2-Benzopyrylium salts

The properties of 1,3-dimethyl-6,7-dialkoxy-2-benzopyrylium salts were studied. The heterocyclic oxygen atom is readily replaced by nitrogen by reaction of the 2-benzopyrylium salts with primary amines, hydrazine, phenylhydrazine, glycine ethyl ester, and hydroxylamine; reaction with secondary amines leads to naphthalene derivatives. The activities of the methyl groups in the 1 and 3 positions of the heterocyclic ring are compared.For Communication IX, see [6].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1308–1312, October, 1970.     

Zur synthese von 3,4-dihydro-2H-1,4-benzoxazin-2- und 3-carbonitrilen. II. Mitteilung über studien zur chemie der 1,4-oxazine

Reaction ofo-aminophenols la, lb and lc with alkeyl dibromopropionates selecrively leads to 2-substitured dihydro-1,4-benzoxazines. This high regioselectivity is explained by initial elimination of hydrogen bromide from the dibromopropionate to from a reactive Michael acceptor, which cyclized to the benzoxazines 3a, 3b and 3c after Michael addition to the amines 1. This mechanism is proven by reaction of the amines la-ld with the Michael acceptor 15 to yield the 2-carbonitriles 16a-l6d. Substitution of the methoxyl group in 18 by cyanide leads to the 3-carbonitrile 19.     

Attack of S- vs N-Nucleophiles on 2-halomethylquinazoline 3-Oxides

A comparison is made of thiols with amines in their mode of reaction with different substituted 2-halomethylquinazoline 3-oxides. Whereas the reaction of some amines (particularly small primary ones), as has long been known, leads to ring-enlarging rearrangement under certain conditions, all thiol nucleophiles we have observed, ranging from small to large, lead without rearrangement to direct benzylic substitution only. Preformed aminomethylquinazoline 3-oxides are shown not to rearrange to the corresponding 1,4-benzodiazepine 4-oxides. The mechanistic implications of these and other observations are discussed. Data on over forty new compounds are presented.     

Synthesis of substituted nortrop-2-enes and 3-vinylpyridin-2-ones via reaction of 1,2,3,4,5,6,7-heptamethoxycarbonylcycloheptatriene with primary amines

The mode of reaction of the 1,2,3,4,5,6,7-heptamethoxycarbonylcycloheptatriene with primary amines depends on the reaction conditions and leads to selective formation of N-substituted (heptamethoxycarbonyl)nortrop-2-enes and/or 3-vinylpyridin-2-ones bearing six ester groups. The influence of the solvent on the selectivity of the formation of nortropenes and pyridinones was studied.     

Selected Reactions of Diethyl (E)‐1‐(bromomethyl)‐2‐cyanovinylphosphonate with Secondary and Tertiary Amines

An easy regio‐ and stereoselective synthesis of new nitrogenous molecules 2a–e was successfully realized via an effective coupling reaction of diethyl (E)‐1‐(bromomethyl)‐2‐cyanovinylphosphonate 1 with various secondary amines in methanol. Hence, the use of less and more bulky secondary amines gives rise, respectively, to the successive (S_N2′) substitution–isomerization and (S_N2) substitution derivatives 2a–c and 2d–e . Moreover, the addition of tertiary amines to 1 in the same reaction conditions, leads exclusively to the rearranged vinyl ether 3 in good yields.     

Reactions of 4-chloro-3-formyl-coumarin with primary amines

The reaction of 4-chloro-3-formylcoumarin with primary amines in the presence of triethylamine was studied. The reaction with aliphatic and aromatic amines leads to N-substituted 4-amino-3-formylcoumarins, whereas hetarylamines react primarily with the formyl group to form a mixture of the Z-and E-isomers of N-substituted 3-aminomethylenechroman-2,4-diones. Replacement of the triethylamine by anhydrous sodium acetate in the reaction of chlorocoumarin with 2-aminopyridines leads to the formation of the condensed benzopyranopyridopyrimidine system as a result of nucleophilic attack of the amino group by the chlorine atom at position 4. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 660–668, May, 2006.     

