5-AMINO-8-METHYL-1,2-DIHYDROTHIENO-(AND FURO)[2,3-H][1,6]NAPHTHYRIDINES

X-ray structure analyses of Smiles rearrangement and further cyclizati on products of 2-[3-cyanopropylthio-(and oxy)]pyridine-3-carbonitriles revealed the structures of ethyl-1,2-dihydrothieno[2,3-h][1,6]-naphth yridine, C11H11N3S, and 8-methyl-1,2-dihydrofuro[2,3-h][1,6]naphthyrid ine, C11H11N3O. The crystals of both compounds are isomorphous; monocl inic, space group P2(1)/n. The molecules, related by a centre of symme try, are linked through N-H ... N hydrogen bonds. Common features of b ond lengths and angles that characterize the thieno and furo[2,3-h][1, 6]-naphthyridine skeletons are described.