Polysubstituted pyrroles have been synthesized in good yields via a four-component one-pot reaction of 1,3-dicarbonyl compounds, amines, aldehydes, and nitroalkanes using natural hydroxyapatite (HAp) as an efficient green catalyst. This strategy provides advantages such as simple experimental and work-up procedures, mild conditions, high selectivity, low cost, high atom economy, and environmental friendliness; it uses a green commercial catalyst and does not require a solvent. The electrochemical behavior of S300 steel in 1 M hydrochloric acidic was studied in the presence of these heterocyclic compounds. The results showed good inhibition efficiency for steel in acidic media.

中文翻译：

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天然羟基磷灰石：合成吡咯，缓蚀剂的绿色催化剂

使用天然羟基磷灰石（HAp）作为有效的绿色催化剂，通过1,3-二羰基化合物，胺，醛和硝基烷的四组分一锅法反应，可以高收率合成多取代的吡咯。该策略具有以下优点：简单的实验和后处理程序，温和的条件，高选择性，低成本，高原子经济性和环境友好性。它使用绿色的商用催化剂，不需要溶剂。在这些杂环化合物的存在下，研究了S300钢在1 M盐酸中的电化学行为。结果表明，钢在酸性介质中具有良好的缓蚀效果。