Diaziridine Ring Research Articles

Pyridine‐Catalysed Desulfonylative Addition of β‐Diketones to Arylazosulfones via Diaziridine Rearrangement

AbstractA pyridine‐catalysed desulfonylative addition of β‐diketones to arylazosulfones was developed to obtain diazenyl β‐dicarbonyl compounds. The aryldiazenyl group was observed in the desired product from arylazosulfones, and this diazenylation reaction was achieved via a possible rearrangement process based on diaziridine ring cleavage. The scope of the protocol was investigated and a plausible mechanism was given.magnified image

ChemInform Abstract: CAN‐Mediated New, Regioselective One‐Pot Access to Bicyclic Cationic Structures with 2,3‐Dihydro‐1H‐pyrazolo[1,2‐a]pyrazol‐4‐ium Core.

Abstract A new, facile, regioselective ceric ammonium nitrate (CAN)-mediated one-pot access to bridgehead hydrazine bicyclic cationic structures with 2,3-dihydro-1H-pyrazolo[1,2-a]pyrazol-4-ium cations and [Ce3+(NO3)6]3− anion has been developed. The approach comprises [3+2]-cycloaddition of (2-bromo-2-nitrovinyl)arenes to N,N-cyclic azomethine imines, generated in situ by diaziridine ring opening in 6-Ar-1,5-diazabicyclo[3.1.0]hexanes or by metathesis of initially formed azomethine imine, followed by one-pot aromatization of the formed pyrazolidine ring.

CAN-mediated new, regioselective one-pot access to bicyclic cationic structures with 2,3-dihydro-1H-pyrazolo[1,2-a]pyrazol-4-ium core

A new, facile, regioselective ceric ammonium nitrate (CAN)-mediated one-pot access to bridgehead hydrazine bicyclic cationic structures with 2,3-dihydro-1H-pyrazolo[1,2-a]pyrazol-4-ium cations and [Ce3+(NO3)6]3− anion has been developed. The approach comprises [3+2]-cycloaddition of (2-bromo-2-nitrovinyl)arenes to N,N-cyclic azomethine imines, generated in situ by diaziridine ring opening in 6-Ar-1,5-diazabicyclo[3.1.0]hexanes or by metathesis of initially formed azomethine imine, followed by one-pot aromatization of the formed pyrazolidine ring.

ChemInform Abstract: Generation and Metathesis of Azomethine Imines in Reaction of 6‐Aryl‐1,5‐diazabicyclo[3.1.0]hexanes with Het(aryl)methylidenemalononitriles.

A new metathesis reaction of azomethine imines is found. Catalytic or thermal diaziridine ring opening of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes leads to azomethine imines reacting further with het(aryl)methylidenemalononitriles to give in situ new azomethine imines inaccessible by common synthetic methods. New azomethine imines are detected as pyrazolines formed via a 1,4-H shift and trapped by the [3+2] cycloaddition with various dipolarophiles to yield 1,5-diazabicyclo[3.3.0]octane derivatives bearing pharmacophoric heterocycles, e.g. furan, nitrofuran, thiophene, and indole. The best results are achieved in the Et2O·BF3-catalyzed reactions in ionic liquids.

Synthesis and Transformations of Nitrogen Heterocycles in Ionic Liquids (Review)

A review is given for our work in the Nitrogen Compound Laboratory of the Institute of Organic Chemistry of the Russian Academy of Sciences over the past 10 years on the use of ionic liquids as reaction media and catalysts in the 1,3-dipolar cycloaddition of various 1,3-dipoles, such as azomethine imines, azides, and nitrile oxides, including domino reactions for the expansion of the three-membered diaziridine ring in monocyclic diaziridine derivatives and condensation reactions such as the synthesis of aminothiadiazoles and dihydroisoquinolines. The Schmidt rearrangement and Henry and Mannich reactions of polynitroalkanes in ionic liquids are also discussed.

Generation and metathesis of azomethine imines in reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with het(aryl)methylidenemalononitriles

A new metathesis reaction of azomethine imines is found. Catalytic or thermal diaziridine ring opening of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes leads to azomethine imines reacting further with het(aryl)methylidenemalononitriles to give in situ new azomethine imines inaccessible by common synthetic methods. New azomethine imines are detected as pyrazolines formed via a 1,4-H shift and trapped by the [3+2] cycloaddition with various dipolarophiles to yield 1,5-diazabicyclo[3.3.0]octane derivatives bearing pharmacophoric heterocycles, e.g. furan, nitrofuran, thiophene, and indole. The best results are achieved in the Et2O·BF3-catalyzed reactions in ionic liquids.

