53864-51-0

The invention discloses a method for preparing deuterated internal standard substances of tetracyclines and epimers thereof. According to the method, a demethylated primary amine intermediate is obtained through three-step reaction including cyclization, ring-opening reaction and reduction reaction, and deuterated paraformaldehyde is subjected to reductive amination to obtain a deuterated internalstandard reagent of tetracyclines finally. Compared with a traditional method for preparing stable isotope labeled tetracycline internal standard reagents through fermentation or total synthesis, themethod has advantages of short steps, simplicity and convenience in operation, high yield, low cost, high quality and the like. In addition, product purity and the atom deuterated ratio are both 98%or above.

A novel flower-like BiVO4 and BiVO4/Bi2Ti2O7 heterojunction photocatalyst was firstly synthesized by surfactant-free hydrothermal route, which is very convenient, rapid, controllable and environmentally friendly. The crystal structures, chemical composition, morphology, optical and photo-catalytic property of the as-prepared samples were characterized by the techniques of XRD, XPS, SEM, HRTEM, BET, UV–vis DRS, and PL. The BiVO4/Bi2Ti2O7 heterojunction photocatalyst exhibited higher photocatalytic activity than pure BiVO4 and Bi2Ti2O7 for the degradation of tetracycline (TC) under xenon lamp irradiation. The enhanced photocatalytic activities of BiVO4/Bi2Ti2O7 composites were either related to the particular structural features or the mass ratios of BiVO4 and Bi2Ti2O7 in the composites. The possible photocatalytic mechanism of the BiVO4/Bi2Ti2O7 composite has been speculated by detecting reactive species based on free radicals trapping experiments. The preliminary removal pathways of tetracycline was proposed on the basis of the identified intermediates using LC-TOF/MS.