감압 필터로 모아진 결정을 메탄올로 세척하여 노란색 결정으로 중간체 1-2 5.2 g (수율 90%) 을 얻었다.
The crystals collected through a reduced pressure filter are washed with methanol to obtain 5.2 g (yield 90%) of intermediate 1-2 as yellow crystals.