Hydrazides in organic chemistry are a class of organic compounds with the formula R−NR1−NR2R3 where R is acyl (R'−C(=O)−), sulfonyl (R'−S(=O)2), phosphoryl ((R'−)2P(=O)−), phosphonyl ((R'−O−)2P(=O)−) and similar groups (chalcogen analogs are included, for example sulfur analogs called thiohydrazides),[1] R1, R2, R3 and R' are any groups (typically hydrogen or organyl).[2] Unlike hydrazine and alkylhydrazines, hydrazides are nonbasic owing to the inductive influence of the acyl, sulfonyl, or phosphoryl substituent.

Sulfonyl hydrazides edit

A common sulfonyl hydrazide is p-toluenesulfonyl hydrazide, a white air-stable solid. They are also widely used as organic reagents.

Toluenesulfonyl hydrazide is used to generate toluenesulfonyl hydrazones. When derived from ketones, these hydrazones participate in the Shapiro reaction[3] and the Eschenmoser–Tanabe fragmentation.[4][5]

2,4,6-Triisopropylbenzenesulfonylhydrazide is a useful source of diimide.[6]

Acyl hydrazides edit

 
An example of an acylhydrazine. This compound has been called acetylhydrazide, acetohydrazide, or acetic acid hydrazide.[7]

Acylhydrazines are derivatives of carboxylic acids, although they are typically prepared by the reaction of esters with hydrazine:[8]

Use edit

An applied example is a synthesis of sunitinib begins by mixing 5-fluoroisatin slowly into hydrazine hydrate.[9] After 4 hours at 110 °C, the indole ring structure has been broken into (2-amino-5-fluoro-phenyl)-acetic acid hydrazide with reduction of the ketone at the 3-position. Subsequent annelation in strong acid creates the 1,3-dihydro-2-oxo indole structure required for the drug.

See also edit

References edit

  1. ^ "Search". chem-space.com. Retrieved 24 May 2023. (subscription required)
  2. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "Hydrazides". doi:10.1351/goldbook.H02879
  3. ^ Shapiro, Robert H. (1976). "Alkenes from Tosylhydrazones". Org. React. 23 (3): 405–507. doi:10.1002/0471264180.or023.03. ISBN 0471264180.
  4. ^ Schreiber, J.; Felix, D.; Eschenmoser, A.; Winter, M.; Gautschi, F.; Schulte-Elte, K. H.; Sundt, E.; Ohloff, G.; Kalovoda, J.; Kaufmann, H.; Wieland, P.; Anner, G. (1967). "Die Synthese von Acetylen-carbonyl-Verbindungen durch Fragmentierung von α-β-Epoxy-ketonen mit p-Toluolsulfonylhydrazin. Vorläufige Mitteilung". Helv. Chim. Acta (in German). 50 (7): 2101–2108. doi:10.1002/hlca.19670500747.
  5. ^ Tanabe, Masato; Crowe, David F.; Dehn, Robert L. (1967). "A novel fragmentation reaction of α,β-epoxyketones the synthesis of acetylenic ketones". Tetrahedron Lett. 8 (40): 3943–3946. doi:10.1016/S0040-4039(01)89757-4.
  6. ^ Chamberlin, A. Richard; Sheppeck, James E.; Somoza, Alvaro (2008). "2,4,6-Triisopropylbenzenesulfonylhydrazide". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rt259.pub2. ISBN 978-0471936237.
  7. ^ "ChemicalBook:2-(4-ethylphenoxy)acetylhydrazide". Retrieved 24 May 2023.
  8. ^ Schirmann, Jean-Pierre; Bourdauducq, Paul (2001). "Hydrazine". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_177. ISBN 978-3527306732.
  9. ^ "US patent 6573293". Archived from the original on 2012-09-06.