 compounds catalyze this reaction and the order of catalytic activity is phosphine oxide > phosphinate > phosphonate > phosphate. For example, addition of a catalytic amount of hexamethylphosphoric acid triamide inaeases the rate of conversion of phenyl isocyanate to diphenylcarbodiimide. The catalytic conversion of phenyl isocyanate to diphenylcarbodiimide, using isopropylmethylphosphonofluoridate,... 

The prototype of this class, OP(NH2)3, is formed in the reaction of OPCI3 with liquid ammonia orwith gaseous NH3 in trichloromethane solution at low temperature. Substituted phosphoric acid triamides 0=P(NR2)3 are prepared in the reaction of phosphoras oxotrichloride with secondary amines, under heating or in the presence of acid scavengers under milder conditions the mono- and diamido chlorides can be easily obtained (equation 6). Hexamethylphosphoric acid triamide, OP(NMc2)3, an excellent aprotic organic solvent prepared from OPCI3 and dimethylamine, deserves to be mentioned here. ... 

HEXAMETHYLPHOSPHORAMIDE see HEKOOO HEXAMETHYLPHOSPHORIC ACID TRIAMIDE (xMAK) see HEKOOO... 

The absorption peaks ranged from 499 nm for hexafluoroisopropanol (a very strong HBD solvent with high a) to 704 nm for hexamethylphosphoric acid triamide (a very strong EPD solvent with high /S). 

In considering the solvation of charged species by a polar solvent, the polar solvents we considered were hydrogen bond donors (protic polar solvents) such as water and alcohols. Some polar solvents—for example, Ai,77-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and hexamethylphosphoric acid triamide (HMPA)—are not hydrogen bond donors (they are aprotic polar solvents) (Table 10.7). 

The reported synthesis for (5Z,9Z)-14-methylpentadeca-5,9-dienoic acid (14) started with commercially available 4-methylpentan-l-ol, which upon reaction with phosphorous tribromide afforded l-bromo-4-methylpentane [52], Commercially available pent-4-yn-l-ol was also protected as the tetrahydropyranyl ether as shown in Fig. (18). Formation of the lithium acetylide with n-BuLi in THF and subsequent addition of 1-bromo-4-methylpentane in hexamethylphosphoric acid triamide resulted in the isolation of the tetrahydropyranyl protected 9-methyldec-4-yn-l-ol. Hydrogenation of the alkyne with Lindlar s catalyst and quinoline in dry hexane afforded the cis hydropyranyl-protected 9-methyldec-4-en-l-ol. Deprotection of the alcohol with />-toluenesulfonic acid afforded (Z)-9-methyldec-4-en-l-ol. Pyridinium chlorochromate oxidation of the alcohol resulted in the isolation of the labile (Z)-9-methyldec-4-enal. Final Wittig reaction with (4-carboxybutyl) triphenylphosphonium bromide in THF/DMSO resulted in the desired (5Z,9Z)-14-methylpentadeca-5,9-dienoic acid (14). 

Hexamethylphosphoric acid triamide (HMPA) (2.0 equiv) was added. 

Category 1 No substance has yet been included in category 1 Category 2 e.g. Hexamethylphosphoric-acid-triamide, ethylene oxide, ethylen-imine, diethyl sulphate, acrylamide Category 3 e.g. 4,6-Dinitro-o-cresoI... 

Boiling nitrobenzene, benzophenone, diphenyl ether, N-methylpyrrolidinone, tetralin, naphthalene, and hexamethylphosphoric acid triamide... 

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