A. A. Potekhin

New one-step procedure for the synthesis of 6H-chromeno[4,3-b]quinolines and 8a,9,14,14a-tetrahydro-8H-benzo[5,6]chromeno[4,3-b]quinolines

Schiff bases generated in situ from substituted anilines and 2-allyloxybenzaldehyde underwent acid-catalyzed intramolecular Diels-Alder reaction followed by dehydrogenation to give 6H-chromeno[4,3-b]-quinolines. Under analogous conditions, derivatives of 2-allyloxynaphthalene-1-carbaldehyde were converted into 8a,9,14,14a-tetrahydro-8H-benzo[5,6]chromeno[4,3-b]quinolines. Possible dehydrogenation mechanisms are discussed.

Addition of organometallic reagents to nitriles promoted by titanium(IV) isopropoxide as a procedure of synthesis of primary tert-alkylamines

Grignard reagents are able to add twice to nitriles in the presence of titanium(IV) isopropoxide providing primary tert-alkylamines in a fair yield. The conditions and structural features of reagents required for successful reaction were established. A possibility to apply two different organometallic reagents was demonstrated, in particular, the use of organolithium compounds in the second stage.

Reactions of 2-(α-Haloalkyl)thiiranes with Nucleophilic Reagents: IV. Alkylation of Sulfonamides with 2-Chloromethylthiirane. Synthesis and Properties of 3-(Arylamino)thietanes

Alkylation of primary and secondary sulfonamides with 2-chloromethylthiirane in the presence of alkali gives the corresponding N-(thiiran-2-ylmethyl)- and/or N-(thietan-3-yl)sulfonamides. The selectivity of the process depends on the solvent: in water, thiirane-thietane rearrangement products are formed exclusively, while ethanol favors Ad-E reaction leading to thiiranylmethyl derivatives. A procedure has been proposed for the synthesis of 3-(arylamino)thietanes which undergo selective acylation at the nitrogen atom. The possibility for synthesizing analogous derivatives of thietane 1-oxide and thietane 1,1-dioxide is considered.

Reaction of 4-(N,N-Dimethylaminophenyl)magnesium Bromide with Palladium Tetrakis(triphenylphosphine)

Abstract(α-Chloroalkyl)thiiranes react with sodium phenolates at heating in water-alcohol mixtures furnishing phenoxymethylthiiranes, 3-phenoxythietanes (resulting from thiirane-thietane rearrangement), or their mixture. The increased polarity of solvent favors the thiirane-thietane rearrangement. 2,2-Dimethyl-3-(chloromethyl)thiirane forms an exclusion for it does not afford (phenoxymethyl)thiirane even in anhydrous ethanol. Diastereomeric erythro- and threo-(1-chloroethyl)thiiranes react stereospecifically giving 2-methyl-3-phenoxymethylthiiranes or 2-methyl-3-phenoxythietanes of trans- and cis-configuration respectively. Specific features of these reactions are discussed from the viewpoint of solvent polarity effect on the competition between formal chlorine substitution along “recyclization” mechanism or through thiirane-thietane rearrangement.

Ring-chain tautomerism of substituted hydrazones

It is shown that 5,6-dihydro derivatives are formed as a result of the oxidation of 2-unsubstituted or 2-monosubstituted perhydro-1,3,4-oxadiazines with yellow mercuric oxide.

Synthesis of nitrogen heterocycles by means of nitrenes: II. Five-membered heterocycles with several heteroatoms (review)

The intramolecular cyclization of heteroanalogs of 1,3-butadien-1-ylnitrenes, the expansion and contraction of the rings of hetarylnitrenes, the incorporation of nitrenes, and the intermolecular dipolar cycloaddition of acylnitrenes to unsaturated compounds, which leads to the formation of five-membered nitrogen heterocycles with several heteroatoms, are examined.

Chemoselective cyclocondensation of α-acylacetamidines with 2-methylsulfanyl-4,6-dichloropyrimidine-5-carbaldehyde

Cyclocondensation of α-acylacetamidine with 2-methylsulfanyl-4,6-dichloropyrimidine-5-carbaldehyde proceeds chemo- and regioselectively involving replacement by the α-carbon of the amidine of the chlorine in the aromatic ring and a reaction of the amino group with the formyl group.

Cyclocondensation of 2-Fluoro-5-nitrobenzaldehyde with Amidines. New Synthesis of Isoquinolines

The direction of the cyclocondensation of 2-fluoro-5-nitrobenzaldehyde with five amidines having α-hydrogen atoms has been studied. It was established that depending on the structure of the amidine the main products of the reaction may be not only quinazolines but also 3-aminoisoquinolines. A new convenient route has been found for the synthesis of 3-aminoisoquinolines consisting of the cyclocondensation of α-acylacetamidines with 2-fluoro-5-nitrobenzaldehyde.

Addition of thiiranes to δ1-piperideines and δ1-pyrrolines

The reaction of 2,3,4,5-tetrahydropyridines and 1-pyrrolines with thiiranes, which leads to perhydrothiazolo[2,3-a]pyridines and perhydropyrrolo[2,1-b]thiazoles, is described. The regiospecificity and stereoselectivity of the reaction are examined.

Synthesis of nitrogen heterocycles by means of nitrenes

The literature data on the synthesis of pyrroles, indoles, carbazoles, and other condensed systems containing a pyrrole ring and on their hydrogenated derivatives by means of nitrenes and potential precursors of the latter are correlated.