Studies on the syntheses of azole derivatives. Part VIII. Photolysis of N-aryl-N-benzylearbamoyl azides [studies on the syntheses of heterocyclic compounds. Part CDXV

Photolysis of N-benzyl-N-phenylearbamoylazide (IVc) afforded 1-benzy 1-2-benzimidazolinone (Ic), 2-benzimidazolinone (IIe), 4-benzy 1-2-benzimidazolinone (IIe), and 5-benzy1-2-benzimidazo-linone (IIf)- The same reaction of N-benzyl-N-(4-chlorophenyl) carbamoyl azide (IVd) gave 3-benzyl-1-(phenylhydrazocarbonyl)-2-benzimidazolinone (VIb) besides the above four products. In the case of N-benzyl-4-(4-butoxyphenyl)carbamoyl azide (IVe), 1-benzy1-5-butoxy-2-benz-imidazolinone (1e), 5-butoxy-2-benzimidazolinone (IId), 5-benzy1-2-benzimidazolinone (IIf), and 4-benzy1-6-butoxy-2-benzimidazolinone (IIg).     

Two-dimensional assembly of functionalized 4-aryl-1-alkenyl-3,5-dioxo-1,2,4-triazolidines

Acid functionalized derivatives of 4-aryl-1-alkenyl-3,5-dioxo-1,24-triazolidines (4-arylurazoles), i.e. 4-(-but-1-en-3-yl-3, 5-dioxo-1,2,4-triazolidin-4-yl) benzoic acid (1), 4-urazoyl benzamide, i.e. 4-(1-but-1-en-3-yl-3, 5-dioxo-1,2,4-triazolidin-4-yl) benzamide (2), and 4-urazoylphenylazobenzoic acid, i.e. 4-(1-but-1-en-3-yl-3, 5-dioxo-1,2,4-triazolidin-4-yl) phenylazobenzoic acid (3), organize into two-dimensional supramolecular assemblies via intermolecular hydrogen bonding. Hydrogen bonds are formed between two acid (or amide) and two urazole groups, as well as between a carbonyl group of the urazole heterocycle and a hydrogen atom of the phenyl ring. These two-dimensional layers also persist if the polar groups are attached randomly to flexible polybutadiene chains.     

Studies on the syntheses of azole derivatives. Part IV. Novel Syntheses of 1-Benzylbenzimidazolines by Photolysis of N-Aryl-N-benzylcarbamoyl Azides [Studies on the Syntheses of Heterocyclic Compounds. Part CCCLXXVIII

Photolysis of N-benzyl-N-(4-substituted-phenyl)carbamoyl azides (Ia and Ib) afforded N-benzylidene-N′-benzylhydrazines (XIIa and XIIb) and the debenzylated benzimidazolines (XIIIa and XIIIb).     

Synthesis of 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one. Derivatives and their ring transformation into 5-benzamido-1,2,4-triazolidine-3,5-dione derivatives

Some 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one derivatives 6 and 9 have been synthesized in two ways. The expected thermal ring transformation into 2,5-disubstituted 1,3,4-oxadiazoles did not occur but, by acid hydrolysis of 5-aryl-3-[3-benzylidene-2-methyl(or phenyl)carbazoyl]-1,3,4-oxadiazol-2(3H)-ones 6 , a new ring transformation took place and the corresponding 4-benzamido-1-methyl(or phenyl)-1,2,4-triazolidine-3,5-dione derivatives 11 were formed. The 4-amino-1-phenyl-1,2,4-triazolidine-3,5-dione ( 19 ) has been prepared and its structure was confirmed by some reactions.     

One-pot and novel route for the synthesis of 4-substituted-l,2,4- triazolidine-3,5-diones

The efficient and one-pot synthesis of 4-substituted-1,2,4-triazolidin-3,5-dione derivatives(4-substituted urazoles) via combination of triphosgene, substituted anilines, and ethyl carbazate in the presence of cesium carbonate is presented.     

Reactions of 1,2,4-triazole derivatives with a “model” thiirane

Reactions of 3-mono- and 3,5-disubstituted 1,2,4-triazoles with a “model” thiirane, 8-bromo-1,3-dimethyl-7-(thiiran-2-ylmethyl)-3,7-dihydro-1H-purine-2,6-diones proceed at the positions N¹ and N² of the triazole ring and yield 7-(5-R-3-R′-1,2,4-triazol-1-yl)methyl- and/or 7-(5-R′-3-R-1,2,4-triazol-1-yl)methyl-1,3-dimethyl-6,7-dihydro[1,3]thiazolo[2,3-f]-purine-2,4-(1H,3H)-diones. 3-Methylsulfonyl-1,2,4-triazole reacted regiospecifically at the position N¹ forming 1,3-dimethyl-7-[(3-methyl-sulfonyl-1,2,4-triazole-1-yl)-methyl]-6,7-dihydro[1,3]thiazolo-[2,3-f]purine-2,4(1H,3H)-dione.     

