Kondrat’eva, G. Ya. published the artcileCondensation of homologs of oxazole with maleic anhydride, COA of Formula: C5H7NO, the publication is Khimicheskaya Nauka i Promyshlennost (1957), 666-7, database is CAplus.
The reaction of oxazoles with dienophiles in C6H6 solutions do not give the expected endoxo derivatives of tetrahydropyridine series but the substituted cinchomeronic acid. Apparently the usual mechanism of diene synthesis gives bicyclo-endoxo-compounds which rearrange immediately to give cinchomeronic acid. Condensation of the following oxazoles with maleic anhydride gave the corresponding cinchomeronic acid derivatives: 2,4-, 2,5-, and 4,5-dimethyloxazole, 2,5,6-trimethyloxazole, and 2-methyl-4,5-tetramethyleneoxazole. The yields, m.p., of the respective acids and the m.p. of the anhydrides obtained with P2O5 were as follows: 80%, 270-3°, 111°; 78%, 246°, 104-4.5°; 85%, 262°, 92°; 52%, 234°, 83°; 35%, 220°, 140°.
Khimicheskaya Nauka i Promyshlennost published new progress about 20662-83-3. 20662-83-3 belongs to oxazolidine, auxiliary class Oxazole, name is 4,5-Dimethyloxazole, and the molecular formula is C5H7NO, COA of Formula: C5H7NO.
Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem