Acridin-9-yl hydrazine upon treatment with various isothiocyanates (RNCS, R = methyl, allyl, phenyl, p-methoxy phenyl, and p-nitro phenyl) yielded the corresponding thiosemicarbazides with acridine substituted on the carbazide-type side. The alkyl-substituted compounds were present in solution as equilibria consisting of the major H-10, H-12 tautomer (either E or Z or both about the C 13 N 14 bond) and the minor H-10, SH tautomer (either E or Z or both). The major species for the aromatic-substituted compounds was the H-10, H-12 E tautomer, with the evident minor species being the H-10, H-12 Z tautomer. The thiosemicarbazides were each quantitatively converted into the analogous semicarbazides upon treatment with mesitylnitrile oxide wherein all structures were present in solution as the H-10 tautomers with Z conformation about the C 13 N 14 bond. Methylation of the compounds with methyl iodide yielded S-methylated compounds wherein the Z configuration dominated in each case over the E configuration along the N 12 C 13 double bond. Treatment of the thiosemicarbazides with methyl bromoacetate resulted in the formation of 1',3'-thiazolidin-4'-ones wherein the Z configuration predominated in each case over the E configuration along the N 12 C 13 double bond. With bromoacetonitrile as the bifunctional electrophile, the initial 1',3'-thiazolidin-4'-imines that formed spontaneously underwent Dimroth-type rearrangement to the regiosiomeric 1',3'-thiazolidin-4'-imines.

No abstract

N‐Acridin‐9‐yl methyl N′‐acridin‐9‐yl thiourea spontaneously spiro cyclises via nucleophilic attack of the methylene carbon onto the C‐9 of the other acridine moiety. The thiourea, upon reaction with bromoacetonitrile, provided a spiro fused‐bicyclic product displaying unusual dynamic behavior.

No abstract

Acridine derivatives R 0430Tautomerism, Regioisomerism, and Cyclization Reactions of Acridinyl Thiosemicarbazides. -The behavior of methyl-and phenylhydrazine (II) and (V) in the reaction with isothiocyanate (I) is different, while the reaction of (II) with (I) proceeds regioselectively with the α-nitrogen more nucleophilic than the β-nitrogen, the regioselectivity in the reaction of (V) with (I) is poor but varies with the solvent. Only in the case of ethanol as solvent, the nucleophilic predominance of the α-nitrogen is pronounced. Interestingly, whereas the methyl product exists as an equilibrium mixture of open-chain (III) and spiro thiosemicarbazide (IV), the phenyl thiosemicarbazides (VI) and (VII) exist only as spiro forms. Reaction of (I) with acetone methyl hydrazone (VIII) yields the expected thiosemicarbazide (IX) accompanied by the new ring system (X). Cyclization reaction of (IX) and (X) with the bifunctional electrophiles (XI) afford the spirocycles (XII). -(KLIKA*, K. D.; BALENTOVA, E.; BERNAT, J.; IMRICH, J.; VAVRUSOVA, M.; KLEINPETER, E.; PIHLAJA, K.; KOCH, A.; J. Heterocycl.