Reaktionen vonN-Sulfinylverbindungen mit dem 1,2,4-Trithia-3,5-diborolan-Ringsystem und Substitutionsreaktionen am 1,2,4-Trithia-3,5-diborolan und 1,2-Dithia-4-aza-3,5-diborolidin

The reaction of trimethylsilyl- and pentafluorophenyl-N-sulfinylamine respectively with 3,5-dihalogeno-1,2,4-trithia-3,5-diborolanes yields the 1,2-dithia-4-aza-3,5-diborolidines1-3.Tert-butyl-N-sulfinylamine and 3,5-dimethyl-1,2,4-trithia-3,5-diborolane react analogous. OtherN-sulfinylamines however split the disulfane bridge in 3,5-dimethyl-1,2,4-trithia-3,5-diborolane and the 1,4-dithia-2-aza-3,5-diborolidines5A-7(A) are formed. Besides of boroxines, cyclo-2,4,6-trimethyl-1,3-dioxa-5-aza-2,4,6-triboranes and cyclo-2,4,6-trimethyl-1-oxa-3,5-diaza-2,4,6-triboranes are formed as byproducts,8–10 have been isolated. In 1,2,4-trithia-3,5-diborolanes and 1,2-dithia-4-aza-3,5-diborolidines the bromo-atoms can be substituted by alkyl (13, 14), by amino (15–20) and by isothiocyanato groups. The compounds were characterised analytically and spectroscopically (MS; NMR:¹H,¹¹B,¹⁹F,²⁹Si; IR).

     

Efficient synthesis of 1,2,4-dithiazolidine-3,5-diones (dithiasuccinoyl-amines) and observations on formation of 1,2,4-thiadiazolidine-3,5-diones by related chemistry

An efficient synthesis of 1,2,4-dithiazolidine-3,5-diones ( 1 ) from chlorocarbonylsulfenyl chloride ( 3 ) plus O-dimethylaminoethyl-N-alkyl or aryl thiocarbamates ( 4 ) has been worked out. In this synthesis, 1,2,4-thiadiazolidine-3,5-diones ( 5 ) have been shown to arise as low-level by-products, and experiments were conducted to elucidate the mechanism of the side reaction. N,N′-Dimethyl-1,2,4-thiadiazolidine-3,5-dione ( 5a ) was prepared in one step from N,N′-dimethylurea plus 3 , or from 4a plus one equivalent of sulfuryl chloride. A general route to 5 involved reaction of equimolar amounts of isocyanates ( 6 ), isothiocyanates ( 7 ) and sulfuryl chloride followed by hydrolysis of intermediate 9 . Heterocycles reported have been characterized by nmr, ir, uv, ms, and hplc.     

Reactions of diazenediyl compounds with pyridones: A novel [4 + 2] cycloaddition

Low temperature cycloaddition of 1,4-phthalazinedione (2) and 4-phenyl-1,2,4-triazoline-3,5-dione (10) with a variety of N-substituted pyridones affording novel azabicyclic structures is described. The structures of these compounds were confirmed by spectral analyses and hydrogenation to their dihydro derivatives.     

Synthesis of 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones and their conversion into 2-aryl-1,2,4-triazine-3,5-(2H,4H)odiones. A new synthesis of 1-aryl-6-azauracils

Treatment of 6-amino-5-arylazo-1,3-dimethyluracils with urea or N,N′-carbonyldiimidazole gave the respective 6-aryl-1,3-dimethyl-6,7-dihydro-6-azalumazin-7-(6H)ones, which were hydrolyzed with alkali to afford 2-aryl-2,3,4,5-tetrahydro-3,5-dioxo-1,2,4-triazine-6-carboxylic acids (1-aryl-6-azauracil-5-carboxylic acids). Thermal decomposition of these carboxylic acids gave the corresponding 2-aryl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-6-azauracils). Methylation of the latter with methyl iodide gave the corresponding 2-aryl-4-methyl-1,2,4-triazine-3,5-(2H,4H)diones (1-aryl-3-methyl-6-azauracils).     