Preparation of 5-methyl-3H-oxazolo[4,5-b]pyridine-2-thione and its reaction with amines

5-Methyl-3H-oxazolo[4,5-b]pyridine-2-thione, which exists in the dipolar form, was obtained by the reaction of 6-methyl-2-amino-3-hydroxypyridine with potassium ethylxanthate. The reaction of the product with amines leads to the corresponding thioureas.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 608–610, May, 1981.     

Reaction of 2-chloroindole-3-carbaldehyde with epihalogenohydrins. Tandem oxirane-opening—1,3-oxazole-closure process

Reaction of 2-chloroindole-3-carbaldehyde with epibromohydrin gives the expected 1-(oxiran-2-ylmethyl) derivative. However the analogous reaction with epichlorohydrin leads to the formation of the oxazolo[3,2-a]indole skeleton. Some chemical properties of this tricyclic system were investigated. Its reaction with secondary amines unexpectedly proceeds with the opening of the oxazole ring.     

Recyclization of 4,5-diphenyloxazolin-2-one and -2-thione under the influence of amines

4,5-Diphenyl-4-oxazolin-2-one and -2-thione undergo recyclization to 1-substituted 4,5-diphenyl-4-imidazolin-2-ones and -2-thiones, respectively, under the influence of primary amines. The action of hydrazine hydrate on the oxazolone leads to 5,6-diphenyl-1,2,3,4-tetrahydro-1,2,4-triazin-3-one. The corresponding ureas were isolated from the reaction mixtures in a number of cases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1028–1030, August, 1981.     

Aminomethylation of N-methylmorpholinium 6-amino-4-aryl-3,5-dicyano-1,4-dihydropyridine-2-selenolates as an approach to the preparation of 3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene-8-selenone derivatives

A reaction of N-methylmorpholinium 6-amino-4-aryl-3,5-dicyano-1,4-dihydropyridine-2-selenolates with primary amines and excess of formaldehyde leads to 3,5,7,11-tetraazatricyclo[7.3.1.0^2,7]tridec-2-ene-8-selenone derivatives. The same compounds were obtained by a multicomponent cascade cyclocondensation of benzaldehyde, cyanoselenoacetamide, primary amine, and excess of formaldehyde.     

Synthesis of 2-dialkylaminomethyltetrahydrofuran-3-ols

The reaction of esters of 4-R-3-methyl-2,3,4,5-diepoxyvaleric acids with secondary amines leads to the formation of esters of 4-R-5-dialkylamino-4-hydroxy-3-methyl-2,3-epoxyvaleric acids. The reduction of the latter with lithium tetrahydroaluminate and the cyclization of the reduction products in the presence of p-toluenesulfonic acid has given 2-dialkylaminoethyltetrahydrofuran-3-ols, the methiodides of which possess ganglion-blocking activity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1446, November, 1973.     

4-arylamino-2-(2-acetoxyethyl)amino-6-methylpyrimidines: Synthesis,deacetylation, and biological activity

The reaction of 2-(2-acetoxyethyl)amino-4-chloro-6-methylpyrimidine with aromatic amines leads to a series of 4-arylamino-2-(2-acetoxyethyl)amino-6-methylpyrimidines. Deacetylation of these compounds proceeds in both acidic and basic media. Most of the arylaminopyrimides obtained exhibit a pronounced antituberculous effect.     

2,2-Diorganyl-6-(O,O-diethylphosphonomethyl)-1,3-dioxa-6-aza-2-silacyclooctanes and 0,0-diethyl-phosphonomethylbis(2-trimethylsiloxyethyl)amine

Conclusions The reaction of O,O-diethylphosphonomethylbis(2-hydroxyethyl)amine with dialkylbis(di-ethylamino)silanes and hexamethyldisilazane leads to 2,2-dialkyl-6-(O,O-diethylphosphono-methyl)-1,3-dioxa-6-aza-2-silacyclooctanes and O,O-diethylphosphonomethylbis(2-trimethyl-silyloxyethyl)amines, respectively.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2590–2591, November, 1987.     

Polymers of tertiary amines

Polymers of tertiary amines and their hydrochlorides of molecular weights in the range 300–2000 have been prepared, starting from trans-1,4-dichlorobutene-2, and primary amines. The polymers present interesting solubility properties. Variation of the reaction conditions leads to crosslinked insoluble polymers. Reaction of the soluble tertiary amine polymers with organic acid dichlorides leads to polymers of tertiary amine–amides, a new type of polymer.     

