The hydrochloride salt of ɑ-aminocyclobutanone protected as its dimethyl acetal 2,2-dimethoxycyclobutan-1-aminium chloride (3) has been prepared as a modular synthon for convenient access to cyclobutanone-containing lead inhibitors of hydrolase enzymes including serine proteases and metalloproteases. Protected ɑ-aminocyclobutanone 3 was converted to representative amide and sulfonamide-functionalized 2-aminocyclobutanone derivatives. Reaction of the amino acetal 3 with phenylthioisocyanate afforded the bicyclic urea 1-hydroxyl-2,4-diazabicyclo[3.2.0]heptane-3-thione (9) as confirmed by a single crystal X-ray structure.

中文翻译：

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受保护的2-氨基环丁酮的合成作为药物化学的模块化过渡态合成子

被保护为二甲基乙缩醛2，2-二甲氧基环丁-1-氯化铵的α-氨基环丁酮盐酸盐（3）已被制备为模块合成子，可方便地使用含环丁酮的水解酶的丝氨酸蛋白酶和金属蛋白酶的铅抑制剂。将保护的β-氨基环丁酮3转化为代表性的酰胺和磺酰胺官能化的2-氨基环丁酮衍生物。氨基缩醛3与苯硫异氰酸酯的反应得到双环脲1-羟基-2，4-二氮杂双环[3.2.0]庚烷-3-硫酮（9），如通过单晶X射线结构所证实的。