Tricyclic heteroaromatic systems. 1,2,4-triazolo[1,5-a]quinoxaline

The parent 1,2,4-triazolo[1,5-a]quinoxaline was prepared by a few-step reaction from ethyl N¹-(2-nitrophenyl)-N³-ethoxalyloxamidrazonate, which afforded the key intermediate diethyl 1-(2-nitrophenyl)-1,2,4-triazole-3,5-dicarboxylate in satisfactory yield. The latter was cyclized, hydrolyzed, decarboxylated, reduced and dehydrogenated to yield the title compound.     

Regioselective Reaction of N1-Benzyl-N2-(4-nitrophenyl)ethanediamide and Acetylenic Esters

The regioselective reaction of N¹-benzyl-N²-(4-nitrophenyl)ethanediamide with dialkyl acetylenedicarboxylates or alkyl propiolates in the presence of triphenylphosphine leads to dialkyl 4-benzylamino-1-(4-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates or alkyl 4-benzylamino-1-(4-nitrophenyl)-2-oxo-5-pyrrolidinecarboxylates in good yields.     

Sulfonylcarbamimidic azides from sulfonyl chlorides and 5-aminotetrazole

Treatment of o-nitrobenzenesulfonyl chloride ( 3 ) with 5-aminotetrazole (5-AT) gave [(2-nitrophenyl)-sulfonyl]carbamimidic azide ( 6 ), a ring-opened isomer of the expected N-(1H-tetrazol-5-yl)-2-nitrobenzenesulfonamide ( 4 ). Sulfonylcarbamimidic azide 6 was converted to 2-amino-N-(aminoiminomethyl)benzene-sulfonamide ( 7 ) with ethanolic stannous chloride, and to 3-amino-1,2,4-thiadiazine 1,1-dioxide ( 8 ) with sodium dithionite. Methanesulfonyl chloride ( 9 ) and 5-AT gave 2-(methylsulfonyl)carbamimidic azide ( 10 ), which isomerized to 5-[(methylsulfonyl)amino]-1H-tetrazole ( 11 ) in warm ethanol. Attempted cycloaddition of 2-(phenylsulfonyl)carbamimidic azide ( 13 ) and ethyl vinyl ether led only to alkylated tetrazole products. In addition, other tetrazole-alkylating reactions are described. Isomers produced from these alkylations were differentiated with ¹³C nmr spectroscopy.     

The synthesis of 7-(substituted-amino)-3-azabicyclo[3.2.0] heptanes

1,2-Cycloaddition reactions of several enamines with N-substituted maleimides and 4-phenyl-1,2,4-triazoline-3,5-dione have been carried out. The adducts were transformed into 7-(substituted-amino)-3-azabicyclo[3.2.0]heptanes and a 1,2,4-triazolidine-1-acetaldehyde, respectively. These are the first reported examples of 3-azabicyclo[3.2.0]heptanes substituted in any position other than the 3-position. The reaction of an ynamine with N-benzylmaleimide afforded a bicyclic intermediate which upon hydrolysis gave a 2,5-dioxo-3-pyrrolidineacetic acid.     

Proton NMR spectroscopy of asymmetric benzylamines. The long-range effects of an asymmetric environment

¹H NMR Spectra of the asymmetric benzylamines N-benzyl-N-butyl-2-hydroxy-1,3-propandiamine, N-benzyl-N-(2-ethylhexyl)-2-hydroxy-1,3-propandiamine, N-benzyl-N-butyl-2,3-epoxypropanamine and N-benzyl-N-(2-ethylhexyl)-2,3-epoxypropanamine, were analysed. A pronounced non-equivalance of the benzylic hydrogens is induced by asymmetric carbons in γ position with respect to the benzylic group. [Δδ=0.2–0.3 ppm; J(AB)～13.5 Hz]. Two sets of AB patterns were observed when two asymmetric carbons were present in the same molecule. RS+SR Diastereomers can thus be distinguished from the RR+SS enantiomers.     

Synthesis of nitrogen-containing heterocycles. 3. Formation and structure of new 1,2,4-triazole derivatives

Treatment of N(3)-[(2-cyano-2-ethoxycarbonyl)vinyl]amino-N(4),N(4)-dimethylaminomethylenehydrazones of aromatic carbonyl compounds with hot acetic acid resulted in the formation of symmetrical gem-bis-(3-dimethylamino-1,2,4-triazol-1-yl)methanes, (3-dimethylamino-1,2,4-triazol-1-yl)arylmethyl acetates, and (3-dimethylamino-1,2,4-triazol-1-yl)alkenes of a gem-diaryl type depending upon whether the carbonyl compound was aldehyde or ketone.     

