Oxazole-2-amine synthesis
- Product Name:Oxazole-2-amine
- CAS Number:4570-45-0
- Molecular formula:C3H4N2O
- Molecular Weight:84.08
420-04-2
141-46-8
4570-45-0
Example 2: Preparation of 2-aminooxazole. To a tetrahydrofuran (THF, 60 mL) solution of cyanamide (19.8 mL, 50% w/w aqueous solution, 0.25 mol) was added a 24 mL aqueous solution of 2-hydroxyacetaldehyde (15 g, 0.25 mol). The reaction mixture was treated with 2 M aqueous sodium hydroxide (25.2 mL, 0.05 mol) at 0 °C. The mixture was slowly warmed to room temperature and stirred continuously for 24 hours. Upon completion of the reaction, the volatile solvent (THF) was removed by distillation under reduced pressure. The remaining aqueous solution was extracted with ethyl acetate (4 × 200 mL). The organic phases were combined, dried with anhydrous sodium sulfate, and subsequently concentrated under reduced pressure to give 14.968 g (71.3% yield) of white solid product. The product was characterized by 400 MHz 1H NMR (CDCl3): δ 7.13 (s, 1H), 6.74 (s, 1H), 5.26 (br.s, 2H). Elemental analysis calculated values (C3H4N2O): C 42.86%, H 4.80%, N 33.32%; measured values: C 43.01%, H 4.87%, N 33.11%.
Yield:4570-45-0 71.3%
Reaction Conditions:
with sodium hydroxide in tetrahydrofuran;water at 0 - 20; for 24 h;
Steps:
2
Example 2: Preparation of 2-amino-oxazole. To a solution of cyanamide (19.8 ml of 50% w/w in water, 0.25 mol) in THF (60 ml) was added the hydroxyacetaldehyde (15 g, 0.25 mol) in 24 ml of water. The reaction mixture was treated at 00C with a solution of sodium hydroxide 2 M (25.2 ml, 0.05 mol). The mixture was allowed to warm to room temperature and stirred for 24 hrs. The volatiles were removed in vacuo (THF) and the remaining aqueous solution was extracted with four portions of 200 ml of ethyl acetate. The organic extracts were dried over sodium sulfate and concentrated in vacuo, yielding 14.968 g (71.3%) of a white solid. 400 MHz 1H NMR (CDCl3) δ: 7.13 (s, IH), 6.74 (s, IH), 5.26 (br. s, 2H). CaIc. for C3H4N2O: C 42.86, H 4.80, N 33.32; found C 43.01, H 4.87, N 33.11.
References:
ARQULE INC. WO2007/123892, 2007, A2 Location in patent:Page/Page column 50
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