81287-12-9

Upstream product

• 81758-57-8 <(3,4-Dioxo-2-phenylcyclobut-1-enyl)methylen>diacetat 
• 81287-10-7 3-<(E)-Hydroxyiminomethyl>-4-phenyl-3-cyclobuten-1,2-dion 
• 34667-97-5 3-methyl-4-phenylcyclobut-3-ene-1,2-dione 

Downstream Products

• 81287-13-0 4,5-Dimethoxy-2-phenyl-4-cyclopenten-1,3-dion 
• 36394-23-7 4-Hydroxy-5-phenyl-4-cyclopenten-1,2,3-trion 
• 36394-24-8 4-Hydroxy-5-phenyl-4-cyclopenten-1,2,3-trion-hydrat 

Relevant academic research and scientific papers

Reactions with Cyclobutenediones, LXI. Ring Expansions and Conversions of 3-Alkyl-4-phenylcyclobutenediones

In a novel reaction for the cyclobutenedione system, oxidation of the title compounds 1a and 1b leads to ring expansion with formation of cyclopentenetrione 3 and cyclopentenedione 5.The oximes 6a and b, produced by nitrosation of 1a and b, can be hydrolysed to the ring enlarged structures 4d and 5. 4d is oxidized to 3 and methylated to 7.Beckmann-conversion of 6a and b results in the formation of the amide 10 and the amine 11. 6a is acetylated to 13 or dehydrated to the nitrile 14.

Reactions of Cyclobutenediones, LXII. - 3-(α-Bromoalkyl)-4-phenylcyclobutene-1,2-diones

Bromination of 3-alkyl-4-phenylcyclobutene-1,2-dione 1a-c leads to the title compounds 2a-c and 4 which react with C, O, and S nucleophiles to yield the substitution products 3a-r, 5a, and 5b.Hydrolysis of the acylal 5a furnishes the ring enlarged structure 7.With hydrogen sulfide 2a, b are converted into the dispiro compounds 9a, b.Reaction of 2a with the thiocarbonyl compounds 11a-d affords the salts 12a-d from which 12c and 12d can be degraded to give the (β-anilinoalkenyl)cyclobutenediones 13a and b.