72284-72-1

Basic information

• Product Name: 2-Cyclobuten-1-one, 4,4-dichloro-2,3-dimethyl-
• Synonyms: 2-Cyclobuten-1-one, 4,4-dichloro-2,3-dimethyl-
• CAS NO: 72284-72-1
• Molecular Formula: C₆H₆Cl₂O
• Molecular Weight: 0
• Mol File: 72284-72-1.mol
• Article Data: 3

Chemical Properties

• Appearance: /
• CAS DataBase Reference: 2-Cyclobuten-1-one, 4,4-dichloro-2,3-dimethyl-(CAS DataBase Reference)
• NIST Chemistry Reference: 2-Cyclobuten-1-one, 4,4-dichloro-2,3-dimethyl-(72284-72-1)
• EPA Substance Registry System: 2-Cyclobuten-1-one, 4,4-dichloro-2,3-dimethyl-(72284-72-1)

Safety Data

• Hazardous Substances Data: 72284-72-1(Hazardous Substances Data)

Upstream product

• 110655-89-5 2,4-dichloro-3,4-dimethylcyclobut-2-enone 
• 503-17-3 dimethylacetylene 
• 76-02-8 trifluoroacetyl chloride 
• 91359-03-4 2,2-Dichloro-3,4-dimethyl-3-phenylsulfanyl-cyclobutanone 

Downstream Products

• 1121-15-9 3,4-dimethylcyclobut-3-ene-1,2-dione 
• 91359-07-8 2-Chloro-3,4-dimethyl-4-phenylsulfanyl-cyclobut-2-enone 

Relevant articles and documents

Cyclobut-2-enones from Alkynes via Dichlorocyclobut-2-enones

The -cycloaddition of dichloroketene (prepared in situ from CCl3COCl and Zn(Cu)) with three alkynes 1a-c to form 2,3-dimethyl- (2a), 2,3-diethyl- (2b) and 3-butyl-4,4-dichlorocyclobut-2-enone (2c) proceeds rapidly in the absence of POCl3.The primary products 2a-c rearrange in situ to the 2,4-dichlorocyclobut-2-enones 3a-c under the influence of ZnCl2 produced during the reaction.ZnCl2 converts both 2a and 3a into a 4:6 equlibrium mixture of the two; this isomerization does not occur with LiCl.The Cl-atoms of both 2a,b and 3a,b and of 2c may reductively be removed with Zn(Cu) in AcOH/pyridine to afford the alkylcyclobutenones 4a-c.Without pyridine, this reduction gives ca. 1:1 mixtures of the double-bond isomers 4 and 5 in low yields.The cyclobutenones 2c and 4c may be deuterated by CD3COOD in the presence of pyridine.D-Atom is introduced into 2c at C(4) and at C(γ), and into 4c at C(2) and C(4).A mechanism for this deuteration is considered, which does not involve a cyclobutadienolate 7, but rather a cyclobutenolate of type 8.The reductions of 2 and 3 to 4 might also pass through the same type of intermediate 8.

Synthesis, Regiochemistry, and Reactions of Dichlorocyclobutenones

Dichlorocyclobutenones previously obtained only with difficulty were prepared by the cycloaddition of dichloroketene with alkynes in the presence of phosphorus oxychloride in fair to good yields.The regiochemistry of addition can be rationalized on the ba