<
span cla
ss="TH_term4">Cycloconden
sation
span> of
s:w="http://www.wiley.com/namespaces/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns:mml="http://www.w3.org/1998/Math/MathML" id="jhet2556-eo-0001"><
span cla
ss="TH_term3">5-amino-6-methyl-2-morpholinopyrimidine-4-thiol
span> (
s:#jhet2556-eo-0001">) and
s:w="http://www.wiley.com/namespaces/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns:mml="http://www.w3.org/1998/Math/MathML" id="jhet2556-eo-0002"><
span cla
ss="TH_term3">2-bromo-5,5-dimethylcyclohexane-1,3-dione
span> (
s:#jhet2556-eo-0002">) under mild reaction condition afforded
s:w="http://www.wiley.com/namespaces/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns:mml="http://www.w3.org/1998/Math/MathML" id="jhet2556-eo-0003"><
span cla
ss="TH_term3">4,7,7-trimethyl-2-morpholino-7,8-dihydro-5
H-benzo[
b]pyrimido[5,4-
e][1,4]thiazin-9(6
H)-one
span> (
s:#jhet2556-eo-0003">). The <
sup>1
sup>H and <
sup>13
sup>C NMR data of compound (
s:#jhet2556-eo-0003">) are demon
strated that thi
s compound exi
st
s primarily in the enamino ketone form. Reaction of compound (
s:#jhet2556-eo-0003">) with
s:w="http://www.wiley.com/namespaces/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns:mml="http://www.w3.org/1998/Math/MathML" id="jhet2556-eo-2004"><
span cla
ss="TH_term3">pho
sphorou
s oxychloride
span> gave
s:w="http://www.wiley.com/namespaces/wiley" xmlns:cr="urn://wiley-online-library/content/render" xmlns:mml="http://www.w3.org/1998/Math/MathML" id="jhet2556-eo-0004"><
span cla
ss="TH_term3">4-(9-chloro-4,7,7-trimethyl-7,8-dihydro-6
H-benzo[
b]pyrimido[5,4-
e][1,4]thiazin-2-yl)morpholine
span> (
s:#jhet2556-eo-0004">). <
span cla
ss="TH_term4">Nucleophilic
sub
stitution
span> of chlorine atom of compound (
s:#jhet2556-eo-0004">) with typical
secondary amine
s in DMF and K<
sub>2
sub>CO<
sub>3
sub> furni
shed the new
sub
stituted derivative
s of 4-(4,7,7-trimethyl-7,8-dihydro-6
H-benzo[
b]pyrimido[5,4-
e][1,4]thiazin-2-yl)morpholine (
s:#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 the
synthe
sized product
s were characterized and confirmed by their
spectro
scopic and microanalytical data.