87691-27-8Relevant articles and documents
Synthesis process of N-BOC-cis-4-hydroxyproline methyl ester
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Paragraph 0018-0019, (2021/01/20)
The invention discloses a synthesis process of N-BOC-cis-4-hydroxyproline methyl ester. The synthesis process comprises the following steps: (1) adding raw materials including dichloromethane, 4-hydroxy-L-proline and DMAP into a 2 L reaction flask, stirring, slowly dropwise adding BOC anhydride into the reaction liquid, after dropwise adding, sampling, carrying out TLC, completely reacting the rawmaterials, adding water into the reaction liquid after treatment, stirring at a temperature of 20-30 DEG C, separating the liquid, drying an organic phase by using anhydrous sodium sulfate, and concentrating under reduced pressure to obtain a white solid product; and (2) taking the obtained product, adding tetrahydrofuran and DCC into a 5 L reaction flask, stirring at 20-30 DEG C to react for 1 hour, dropwise adding methanol into the reaction solution, keeping the temperature after dropwise adding, sampling, carrying out TLC until the reaction is complete, filtering the reaction solution, collecting the filtrate, concentrating under reduced pressure until no liquid flows out to obtain a white solid crude product, heating, collecting the filtrate, collecting a filter cake, and drying the filter cake to obtain a white solid. According to the invention, the product is prepared with high quality and high yield.
Automated Radiosynthesis of cis- And trans-4-[18F]Fluoro- l -proline Using [18F]Fluoride
Morgan, Timaeus E. F.,Riley, Leanne M.,Tavares, Adriana A. S.,Sutherland, Andrew
, p. 14054 - 14060 (2021/05/29)
The positron emission tomography imaging agents cis- and trans-4-[18F]fluoro-l-proline are used for the detection of numerous diseases such as pulmonary fibrosis and various carcinomas. These imaging agents are typically prepared by nucleophilic fluorination of 4-hydroxy-l-proline derivatives, with [18F]fluoride, followed by deprotection. Although effective radiofluorination reactions have been developed, the overall radiosynthesis process is suboptimal due to deprotection methods that are performed manually, require multiple steps, or involve harsh conditions. Here we describe the development of two synthetic routes that allow access to precursors, which undergo highly selective radiofluorination reactions and rapid deprotection, under mild acidic conditions. These methods were found to be compatible with automation, avoiding manual handling of radioactive intermediates.
Pyrrolidine ring puckering and prolyl amide bond configurations of 2-methyl-allo-hydroxyproline-based dipeptides
Tiwari, Vinay Shankar,Singh, Gajendra,Gurudayal,Ampapathi, Ravi Sankar,Haq, Wahajul
, p. 4460 - 4464 (2019/05/17)
An expeditious method for the synthesis of homo and heterochiral dipeptides containing l-alanine and d/l 2-methyl allo-hydroxyl prolines was developed using direct aminolysis of bicyclic lactones derived from d/l alanine. The impact of C-2 methylation and its spatial orientation on the pyrrolidine ring puckering and prolyl amide bond configuration was ascertained by solution NMR studies. The present studies reveal that C-2 methylation causes the prolyl amide bond to exist exclusively in the trans geometry in both homo- and heterochiral dipeptides. However, the spatial orientation of the C-2 methyl group and its i + 2 position in appropriately capped model dipeptides may nucleate into a turn like structure.
