13C-NMR study of 4H-1,3,4-thiadiazino[5,6-b]quinoxalines. A proof for the N5-deuteration in deuteriotrifluoroacetic acid |
| |
Authors: | Ho Sik Kim Yoshihisa Okamoto Yoshihisa Kurasawa |
| |
Abstract: | The carbon signals of the 2-acylamino-4H-1,3,4-thiadiazino5,6-b]quinoxalines 1a,b , 2-acylamino-4H-1,3,4-thiadiazino5,6-b]quinoxaline 1,1-dioxides 2a,b , and 2-amino-4H-1,3,4-thiadiazino5,6-b]quinoxaline 3 in deuteriodimethyl sulfoxide and in deuteriotrifluoroacetic acid were assigned by the nmr (HMBC, HMQC) spectroscopy. The comparison of the carbon chemical shifts in deuteriodimethyl sulfoxide with those in deuteriotrifluoroacetic acid clarified that compounds 1a, 1b , and 3 were deuterized at the N5-position in deuteriotrifluoroacetic acid, while the 1,1-dioxides 2a,b did not undergo the N5-deuteration in deuteriotrifluoroacetic acid. |
| |
Keywords: | |
|
|