o-Alkoxy-substituted l-oxa-3,5-diazahexatrienes ( 5 ) , l-oxa-3,5,7-triazaoctatetraenes (?), and l-oxa-3,5,7,9-tetraazadecapentaenes (9) were synthesized by condensation of 1,3-dialkoxy-2-azapropenylium salts (3) or 1,5-dialkoxy-2,4-diazapentadienylium salts (8) with N-acyl-and N-alkoxycarbonylamidines (4). It is the nature of the leaving group which mainly determines the chain length of the products obtained.-Compounds ? show ring-chain tautomerism involving the cyclic form 6 in dependence of the substitution pattern. All o-alkoxy substituted oligonitriles 5, 7, and 9 may easily converted to the corresponding o-amino compounds 11, 14, and 15 by reaction with secondary amines 10. Reaction of 5a, b with the primary amine 12 leads to the triazinone 13. The lithiated ketimine 16 converts 5b and 7d to the corresponding l-oxa-3,5,7-triazaoctatetraenes 17 and l-oxa-3,5,7,9-tetraazadecapentaenes 18. Helical geometries dominate the structures of the new oligonitriles in the crystalline state as derived from X-ray analyses of compounds 5a, 7c, 9a, and 18. Push-pull substitution effects, which should be strong in the amino derivatives 11, 14, and 15, have no significant influence on the structure of the oligonitriles. Ph Ph R BF; 3 4a, Sa, 6a: R = OMe 4b, 5b, 6 b R = OEt 4c, Sc, 7c: R =p-To1
