Reactions of 2-Arylthio- and 2-Arylsulfonyl-1-nitro-1-phenylethenes with Amines

2-Arylthio- and 2-arylsulfonyl-1-nitro-1-phenylethenes react with amines to give the corresponding nitroenamines whose configuration (E or Z) depends on the amine structure. Primary amines gives rise to Z-nitroenamines, secondary cyclic amines with 2-arylthio-1-nitroalkenes form E-nitroenamines, and with more reactive 2-arylsulfonyl-1-nitroalkenes E/Z-isomeric mixtures are obtained.     

Reactions of 2-amino-, 2-alkylamino-, and 2-piperidino-1-azaazulenes with aryl and chlorosulfonyl isocyanates

Reaction of 2-amino-1-azaazulene with phenyl isocyanate gave 3-phenyl-2H-3,4-dihydro-1,3,4a-triazabenz[5,4-a]azulene-2,4-dione. Reactions of 2-alkylamino-1-azaazulenes with aryl isocyanates gave 2-(N-ethyl-N′-arylureido)-1-azaazulenes initially, which rearranged to N-aryl-2-alkylamino-1-azaazulene-3-carboxamides and successive reaction with another molar amount of aryl isocyanate furnished uracil-fuzed 1-azaazulenes. Reaction of 2-piperidino-1-azaazulene with aryl isocyanate gave N-aryl-2-piperidino-1-azaazulene-3-carboxamide. Reaction of 2-(substituted amino)-1-azaazulenes with chlorosulfonyl isocyanate gave 3-cyano- and 3-chloro-2-(substituted amino)-1-azaazulenes.     

Reactions of cis-2-Boryl-1-stannylalkenes with Carbodiimides, Thiocyanates, Isothiocyanates, and Isocyanates

The reactions of (E)-2-diethylboryl-1-trimethylstannylbut-1-ene and (Z)-3-diethylboryl-2-trimethylstannylpent-2-ene with carbodiimides, methyl thiocyanate, thioisocyanates, and isocyanates were studied, and the products were characterized by multinuclear magnetic resonance spectroscopy (¹H, ¹¹B, ¹³C and ¹¹⁹Sn NMR). It was found that carbodiimides bearing tert-butyl or trimethylsilyl groups at the nitrogen atoms do not react with (E)-2-boryl-1-stannylalkenes, in contrast to dicyclohexylcarbodiimide. There was also no reaction in the case of MeSCN. All other reactions proceed via a weak NB adduct formation in the initial step, followed by different rearrangements, depending on the structure of reagents as well as on the substitution pattern at the C=C bond in alkenes. New heterocycles are formed, in which the boron atom is either tricoordinated (1,2-azaborolenes, 1,2-azaborolan! es), a nd one ethyl group has been transferred to the neighbor olefinic carbon atom, or the boron atom is tetracoordinated (1,2-azaboratoles, 1,2-oxoniaboratoles), and the trimethylstannyl group has migrated to one of the heteroatoms of the heterocumulenes.     

Reactions of 2-hydroxybenzonitrile with isocyanates

Triethylamine catalyzes the reaction of 2-hydroxybenzonitrile ( 1 ) with aryl isocyanates to form the corresponding carbamates 2a-c , as well as the cyclization of the latter compounds to either 4[N-(N-arylcarbamoyl)-imino]-3-aryl-2H-1,3-benzoxazin-2-ones 4a-c , or 4-arylamino-2H-1,3-benzoxazin-2-ones 7a-c , depending on the reaction temperature. Under analogous conditions, the carbamates obtained from 1 and 2-chloroethyl isocyanate, 3-chloropropyl isocyanate and ethyl isocyanatoacetate undergo a double cyclization yielding imidazo- and pyrimido[1,2-c|1,3]benzoxazinones 13a,b,17 . Upon heating in phenyl ether, compounds 7a-c , rearrange to 2-(2-hydroxyphenyl)-4(3H)-quinazolinones 10a-c .     

