Hexamethylphosphoric Triamide oxidation

The synthesis of phenoxaphosphine-containing PODs by the cyclodehydration of polyhydra2ides obtained from 2,8-dichloroformyl-lO-phenylphenoxaphosphine-lO-oxide and aUphatic and aromatic dihydra2ides has been described (60). All polymers are soluble in formic acid, y -cresol, and cone H2SO4, but insoluble or partially soluble in ben2ene, chloroform, and hexamethylphosphoric triamide. 

Isoquinoline can be reduced quantitatively over platinum in acidic media to a mixture of i j -decahydroisoquinoline [2744-08-3] and /n j -decahydroisoquinoline [2744-09-4] (32). Hydrogenation with platinum oxide in strong acid, but under mild conditions, selectively reduces the benzene ring and leads to a 90% yield of 5,6,7,8-tetrahydroisoquinoline [36556-06-6] (32,33). Sodium hydride, in dipolar aprotic solvents like hexamethylphosphoric triamide, reduces isoquinoline in quantitative yield to the sodium adduct [81045-34-3] (25) (152). The adduct reacts with acid chlorides or anhydrides to give N-acyl derivatives which are converted to 4-substituted 1,2-dihydroisoquinolines. Sodium borohydride and carboxylic acids combine to provide a one-step reduction—alkylation (35). Sodium cyanoborohydride reduces isoquinoline under similar conditions without N-alkylation to give... 

Bromine or chlorine dissolved in hexamethylphosphoric triamide [680-31-9] (HMPT) with a base, eg, NaH2PO, present, oxidizes primary and secondary alcohols to carbonyl compounds in high yield (38). 

Hexamethylphosphorous triamide general reaction with aromatic and heteroaromatic aldehydes to give diaryl ethylene oxides, 46,... 

Cuprous iodide catalyzes the reaction of various alkyl chlorides, bromides, and iodides in hexamethylphosphoric triamide (HMPT), to give the complexed product RaSnXj, which can then be further alkylated with a Grignard reagent, or can be hydrolyzed to the oxide and converted into various other compounds, R2SnY2 (43). This promises to be a useful laboratory method, e.g.,... 

Transformations of Methyl 5-0-Benzyl-2-0-methyl-/3-I)-glueofuranosidurono-6,3-lae-tone (86) to Dimethyl (Z,E)-2-Methoxy-5-(phenylmethoxy)-2,4-hexadienedioatevl (87). ( Elimination employing DBU b oxidation with silver oxide-sodium hydroxide followed by diazomethane esterification c acidic glycoside cleavage, oxidation by dimethyl sulfoxide-acetic anhydride with formation of 5-0-benzyl-2-0-methyI-D-glucaro-1,4 6,3-dilactone, elimination by using DBU, followed by short treatment with diazomethane d elimination by DBU with subsequent diazomethane esterification e sodium borohydride in hexamethylphosphoric triamide 1 catalytic oxidation followed by short treatment with diazomethane " dimethyl sulfoxide-sulfur trioxide-pyridine-triethylamine.150)... 

The amount of molecular sieves 4 A largely influences the product s ee[11]. Usually 100 mg (for the CMHP oxidation) or 1 g (for the TBHP oxidation) of MS 4A for 1 mmol of substrate is enough however, in the case where chemical yield and/or optical yield are not high, use of excess MS 4A often improves them. The addition of achiral ligands such as tributylphosphine oxide, tri-o-tolyl- and tri-/)-tolylphosphine oxides, hexamethylphosphoric triamide, triphenylpho-sphate, lutidine N-oxide, and l,3-dimethyl-2-imidazolidinone were found to be less effective than that of triphenylphosphine oxide in the epoxidation of chalcone. 

A comparison of the basicities of Group VA element organic derivatives in nitro-methane solution showed that trioctylphosphine oxide (165 R = octyl) is a much weaker base than the corresponding amine oxide or hexamethylphosphoric triamide. 

