158665-15-7Relevant articles and documents
Pd/PTABS: Low-Temperature Thioetherification of Chloro(hetero)arenes
Bandaru, Siva Sankar Murthy,Bhilare, Shatrughn,Cardozo, Jesvita,Chrysochos, Nicolas,Schulzke, Carola,Sanghvi, Yogesh S.,Gunturu, Krishna Chaitanya,Kapdi, Anant R.
, p. 8921 - 8940 (2019/07/08)
The thioetherification of heteroaryl chlorides is an essential synthetic methodology that provides access to bioactive drugs and agrochemicals. Due to their (actual or potential) industrial importance, the development of efficient and low-temperature protocols for accessing these compounds is a requirement for economic and ecologic reasons. A particular highly effective catalytic protocol using the Pd/PTABS system at only 50 °C was developed accordingly. The coupling between chloroheteroarenes and a variety of less reactive arylthiols and alkylthiols was carried out with a high efficiency. Heteroarenes of commercial relevance such as purines and pyrimidines were also found to be useful substrates for the reported transformation. The commercial drug Imuran (azathioprine) was synthesized as an example, and its preparation could be optimized. DFT studies were performed to understand the electronic effects of the tested ligands on the catalytic reaction.
Convenient syntheses of 9-[4-hydroxy-3-(hydroxymethyl)butyl]guanine (penciclovir) and 9-[4-acetoxy-3-(acetoxymethyl)butyl]-2-amino-9h-purine (famciclovir)
Brand, Briony,Reese, Colin B.,Song, Quanlai,Visintin, Cristina
, p. 5239 - 5252 (2007/10/03)
Guanine 11 was converted, in a one pot reaction, into 2-amino-6-[(4- chlorophenyl)sulfanyl]purine 9a in 88% isolated yield. 4-Acetoxy-3- (acetoxymethyl)butanol 123 was prepared from 2-chloroethanol in five steps and in 46% overall yield. The mesylate ester of compound 23 reacted with 9a in the presence of potassium carbonate with a high degree of regioselectivity (89%) to give the N-9 alkylated product 26 which was isolated in 80% yield. Acidic hydrolysis of the latter compound 26 gave penciclovir 4 in virtually quantitative yield. Penciclovir 4 and famciclovir 5 were prepared from 2- amino-6-[(4-chlorophenyl)sulfanyl]purine 9a in four and five steps, respectively, by procedures involving initial alkylation with 1,2- dibromoethane. The overall yields obtained were 65 and ca. 60%, respectively.