Reactions of diazoalkanes with unsaturated compounds. 14. Reactions of diazomethane,diazocyclopropane, and methyl diazoacetate with 1,1,2,2-tetrafluoro-3-vinylcyclobutane and 2,3,3-trifluoro-1-vinylcyclobutene to form [3+2] and [1+2] cycloadducts

The reactions of diazomethane and diazocyclopropane generated in situ with 1,1,2,2-tetrafluoro-3-vinylcyclobutane (1) and 2,3,3-trifluoro-1-vinylcyclobutene (2) proceeded at the double bond of the substituent as the 1,3-dipolar cycloaddition to form the corresponding 1-pyrazolines. Under the conditions of thermolysis (340—400 °C), the resulting cyclobutylpyrazolines 4 and 5 selectively lost the dinitrogen molecule to generate 3-cyclopropyl-1,1,2,2-tetrafluorocyclobutane (6) or 1,1,2,2-tetrafluoro-3-spiropentylcyclobutane (7), respectively, in high yields. In the presence of Pd(acac)₂, the reactions of these fluorine-containing unsaturated compounds and 2-chloro-1,1,2-trifluoro-3-vinylcyclobutane (3) with diazomethane gave rise directly to cyclopropane derivatives 6, 11, and 12, respectively. The reactions of compounds 1 and 2 with methyl diazoacetate in the presence of Rh₂(OAc)₄ proceeded analogously to yield cis- and trans-disubstituted cyclopropanes.     

Reactions of methyl 1-acetylenyl-9,10-anthraquinone-2-carboxylates with hydrazine

Methyl 1-acetylenyl-9,10-anthraquinone-2-carboxylates react with NH₂NH₂ in ethanol at 80°C to give commensurable amounts of substituted 7H-dibenzo[de,h]quinolin-7-ones and 3,4-dihydro-3-aminonaphtho[2,3-f]isoquinoline-4,7,12-triones. The main, route of the reaction apparently includes nucleophilic addition of the reagent to the triple bond of the ester followed by intramolecular cyclization of the adduct with either the carbonyl or the methoxycarbonyl groups involved. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10 pp. 2031–2035, October, 1998.     

Phosphirenes and Azaphosphetines: IX. 1-Aza-2-phospha-1,3-dienes, 1,2-Azaphosphetines,and 1-Aza-2-phosphacyclohexa-2,4-dienes in Reactions with P-Bromoimino-N-(tri-tert-butylphenyl)phosphine with 1-Dialkylamino-1-alkynes

The reaction of P-bromoimino-N-(tri-tert-butylphenyl)phosphine with 1-dialkylamino-1-alkynes primarily forms 1-aza-2-phosphabitadienes. The latter are unstable and can further rearrange into 1,2-azaphos-phetines or take up one more aminoacetylene molecule to give 1-aza-2-phospha-2,4-cyclohexadienes.     

Reactions of 1-aryl-2-bromodiazene 1-oxides with acids and bases

The reactions of 1-aryl-2-bromodiazene 1-oxides with HCl in nonaqueous media give aryldiazonium chlorides, while 1,3,3-substituted triazenes-1 are formed in the reactions with secondary amines. Using 2-{¹⁵N} label, it was shown that the aryl group does not migrate in these reactions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 613–615, March, 1997.     

Reactions of 4-aminocycloheptimidazoles with alkyl iodides,acyl chlorides,and α-haloketones

The reactions of 4-amino-2-phenylcycloheptimidazole with alkyl iodides and α-bromoketones gave respectively 1-alkyl- and 1-acetonyl- (or 1-phenacyl)-substituted cycloheptimidazol-4(1H)-ones, while the reactions with acyl chlorides gave 4-arylamino-2-phenylcycloheptimidazoles. On the other hand, 2,4-diaminocycloheptimidazole were benzoylated with benzoyl chloride on the amino group at the 2- and/or 4-position and reacted with α-haloketones to give tricyclic 2-substituted 9-aminocyclohept[d]imidazo[1,2-a]imidazoles.     

Reactions of 2-aryl-1,1-dicyanoethenes with L-proline and aldehydes

Three-component heterocyclization of 2-aryl-1,1-dicyanoethenes with L-proline and aldehydes leads to the formation of 1-aryltetrahydro-1H-pyrrolysines that under acid (alkaline) hydrolysis conditions are converted into derivatives of 6-carboxy-7-phenyl-2,3,5,7a- or 1,3-diaryl-2-carboxy-5,6,7,7a-tetrahydro-1H-pyrrolysine.     

Reactions of 1-Aryl-2,2-dibromobutan-1-ones with Zinc and Alkyl 6-Bromo-2-oxo-2-H-chromen-3-carboxylate

Zinc enolates formed from 1-aryl-2,2-dibromobutan-1-ones and zinc react with alkyl 6-bromo-2-oxo-2-H-chromen-3-carboxylates affording alkyl 1-aroyl-6-bromo-2-oxo-1-ethyl-1,7b-dihydrocyclopropa[c]-chromen-1a(2H)-carboxylates as a single isomer.     

