161760-09-4Relevant articles and documents
Synthesis of Rovafovir Etalafenamide (Part III): Evolution of the Synthetic Process to the Phosphonamidate Fragment
Ambrosi, Andrea,Bringley, Dustin A.,Calimsiz, Selcuk,Curl, Jonah,Garber, Jeffrey A. O.,Huynh, Huy,Kwong, Bernard,Lapina, Olga,Leung, Edmund,Lin, Lennie,Martins, Andrew,McGinitie, Teague,Mohan, Sankar,Phull, Jaspal,Roberts, Ben,Rosario, Mary,Sarma, Keshab,Shen, Jinyu,Shi, Bing,Standley, Eric A.,Wang, Li,Wang, Xueqing,Yu, Guojun
supporting information, p. 1247 - 1262 (2021/05/29)
Phosphonamidate 1 is a key fragment in the assembly of rovafovir etalafenamide, a novel nucleotide reverse transcriptase inhibitor under development at Gilead Sciences for the treatment of HIV infection. An early manufacturing route, relying on simulated moving bed (SMB) chromatography for the separation of phosphorus diastereomers, was executed on scale to produce multiple batches of 1. However, developing alternative synthetic conditions became desirable in consideration of the high production cost, long lead time, and high process mass intensity (PMI) associated with SMB. Several strategies to improve these factors are described herein, including epimerization and recycling of the undesired (R)-phosphorus diastereomer, design of stereoselective approaches to establish the desired (S)-configuration at phosphorus, and identification of conditions or derivatives to allow for selective crystallization. Ultimately, a second-generation route to 1 was developed and demonstrated on scale. The new route achieves the separation of phosphorus diastereomers by means of selective crystallization, does not require SMB, and offers lower PMI, cost, and lead time.
An Efficient Synthesis of Tenofovir (PMPA): A Key Intermediate Leading to Tenofovir-Based HIV Medicines
Arduengo, Anthony J.,Cardoso, Flavio S. P.,Derstine, Brenden P.,Dietz, Jule-Phillip,Gupton, B. Frank,Herrera, Brenden T.,McQuade, D. Tyler,Opatz, Till,Paymode, Dinesh J.,Peck, Cheryl L.,Snead, David R.,Stringham, Rodger W.,Tomlin, John W.,Yue, Andrew C.
supporting information, p. 1420 - 1427 (2020/10/12)
Herein, we report further improvements to the synthesis of tenofovir 1, the precursor to tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide fumarate (TAF). Starting from acyclic precursor diaminomalononitrile 12, a four-step protocol to tenofovir 1 will allow for vertical integration for more manufacturers. The key transformation is a convergent one-step procedure from 6 as compared to the current commercial process, with an improved yield from 59% (two steps) to 70%. Further improvements include eliminating the need for problematic magnesium tert-butoxide (MTB) and significant solvent reduction by avoiding an intermediate workup. With the costs of HIV/AIDS treatments remaining a barrier for those most in need, lowering the raw material/processing costs and increasing the security of supply can increase patient access.
