The hydrolytic degradation of four β-sultams was investigated using isothermal microcalorimetry to determine kinetic and enthalpic
data. Firstly, all four compounds were analysed in the solid-state at 310 K, with a significant substituent-based stabilising/destabilising
effect being observed. Secondly, the four compounds were analysed in the presence of pH 4 acetate buffer, at three temperatures
(298, 310 and 323 K). Under these conditions, the substituent choice affected the rate of hydrolysis and the associated change
in enthalpy for each compound. Based on the calorimetric data presented in this work, no change in reaction mechanism for
the hydrolytic degradation was observed over the temperature range considered.
Authors:Michael G. Organ, Paul R. Hanson, Alan Rolfe, Thiwanka B. Samarakoon, and Farman Ullah
The generation of stereochemically rich benzothiaoxazepine-1,1´-dioxides for enrichment of high-throughput screening collections is reported. Utilizing a microwave-assisted, continuous-flow organic synthesis platform (MACOS), scale-out of core benzothiaoxazepine-1,1´-dioxide scaffolds has been achieved on multigram scale using an epoxide opening/SNAr cyclization protocol. Diversification of these sultam scaffolds was attained via a microwave-assisted intermolecular SNAr reaction with a variety of amines. Overall, a facile, two-step protocol generated a collection of benzothiaoxazepine-1,1´-dioxides possessing stereochemical complexity in rapid fashion, where all eight stereoisomers were accessed from commercially available starting materials.
Authors:Farman Ullah, Qin Zang, Salim Javed, Aihua Zhou, Christopher A. Knudtson, Danse Bi, Paul R. Hanson, and Michael G. Organ
A microwave-assisted, continuous-flow organic synthesis (MACOS) protocol for the synthesis of functionalized 1,2,5-thiadiazepane 1,1-dioxide library, utilizing a one-pot elimination and inter-/intramolecular double aza-Michael addition strategy is reported. The optimized protocol in MACOS was utilized for scale-out and further extended for library production using a multicapillary flow reactor. A 50-member library of 1,2,5-thiadiazepane 1,1-dioxides was prepared on a 100- to 300-mg scale with overall yields between 50 and 80% and over 90 % purity determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy.
a three-component cascade approach using a continuous-flow microreactor” M. Lei , W. Tian , R. Hu , H. Zhang Synthesis 2012 , 44 , 2519 – 2526 .
“ Synthesis of an isoindoline-annulated, tricyclic sultam library via
. Cosford Journal of Flow Chemistry 2011 , 1 , 28 – 31 .
“ Accessing stereochemically rich sultams via microwave-assisted, continuous-flow organic synthesis (MACOS) scale-out ” M. G. Organ , P. R. Hanson , A. Rolfe , T. B