Hydrazonoyl halides 4 react readily with either 3-amino-2,3-dihydro-6-methy
l-2-thioxo-4(IH)-pyrimidinone 5 or 3-amino-6-methyl-2-methyl-thio-4(3H)-pyr
imidinone 6 to form 6H-pyrimido[1,2-b][1,2,4, 5]tetrazin-6-ones 9. The mech
anism of the studied reactions is discussed (C) 2000 John Wiley & Sons, Inc
.