関: HEMPA、HMPA

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/10/15 10:19:15」(JST)

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Hexamethylphosphoramide, often abbreviated HMPA, is a phosphoramide (i.e. an amide of phosphoric acid) having the formula [(CH₃)₂N]₃PO. This colorless liquid is a useful polar aprotic solvent and additive in organic synthesis.

Structure and reactivity

HMPA is the oxide of the highly basic tertiary phosphine hexamethylphosphorous triamide (HMPT), P(NMe₂)₃. Like other phosphine oxides (e.g., triphenylphosphine oxide), the molecule has a tetrahedral core and a P-O bond that is highly polarized, with significant negative charge residing on the oxygen atom.

Compounds containing a nitrogen-phosphorus bond typically are degraded by hydrochloric acid to form a protonated amine and phosphate.

Applications

HMPA is a speciality solvent for polymers, gases, and organometallic compounds. It improves the selectivity of lithiation reactions by breaking up the oligomers of lithium bases such as butyllithium. Because HMPA selectively solvates cations, it accelerates otherwise S_N2 reactions by generating more "naked" anions. The basic oxygen centers in HMPA coordinate strongly to Li⁺.^[2]

HMPA is a ligand in the useful reagents based on molybdenum peroxide complexes, e.g., MoO(O₂)₂(HMPA)(H₂O) is used as an oxidant in organic synthesis.^[3]

Alternative reagents

Dimethyl sulfoxide can often be used in place of HMPA as a solvent. Both are strong hydrogen bond acceptors, and their oxygen atoms bind metal cations. Other alternatives to HMPA include the tetraalkylureas^[4] and the cyclic alkylureas like DMPU.^[5]

Toxicity

HMPA is only mildly toxic but has been shown to cause nasal cancers in rats.^[2] Still, many organic chemists regard HMPA as an exceptionally hazardous molecule due to its known carcinogenicity, and avoid its use when possible. HMPA can be degraded to less toxic compounds by the action of hydrochloric acid. For laboratory uses it can be substituted by the less carcinogenic solvent DMI.^[6]

References

^ Haynes, William M. (2010). Handbook of Chemistry and Physics (91 ed.). Boca Raton, Florida: CRC Press. p. 3-280. ISBN 978-1439820773.
^ ^a ^b Dykstra, R. R. (2001). "Hexamethylphosphoric Triamide". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.rh020.
^ Dickman, Michael H.; Pope, Michael T. "Peroxo and Superoxo Complexes of Chromium, Molybdenum, and Tungsten" Chemical Reviews,1994, vol. 94, pp. 569-84. doi:10.1021/cr00027a002
^ Beck, A. K.; Seebach, D. (2001). "N,N'-Dimethylpropyleneurea". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.rd366.
^ Mukhopadhyay, T.; Seebach, D. (1982). "Substitution of HMPT by the Cyclic Urea DMPU as a Cosolvent for highly Reactive Nucleophiles and Bases". Helvetica Chimica Acta 65 (1): 385–391. doi:10.1002/hlca.19820650141.
^ Lo, C. C.; Chao, P. M. (1992). "Replacement of Carcinogenic Solvent HMPA by DMI in Insect Sex Pheromone Synthesis" (pdf). Journal of Chemical Ecology 18 (2): 3245–3253. doi:10.1007/BF00982095.

External links

"Hexamethylphosphoramide CAS No. 680-31-9" (pdf). Report on Carcinogens, Twelfth Edition. National Toxicology Program, Department of Health and Human Services. 2011.
"Hexamethyl phosphoramide". NIOSH Pocket Guide to Chemical Hazards. Centers for Disease Control and Prevention, Department of Health and Human Services. 2011.
Merck Index, 12th Edition, 4761.

English Journal

Lithium Pinacolone Enolate Solvated by Hexamethylphosphoramide.

Guang J1, Liu QP1, Hopson R1, Williard PG1.
Journal of the American Chemical Society.J Am Chem Soc.2015 Jun 17;137(23):7347-56. doi: 10.1021/jacs.5b01906. Epub 2015 May 15.
We report the crystal structure of a substoichiometric, HMPA-trisolvated lithium pinacolone enolate tetramer (LiOPin)4·HMPA3 abbreviated as T3. In this tetramer one HMPA binds to lithium more strongly than the other two causing a reduction in spatial symmetry with corresponding loss of C3 symmetry.
PMID 25933508

Indole synthesis from N-allenyl-2-iodoanilines under mild conditions mediated by samarium(II) diiodide.

