Bredereck, Hellmut published the artcileFormamide reactions. I. Imidazole syntheses with formamide, SDS of cas: 20662-83-3, the publication is Chemische Berichte (1953), 88-96, database is CAplus.
α-HO, α-halo, α-NH2, and, under reducing conditions, α-isonitroso ketones give 4,5-disubstituted imidazoles. Boiling 10 g. acetoin with 50 cc. HCONH2 (I) 4 h. gives 55% 4,5-dimethylimidazole, HN.CH:N.CR:CR’ (II, R = R’ = Me) (III), b11 165-75°, m. 117° (HCl salt, m. 305°). Similarly, the following II (R = R’) are prepared (R, % yield, b.p., m.p., HCl salt (a) m.p. in the order given): Et, from propionoin, 67, b10 150-60°, 82-5°, a 252-3°; Pr, 81, b10 168°, 66°, a 163°; Bu, 72, b11 197-203°, -, a 147°; iso-Bu, 61, yellow oil, b. 177-9°, a (crystallizing with 1 H2O) m. 72°, 131° (H2O-free); Am, 51, light yellow oil, b9 210-16°, a 142°; C6H13, 45, -, -, a 130°; Me2CH (IV), -, -, 214°, a 221° (formate salt, C9H16N2.CH2O2 85% yield, m. 140°; HBr salt, m. 225°). Refluxing 4 g. sebacoin with 15 cc. I 2 h. gives 87% 4,5-octamethyleneimidazole, needles, m. 229°, HCl salt m. 270°. 1-Cyclohexadecanol-2-one, b0.03 156°, (8 g.) refluxed 2 h. with 50 cc. I gives 91% 4,5-tetradecamethyleneimidazole, leaflets, m. 115°, HCl salt m. 241°. 1,6-Diphenylpropionoin, b0.05 180-90°, prepared in 53% yield from 29 g. PhCH2CH2CO2Et and 8 g. Na in xylene, (5 g.) and 25 cc. I 2 h. give 66% II (R = R’ = PhCH2CH2), m. 112°. II are also prepared from benzoins, NH2 ketones, and halogen ketones. Refluxing 10 g. benzoin with 20 cc. I 2 h. gives 91% II (R = R’ = Ph) (V), m. 231°; 10 g. furoin and 50 cc. I 2 h. give 89% II (R = R’ = α-furyl), m. 163°; p-dimethylaminobenzoin and I give 62% II [R = 4(5)-p-Me2NC6H4, R’ = 5(4)-Ph], yellowish crystals, m. 230°; and 4 g. α-hydroxybutyrophenone and 20 cc. I 3 h. give 70% II (R = Ph, R’ = Et, or R and R’ may be interchanged), m. 172°. Refluxing 5 g. PhCOCHPhNH2 2 h. with 30 cc. I gives 90% V. Warming 10 g. benzilmonoxime with 70 cc. I and 3 cc. HCO2H at 70° with slow addition of 2 g. NaHSO3 and refluxing the mixture gently 1 h. give 71% V. Refluxing 8 g. PhCOCH3Br and 50 cc. I 2 h. gives 90% II (R = Ph, R’ = H, or R and R’ may be interchanged), m. 128°; PhCOCHBrCHMe2 and I give 69% II (R = Ph, R’ = Me2CH, or R and R’ may be interchanged) b15 210-15°, m. 200°. PrCOCHBrEt and I 4 h. give 49% II (R = Et, R’ = Pr, or R and R’ may be interchanged), b20 185-95°; HCl salt m. 162°. Refluxing 25 g. MeCOCHBrMe and 100 cc. I 3 h. and fractionally distilling the product give 22% 4,5-dimethyloxazole, b760 129-35° [H2PtCl6 salt m. 240° (decomposition)], and 47% III, b15 170° (HBr salt, m. 265°). m-O2NC6H4COCH2Br and I 2 h. give 72% II (R = m-O2NC6H4, R’ = H, or R and R’ may be interchanged), yellow crystals, m. 224°; p-MeO analog, 62%, leaflets, m. 137°.
Chemische Berichte 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, SDS of cas: 20662-83-3.
Referemce:
https://en.wikipedia.org/wiki/Oxazolidine,
Oxazolidine | C3H7NO – PubChem