3-氧己二酸二甲酯

反应条件: temp:160.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 3-Amino-5-methyl-1H-s-triazole (19.8 g) (about 0.12 mol) (about 70%) and 30 g (0.16 mol) of dimethyl 3-oxo-adipate are melted together while gassing with argon for 1 hour in a bath heated at 160° C. In so doing, the volatile products are removed in a water-jet vacuum. After cooling the solid residue is dissolved in dichloromethane/methanol (1:1 v/v). The turbid yellowish solution is filtered and concentrated. The crystals which thereby result are filtered off under suction and washed with ethanol, subsequently with diethyl ether. There are obtained 20 g of methyl 4,7-dihydro-2-methyl-7-oxo-s-triazolo[1,5-a]pyrimidine-5-propionate as a white crystals of melting point 222°-225° C. the volatile products are removed in a water-jet vacuum After cooling the solid residue is dissolved in dichloromethane/methanol (1:1 v/v) The turbid yellowish solution is filtered concentrated The crystals which thereby result are filtered off under suction washed with ethanol, subsequently with diethyl ether

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A solution of 4.00 g (21 mmol) of 3-ketohexanedioic acid dimethyl ester [B. J. Whitlock and H. W. Whitlock, J. Org. Chem., 39:3144 (1974)] in 100 mL of benzene was refluxed in the presence of 14.5 g (230 mmol) of ethylene glycol and 100 mg of p-toluene-sulfonic acid while water was azeotropically removed in a Dean-Stark trap. After 2.5 h, the mixture was cooled and washed with equal volumes of saturated sodium bicarbonate solution and water. The benzene layer was dried (MgSO4) and reduced to dryness to leave a clear oil; IR (neat) 1740 cm-1, NMR (CDCl3) δ2.30 (A2B2 multiplet, 4), 2.60 (s,2), 3.65 (s,6), and 3.95 (s,4). The oily ketal was immediately hydrolyzed under reflux for 1.5 h in a solution of 4.4 g of 86% KOH in 50 mL of 95% ethanol. After cooling, the slight precipitate formed was dissolved by adding a small amount of water. Sufficient cation exchange resin AG50W-X8 (H+) was added to neutralize the base (pH~6.5) and removal of the resin afforded a filtrate which was reduced to dryness to leave 4.3 g (99%) of 3-ketohexanedioic acid ethylene ketal as a yellowish oil which yielded a very hygroscopic solid after trituration with acetone; IR 1720 cm-1 (broad); NMR δ(D2O) 2.20 (A2B2 multiplet, 4), 2.60 (s,2), and 4.0 (s,4). This compound was not further characterized and used as such in the following step. was azeotropically removed in a Dean-Stark trap the mixture was cooled washed with equal volumes of saturated sodium bicarbonate solution and water The benzene layer was dried (MgSO4) to leave a clear oil After cooling the slight precipitate formed was dissolved (H+) was added the base (pH~6.5) and removal of the resin afforded a filtrate which