Difference between revisions of "Hydrazone"
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The direct reaction cannot be used with [[hydrazine]] itself, as the hydrazone that is initially formed will react with a second equivalent of the carbonyl compound to form an [[azine]]. However the azine can be isolated, and then reacted with excess hydrazine to reform the hydrazone.<ref name="acetone">{{OrgSynth | first1 = A. C. | last1 = Day | first2 = M. C. | last2 = Whiting | title = Acetone hydrazone | collvol = 6 | collvolpages = 10 | volume = 50 | pages =3 | year = 1970 | prep = cv6p0010}}.</ref><ref name="Ber">{{citation | first1 = H. | last1 = Staudinger | first2 = Alice | last2 = Gaule | title = Vergleich der Stickstoff-Abspaltung bei verschiedenen aliphatischen Diazoverbindungen | journal = Ber. Dtsch. Chem. Ges. | year = 1916 | volume = 49 | issue = 2 | pages = 1897–1918 | doi = 10.1002/cber.19160490245}}.</ref> | The direct reaction cannot be used with [[hydrazine]] itself, as the hydrazone that is initially formed will react with a second equivalent of the carbonyl compound to form an [[azine]]. However the azine can be isolated, and then reacted with excess hydrazine to reform the hydrazone.<ref name="acetone">{{OrgSynth | first1 = A. C. | last1 = Day | first2 = M. C. | last2 = Whiting | title = Acetone hydrazone | collvol = 6 | collvolpages = 10 | volume = 50 | pages =3 | year = 1970 | prep = cv6p0010}}.</ref><ref name="Ber">{{citation | first1 = H. | last1 = Staudinger | first2 = Alice | last2 = Gaule | title = Vergleich der Stickstoff-Abspaltung bei verschiedenen aliphatischen Diazoverbindungen | journal = Ber. Dtsch. Chem. Ges. | year = 1916 | volume = 49 | issue = 2 | pages = 1897–1918 | doi = 10.1002/cber.19160490245}}.</ref> | ||
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| + | ==Reactions and uses== | ||
| + | Hydrazones can be [[Hydrolysis|hydrolysed]] to the corresponding carbonyl compounds: the reaction is usually endothermic and is [[Acid catalysis|acid-catalyzed]]. An excess of acid is often used to remove the hydrazine as a hydrazonium salt. | ||
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| + | The 1-aminopyrrolidine derivatives RAMP and SAMP<ref>{{OrgSynth | first1 = Dieter | last1 = Enders | first2 = Peter | last2 = Fey | first3 = Helmut | last3 = Kipphardt | title = (''S'')-(−)-1-Amino-2-methoxymethylpyrrolidine (SAMP) and (''R'')-(+)-1-amino-2-methoxymethylpyrrolidine (RAMP), versatile chiral auxiliaries | collvol = 8 | collvolpages = 26 | volume = 65 | pages = 173 | year = 1987 | prep = cv8p0026}}.</ref> are [[Chiral auxilairy|chiral auxiliaries]] that function by forming hydrazones with carbonyl groups in the compound to be derivatized.<ref>{{OrgSynth | first1 = Dieter | last1 = Enders | first2 = Helmut | last2 = Kipphardt | first3 = Peter | last3 = Fey | title = Asymmetric syntheses using the SAMP-/RAMP-hydrazone method: (''S'')-(+)-4-methyl-3-heptanone | collvol = 8 | collvolpages = 403 | volume = 65 | pages = 183 | year = 1987 | prep = CV8P0403}}.</ref> | ||
==Notes and references== | ==Notes and references== | ||
Revision as of 19:11, 19 September 2010
Hydrazones are a functional class of organic compounds formed by the condensation reaction of hydrazine (or, more usually, an N-substituted hydrazine) with an aldehyde or a ketone.[1][2]
Preparation
Substituted hydrazines will react directly with carbonyl compounds to form the corresponding hydrazone.[3] The reaction follows the normal addition–elimination mechanism for reactions at carbonyl carbon, and is acid-catalyzed.
The direct reaction cannot be used with hydrazine itself, as the hydrazone that is initially formed will react with a second equivalent of the carbonyl compound to form an azine. However the azine can be isolated, and then reacted with excess hydrazine to reform the hydrazone.[4][5]
Reactions and uses
Hydrazones can be hydrolysed to the corresponding carbonyl compounds: the reaction is usually endothermic and is acid-catalyzed. An excess of acid is often used to remove the hydrazine as a hydrazonium salt.
The 1-aminopyrrolidine derivatives RAMP and SAMP[6] are chiral auxiliaries that function by forming hydrazones with carbonyl groups in the compound to be derivatized.[7]
Notes and references
Notes
References
- ↑ Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995). Pure Appl. Chem. 1995, 67 (8-9), 1307–75 at 1341. DOI: 10.1351/pac199567081307.
- ↑ hydrazones, <http://goldbook.iupac.org/H02884.html> (accessed 20 September 2010), Compendium of Chemical Terminology Internet edition; International Union of Pure and Applied Chemistry (IUPAC).
- ↑ Stork, G.; Benaim, J. Monoalkylation of α,β-Unsaturated Ketones via Metalloenamines: 1-butyl-10-methyl-Δ1(9)-2-octalone. Org. Synth. 1977, 57, 69, <http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0242>; Coll. Vol., 6, 242.
- ↑ Day, A. C.; Whiting, M. C. Acetone hydrazone. Org. Synth. 1970, 50, 3, <http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0010>; Coll. Vol., 6, 10.
- ↑ Staudinger, H.; Gaule, Alice Vergleich der Stickstoff-Abspaltung bei verschiedenen aliphatischen Diazoverbindungen. Ber. Dtsch. Chem. Ges. 1916, 49 (2), 1897–1918. DOI: 10.1002/cber.19160490245.
- ↑ Enders, Dieter; Fey, Peter; Kipphardt, Helmut (S)-(−)-1-Amino-2-methoxymethylpyrrolidine (SAMP) and (R)-(+)-1-amino-2-methoxymethylpyrrolidine (RAMP), versatile chiral auxiliaries. Org. Synth. 1987, 65, 173, <http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv8p0026>; Coll. Vol., 8, 26.
- ↑ Enders, Dieter; Kipphardt, Helmut; Fey, Peter Asymmetric syntheses using the SAMP-/RAMP-hydrazone method: (S)-(+)-4-methyl-3-heptanone. Org. Synth. 1987, 65, 183, <http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV8P0403>; Coll. Vol., 8, 403.
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