Alguns novos derivados de pirazol-5-carbonitrila 8,9 e pirazol-5-carboxamida 13 foram sintetizados pela reação de cicloadição de nitriliminas 3,4 a α-cianocinamonitrilas 5a-f e α-cianocinamamida 12a,b, respectivamente. Por outro lado, a adição de 3,4 a α-cianocinamato de etila 14a-f leva à produção de derivados de 2-pyrazoline-5-carboxilato de etila, 15, 16. Também, a cicloadição de 3,4 à 3-cianocumarina 19a ou à 3-fenilsulfonilcumarina 19b ou à 3-bromocumarina 19c leva à produção de derivados do cromeno[3,4-c]pirazol-4(3H)-ona, 20. A cicloadição de 3,4 à 3-acetilcumarina, 22 e 3-benzoilcumarina, 23, produz o correspondente diidrocromeno [3,4-c] pirazol-4(3H)-ona, 24 e 25, respectivamente. A oxidação de 24 e 25 produz 20. A maioria dos compostos preparados mostrou boa a moderada atividade antibacteriana e antifúngica.Some new pyrazole-5-carbonitrile derivatives 8,9 and pyrazole-5-carboxamide 13 were synthesized by the cycloaddition reaction of nitrilimines 3,4 to α-cyanocinnamonitriles 5a-f and α-cyanocinnamamide 12a,b respectively. On the other hand 3,4 add to ethyl α-cyanocinnamate 14a-f to give ethyl 2-pyrazoline-5-carboxylate derivatives 15,16. Also, cycloaddition of 3,4 to 3-cyanocoumarin 19a or 3-phenylsulphonylcoumarin 19b or 3-bromocoumarin 19c give chromeno [3,4-c]pyrazol-4(3H)-one derivatives 20. In the same direction, the cycloaddition of 3,4 to 3-acetylcoumarin 22 and 3-benzoylcoumarin 23 gives the corresponding dihydrochromeno[3,4-] pyrazol-4(3H)-one 24 and 25 respectively. Oxidation of 24 and 25 give 20. Most of the prepared compounds showed good to moderate antibacterial and antifungal activities.

The synthesis of antimicrobial activity spirocompounds was achieved via the reaction of hydrazonoyl halides 1 with exocyclic 4-arylidene-2-methylimidazolin-5-one 3 in benzene in the presence of triethylamine. Correct elemental analyses and spectral data (IR, 1 H NMR, 13 C NMR and MS) confirm the structure of the synthesized spirocompounds. All the synthesized compounds were evaluated in vitro for their antimicrobial activity against five gram-positive and two gram-negative bacteria using well diffusion method in Mueller-Hinton agar. Most of them exhibited significant antibacterial activity compared with selected standard drugs.