Utility of Cyano Acid Hydrazide in Heterocyclic Chemistry: A New Route for the Synthesis of New 1,2,4-Triazolo[1,5-a]pyridines and 1,2,4-Triazolo[1,5-a]isoquinolines

Abstract

A b d el H aleem M ostafa HusseinC hem istry D ep artm en t, Faculty o f Science, A l-A zh ar U niversity, A ssiu t 71524, Egypt Z. N aturforsch. 53b, 4 8 8 -4 9 4 (1998); received O ctob er 27, 1997 l,2,4-T riazolo[l,5-a]p yrid in es, l,2,4-T riazolo[l,5-a]isoq u in olin es C yan o acid hydrazide 1 was con d en sed with cycloh exan on e in refluxing eth an olic piperidine to yield the hydrazone 4. C om pound 4 reacts with arylidines 5 a -i to yield the 1,2,4triazolo[l,5-a]p yrid in es 7 a -i. C om pound 4 also reacts w ith m ixtures o f aliphatic aldehyd es and different active m eth ylen e reagents to yield l,2.4 -tria zo lo [l,5 -a ]p y rid in es 8 a -d . Sim ilarly reaction o f 4 with arylazom alononitrile to yield the triazolop yrid in es lO a-d. R eaction o f 4 with arom atic ald eh yd es gives 12a-e. C om pound 8a reacts w ith elem en tal sulfur to yield the th ien o-l,2,4-triazolop yrid in e 13. This underw ent cycloadd ition w ith acrylonitrile, a»-nitrostyrene. chalcon e, N -p henylm alem ide, dim eth ylacetylen ed icarb oxylate and tetracyanoethylen e yield in g the isoq u in olin es 15-18. A ll new com poun ds have b een characterized by their IR , 'H N M R and m ass spectra.

Comparative Studies of Some Novel Cu(II) Polymeric Complexes Derived from Cyanoacetylhydrazine (CAH; L). The Role of Solvents Used on the Structure and Geometry of the Isolated Cu<sup>2+</sup> Complexes

“…The value of magnetic moment of complex (2, C 11 H 23 Cl 2 N 9 O 6 Cu 3 ) was found to be 1.95 BM. The high value of magnetic moment of complex (2) in comparison to the previous complexes (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) in spite of the polymeric nature of this complex, which contains three copper atoms, is due to the absence of any Cu-Cu interaction within this complex either in the xy or directions. The data of electronic spectra and magnetic moments are shown in Table 2.…”

“…The value of o λ (spin-orbital coupling constant) for d 9 -system equals −828 cm −1 . Hathaway [31] pointed out that that in case of pure σ-bonding, K || = K ⊥ = 0.77 and for in-plane π-bonding K || < K ⊥ , while for out-of-plane π-bonding K ⊥ < K || the following simplified expressions were used to calculate K || and K ⊥ .…”

“…CAH is considered as an intermediate for the synthesis of a variety of heterocyclic compounds. The β-functional nitrile [6] [7] [8] [9] moiety in the compound is a favorable unit for addition followed by cyclization or via cyclo-addition with numerous reagents providing heterocyclic compounds having different ring sizes with one or several heteroatoms that are interesting as pharmaceuticals [10] [11], herbicides [12], antibacterial agents [13], and dyes [14] [15]. Also, hydrazides find wide applications as drugs, chemical preservers for plants, manufacturing polymers, glues and many other purposes [16].…”

Triazole‐Pyridine Dicarbonitrile Targets Phosphodiesterase 4 to Induce Cytotoxicity in Lung Carcinoma Cells

“…In the present study, the green procedure for the synthesis of triazolo‐pyridine dicarbonitriles and dihydropyridine dicarbonitriles catalyzed by TBAB in water has been reported. In a similar eco‐friendly approach, the synthesis of highly functionalized pyridines, 1,2,4‐triazolo[1,5‐ a ]pyridines and 1,2,4‐triazolo[1,5‐ a ]isoquinolines were reported earlier . The reaction between 4‐bromobenzaldehyde ( 1 ), malononitrile ( 2 ), cyanoacetohydrazide ( 3 ) and cyclohexanone ( 4 ) was considered to optimize the reaction conditions using various solvents and catalysts ( Table ).…”

“…In a similar ecofriendly approach, the synthesis of highly functionalized pyridines, 1,2,4-triazolo[1,5-a]pyridines and 1,2,4triazolo [1,5-a]isoquinolines were reported earlier. [35,36] The reaction between 4-bromobenzaldehyde (1), malononitrile (2), cyanoacetohydrazide (3) and cyclohexanone (4) was considered to optimize the reaction conditions using various solvents and catalysts (Table 1).…”