Substituted hexahydroindazoles were obtained by the reaction of 6-arylidene-2-furfurylidenecyclohexanones with phenylhydrazine. It was concluded by means of the NMR spectra that azacyclization takes place regioselectively with participation of the arylidenecyclohexanone fragment.Compounds containing the hexahydroindazole fragment are biologically active and can be used as depressants of the central nervous system [1, 2] and antiinflammatory [3][4][5] and antimicrobial [6] agents. α,β-Unsaturated ketones are widely used in organic synthesis for the production of heterocyclic compounds.There are data on the synthesis of hexahydroindazoles by the reaction of alicyclic α,β-unsaturated ketones and their hetero analogs (2,6-diarylidene-and 2,6-difurfurylidenecyclanones [7-11], 3,5-diarylidenethiopyran-4-ones [12], 3,5-diarylidenepiperid-4-ones [3]) with hydrazines. The reactions of unsymmetrical arylidenehetarylidenecyclanones with hydrazines have not been studied before.In the present work we describe the synthesis and discuss the structure of the previously unknown 3-aryl-7-(5-R-furfurylidene)-2-phenyl-3,3a,4,5,6,7-hexahydroindazoles 1a-i. Compounds 1a-i were obtained by the reaction of our previously described [13] 6-arylidene-2-furfurylidenecyclohexanones 2a-i with phenylhydrazine by boiling in alcohol solution with a ketone-phenylhydrazine ratio of 1:8. Here it was found that the nature of the substituent R 1 had a significant effect on the activity of the ketones 2 in the reaction and, consequently, on the yields of the products 1 (55-89%).The hexahydroindazoles 1a,b,g,i were obtained with the highest yields (82-89%). The yields of the products 1e,f were significantly lower (55-62%) on account, probably, of the steric effect of the ortho substituent on the azacyclization process. O O R N N H H O R R 1 R 1 NH 2 NHPh 2 a-i 1 a-i a R = R 1 = H; b R = H, R 1 = 3-NO 2 ; c R = H, R 1 = 4-OMe; d R = H, R 1 = 4-Br; e R = H, R 1 = 2-Cl; f R = H, R 1 = 2-F; g R = Me, R 1 = 3-NO 2 ; h R = Me, R 1 = H; i R = NO 2 , R 1 = H __________________________________________________________________________________________ N.