Reactions of Alkyl 1H,1H-Perfluoroalkyl Sulfones with Ammonia, Amines, and Hydrazines

2,2,3,3-Tetrafluoropropyl and 2,2,3,3,4,4,5,5-octafluoropentyl alkyl sulfones react with ammonia, primary and secondary amines, hydrazine hydrate, phenylhydrazine, and N,N-dimethylhydrazine to afford, depending on the length of the polyfluoroalkyl chain and reaction conditions, the corresponding enamines, imines, or mono- and bis-hydrazones. The bis-hydrazone obtained from phenylhydrazine and 2,2,3,3,4,4,5,5-octafluoropentyl benzyl sulfone is capable of undergoing further dehydrofluorination to give 5-difluoromethyl- or 5-unsubstituted 1-phenylpyrazole.     

Reactions of 2-aminothiobenzamide with isocyanates: A new synthesis of 2, 3-dihydroimidazo[1, 2-c]quinazolin-5(6H)-one and 3, 4-Dihydro-2H-pyrimido[1, 2-c]quinazolin-6(7H)-one

2-(2-Chloroethylureido)- and 2-(3-chloropropylureido)thiobenzamides 5a, b were prepared in good yields by treating 2-aminothiobenzamide with 2-chloroethyl and 3-chloropropyl isocyanates respectively. Subsequent treatment of compound 5a and 5b either with alkali or mineral acid led to the formation of 2, 3-dihydro-imidazo[1, 2-c]quinazolin-5(6H)-one 7a and 3, 4-Dihydro-2H-pyrimido[1, 2-c]quinazolin-6(7H)-one 7b .     

Photochemical Reactions of Tetrahydroquinoxalin-2(1H)-ones and Related Compound

Photochemical behaviors of the pyrazinone derivatives 5,6,7,8-tetrahydroquinoxalin-2(1H)-ones 1a – c and 1,5,6,7,8,9-hexahydro-2H-cyclohepta[b]pyrazin-2-one 1d were investigated. Dye-sensitized photo-oxygenation of 1a-c gave the 1:1 adducts 5a – c of the corresponding 3,8a-epidioxy-3,5,6,7,8,8a-hexahydroquinoxalin-2(1H)-one 4 and H₂O, whereas 1d gave 3,9a-epidioxy-1,3,5,6,7,8,9,9a-octahydro-2H-cyclohepta[b]pyrazin-2-one 4d (Scheme 2). The different kind of products was interpreted as being the result of the ring strain and steric hindrance of endoperoxides produced from 1a – d with singlet oxygen. Irradiation of 1a – b in the presence of alkenes gave tricyclic azetidine derivatives 9 by [2 + 2] cycloaddition of the C?N bond of 1 to the alkene.     

Reactions of 3-alkylsulfanyl-2-arylazo-3-(1-azacycloalk-1-yl)acrylonitriles with maleimide

Reactions of 2-arylazo-3-(1-azacycloalk-1-yl)-3-methylsulfanylacrylonitriles with male-imide in benzene gave octahydropyrrolo[3,4-a]pyrrolizines 2a–c, decahydro-2,7a-diaza-cyclopenta[a]indene 2e, and decahydro-5-oxa-2,7a-diazacyclopenta[a]indene 2f as a result of 1,3-dipolar cycloaddition. In a similar reaction with 3-allylsulfanyl-2-arylazo-3-(1-azacycloalk-1-yl)acrylonitriles 3, dipolar cycloaddition and intramolecular cyclization competed to give a mixture of compounds 2 (major products) and 1,4,6,7,8,8a-hexahydropyrrolo[2,1-c]-1,2,4-triazines 4b–d, 1,6,7,8,9,9a-hexahydro-4H-pyrido[2,1-c]-1,2,4-triazine 4e, and 1,4,6,7,9,9a-hexahydro-1,4-oxazino[3,4-c]-1,2,4-triazine 4f (minor products).     

