Cyclocondensation of
Math/MathML" id="jhet2556-eo-0001">5-amino-6-methyl-2-morpholinopyrimidine-4-thiol (
het2556-eo-0001" rel="references:#jhet2556-eo-0001">) and
het2556-eo-0002">2-bromo-5,5-dimethylcyclohexane-1,3-dione (
het2556-eo-0002" rel="references:#jhet2556-eo-0002">) under mild reaction condition afforded
het2556-eo-0003">4,7,7-trimethyl-2-morpholino-7,8-dihydro-5H-benzo[b]pyrimido[5,4-e][1,4]thiazin-9(6H)-one (
het2556-eo-0003" rel="references:#jhet2556-eo-0003">). T
he 1H and
13C NMR data of compound (
het2556-eo-0003" rel="references:#jhet2556-eo-0003">) are demonstrated that this compound exists pri
marily in t
he enamino ketone form. Reaction of compound (
het2556-eo-0003" rel="references:#jhet2556-eo-0003">) with
het2556-eo-2004">phosphorous oxychloride gave
het2556-eo-0004">4-(9-chloro-4,7,7-trimethyl-7,8-dihydro-6H-benzo[b]pyrimido[5,4-e][1,4]thiazin-2-yl)morpholine (
het2556-eo-0004" rel="references:#jhet2556-eo-0004">).
Nucleophilic substitution of chlorine atom of compound (
het2556-eo-0004" rel="references:#jhet2556-eo-0004">) with typical secondary amines in DMF and K
2CO
3 furnis
hed t
he new substituted derivatives of 4-(4,7,7-trimethyl-7,8-dihydro-6
H-benzo[
b]pyrimido[5,4-
e][1,4]thiazin-2-yl)morpholine (
het2556-eo-0006" rel="references:#jhet2556-eo-0006 #jhet2556-eo-0007 #jhet2556-eo-0008 #jhet2556-eo-0009 #jhet2556-eo-0010 #jhet2556-eo-0011 #jhet2556-eo-0012 #jhet2556-eo-0013">). All t
he synt
hesized products were characterized and confirmed by t
heir spectroscopic and microanalytical data.