Oxirene
Oxirenes are a class of chemical compounds that contain an unsaturated three-membered cycle with an oxygen atom . They belong to the group of heterocycles . Their basic structure is formally derived from cyclopropene , in which a methylene group is replaced by an oxygen atom. Their saturated analogues are the epoxides . Oxiren, as the simplest representative of the oxirenes, is unstable and decomposes at room temperature.
Manufacturing
Oxirenes can be prepared by the reaction of alkynes with peroxycarboxylic acids . This reaction is related to the Prileschajew reaction for the synthesis of epoxides.
Another synthesis starts from ketones which have dibromomethyl radicals in the α position. The dibromomethyl group is first deprotonated by a base , which then attacks nucleophilically on the oxygen atom to form the ring.
Synthesis of oxirenes from dibromomethyl-substituted ketones with sodium methoxide
properties
Oxirenes have high ring tensions and therefore react with electrophiles and nucleophiles with ring opening. The Baeyer stress is mainly responsible for the ring stress .
Reactions
Oxiren can be used to introduce hydroxyethyl residues. Here, organolithium compounds are used as nucleophiles that attack oxirene with ring opening.
Formation of a dihydroxyethyl derivative of anthracene with oxirene
Web links
Individual evidence
- ^ A b V. Franzen: The constitution of the compound C 10 H 18 O obtained from dibutylacetylene and peracetic acid , in: Chem. Ber. 1954 , 87 , 1478-1488.
- ↑ MS Sheela, K. Sreekumar in: Indian J. Chem. Sect. B , 2006 , 45 , 943-950.
- ↑ W. Madelung, ME Oberwegner: Investigations in the series of three- and six-membered cyclic oxido compounds , in: Liebigs Ann. , 1931 , 490 , 201-235.
- ↑ a b D.F. Evans, MW Upton in: J. Chem. Soc., Dalton Trans. , 1985 , 1141-1145.
- ↑ T. Dahlgren, DR Deardorff, AR Martin in: Heterocycles , 1983 , 20 , 641-645.