DeStevens, George published the artcileHeterocycles. VII. Oxazolin-2-ones, Name: 4,5-Dimethyloxazole, the publication is Journal of Organic Chemistry (1958), 1572-3, database is CAplus.
cf. preceding abstract Since some thiazolin-2-ones (Ia) showed a marked analgetic effect in laboratory animals it was interesting to modify the hetero atoms; thus the exchange of S for O was studied. In the synthesis of the desired 2,3,4,5,6,7-hexahydrobenzoxazolin-2-one (I) some difficulties were encountered. α-Hydroxycyclohexanone (II), when freshly distilled exists as a true monomer which was demonstrated by its strong infrared absorption bands at 3480 and at 1715 cm.-1 but on standing several hrs. dimerizes to a hemiacetal. Thus the monomer II condensed with H2NCO2Et (III) to give only I whereas the dimer condenses with III to give 4,5,6,7-tetrahydrobenzimidazolin-2-one (IV) plus an oil which analyzes for the carbamate (V) of the dimer. The structure of V is not fully elucidated. Finally the alternate approach through α-aminocyclohexane (VI).HCl and COCl2 gave a small amount of I. I tested for analgesia according to the rat-tail burn technique was comparable with Ia in activity. I was found to be more toxic than Ia. Further work in this series is underway. Acetoin (44 g.), 125 g. III, and 250 ml. HCONMe2 refluxed 25 hrs., solvent and excess III distilled in vacuo, and the residue distilled gave 75% 4,5-dimethyloxazolin-2-one (VII), m. 112-13° (alc.-hexane). VII (1.2 g.) refluxed 15 min. with 0.23 g. Na in 50 ml. MeOH, excess MeI added and the mixture refluxed 24 hrs., the solution evaporated to dryness, the residue extracted with C6H6, and distilled gave 55% 3,4,5-trimethyloxazolin-2-one, b0.12 76°, needles, m. 62° (H2O). VII (6 g.) refluxed 15 min. with 1.24 g. Na in 200 ml. iso-PrOH, 6.7 g. PhCH2Cl added, the refluxing continued 16 hrs., chilled, the NaCl removed, and the filtrate concentrated gave on distillation 3.2 g. 3-benzyl-4,5-dimethyloxazolin-2-one (VIII), b0.06 140°, m. 90-1° (C6H6). 3-(p-Acetamidophenoxyethyl)-4,5-dimethyloxazolin-2-one was prepared as was VIII, m. 150-1° (C6H6). VII (6.8 g.) refluxed 10 min. with 1.38 g. Na in 200 ml. iso-PrOH, then 24 hrs. longer with a molar equivalent of Me2N(CH2)3Cl, the alc. removed, the residue extracted with 10% HCl, the aqueous extract made slightly alk., extracted with Et2O, dried, and treated with dry HCl gave 3-(3-dimethylaminopropyl)-4,5-dimethyloxazolin-2-one-HCl (IX), m. 222-3° (alc.). 3-(2-Piperidinoethyl)-4,5-dimethyloxazolin-2-one-HCl was prepared as in the previous example for IX, m. 226° (alc.). The MeI of the free base was prepared by treating an Et2O solution of the free base with MeI and leaving 3 days at room temperature, m. 216-18° (decomposition) (alc.). VII (0.5 g.) and 6 ml. Ac2O refluxed 3 hrs. gave 3-acetyl-4,5-dimethyloxazolin-2-one, b0.08 67-9°, m. 50° (H2O). Freshly distilled II (17 g.), 32 g. III, 350 ml. HCONMe2, and 1 ml. C5H5N refluxed 20 hrs., the solvent removed, and the residue distilled in vacuo gave a yellow oil, b0.6 160°. This was taken up in 2 ml. alc. and 2 ml. hexane and 2 ml. Et2O added to give on chilling I, m. 130-1° (alc.-Et2O). Using identical reaction conditions but using the dimer of II (m. 111-20°) resulted in formation of 90% IV, m. 340°, and a small amount of V, b0.1 94°. VI (14.8 g.) in PhMe saturated with COCl2 and refluxed 2 hrs., chilled, filtered, the filtrate evaporated to dryness, and the residue worked up gave 0.5 g. I, identical in properties with the above prepared specimen.
Journal of Organic Chemistry 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, Name: 4,5-Dimethyloxazole.
Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem