A green approach for the one-pot four-component sonochemical synthesis of 5-methyl-7-aryl-4,7-dihydrotetrazolo[1,5-a]pyrimidine-6-carboxylic esters from the reaction of 2-cyano-guanidine, sodium azide, various aromatic aldehydes and methyl or ethyl acetoacetate in the presence of a catalytic amount of Fe₂O₃@SiO₂-(CH₂)₃NHC(O)(CH₂)₂PPh₂ as a new hybrid organic-inorganic core–shell nanomagnetic catalyst is described. This is the first design, preparation, characterization and application of the present nanomaterial and also the first ultrasound irradiated synthesis of the biologically and pharmaceutically important heterocyclic compounds in water as a green solvent. This novel sonocatalysis/nanocatalysis protocol offers several advantages such as high yields, short reaction times, environmentally-friendly reaction media, easily isolation of the products, simple preparation, full characterization and recoverability of the nanocatalyst by an external magnet and reusing several times without significant loss of activity.

一种从2-氰基胍反应中一锅四组分声化学合成5-甲基-7-芳基-4,7-二氢四唑并[1,5 - a ]嘧啶-6-羧酸酯的绿色方法，催化量的Fe ₂ O ₃ @SiO _2-（CH ₂）₃ NHC（O）（CH ₂）₂ PPh ₂存在下的叠氮化钠，各种芳香醛和乙酰乙酸甲酯或乙酰乙酸乙酯作为一种新型的杂化有机-无机核-壳纳米磁性催化剂。这是本纳米材料的首次设计，制备，表征和应用，也是在水中作为绿色溶剂的生物学和药学上重要的杂环化合物的首次超声辐照合成。这种新颖的声催化/纳米催化方案具有多个优点，例如高收率，较短的反应时间，环境友好的反应介质，易于分离产物，制备简单，通过外部磁体对纳米催化剂进行全面表征和可回收性以及多次重复使用而没有明显的影响。活动丧失。