The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Stereochemistry of cyclic compounds. 1,3-Cyclopentenedione in Diels-Alder reaction》. Authors are Kucherov, V. F.; Ivanova, L. I..The article about the compound:cis-Cyclohexane-1,2-dicarboxylic acidcas:610-09-3,SMILESS:O=C([C@H]1[C@@H](C(O)=O)CCCC1)O).Recommanded Product: 610-09-3. Through the article, more information about this compound (cas:610-09-3) is conveyed.
Oxidation of 1,3-cyclopentenediol with CrO3 in AcOH with ice cooling gave 26% 1,3-cyclopentenedione (I), b1 60°, n20D 1.5045, m. 35-6°, after cooling. The dione condenses readily with butadiene in C6H6 (pyrogallol added) in 2 weeks at room temperature to yield cis-Δ5-hexahydroindene-1,3-dione, m. 157.5-8.5°; hydrogenation over Pd gave 1,3-hydrindandione, m. 86-6.5°, which with Br2-NaOH gave cis-1,2-cyclohexanedicarboxylic acid, m. 186.5-7.5°. I condensed with isoprene in C6H6 to the adduct, 5-methyl-Δ5-hexahydroindene-1,3-dione, m. 84.5-5.5°. Cyclopentadiene gave the adduct, C10H10O2, m. 178-8.5°, which hydrogenated over Pd to endomethylenehydrindan-1,3-dione, m. 166-6.5°. I and 1-vinylcyclohexene gave the adduct, 4,5-tetramethylene-Δ5-hexahydroindene-1,3-dione, m. 120-1°. I and 6-methoxy-1-vinyl-Δ3,4-dihydronaphthalene similarly gave in 1 day at room temperature II, m. 206.5-7.5°.
There is still a lot of research devoted to this compound(SMILES：O=C([C@H]1[C@@H](C(O)=O)CCCC1)O)Recommanded Product: 610-09-3, and with the development of science, more effects of this compound(610-09-3) can be discovered.
Reference:
Benzisoxazole – Wikipedia,
Benzisoxazole – an overview | ScienceDirect Topics