PURPOSE: A crystalline t-butyl 2-&lsqb(4R,6S)-6-formyl-2,2-dimethyl-1,3-dioxane-4-yl&rsqbacetate is provided to easily isolated a product of high yield.CONSTITUTION: A method for preparing a crystalline t-butyl 2-&lsqb(4R,6S)-6-formyl-2,2-dimethyl-1,3-dioxane-4-yl&rsqbacetate comprises: a first step of mixing a mixture solution of TEMPO(2,2,6,6-tetramethyl-1-piperidinyloxy, free radical), potassium bromide or iodine bromide, sodium hydrogen carbonate or sodium hydrophosphate and organic solvent with a mixture solution of t-butyl2-((4R, 6S)-6-(hydroxymethyl)-2,2-dimethyl-1,3-deoxane-4-yl)acetate and organic solvent under 5°C a second step of administering a sodium hypochlorite solution to t-butyl 2-((4R, 6S)-6-(hydroxymethyl)-2,2-dimethyl-1,3-deoxane-4-yl)acetate of the second step at -30 to -15°C and stirring at -10 to -5°C a third step of filtering the reactant of the second step and adding sodium thiosulfate solution to separate an organic layer a fourth step of distilling the organic solvent of the organic layer of the third step by reduced pressure to prepare concentrated residue and a fifth step of drying the concentrated residue at 60-80 °C and 3-6 cmHg of pressure for 5 minutes to one hours.COPYRIGHT KIPO 2012본 발명은 결정형 t-부틸 2-[(4R,6S)-6-포밀-2,2-디메틸-1,3-디옥산-4-일]아세테이트를 제공하며, 이의 제조방법을 제공한다.