Reactions of 2-Alkoxypropenals with Thiols in Neutral and Acid Media

Addition of thiols to 2-alkoxypropenal in neutral medium at 20°C in the absence of a catalyst occurs regioselectively, following the Markownikoff pattern. The resulting 2-alkoxy-2-R-thiopropanals are capable of undergoing spontaneous isomerization to 1-alkoxy-1-R-thiopropanones. The addition and isomerization processes are accelerated by heating to 60°C or in the presence of acid catalysts (TsOH, HCl). The reaction is also accompanied by partial disproportionation of 2-oxopropanal O,S-acetals to give O,O- and S,S-acetals.     

Reactions of alkyl 2-benzylidene-2-polyfluoroacylacetates with N,N-dinucleophiles

Alkyl 2-benzylidene-2-polyfluoroacylacetates react with urea and thiourea to yield 5-ethoxycarbonyl-4-fluoroalkyl-4-hydroxy-6-phenylhexahydropyrimidin-2-ones and -2-thiones and with guanidine sulfate to form 2-amino-5-ethoxycarbonyl-4-fluoroalkyl-6-phenyl-1,6-dihydropyrimidines and 3,6-diethoxycarbonyl-2,7-difluoroalkyl-4,5-diphenyl-4,5-dihydro-1H-pyrido[1,2-a]pyrimidines, and they react with phenylhydrazine to afford 4-alkoxycarbonyl-3-fluoroalkyl-3-hydroxy-1,5-diphenylpyrazolidines. Hydrazine hydrate catalyzes the formation of 3,5-diethoxycarbonyl-2,6-difluoroalkyl-2,6-dihydroxy-4-phenyltetrahydropyrans. When treated with anhydrous hydrazine and o-phenylenediamine, these esters cleave to form the products of condensation of fluoroacyl ester and benzaldehyde with diamines.     

Reactions of 2-Butylsulfanyl-2-alkenals with Alcohols and Water

2-Butylsulfanyl-2-alkenals react with alcohols at room temperature in the presence of acid catalysts to give 45–90% of the corresponding acetals. Acetals derived from 2-butylsulfanylpropenal readily undergo hydrolysis at the vinylsulfanyl group (20°C, catalysis by HCl or TsOH) with formation of 2-oxopropionaldehyde O,O- or O,S-acetals in 70–90% yield. Unlike 2-butylsulfanyl-2-propenal O,O-dialkyl acetals, the initial aldehydes and 2,4-dinitrophenylhydrazones derived therefrom are stable to hydrolysis under analogous conditions: the vinyl sulfide moiety remains unchanged even under considerably more severe conditions (100°C, 3 h; HCl, H₂SO₄, CF₃SO₂OH, or TiCl₄).__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 832–836.Original Russian Text Copyright © 2005 by Keiko, Chuvashev, Stepanova, Larina.     

Reactions of 2-aminopyridine with picryl halides

2-Aminopyridine reacts with picryl halides to give mixtures of 1-picryl-2-(N-picrylimino)-1,2-dihydropyridine and 2-(N-picrylamino)pyridine. When picryl fluoride is treated with an excess of 2-aminopyridine, the 1-picryl-2-(N-picrylimino)-1,2-dihydropyridine reacts further with 2-aminopyridine to yield two molecules of 2-(N-picrylamino)pyridine in a reaction catalyzed by the by-product, hydrogen fluoride. In contrast, the compositions of the mixtures obtained from the reactions of picryl chloride and picryl bromide with excess 2-aminopyridine are stable in their reaction media.     

Reactions of 2-isocyanatobenzoyl chloride and 2-carbomethoxyphenyl isocyanate with 5-aminotetrazole

Treatment of 2-isocyanatobenzoyl chloride ( 4 ) with 5-aminotetrazole (5-AT) gave 3-(5-tetrazolyl)quinazoline-2,4(1H,3H)-dione ( 1 ) directly. Treatment of 2-carbomethoxyphenyl isocyanate ( 5 ) with 5-AT gave 2-[((5-amino-1H-tetrazol-1-yl)carbonyl)amino]benzoic acid methyl ester ( 6 ) as a kinetic product, which was thermally isomerized to 2-[((1H-tetrazol-5-ylamino)carbonyl)amino]benzoic acid methyl ester ( 7 ), the thermodynamically more stable urea. Cyclization of 7 with polyphosphoric acid gave 2-(1H-tetrazol-5-ylamino)-4H-3,1-benzoxazin-4-one ( 2 ). Urea 6 was quite labile in solution, as shown by nmr, and readily reacted with methanol to give 2-[(methoxycarbonyl)amino]benzoic acid methyl ester ( 10 ).