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ChemicalBook CAS DataBase List 1,2,5-OXADIAZOLE-3,4-DICARBOXYLIC ACID, DIETHYL ESTER
65422-98-2

1,2,5-OXADIAZOLE-3,4-DICARBOXYLIC ACID, DIETHYL ESTER synthesis

4synthesis methods
-

Yield:65422-98-2 81.4%

Reaction Conditions:

Stage #1: ethyl acetoacetatewith sulfuric acid;nitric acid;acetic anhydride at -5 - 15; for 1 h;
Stage #2: with sulfuric acid at 20; for 1.1 h;Reagent/catalyst;Temperature;

Steps:

Example 1 Example 1

0.196 g of concentrated H2SO4 was added to 50 mL of acetic anhydride. After the mixture was cooled to -10 ° C, it was added dropwise with stirring12.7mL mass fraction of 95% HNO3, the control temperature 10 ~ 15 .The reaction mixture was cooled to -5 ° C, 26.028 g of ethyl acetoacetate was added dropwise and the temperature was maintained at -5 ° C. After the addition was completed, the reaction was maintained for 1 hour.The temperature was raised to 20 ° C, 3.20 mL of concentrated sulfuric acid was added dropwise to the reaction solution, and TLC was followed until the reaction was completed (1.1 h).The mixture was extracted three times with ethyl acetate and washed with saturated brine. The combined extracts were dried over anhydrous Na2SO4 and filtered.Evaporation of ethyl acetate, distillation of the residue under reduced pressure, collecting fractions.The resulting diethyl furazan oxide-3,4-dicarboxylate is a pale yellow liquid with a yield of 81.4% and a purity of more than 98%.

References:

CN105884708,2016,A Location in patent:Paragraph 0019-0020; 0022; 0024; 0026; 0028; 0030