METHYL 4-HYDROXY-6-METHYL-2-OXO-3-CYCLOHEXENE-1-CARBOXYLATE synthesis
- Product Name:METHYL 4-HYDROXY-6-METHYL-2-OXO-3-CYCLOHEXENE-1-CARBOXYLATE
- CAS Number:39493-62-4
- Molecular formula:C9H12O4
- Molecular Weight:184.19
Yield:39493-62-4 70%
Reaction Conditions:
with sodium in methanol; for 6 h;Reflux;
Steps:
224 Example 224
Preparation of methyl 2-oxo-4-hydroxy-6-methyl-cyclohexen-3-yl carboxylate (38)
Example 224
Preparation of methyl 2-oxo-4-hydroxy-6-methyl-cyclohexen-3-yl carboxylate (38)
Dissolve sodium metal (3.1 g, 0.134 mol) in dry methanol (200 ml), add in methyl acetoacetate (12.0 g, 0.103 mol) and methyl crotonate (12.4 g, 0.124 mol at room temperature), after finishing the addition, reflux to react for 6h to complete the reaction, then distill out most of the methanol, pour the residue into ice water (200 ml), extract with ethyl acetate (3*50 ml), adjust pH of the aqueous layer to less than 2 with dilute 15% hydrochloric acid, extract again with ethyl acetate (3*50 ml).
Pool the organic layer, and wash with saturated brine, dry the solution over anhydrous MgSO4.
Filter and evaporate the solution to dryness, redissolve the residue, recrystallize the solution to obtain a white solid as the target product (13.2 g, 70%) with petroleum etherethyl acetate and recrystallized. 1H NMR (400 MHz, DMSO-d6): 0.94 (d, J=6.0 Hz, 3H), 2.32 (m, 3H), 3.09 (d, J=9.2 Hz, 1H), 3.63 (s, 3H), 5.21 (s, 1H), 11.37 (s, 1H).
References:
US2014/371232,2014,A1 Location in patent:Paragraph 0305
