The reaction of substituted 4,4-diphenyl-3,4(1,4)-dihydroquinazolines with various alkylating agents in DMSO–KOH leads (depending on the structure of the alkylating agent) to the formation of the corresponding N¹-monoalkyl-substituted 1,4-dihydroquinazolines or, in the reaction with ethyl bromoacetate, to N-{[5-bromo-2-(methylamino)phenyl]diphenylmethyl}benzamide with opening of the heterocyclic ring. The molecular structures of 1-ethyl-2,4,4-triphenyl-1,4-dihydroquinazoline and 1-ethyl-2-(7-methoxy-1,3-benzodioxol-5-yl)-4,4-diphenyl-1,4-dihydroquinazoline were investigated and proven by X-ray structural analysis.

取代的4,4-二苯基-3,4（1,4）-二氢喹唑啉与各种烷基化剂在DMSO-KOH中的反应导致（取决于烷基化剂的结构）形成相应的N ^1-单烷基-取代的1，4-二氢喹唑啉或在与溴乙酸乙酯反应中，在杂环开环的情况下生成N -{[5-溴-2-（甲基氨基）苯基]二苯基甲基}苯甲酰胺。1-乙基-2,4,4-三苯基-1,4-二氢喹唑啉和1-乙基-2-（7-甲氧基-1,3-苯并二恶唑-5-基）-4,4-二苯基-的分子结构对1,4-二氢喹唑啉进行了研究，并通过X射线结构分析对其进行了验证。