64744-50-9Relevant articles and documents
Synthesis of N-(2,3,4,5,6-pentafluorobenzyloxy)-γ-lactams by rhodium-catalyzed cyclization of diazo amides
Budny, Marcin,Nowak, Magdalena,Wojtczak, Andrzej,Wolan, Andrzej
, p. 6361 - 6365 (2014)
Rhodium-catalyzed cyclization of N-(2,3,4,5,6-pentafluoro-benzyloxy) diazo amides leading to the corresponding γ-lactams is described. The cyclization is based on the intramolecular catalytic insertion into the C-H bond. Fourteen lactams were obtained with up to 91 % yield and 88 % ee. Gabapentin hydrochloride, a GABA analog, was also synthesized by this method, which shows that deprotection of the 2,3,4,5,6-pentafluorobenzyloxy group is possible. The rhodium-catalyzed cyclization of diazo amides, derived from O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, is reported. The reaction leads to a variety of lactams in up to 91 % yield and 88 % ee. The developed method was applied in the synthesis of gabapentin hydrochloride, an important GABA analog.
Rapid and Mild Lactamization Using Highly Electrophilic Triphosgene in a Microflow Reactor
Fuse, Shinichiro,Komuro, Keiji,Otake, Yuma,Masui, Hisashi,Nakamura, Hiroyuki
supporting information, p. 7525 - 7532 (2021/03/17)
Lactams are cyclic amides that are indispensable as drugs and as drug candidates. Conventional lactamization includes acid-mediated and coupling-agent-mediated approaches that suffer from narrow substrate scope, much waste, and/or high cost. Inexpensive, less-wasteful approaches mediated by highly electrophilic reagents are attractive, but there is an imminent risk of side reactions. Herein, a methods using highly electrophilic triphosgene in a microflow reactor that accomplishes rapid (0.5–10 s), mild, inexpensive, and less-wasteful lactamization are described. Methods A and B, which use N-methylmorpholine and N-methylimidazole, respectively, were developed. Various lactams and a cyclic peptide containing acid- and/or heat-labile functional groups were synthesized in good to high yields without the need for tedious purification. Undesired reactions were successfully suppressed, and the risk of handling triphosgene was minimized by the use of microflow technology.
A Simple and Expedient Procedure for the Preparation of Gabapentin Lactam (2-Aza-spiro[4,5]decan-3-one)
Katuri, Jashuva V. P.,Ekkundi, Vadiraj S.,Nagarajan, Kuppuswamy
, p. 1828 - 1832 (2016/10/31)
A novel process has been described on 100 g scale for the preparation of gabapentin lactam which is a penultimate intermediate for the preparation of gabapentin, comprising a Hofmann reaction of 1,1-cyclohexanediacetic acid monoamide using chlorinating agents such as trichloroisocyanuric acid, sodium dichloroisocyanurate, 1,3-dichloro-5,5-dimethylhydantoin, and N-chlorosuccinimide, which have not been employed so far for making this molecule. Reactions done in aqueous alkali on the 1,1-cyclohexanediacetic acid monoamide led to a solution of gabapentin sodium salt which on heating led to the formation of the gabapentin lactam in good yield.
