A thermolabile protecting group strategy for carboxylic acids is expanded. Thermosensitive esters are readily prepared using a known procedure, and their stability under neutral condition is investigated. Effective thermolytic deprotection initiated only by temperature for different carboxylic acids is demonstrated, and the compatibility of a thermolytic protecting group with acidic and basic protecting groups in an orthogonal protection strategy is also presented. This study showed interesting correlations between the pKa of acids and the deprotection rate of their well-protected moieties.

中文翻译：

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2-吡啶基-N-（2,4-二氟苄基）氨基乙基作为热控制工具，用于保护羧酸

扩展了羧酸的热不稳定保护基策略。热敏酯易于使用已知方法制备，并且研究了它们在中性条件下的稳定性。证明了仅由温度引发的对不同羧酸的有效热解脱保护，并且还提出了在正交保护策略中热解保护基与酸性和碱性保护基的相容性。这项研究表明，在酸的pKa和其保护良好的部分的脱保护率之间存在有趣的相关性。