2-cyclopenten-1-one

Structural formula
General
Surname	2-cyclopenten-1-one
other names	Cyclopentenone (ambiguous) 2-cyclopentenone
Molecular formula	C 5 H 6 O
Brief description	light yellow liquid
External identifiers / databases
CAS number 930-30-3 EC number 213-213-0 ECHA InfoCard 100.012.012 PubChem 13588 Wikidata Q2292678
properties
Molar mass	82.10 g mol −1
Physical state	liquid
density	0.98 g cm −3 (25 ° C)
boiling point	64-65 ° C (19 mmHg)
solubility	almost insoluble in water
Refractive index	1.481 (20 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 226 P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

2-Cyclopenten-1-one is a chemical compound from the group of the enones and isomeric to 3-Cyclopenten-1-one .

Occurrence

2-Cyclopenten-1-one occurs naturally as the basic structure in a number of chemical compounds such as jasmine .

Extraction and presentation

In general, cyclopentenones can be synthesized in a number of ways. The most widespread industrial route is the dehydrohalogenation of 2-bromocyclopentanone with lithium carbonate and the Claisen condensation - decarboxylation - isomerization of unsaturated diesters reaction cascade .

Synthesis from cyclopentadiene is also possible , with 1,4-addition with water forming 2-cyclopentenol , which is oxidized to the ketone by aqueous chromic acid .

There are other routes available for the synthesis of substituted cyclopentenones: Nazarov cyclization reaction of divinyl ketones, Saegusa – Ito oxidation of cyclopentanones , ring-closing metathesis of the associated dienes , oxidation of the associated cyclic allyl alcohols and the Pauson-Khand reaction of alkenes , Alkynes and carbon monoxide .

properties

2-Cyclopenten-1-one is a light yellow liquid that is insoluble in water.

use

2-Cyclopenten-1-one can be used to make other chemical compounds (such as cubane ).

Individual evidence

1. ↑ ^{a b c d e f g h} Data sheet 2-Cyclopenten-1-one, 98% from Sigma-Aldrich , accessed on January 6, 2013 ( PDF ).
2. ↑ ^{a b} Data sheet 2-Cyclopenten-1-one (PDF) from Fisher Scientific , accessed on February 13, 2014.
3. ↑ US EP1418166, Daisuke, Fukushima & Hirata Norihiko, "Process for producing 2-bromocyclopentanone", published May 12, 2004
4. ↑ US EP1422212, Liang, Shelue; Andrea Haunert & Sylvia Huber-Dirr et al., "Process for preparing cyclopentenone", published November 25, 2004.
5. ↑ Organic Reactions Portal: Cyclopentenone synthesis