Oxitranyl-Β-aminovinyl ketones. 2. Synthesis of 3(2H)-furanones

The reaction of oxiranyl--dimethylaminovinyl ketones with secondary amines, hydrochloric, and hydrobromic acids leads to the formation of the corresponding 2-aminomethyl- and 2-halomethyl-3-(2H)-furanones.For Communication 1, see [1].Translated from Khimiii Geterotsiklicheskikh Soedinenii, No. 12, pp. 1600–1603, December, 1988.Original article submitted May 20, 1987.     

Facile reaction of thiols and amines with alkyl 4-hydroxy-2-alkynoates in water under neutral conditions and ultrasound irradiation

This Letter describes an alternative protocol for the Michael addition of thiols to 4-hydroxy-2-alkynoates. The reaction proceeds at room temperature in water under ultrasound irradiation. With amines instead of thiols a sequential conjugate addition/lactonization reaction leads to important 4-amino-furan-2-one derivatives.     

CO2 Conversion with Alcohols and Amines into Carbonates,Ureas, and Carbamates over CeO2 Catalyst in the Presence and Absence of 2‐Cyanopyridine

Recent progress on the CeO₂ catalyzed synthesis of organic carbonates, ureas, and carbamates from CO₂+alcohols, CO₂+amines, and CO₂+alcohols+amines, respectively, is reviewed. The reactions of CO₂ with alcohols and amines are reversible ones and the degree of the equilibrium limitation of the synthesis reactions is strongly dependent on the properties of alcohols and amines as the substrates. When the equilibrium limitation of the reaction is serious, the equilibrium conversion of the substrate and the yield of the target product is very low, therefore, the shift of the equilibrium reaction to the product side by the removal of H₂O is essential in order to get the target product in high yield. One of the effective method of the H₂O removal from the related reaction systems is the combination with the hydration of 2‐cyanopyridine to 2‐picolinamide, which is also catalyzed by CeO₂.     

Synthesis of substituted 1,1′-diaminoferrocenes from cyclo-2-pentene imines

Condensation of anilines and primary aliphatic amines with 3,4-diphenylcyclo-2-pentenone leads to the corresponding diphenylcyclopentene imines in good yields of 72-90%. Deprotonation of these aminocyclopentadiene tautomers and reaction with FeCl₂ leads to the synthesis of the respective 1,1′-diamino-3,3′,4,4′-tetraphenylferrocenes. Yields increase from 33% to 65% with a decrease in the steric bulk of the amine substituent. The observation that a successful conversion requires two equivalents of base is conceived on the basis of the discussed reaction mechanism. The molecular structure of 1,1′-dianilino-3,3′,4,4′-tetraphenylferrocene (3a), which was determined by single crystal X-ray analysis reveals a trans coordination of the two amine moieties with respect to the central Cp-Fe-Cp axis of the ferrocenyl backbone.     

Zur Umsetzung des 3,4,5,6-Tetrahydro-6-hydroxy-4,4,6-trimethyl-1,3-thiazin-2-thions mit sekundären Aminen

Tetrahydro-6-hydroxy-trimethyl-1,3-thiazine-2-thione (1) reacts with secondary amines via the dialkylammonium-3-oxoalkyldithiocarbamate3, either via isothiocyanates6 to 4-dialkylaminodihydro-2(1H)-pyridinethiones7 or to dialkylammonium dithiocarbamates (13), depending on the amine used and the reaction conditions. Subsequently, 6-dialkylaminotetrahydro-1,3-thiazine-2-thiones11 or tetrahydro-6-mercapto-1,3-thiazine-2-thione10 are formed. On being heated to reflux,11 reacts to pyridinethione7 and 4-dialkylaminodihydrothiopyranthione19. With secondary amines only13 is formed from tetrahydro-6-hydroxytetramethyl-1,3-thiazine-2-thione20. The reaction of dihydrotrimethyl-1,3-thiazine-2-thione21 with secondary amines leads to N,N-dialkylthioureas16 or dialkylammonium thiocyanates17 and with dialkylformamides 4-dialkylaminodihydropyridinethiones7 are formed. Dihydrotetramethyl-1,3-thiazine-2-thione24 reacts neither with secondary amines nor with dialkylformamides.