PARTIALLY FLUORINATED HETEROCYCLIC-COMPOUNDS .30. CYCLIZATION REACTIONS OF LITHIUM 1,3,4,5,7,8-HEXAFLUORO-6-ISOQUINOLINETHIOLATE AND LITHIUM 2,3,5,6,7,8-HEXAFLUORO-4-QUINOLINETHIOLATE WITH DIMETHYL ACETYLENEDICARBOXYLATE

The lithium salt of 1,3,4,5,7,8-hexafluoro-6-isoquinolinethiol reacts with dimethyl acetylenedicarboxylate (DMAD) to give dimethyl afluoroth ieno[3,2-f]isoquinoline-1,2-dicarboxylate and dimethyl 9-pentafluoro[2 ,3-g]isoquinoline-1,2-dicarboxylate in the ratio 95.5, respectively. T he lithium salt of 2,3,5,6,7,8-hexafluoro-4-quinolinethiol and DMAD gi ve dimethyl 4,6,7,8,9-pentafluorothieno[3,2-c]quinoline (74%) and dime thyl hexafluoro-4-quinolylthio)ethene-1,2-dicarboxylate (13%). No cycl isation to form a six-membered ring was detected in the reaction of th e lithium salt of 5,7,8-pentafluoro-6-phenylthio-1-isoquinolinethiol a nd DMAD; overall addition of the thiol to the triple bond occurred to give dimethyl nylthio-1-isoquinolylthio)ethene-1,2-dicarboxylate in lo w yield.