求翻译：产物和三氯氧磷与N,N-二甲基甲酰胺反应加热回流反应得到4，6-二氯-5-苯胺基嘧啶，该阶段的实验产率约为40%，且该方案为最佳。是什么意思？

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Product 3 chlorine and oxygen, phosphorus and N N - 2 methyl benzoyl peroxide reaction heat and return responses are 4, 6 - 2 - 5 - chlorine benzene, pyridine, the stage of the experimental production rate of about 40 per cent, and the program is best.

The product and the trichloro oxygen phosphorus and the N, N- dimethyl formamide responded the heating backflow responded obtains 4,6- two chlorine - 5- anilino- pyrimidine, this stage experimental production rate is approximately 40%, also this plan for best.

Products and phosphorus oxychloride and N,N-dimethyl formamide heating return response are 4,6-chloride -5-aniline based pyrimidine, experimental yield is about 40% for this phase, and the programme for the best.

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