Abstract
Cyclocondensation of 2-cyanomethyl-4-thiazolidinone
(1)
with tetracyanoethylene
(2)
furnished pyrano[2,3-d]thiazole derivative
(4)
. Benzo[e]pyrano[2,3-d]thiazole derivative
(6)
was obtained by cyclization of compound
(1)
with salicylaldehyde. In a similar manner, condensation of compound
(1)
with 2-hydroxy-1-naphthaldehyde in refluxing ethanol yielded naphtho[e]pyrano[2,3-d]thiazole derivative
(7)
. Interaction of compound
(9)
with benzylidenemalononitriles
(10)
(1 : 1 molar ratio) at reflux temperature in ethanol in the presence of piperidine afforded thiazolo[3,2-a]pyridines
(12a-c)
. Treatment of compound
(12a)
with hydrazines furnished pyrazolo[3′,4′:4,5] thiazolo[3,2-a]pyridines
(14a,b)
. The reaction of compound
(1)
with benzyli-denecyanoacetate
(16)
yielded 5-hydroxythiazolo[3,2-a]pyridine derivative
(21)
. Cyclization of bis(thiazolinone)
(23)
with benzylidenemalononitriles
(10)
produced bis(thiazolopyridine) derivatives
(25a,b)
.