Reaction of 1,2‐Dialkyldiaziridines and 1,2,3‐Trialkyldiaziridines with Methyl Propiolate in Ionic Liquids and in Organic Solvents

An interaction of 1,2‐dialkyldiaziridine and 1,2,3‐trialkyldiaziridine with methyl propiolate was studied both in organic solvent (MeCN, CH2Cl2, C6H6) and in ionic liquids. Earlier unknown linear structures, in which three molecules of methyl propiolate were suited to one diaziridine molecule (adducts 1 : 3), were obtained in MeCN. The diaziridine ring expansion products 1,2,3,4‐tetrahydropyrimidine derivatives (adducts 1 : 2) and, along with them in some cases, the same linear structures were obtained in ionic liquids. A mechanism of reactions found was offered. The regioselectivity of reactions was supposed to determine by the structure of substituents in initial diaziridines. This conclusion was supported by quantum chemical calculations.

ChemInform Abstract: Metathesis of Azomethine Imines in the Reaction of 6‐Aryl‐1,5‐diazabicyclo[3.1.0]hexanes with Carbonyl Compounds.

AbstractThe interaction of carbonyl compounds (II) or (VII) with azomethine imines generated by diaziridine ring opening in (I) in the presence of catalytic amounts of BF3·OEt2 induces a metathesis to other azomethine imines with the elimination of aldehydes.

Metathesis of azomethine imines in the reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with carbonyl compounds

An interaction of carbonyl compounds (isatins, 4-nitrobenzaldehyde) with azomethine imines generated by the diaziridine ring opening in 6-aryl-1,5-diazabicyclo[3.1.0]hexanes in the presence of BF 3 ·Et 2 O as a catalyst induced the metathesis to other azomethine imines with the elimination of aldehydes ArCHO. New azomethine imines were trapped with diethyl acetylenedicarboxylate, otherwise they transformed to the corresponding pyrazolines due to a 1,4-H shift.

ChemInform Abstract: Diaziridine Ring Expansion in 6‐Aryl‐1,5‐diazabicyclo[3.1.0]hexanes upon Reactions with Activated Olefins in Ionic Liquids.

AbstractReactions of activated trans‐olefins with azomethine imines, generated from diaziridines (I) on catalysis with boron trifluoride etherate in ionic liquids, are found to proceed with high regio‐ and stereoselectivity to afford diaziridine ring expansion products.

Generation of azomethine imines via opening of the diaziridine ring in unsymmetrically substituted 6-aryl-1,5-diazabicyclo-[3.1.0]hexanes and their transformations

Thermally induced opening of the diaziridine ring at the carbon-nitrogen bond in unsymmetrically substituted 6-aryl-1,5-diazabicyclo[3.1.0]hexanes is characterized by low regioselectivity which is likely to be determined by the inductive effect of substituents in the trimethylene bridge. 1,3-Dipolar cycloaddition of the resulting azomethine imines to phenyl isocyanate is regioselective: it occurs at the double carbon-nitrogen bond with predominant formation of the corresponding cis adducts due to dipolarophile approach to Z-azomethine imine at the sterically less hindered side. Analogous approach of dipolarophile is also observed in the reaction with N-arylmaleimides.

Diaziridine ring expansion in 6-aryl-1,5-diazabicyclo[3.1.0]hexanes upon reactions with activated olefins in ionic liquids

Reactions of 1,3-diphenylpropen-2-one and α-nitrostyrenes with azomethine imines, generated from 6-aryl-1,5-diazabicyclo[3.1.0]hexanes on catalysis with Et2O•BF3 in ionic liquids, were found to proceed with high regio- and stereoselectivity to afford the products of the diaziridine ring expansion, viz., [3-aryl-2-phenyltetrahydro-1H,5H-pyrazolo[1,2-a]pyrazol- 1-yl](phenyl)methanones, 1,3-diaryl-2-nitrotetrahydro-1H,5H-pyrazolo[1,2-a]pyrazoles and 5-aryl-6-(3-nitrophenyl)-2,3-dihydro-1H-pyrazolo[1,2-a]pyrazolium tetrafluoroborates (hexafluorophosphates). The reactions discovered are new, more simple methods for the syn- thesis of bicyclic structures.

ChemInform Abstract: Insertion of Carbon Disulfide and the Nitrile Group into the Diaziridine Ring of 6‐Aryl‐1,5‐diazabicyclo[3.1.0]hexanes in Ionic Liquids Catalyzed by BF3·Et2O.

AbstractThe insertion of CS2 as well as activated nitriles (V) into the bicyclic diaziridines (I) proceeds smoothly in ionic liquids in the presence of BF3·OEt2 to afford pyrazolothiadiazoles (III) as well as pyrazolotriazoles (V), respectively.