Modification of polymers via electrophilic aromatic substitution

Three vinyl monomers, 2,4,6-trimethoxystyrene, 4-(N,N-dimethylamino)styrene, and N-methyl-2-vinylpyrrole, were synthesized via the Wittig reaction from the corresponding aldehyes. These monomers were homopolymerized by radical polymerization using α,α′-azoisobutyronitrile (AIBN) as initiator at 60°C. The reaction of these polymers with 4-phenyl-1,2,4-triazoline-3,5-dione (phTD) and 4-methyl-1,2,4-triazoline-3,5-dione (MeTD) was investigated. Although polytrimethoxystyrene reacts slowly with PhTD at room temperature, the other two polymers react fast and lead to the incorporation of the triazolinedione unit into the side chain of the polymer via electrophilic aromatic substitution. The reaction of bistriazolinediones (BTD) with these polymers was performed in dimethylformamide using 10–20% molar concentration of the BTD. The resulting crosslinked polymers are insoluble in polar as well as nonpolar solvents. Some physical properties of the unmodified and modified polymers were studied.     

Synthesis of 4(pyrazol-3-yl)[1,2,4]triazolo[4,3-a]quinoxalines and tetrazolo analog

The transformation of 2-chloro-3-[5-(acetoxymethyl)-1-phenylpyrazol-3-yl]quinoxaline 3 to 1-aryl-4-[5-(hydroxymethyl-1-phenylpyrazol-3-yl][1,2,4]triazolo[4,3-a]quinoxalines 4a-c has been achieved upon treatment with aroylhydrazines in boiling butanol. Compounds 4a-c were smoothly acetylated by acetic anhydride to give their acetyl derivatives 5a-c in good yield. 4-[5-(Acetoxymethyl)-1-phenylpyrazol-3-yl]-1-methyl[1,2,4]triazolo[4,3-a]quinoxaline was prepared by ring closure of 2-hydrazino-3-[5-(hydroxymethyl)-1-phenylpyrazol-3-yl]quinoxaline 6 by the action of acetic anhydride. The reaction of 6 with acetylacetone afforded 3-[5-(hydroxymethyl)-1-phenylpyrazol-3-yl]-2-(3,5-dimethylpyrazol-1-yl)quinoxaline 8 . In addition, the reaction of 3 with sodium azide in boiling N, N-dimethylformamide yielded the fused tetrazolo[1,5-a]quinoxaline 9 .     

Ene Synthesis of Bicyclic Arylmethylenedihydropyrazoles Using 4-Phenyl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione

8-Acetyl-7-aryl-2-arylmethylene-8,9-diaza- and 4,8,9-triazabicyclo[4.3.0]non-9-enes react with4-phenyl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione, following the ene addition pattern. Under similar conditons 7-aryl-2-arylmethylene-8-methyl-8,9-diazabicyclo[4.3.0]non-9-enes give rise to both mono- and polyadditionproducts. The product structures were studied by ¹H and ¹³C NMR, IR, and UV spectroscopy and singlecrystal X-ray diffraction.     

Heterylation of 3-R1-5-R2-1,2,4-Triazoles with Derivatives of 3,5-Dinitro-1,2,4-Triazole

Heterylation of 3-R¹-5-R²-1'2'4-triazoles (pK _a 3-12) with N-alkyl-, N-alkenyl-, N-alkoxy-carbonyl-, N-oxoalkyl-, N-nitroxyalkyl, N-nitroaminoalkyl-3'5-dinitro-1'2'4-triazoles results insubstitution of a nitro group in 5 position of the dinitro compound yielding 1-R-methyl-3-nitro-5-(3-R¹-5-R²-1,2,4-triazolyl)-1,2,4-triazoles. The side processes: Hydroxide-ion attack on C⁵ and (or) N¹ of the ring both in the substrate and in the target compound afford 1-R-methyl3-nitro-1,2,4-triazol-5-ones, 3,5-dinitro-1,2,4-triazole and NH-acids of N-C-bitriazole series. Optimal reaction media are aprotic dipolar substances, and for compounds prone to heterolysis ethyl acetate-water systems. The azole pK _a is the decisive factor controlling the composition and the ratio of reaction products. The process is promising for azoles with pK _a > 5, and the optimal range of pK _a is 8-10.