Iwasaki H1, Suzuki K, Yamane M, Yoshida S, Kojima N, Ozeki M, Yamashita M.
Organic & biomolecular chemistry.Org Biomol Chem.2014 Sep 21;12(35):6812-5. doi: 10.1039/c4ob01164c.
A novel method for indole skeleton synthesis under mild conditions mediated by samarium(ii) diiodide has been developed. The reaction of N-allenyl-2-iodoaniline derivatives with SmI2 in the presence of HMPA and i-PrOH at 0 °C afforded indole derivatives in high yields.
PMID 25072695

Phycocyanobilin in solution--a solvent triggered molecular switch.

Watermann T1, Elgabarty H, Sebastiani D.
Physical chemistry chemical physics : PCCP.Phys Chem Chem Phys.2014 Apr 7;16(13):6146-52. doi: 10.1039/c3cp54307b.
We present a computational investigation of the conformational response of phycocyanobilin (PCB) to the ability of solvents to form hydrogen bonds. PCB is the chromophore of several proteins in light harvesting complexes. We determine the conformational distributions in different solvents (methanol
PMID 24561966

Japanese Journal

Effect of a combination of hexamethylphosphoramide and alkyl alcohol on the stereospecificity of radical polymerization of N-isopropylacrylamide

POLYMER 52(3), 629-634, 2011
NAID 80021639039

Caffeic Acid Phenethyl Ester(CAPE) : Synthesis and X-Ray Crystallographic Analysis

Chemical & pharmaceutical bulletin 49(2), 236-238, 2001-02-01
NAID 110003615879

高配位シリカートを経由する不斉Lewis塩基触媒反応

有機合成化学協会誌 58(9), 839-847, 2000-09-01
NAID 10008821576

「ヘキサメチルリン酸トリアミド」

Hexamethylphosphoramide
	IUPAC name Hexamethylphosphoramide
	Preferred IUPAC name Hexamethylphosphoric triamide
	Other names Hexametapol; HMPA
Identifiers
CAS number	680-31-9
PubChem	12679
ChemSpider	12158
KEGG	C19250
ChEBI	CHEBI:24565
Jmol-3D images	Image 1
	SMILES O=P(N(C)C)(N(C)C)N(C)C ;
	InChI InChI=1S/C6H18N3OP/c1-7(2)11(10,8(3)4)9(5)6/h1-6H3 ; Key: GNOIPBMMFNIUFM-UHFFFAOYSA-N InChI=1/C6H18N3OP/c1-7(2)11(10,8(3)4)9(5)6/h1-6H3; Key: GNOIPBMMFNIUFM-UHFFFAOYAP ;
Properties
Molecular formula	C6H18N3OP
Molar mass	179.20 g mol−1
Density	1.03 g/cm3
Melting point	7.20 °C (44.96 °F; 280.35 K)
Boiling point	232.5 °C (450.5 °F; 505.6 K) CRC
Hazards
MSDS	Oxford MSDS
EU classification	Xn
Flash point	104.4 °C (219.9 °F; 377.5 K)
	Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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	Infobox references

　　[★]

英: hexamethylphosphoramide、HMPA、HEMPA
関: ヘムパ、ヘキサメチルホスホラミド

「HEMPA」

　　[★]

ヘキサメチルリン酸トリアミド、ヘムパ

関: hexamethylphosphoramide、HMPA

「ヘキサメチルホスホラミド」

　　[★]

英: hexamethylphosphoramide
関: ヘムパ、ヘキサメチルリン酸トリアミド

「HMPA」

　　[★]

ヘキサメチルリン酸トリアミド

関: HEMPA、hexamethylphosphoramide

[1] Haynes, William M. (2010). Handbook of Chemistry and Physics (91 ed.). Boca Raton, Florida: CRC Press. p. 3-280. ISBN 978-1439820773.

[Dykstra-2] Dykstra, R. R. (2001). "Hexamethylphosphoric Triamide". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.rh020.

[3] Dickman, Michael H.; Pope, Michael T. "Peroxo and Superoxo Complexes of Chromium, Molybdenum, and Tungsten" Chemical Reviews,1994, vol. 94, pp. 569-84. doi:10.1021/cr00027a002

[4] Beck, A. K.; Seebach, D. (2001). "N,N'-Dimethylpropyleneurea". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.rd366.

[5] Mukhopadhyay, T.; Seebach, D. (1982). "Substitution of HMPT by the Cyclic Urea DMPU as a Cosolvent for highly Reactive Nucleophiles and Bases". Helvetica Chimica Acta 65 (1): 385–391. doi:10.1002/hlca.19820650141.

[6] Lo, C. C.; Chao, P. M. (1992). "Replacement of Carcinogenic Solvent HMPA by DMI in Insect Sex Pheromone Synthesis" (pdf). Journal of Chemical Ecology 18 (2): 3245–3253. doi:10.1007/BF00982095.

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hexamethylphosphoramide