摘要:
A method of preparing (S)-.gamma.-hydroxymethyl-.alpha.,.beta.-butenolide includes the step of oxidizing a levoglucosenone with a peracid in an organic solvent. Peracetic acid, metha-chloroperbenzoic acid or magnesium monoperoxyphthalate hexahydrate can be used as the peracid. According to this method, an (S)-.gamma.-hydroxymethyl-.alpha.,.beta.-butenolide having high optical purity can be easily prepared from a levoglucosenone as a starting material at a high yield.
摘要:
A pick-up assembly for use in a video disc player comprises a stylus having one lengthwise surface provided with an electrode and secured to a stylus carrier with the electrode facing in a direction away from the carrier, and a generally strip-shaped fly lead having one end bent and connected physically and electrically to the electrode by the use of an electroconductive bonding agent, thereby minimizing the required length of the expensive stylus and rendering to decrease the noise of the pick-up assembly.