HMPA hexamethylphosphoramide

Mixtures of products are frequentiy observed. Oxidation by peroxycarboxylic acids usually give similar products (22). Several chemical oxidants give good yields of specific oxidation products. Dimethyl sulfoxide in aqueous acid gives oxindoles (23). In methanol, MoO HMPA (hexamethylphosphoramide) gives 3-hydroxy-2-methoxyindolines (24). 

Several studies have addressed the cubic NLO properties of salts of heteropolymolybdate/ tungstate cluster anions.360,557-561 The tetraanion in a-H4SiW12O40,4HMPA,2H2O (HMPA= hexamethylphosphoramide) has a Keggin structure which has idealized Td point symmetry... 

In the presence of the dioxomolybdenum complex M0O2 (dipic) (HMPA) (dipic = pyridine-2,6-dicarboxylate, HMPA = hexamethylphosphoramide), 2-methylhex-2-ene and phenylhydroxylamine produce the amine 194 in 52% yield other alkenes react analogously199. 

Figure 25 Cyclic voltammograms recorded in solutions of PVF in (a) CH2Cl2 (b) thf (c) hmpa (hexamethylphosphoramide)...

The Reformatsky reactions of ethyl a-bromopropionate and related esters with N-substituted 6-bromo-2-oxochromene-3-carboxamides in a mixed diethyl ether-benzene-HMPA-THF solvent system give substituted 9-bromo-2,3,4,4a,5,10b-hexahydro-l//-chromeno[3,4-f]pyridine-2,4,5-triones (HMPA = hexamethylphosphoramide Scheme 45) <2004RJ0892>. Without the THF present in the mixed-solvent system, the reaction stops at the intermediate Wbenzyl-6-bromo-4-(l-alkoxycarbonylalkyl)-2-oxochroman-3-carboxamide stage. 

Reaction of a purple suspension of TiCl3 in THF with two mol equivalent of HMPA (HMPA = hexamethylphosphoramide) under argon resulted in the formation of a turquoise suspension attributed to TiCl3(HMPA)2. This suspension was stable to argon, but exposure to air or dioxygen caused the formation of a crystalline yellow solid, (9). This contains Ti , and a Raman band at 970 cm-1 is assigned to the O—O stretch.73... 

HMPA hexamethylphosphoramide. This molecule that has been referred to as a potential carcinogenic compound , is now referred to as a useful aprotic solvent cf for instance, Sigma-Aldrich catalogue since edition 2000-2001, p. 921. 

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