New methyl 5-aryl-1-(furan-2-carbonyl)-1H-pyrazole-3-carboxylates were obtained via decyclization reaction of N'-(5-aryl-2-oxofuran-3(2H)-ylidene)furan-2-carbohydrazides under the action of methanol. Starting N'-(5-aryl-2-oxofuran-3(2H)-ylidene)furan-2-carbohydrazides were obtained by intramolecular cyclization of substituted 4-aryl-2-[2-(furan-2-ylcarbonyl)hydrazinylidene]-4-oxobutanoic acids in propionic anhydride. The structure of the compounds obtained was confirmed by the 1H NMR spectroscopy, IR spectrometry and elemental analysis methods. Analgesic activity of some obtained compounds was studied by the “hot plate” method on outbred white mice of both sexes with intraperitoneal injection.

Substituted alkyl 4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with urea to give alkyl 2-(carbamoylamino)-4-hydroxy-5-oxo-2,5-dihydro-1H-pyrrole-2-carboxylates which underwent intramolecular cyclization to 8-hydroxy-1,3,6-triazaspiro[4.4]non-8-ene-2,4,7-triones by the action of sodium methoxide.

Reformatsky reagent generated from methyl 1-bromocyclohexane-1-carboxylate reacted with N-aryl-2-oxochromene-3-carboxamides and N-aryl-6-bromo-2-oxochromene-3-carboxamides to give, depending on the conditions, the corresponding N-aryl-(6-bromo)-4-(1-methoxycarbonylcyclohexyl)-2-oxochroman-3-carboxamides or 3-aryl-(9-bromo)-1,1-pentamethylene-2,3,4,4a,5,10b-hexahydro-1H-chromeno[3,4-c]pyridine-2,4,5-triones. The products were isolated as a single diastereoisomer.

A method was proposed for the synthesis of substituted 2-(2-(furan-2-carbonyl)hydrazono)-4-oxobutanoic acids by the reaction of substituted 2,4-dioxobut-2-enoic acids with furan-2-carbohydrazide. It was found that substituted 2-(2-(furan-2-carbonyl)hydrazono)-4-oxobutanoic acids undergo intramolecular cyclization in the presence of propionic anhydride to form the corresponding N'-(2-oxofuran-3(2H)-ylidene)furan-2-carbohydrazides. The anti-inflammatory activity of the obtained compounds was studied. It was found that the obtained compounds have pronounced anti-inflammatory activity.

A novel and efficient base-catalyzed, transition-metal-free method for the synthesis of diheterocyclic compounds connected by an amidine linker, including apart from the common 1,2,3-triazole ring, either an additional pyrimidinedione, 4-nitroimidazole, isoxazole, 1,3,4-triazole, 2-oxochromone or thiazole ring, has been developed. The process was facilitated by a strong base and includes the cycloaddition reaction of 3,3-diaminoacrylonitriles (2-cyanoacetamidines) to heterocyclic azides followed by a Cornforth-type rearrangement to the final products. The reaction is tolerant to various N-monosubstituted 3,3-diaminoacrylonitriles and to different heterocyclic azides. The developed method has a broad scope and can be applied to obtain a variety of N-heteroaryl-1,2,3-triazole-4-carbimidamides with alkyl, allyl, propargyl, benzyl, cycloalkyl, and indolyl substituents at the N¹ position .