Vol 60, No 1 (2024)

The review summarizes recent achievements in the synthesis of 3-azabicyclo[3.1.0]hexanes (3-ABH). These heterocyclic systems are ubiquitous in the structure of molecules that can act on a variety of biological targets and are actively used in drug design. Classification and analysis of the modern approaches to 3-ABHs based on the use of transition metal complexes are carried out, and the mechanisms of the key processes are considered. The presented reactions include the assembly of 3-ABH by annulation of three- or five-membered rings as well as numerous one-step syntheses from acyclic precursors via tandem cyclizations.

Acid-catalyzed carbonylation of a number of polyfluorinated benzocyclobuten-1-ols, as well as cyclic sulfoesters of benzocyclobuten-1,2-diols, in reaction with carbon monoxide has been carried out. The efficiency of using TfOH and FSO₃H-SbF₅ as acidic systems was evaluated. Both products of CO addition with the remaining four-membered ring — the corresponding carboxylic acids, and various products of carbonylation accompanied by its transformations (ring opening, opening followed by heterocyclization with the formation of isochromane derivatives, expansion to a five-membered one) were obtained. In some cases, the formation of polycyclic dimeric products was also observed.

It was found that the Cp₂ZrCl₂-EtMgBr-catalyzed reaction of 2-alkynylamines with Et₂Zn leads to the regio- and stereoselective formation of (2Z)-allylamines in high yield. It has been established that the presence of morpholyl and piperidyl substituents in the structure of propargylamines does not interfere with the regio- and stereoselective 2-zincoethylzincation of the triple bond. Carbocyclization of α,ω-bis(aminomethyl)alkadiynes based on the Cp₂ZrCl₂-EtMgBr-catalyzed carbozincation reaction with Et₂Zn was carried out for the first time. A mechanism for the catalytic 2-zincoethylzincation of α,ω-bis(aminomethyl)alkadiynes was proposed.

Alkylation of 3,4-methylenedioxyphenylacetоnitrile with 2,2-dichlorodiethyl ether gave the corresponding nitrile the reduction of which with lithium aluminum hydride isolated (4-(benzo[d][1,3]dioxol-6-yl)-tetrahydro-2H-pyran-4-yl)methylamine. The interaction of the latter with aryloxymethyloxiranes gave the corresponding 1-((4-(benzo[d][1,3]dioxol-6-yl)-tetrahydro-2H-pyran-4-yl)methylamino)-3-aryloxypropan-2-ols. By the reaction of the same amine with chloroacetyl chloride isolated chloroacetamide, the interaction of which with a variety of secondary amines and heterylthiols synthesized the corresponding substituted amino- and sulfanylacetamides - derivatives of (4-(benzo[d][1,3]dioxol-6-yl)-tetrahydro-2H-pyran-4-yl)methylamine. The antioxidant activity of the obtained compounds was studied.

By the reaction of 3-alkyl-5-(diethylaminomethyl) pyrazoles with chloroanhydride of monochloroacetic acid, the pyrazoles with chloromethyl carbonyl substituent have been synthesized. Due to presence of reactive COCH₂Cl groups in a molecule, the pyrazoles have been subjected to heterocyclization with thicarbamides (thiobenzamide, thicarbamide and phenylthiocarbamide) in the presence of triethyleamine in a medium of ethanol, as a result of which the previously unknown 3-alkyl-5-diethylaminomethyl-1-(1,3-thiazol)substituted pyrazole derivatives have been obtained.

A four-component approach was developed for the synthesis of cis- and trans-diastereomeric partially hydrogenated pyrido[1,2-a]pyrimidines and pyrido[2,1-b]quinazolines based on the cyclization of ethyl trifluoroacetoacetate with two acetaldehyde molecules and 1,3-diaminopropane or 2-aminomethylaniline. The zwitterionic salt of tetrahydropyrimidine was isolated as a by-product from the reaction with 1,3-diaminopropane. And from the reaction with 2-aminomethylaniline 7-hydroxy-7-(trifluoromethyl)-5,5a,6,7,8,11-hexahydro-9H-pyrido[2,1-b]quinazolin-9-one was obtained as a result of the participation of one aldehyde molecule. The diastereomeric structure of the synthesized heterocycles was established on the basis of ¹Н, ¹⁹F, ¹³С NMR spectroscopy and XRD. A mechanism for the formation of new heteroannulated pyridines was proposed.