Reaction of 1-arylmethylidenepyrazolidin-1-azomethine imines with aryl ketenes

A reaction of aryl ketenes with 1-arylmethylidenepyrazolidin-1-azomethine imines, generated by the diaziridine ring opening in 6-aryl-1,5-diazabicyclo[3.1.0]hexanes catalyzed with Et2O·BF3, leads to 1,2-bis(phenylacetyl)pyrazolidine, 2-arylacetyl-1-arylidenepyrazolidin-1-ium chlorides, or a representative of 1,5-diazabicyclo[3.3.0]octan-2-ones, viz., 4-(4-eth-oxyphenyl)-3,3-diphenyl-1,5-diazabicyclo[3.3.0]octan-2-one, depending on the reaction conditions and the structure of the starting compounds. A mechanism suggested earlier for the transformation of 1,5-diazabicyclo[3.1.0]hexanes in the reaction with ketenes was confirmed.

Insertion of carbon disulfide and the nitrile group into the diaziridine ring of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes in ionic liquids catalyzed by BF3 · Et2O

The present study revealed two new reactions resulting in the diaziridine ring expansion, viz., the insertion of the CS 2 molecule and the CN group of activated nitriles into the C—N bond of the diaziridine fragment of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes. These reactions can be performed only in ionic liquids in the presence of BF 3 · Et 2 O as the catalyst. Based on these reactions, we developed simple one-pot methods for the synthesis of 3-aryldihydro-5 H-pyrazolo[1,2- c][1,3,4]thiadiazole-1-thiones and 1-aryl-6,7-dihydro-1 H,5H-pyrazolo-[1,2-a][1,2,4]triazoles in high yields. Dipolar intermediates of new reactions, which are direct precursors of the final products, were detected by NMR methods. One of the intermediates was isolated and characterized. The reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with benzoyl cyanide affords (2-benzoyrpyrazolidin-1-yl)(aryl)acetonitriles.

ChemInform Abstract: Diaziridine Ring Expansion in 6‐Aryl‐1,5‐Diazabicyclo[3.1.0]hexanes on Treatment with Nitriles Assisted by Ionic Liquids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Diaziridine ring expansion in 6-aryl-1,5-diazabicyclo[3.1.0]hexanes on treatment with nitriles assisted by ionic liquids

The ionic-liquids-assisted insertion of activated nitriles into the diaziridine ring of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes catalysed with BF 3 ·Et 2 O provides a simple method for the preparation of 1-aryl-6,7-dihydro-1 H ,5 H -pyrazolo[1,2- a ][1,2,4]triazoles.

Thermal opening of the diaziridine fragment in 1-methyl-and 1,3,3-trimethyl-1,3,4,8b-tetrahydro-[1,2]diazirino[3,1-a]isoquinolines in the presence of n-arylmaleimides

The thermal opening of the diaziridine ring in 1-methyl-and 1,3,3-trimethyl-1,3,4,8b-tetra-hydro[1,2]diazirino[3,1-a]isoquinolines in the presence of N-arylmaleimides leads to the predominant or exclusive formation of the trans isomers of the products of 1,3-dipolar cycloaddition. In the absence of dipolarophile, the conversion of the starting diaziridines is incomplete over the same time period, while the thermolysis products are N-[3,4-dihydro-2(1H)-isoquinolyl]-and N-[3,3-dimethyl-3,4-di-hydro-2(1H)-isoquinolyl]-N-methyleneamines formed as the result of isomerization of intermediate labile azomethineimines.

Insertion of carbon disulfide into the diaziridine ring of 6-aryl-1,5-diazabicylo[3.1.0]hexanes assisted by ionic liquids

3-(4-Aryl)dihydro-5H-pyrazolo[1,2-c][1,3,4]thiadiazole-1-thiones have been synthesised by the title reaction catalysed by Et2O·BF3.

Quantum-chemical investigation of the mechanism of reaction between 1,2-dialkyldiaziridines and heterocumulenes

By quantum-chemical method in the framework of the density functional theory [B3LYP/6-31G(d)] a mechanism of reaction between 1,2-dialkyldiaziridines and ketenes CH2=C=O, PhCH=C=O, and aroyl isocyanates was investigated. The fragment Ph-CH-C(O) in the intermediate governing the cleavage of the N-N bond of the diaziridine ring is virtually planar leading to a considerable loosening of the bond. In the intermediate governing the cleavage of the C-N bond of the ring the fragment Ph-C(O)-N−C(O) is nonplanar resulting in significantly lesser loosening of the N-N bond and in the C-N-opening of the diaziridine ring. The calculated thermodynamical parameters are well consistent with the experimental data on the reactivity.