Dihydropyrimidine compound and application thereof in medicines

The invention relates to a dihydropyrimidine compound and application thereof in medicines, in particular to application of the dihydropyrimidine compound as a medicine for treating and preventing hepatitis B. Specifically, the invention relates to a compound shown in a general formula (I) or a formula (Ia) or a stereoisomer, a tautomer, a nitric oxide, a solvate, a metabolite, a pharmaceuticallyacceptable salt or a prodrug thereof, and each variable is defined in the specification. The invention also relates to application of the compound shown in the general formula (I) or the formula (Ia)or the stereoisomer, tautomer, nitric oxide, solvate, metabolite or pharmaceutically acceptable salt thereof as a medicine, in particular to application of the compound as a medicine for treating andpreventing hepatitis B. 本发明涉及一种二氢嘧啶类化合物及其在药物中的应用，尤其是作为治疗和预防乙型肝炎的药物的应用。具体地说，本发明涉及通式(I)或式(Ia)所示的化合物或其立体异构体、互变异构体、氮氧化物、溶剂化物、代谢产物、药学上可接受的盐或它的前药，其中各变量如说明书所定义。本发明还涉及通式(I)或式(Ia)所示的化合物或或其立体异构体、互变异构体、氮氧化物、溶剂化物、代谢产物或药学上可接受的盐作为药物的用途，尤其是作为