Next to TBHP also ferf-pentyl hydroperoxide, cumyl hydroperoxide and cyclohexyl hydroperoxide could be employed as oxidant and 2-hydroxycyclobutanone and 2-hydro xycyclododecanone were prepared by this method as well. In 1985, Vedejs and Larsen reported on a preparative method for the a-hydroxylation of camphor and a variety of other ketones utilizing overstoichiometric amounts of oxodiperoxomolybdenum(pyridine)(hexamethylphosphoric triamide) as source of oxygen (equation 67). Yields of products ranged from 34-81% and in some cases also the a-diketone is formed as by-product (0-26%). 

BASF AG CRBPII dba DBN DBU DIBAL-H DMAP DMF DMF-DMA DMPU HMDS HMPA HMPT H-LR LDA LDE LRAT MCPBA MOM NMO NMP PCC PhH = Badische Anilin- Soda Fabrik AG = cellular retinol-binding protein type II r dibenzylideneacetone = 1,5-diazabicyclo[4.3.0]non-5-ene = l,8-diazabicyclo[5.4.0]undec-7-ene = diisobutylaluminium hydride = 4-dimethylaminopyridine = A V-dimethylformamide = A,V-dimethylformamide, dimethylacetal = 1,3 -dimethyl-3,4,5,6-tetrahydro-2( 1H)-pyrimidone = hexamethyldisilazane = hexamethylphosphoramide = hexamethylphosphorous triamide = Hoffmann-La Roche = lithium diisopropylamide = lithium diethylamide = lecithin retinol acyltransferase = m-chloroperbenzoic acid = methoxymethyl = iV-methylmorpholine oxide = l-methyl-2-pyrrolidinone = pyridinium chlorochromate = benzene... 

Trimethylamine N-oxide, 325 Vinyltrimethylsilane, 343 Other reactions (Phenylsulfonyl)allene, 247 Cyclodehydration Diethoxytriphenylphosphorane, 109 Hexamethylphosphoric triamide, 142 Cycloprop anation Simmons-Smith reaction Diiodomethane-Diethylzinc, 276 Simmons-Smith reagent, 275 by other reagents which add CH2 to a carbon-carbon multiple bond Dibromomethane-Zinc-Copper(I) chloride, 93... 

Mercury(II) chloride, 175, 182 Mercury(II) trifluoroacetate, 175 Molybdenum Compounds Molybdenum carbonyl, 194 Molybdenum(VI) oxide, 279 Oxodiperoxymolybdenum(pyridine)-(hexamethylphosphoric triamide),... 

Compounds (p-YC6H4)2SbBr2(acac) (Y = N02, Cl, H, CI[3, CHsO) were prepared from p-YC6H4SbO(OH)2 11, 18h) and p-YC6H4SbCl3(acac) (Y = N()2, H, CH3) were obtained from corresponding stibonic acid (18a, b). HMPA = hexamethylphosphoric triamide DMSO = dimethyl sulfoxide PyO = pyridine iV-oxide 4-CHjPyO = y-picoline JV-oxide TPPO = triphenylphosphine oxide. 

The copolymerisation of propylene oxide and carbon disulphide was carried out with a catalyst consisting of diethylzinc and an electron donor, such as tertiary amine, tertiary phosphine or hexamethylphosphoric triamide, in... 

Dialkyl and diaryl ditellurium compounds are easily reduced to tellurols and tellurolates. Alkali metals in liquid ammonia or in an inert organic solvent, sodium borohydride in methanol, ethanol, alcohol/benzene, THF, DMF, or in a basic aqueous medium, lithium aluminum hydride in dioxane or THF/hexamethylphosphoric triamide, and thiourea dioxide in THF/50% aqueous sodium hydroxide have been used as reducing agents (p. 164). The tellurolates are easily oxidized in air. For this reason they are almost always used in situ. 

Other illustrative examples of carbanionic ion-pair dissociation/aggregation are lithium triphenyhnethide, which exists as a tight ion pair in diethyl ether and as a solvent-separated ion pair in tetrahydrofuran, as shown by UV/Vis spectrophotometric measurements [287], and lithium 10-phenylnonafulvene-10-oxide, which exists as a tight ion pair (2b) in tetrahydrofuran solution and as a solvent-separated ion pair (3b) when hexamethylphosphoric triamide or dimethyl sulfoxide are added ( H and NMR measurements) [288]. 

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