Search results for "Hexamethylphosphoramide"
showing 3 items of 3 documents
Phycocyanobilin in solution – a solvent triggered molecular switch
2014
We present a computational investigation of the conformational response of phycocyanobilin (PCB) to the ability of solvents to form hydrogen bonds. PCB is the chromophore of several proteins in light harvesting complexes. We determine the conformational distributions in different solvents (methanol and hexamethylphosphoramide HMPT) by means of ab initio molecular dynamics simulations and characterize them via ab initio calculations of NMR chemical shift patterns. The computed trajectories and spectroscopic fingerprints illustrate that the energy landscape is very complex and exhibits various conformations of similar energy. We elucidate the strong influence of the solvent characteristics on…
CCDC 1586540: Experimental Crystal Structure Determination
2018
Related Article: Samia Benmansour, Irene Pérez-Herráez, Christian Cerezo-Navarrete, Gustavo López-Martínez, Cristian Martínez Hernández, Carlos J. Gómez-García|2018|Dalton Trans.|47|6729|doi:10.1039/C8DT00143J
Stereoselective reactions of a thioester butanediacetal with various electrophiles
2014
Abstract The reactions of the lithium enolate of S -ethyl (2 R ,5 R ,6 R )-5,6-dimethoxy-5,6-dimethyl-[1,4]-dioxane-2-carbothioate were investigated in the presence or absence of hexamethylphosphoramide (HMPA). Fluorination gave a single isomer with a much better yield than for the corresponding methyl ester. Alkylation with alkyl halides strongly depended upon their structure. Without HMPA, only methyl iodide reacted with moderate yield and gave a single isomer. In the presence of HMPA, all of the alkyl halides reacted almost quantitatively (81–98% yield) with moderate stereoselectivity and preferentially gave products with the alkyl chain attached at the equatorial position. The silyl eno…