A process of converting 2,3,4,5-tetrahydropyrimidines (.DELTA.-1) having at least one hydrogen in the 2-position to 3,4,5,6-tetrahydropyrimidines (.DELTA.-2) which comprises hydrogenating and dehydrogenating said .DELTA.-1 tetrahydropyrimidines. Such hydrogenating and dehydrogenating may be done in either two sequential steps or in one step. Said .DELTA.-1 tetrahydropyrimidines can also be converted to .DELTA.-2 tetrahydropyrimidines by heating in the essential absence of a solvent, and preferably under basic conditions. In addition, corresponding hexahydropyrimidimidines can be converted to corresponding .DELTA.-2 tetrahydropyrimidines by dehydrogenation. This invention also relates to the use of .DELTA.-2 tetrahydropyrimidines, particularly as corrosion inhibitors.
将至少在2位上具有一个氢原子的2,3,4,5-四氢
嘧啶(.DELTA.-1)转化为3,4,5,6-四氢
嘧啶(.DELTA.-2)的过程,包括对所述.DELTA.-1四氢
嘧啶进行氢化和脱氢。这种氢化和脱氢可以在两个连续步骤或一步中完成。所述.DELTA.-1四氢
嘧啶也可以通过在基本无溶剂存在的情况下加热,优选在碱性条件下进行转化为.DELTA.-2四氢
嘧啶。此外,相应的六氢
嘧啶酰胺可以通过脱氢转化为相应的.DELTA.-2四氢
嘧啶。本发明还涉及使用.DELTA.-2四氢
嘧啶,特别是作为
防腐剂。