Nazarov, I. N.; Zav’yalov, S. I. published an article in 1952, the title of the article was Acetylene derivatives. CXXVII. Synthesis of polycyclic compounds related to steroids. 15. Structure of products of condensation of 2-methoxy-1, 3-butadiene with 2-methyl-2-cyclohexen-1-one and methyl methacrylate.Reference of Methyl 1-methyl-4-oxocyclohexanecarboxylate And the article contains the following content:
cf. C.A. 44, 3458i; 46, 2088f; 47, 5366c; 9969b. Condensation of H2C:C(OMe)CH:CH2 with 2-methyl-2-cyclohexen-1-one as described earlier (loc. cit.) gave 8a-methyl-6-methoxy-Δ6-1-octalone, b0.1 88-9°, nD20 1.5089. This (10 g.) refluxed 3 h. with MeMgI, from 13 g. MeI, gave 4.8 g. 1, 8a-dimethyl-1-hydroxy-6-oxodecalin (I), b0.05 118-20°, nD20 1.5140, which on distillation tends to lose H2O, yielding the unsaturated ketone, 1, 8a-dimethyl-6-oxo-Δ1-octahydronaphthalene (II). I with powd. KHSO4 at 160° in vacuo gave some 66% (II), b4 104-8°, nD20 1.5099; semicarbazone, m. 172-4° (from MeOH). II with MeMgI gave some 90% 1,6,8a-trimethyl-6-hydroxy-Δ1-octahydronaphthalene (III), b3 100-5°, nD20 1.5104, which with KHSO4 at 165-75° gave 50% 1,6,8a-trimethyl-Δ1,6-hexahydronaphthalene (IV), b. 229-31°, nD20 1.5035, which, passed over Pd-C at 330°, gave 1,6-C10H6Me2, b13 130-3°, nD20 1.6078; picrate, m. 108-10°. MeMgI with hexahydro-8a-methyl-1,6-(2H, 5H)-naphthalenedione gave after 3 h. refluxing some 90% decahydro-1,6,8a-trimethyl-1, 6-naphthalenediol (V), b0.05 113-16°, nD20 1.5115. This with KHSO4 at 150-5° at 100 mm. gave 60% of a mixture of IV and the corresponding 1,6-oxide; the mixture over Pd-C as above gave 1,6-C10H6Me2. Heating 4 g. CH2:C(OMe)CH:CH2 with 4.8 g. CH2:CMeCO2H in the presence of a little pyrogallol in C6H6 3 h. in an ampul at 219-20° gave 5.2 g. Me 1-methyl-4-methoxy-3-cyclohexene-1-carboxylate (VI), b12 107-8°, nD20 1.4722, which, shaken with 1% HCl 4 h. gave Me 1-methyl-4-oxocyclohexanecarboxylate (VII), b7 99-101°, nD20 1.4610; semicarbazone, m. 166-8°; 2, 4-dinitrophenylhyrazone, m. 125-7° (cf. Rubin and Wishinsky, C.A. 40, 2117.7). This refluxed 6 h. with aqueous AcOH and concentrated HCl gave the free acid (VIII), m. 77-8°, b2 145-8°. Cyclization of MeO2CCMe(CH2CH2CO2Me)2 (loc. cit.) gave Me 1-methyl-4-oxo-1,3-cyclohexanedicarboxylate, b3 130-2°, nD20 1.4859, which, shaken 2-3 min. with 5% NaOH and let stand 8 h., gave the free acid, decompose 104-6° decarboxylated at 120° to VIII, m. 76-8°. With CH2N2 this gave VII. VI (10 g.) treated in CCl4 with ice cooling with 8.4 g. Br over 1 h., then shaken 15 min. with 62 mL. H2O, and the organic layer dried, evaporated, treated with 9.5 g. PhNEt2 at 150° 1 h., made acid to Congo red, with 1:1 HCl and extracted with C6H6 gave 4 g. Me 2-methyl-4-oxo-2-cyclohexene-1-carboxylate, b7 107-10°, nD20 1.4775; semicarbazone, m. 157-8°. This (4 g.) with NaCH(CO2Et)2 from 15 g. CH2(CO2Et)2 after 7 h. at 70-6° and acidification with 1:1 HCl, gave 2.2 g. di-Et 2-carbomethoxy-2-methyl-4-oxocyclopentanemalonate, b1.5 155-7°, nD20 1.4888. The experimental process involved the reaction of Methyl 1-methyl-4-oxocyclohexanecarboxylate(cas: 37480-41-4).Reference of Methyl 1-methyl-4-oxocyclohexanecarboxylate
Methyl 1-methyl-4-oxocyclohexanecarboxylate(cas:37480-41-4) belongs to ethers. Oxygen is more electronegative than carbon, thus the alpha hydrogens of ethers are more acidic than those of simple hydrocarbons. They are far less acidic than alpha hydrogens of carbonyl groups (such as in ketones or aldehydes), however. Reference of Methyl 1-methyl-4-oxocyclohexanecarboxylate
Referemce:
Ester – Wikipedia,
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