On October 8, 2020, Fu, Zhifei; Luo, Miaorong; Zhang, Yang; Cai, Yalei; Zhu, Wu; Li, Jian; Chen, Shuhui published a patent.Safety of tert-Butyl 1-oxo-2,9-diazaspiro[5.5]undecane-9-carboxylate The title of the patent was Nitrogen-containing spiro derivative as RET inhibitor. And the patent contained the following:
The invention disclosed a kind of nitrogen-containing spiro derivative as RET inhibitor. The claimed compound is shown in structure I (T = CN or N; R1,R2,R3 = H, halo, C1-6 alkyl, etc.; R4 = H, amino, hydroxy, etc.; D1,D2 = (un)substituted -CH2CH2-; D3 = methylene, carbonyl, etc.; D4 = ethylene, propylene, -OCH2CH2-, etc.). The claimed compound is prepared via multiple steps (procedure given). The prepared compound can be used as RET inhibitor for treating RET mediated disease. The experimental process involved the reaction of tert-Butyl 1-oxo-2,9-diazaspiro[5.5]undecane-9-carboxylate(cas: 1198284-94-4).Safety of tert-Butyl 1-oxo-2,9-diazaspiro[5.5]undecane-9-carboxylate
The Article related to nitrogen containing spiro derivative preparation ret inhibitor, Heterocyclic Compounds (More Than One Hetero Atom): Pyrimidines and Quinazolines and other aspects.Safety of tert-Butyl 1-oxo-2,9-diazaspiro[5.5]undecane-9-carboxylate
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics