Study of cis–trans stereochemistry of 2-(2-chlorobenzylideneamino)phenol and 2-(2-chlorophenyl imino)methyl)phenol (Schiff bases) by GC and GC-MS spectrometry

Abstract

Cis-trans stereochemistry of 2-(2-chlorobenzylideneamino)phenol (1) and 2-(2-chlorophenyl imino)methyl)phenol (2) (Schiff bases) was studied by GC-MS spectrometry, and cis-trans conversion of the two compounds in solution was investigated by GC. Thus, 2 exists as a sole trans configuration and its conversion to cis was unsuccessful in any circumstance, while compound 1 exists as a mixture of two configurations in solution, occurrence of which were dependent on the temperature, heating time, solvent, and acid catalyst. X-ray crystallography of solid 1 presented a sole trans configuration.

Reinvestigation of alternative method for the preparation of dibenz[b,f][1,4]oxazepine

“…However, their MS fragmentation patterns were completely different (see Experimental Section). It is noteworthy that the X-ray crystallography of 5 indicates a unique trans configuration [25].…”

“…We have reported the results of GC, GC-MS, and 1 H NMR analysis of the imine products [25], according to which we have presumed the formation of 5 cis and 5 trans and only 6 trans in solution.…”

Synthesis and Characterization of Donor-Functionalized N,S-Compounds Containing the ortho-Aminothiophenol Motif

“…Schiff bases can exist in cis and trans configurations, with the trans configuration being thermodynamically favored. 43 The cis configurations are detectable and isolable only if they are in a favorable steric environment, in particular, if an intramolecular hydrogen bond to N=CH is present; 43 therefore, we postulate that the imine compounds 4-6 and 8 have trans configuration. The 2-thienyl pendant compounds 4d-6d and 8d possess a lower solubility in organic solvents compared to the other donor functionalized derivatives and they precipitated readily out of solution, driving the condensation reaction to completion.…”