Ethyl 5-tert-butyl-1,3-oxazole-4-carboxylate synthesis

5synthesis methods

Product Name:Ethyl 5-tert-butyl-1,3-oxazole-4-carboxylate
CAS Number:714273-89-9
Molecular formula:C10H15NO3
Molecular Weight:197.23

2999-46-4
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$13.43/1gm:

1538-75-6
233 suppliers
$17.67/10gm:

Ethyl 5-tert-butyl-1,3-oxazole-4-carboxylate

714273-89-9
35 suppliers
$65.00/100mg

Yield:714273-89-9 99%

Reaction Conditions:

with 1,8-diazabicyclo[5.4.0]undec-7-ene in tetrahydrofuran at 4 - 20;

Steps:

3

Ethyl 5-(tert-butyl)oxazole-4-carboxylate (2); [0204] According to the report by Suzuki et al. (JOC, 38, 3571-3575 (1973)), to a stirring solution of ethyl isocyanoacetate 1 (25 g, 221 mmol, caution: bad smell, it should be treated in a draft chamber, Wako Pure Chemical, Osaka, Japan, Cat. No. 055-06672, Rf 0.70 [CHCl₃:MeOH = 10:0.5]) in anhydrous THF (200 mL, Kanto Chemical, Tokyo, Japan, Cat. No. 40993-05) was added DBU (34.3 mL, 243 mmol, Nacalai Tesque, Kyoto, Japan, Cat. No. 11117-05) and pivalic anhydride (49.3 mL, 243 mmol, Wako Pure Chemical, Osaka, Japan, Cat. No. 168-19661) at 4 °C. After 10 min, the ice-bath was removed and the mixture was stirred overnight at room temperature. start ng mate a reaction mixture[0205] Then, the solvent of the obtained dark brown reaction mixture was removed by evaporation in vacuo. AcOEt (200 mL) was added to the obtained residue, then this mixture was washed with 10% Na₂C0₃ (x 3), 10% citric acid (x 3) and saturated NaCl (x 3), and dried over anhydrous Na₂S0₄, and the solvent was evaporated in vacuo. The residual oil was dissolved in CHC1₃ (20 mL) and applied to silica-gel column chromatography (6 x 30 cm, Merck 107734 silica gel 60, 70-230 mesh, prepared with Hexane: AcOEt = 20:1) and eluted with Hexane: AcOEt (20:1 to 4:1, the desired 2 is eluted at 8:1), to give an pale yellow oil of 2 (66.4 g, 99%). Rf 0.68 (CHCl₃:MeOH = 10:0.5), 1H NMR (300MHz CDC1₃) δ 7.70 (s, 1H), 4.39 (q, J = 7.2 Hz, 2H), 1.46 (s, 9H), 1.41 (t, J = 7.2 Hz, 3H); HRMS(EI): m/z 197.1050 (M⁺) (Calcd for Ci₀Hi₅NO₃: 197.1052).