Reactions of 3-hydrazino-5,6-diphenyl-1,2,4-triazine with 4-arylidene-2-phenyl-5(4H)-oxazolones and 4-benzylidene-3-methyl-5(4H)-isoxazolone

3-Hydrazino-5,6-diphenyl-1,2,4-triazine reacts with 4-arylidene-2-phenyl-5(4H)-oxazolones in toluene to give substituted acrylic acid hydrazides, and in glacial acetic acid to give substituted imidazolones. On the other hand the hydrazinotriazine reacts with 4-benzylidene-3-methyl-5(4H)-isoxazolone, probably via a 1,4 addition reaction followed by an elimination reaction, to give benzaldehyde 5,6-diphenyl-1,2,4-triazin-3-ylhydrazone and 3-methyl-5(4H)-isoxazolone.     

1,3-dipolar cycloaddition of nitrile oxides with 2-phenyl-4-ethoxymethylene-5(4H)-oxazolone

2-Phenyl-4-ethoxymethylene-5(4H)-oxazolone 1 reacts regioselectively with nitrile oxides to give cycloadducts 3 . Reactions of the cycloadducts 3 with nucleophiles lead to 4-aminoisoxazole derivatives.     

Pyridazine Derivatives and Related Compounds,Part 1. Some Reactions with 4-Cyano-5,6-Diphenyl-2,3-Dihydropyridazine-3-One

4-Cyano-5,6-diphenyl-2,3-dihydropyridazine-3-onc 1 reacts with phosphorous oxychloride to give 70% of the corresponding 3-chloro derivative 2. Treating 2 with anthranilic acid in butanol, 4-cyano-2,3-diphenyl-10H-pyridazino[6,1-b]quinoxaline-10-one, 3 was obtained. Compound 1 reacts with phosphorous pentasulphide to give 3-mercapto derivative 4, which was converted by acrylonitrile to S-(2-cyanoethyl)pyridazine derivative 5. Compound 4 reacts with ethyl bromoacetate and with phenacyl bromide gave the corresponding thieno[2,3-c] pyridazine derivatives 8, 9, Alkylation of 1 with ethyl chloroacetate afforded 3-0-carbethoxymethyl derivative 10. Compound 10 reacts with amines (aniline, hydrazine) to give the corresponding amide and acid hydrazide 13, 12 respectively. Hydrolysis of 10 with sodium hydroxide gave the corresponding acid derivative 11. Treating 1 with methyl iodide, 3-0-methyl derivative 14 was obtained, which was converted by ammonium acetate/acetic acid to 3-amino-4-cyano-5,6-diphenyl pyridazine 15. Compound 1 reacts with methyl magnesium iodide gave 4-acetyl derivative 16, which was reacted with hydrazine, phenyl hydrazine and with hydroxylamine to give the substituted I H pyrazolo [3,4-c] pyridazine 17 a,b and isoxazolo [5,4-c] pyridazine 18 derivatives respectively.     

Regioselective hydrodehalogenation of 3,5-dihaloisothiazole-4-carbonitriles: synthesis of 3-haloisothiazole-4-carbonitriles

3,5-Dibromoisothiazole-4-carbonitrile 1 treated with Zn or In dust (5 equiv) and HCO₂H undergoes regioselective hydrodebromination to give 3-bromoisothiazole-4-carbonitrile 3 in 70-74% yield. Similarly, 5-bromo and iodo 3-chloroisothiazole-4-carbonitriles 8 and 9 give 3-chloroisothiazole-4-carbonitrile 4 in 77 and 85% yields, respectively. Also hydrodeamination of 5-amino-3-chloroisothiazole-4-carbonitrile 7 using isoamyl nitrite gives the latter in 95% yield. The dibromoisothiazole 1 reacts with Zn dust in either DCO₂D or HCO₂D to give 3-bromo-5-deuterioisothiazole-4-carbonitrile 10 in 71 and 58% yields, respectively. The 3-bromoisothiazole 3 reacts with cyclic dialkylamines to give the corresponding 2-(dialkylaminomethylene)-malononitriles and not the expected 3-dialkylaminoisothiazole-4-carbonitriles. Finally, the 3-bromoisothiazole 3 is readily converted into both 3-bromoisothiazole-4-carboxamide 19 and the carboxylic acid 20. All products are fully characterized.     

Photoreaktionen des 3-Methyl-4-phenylsydnons

Photoreactions of 3-Methyl-4-phenylsydnone A procedure for the synthesis of 3-methyl-4-phenylsydnone (1) is given. UV. irradiation of 1 in solution generates the nitrile-imine 4 which reacts with activated C, C double bonds and with heterocumulenes to give five-membered heterocycles. In contrast to the 2H-azirines which photochemically react with the C, O double bond of phenylisocyanate, 4 adds to the C, N double bond of the latter.     

1—酰基—4—氯环己烷与取代芳烃的区域与立体选择性反应

从环己烯合成了１－酰基－４－氯环己烷，发现在其在ＡｌＣｌ３催化与苯，氯苯，溴苯等优先生成反式１－芳基－４－酰基环己烷，与联苯反应时选择性较差。     

Sydnone Compounds XXX. The Syntheses and Reactions of 3-Aryl-4-Cyanosydnones and 3-Aryl-4-Formylsydnone Oximes

In the presence of pyridine, 3-aryl-4-formylsydnone (II) reacts with hydroxyl-amine hydrochloride to produce 3-aryl-4-formylsydnone oxime (III). This reaction was performed in ethanol solution with reflux or at room temperature; the latter procedure gave an excellent yield (74-98%) and high purity. (III) reacts in acetic anhydride at room temperature to give 3-aryl-4-formylsydnone oxime O-acetate (IV). A convenient method for the synthesis of 3-aryl-4-cyanosydnone (V) is to dehydrate (III) with acetic anhydride at reflux. When (IV) was refluxed with acetic anhydride, (V) was similarly obtained. Another convenient method to prepare (V) from (III), dehydration with thionyl chloride at room temperature, was also investigated.     

Formation of 5-fluoro-3-(4-fluoro-1-hydroxyimino-4,4-dinitrobutyl)isoxazole from 1,7-difluoro-3-hydroxyimino-1,1,7,7-tetranitroheptan-4-one and hydroxylamine

1,7-Difluoro-3-hydroxyimino-1,1,7,7-tetranitroheptan-4-one reacts with hydroxylamine hydrochloride in MeOH in the presence of AcONa to give 5-fluoro-3-(4-fluoro-1-hydroxyimino-4,4-dinitrobutyl)isoxazole.     

The reactions of 4-dicyanomethylene-2-phenyl-4H-1-benzopyran and some benzologs with nucleophiles

4-Dicyanomethylene-2-phenyl-4H-1-benzopyran (1) reacts with primary amines under mild conditions to give 4-imino-3-alkyl-5-alkylimino-2-phenyl-3,4-dihydro-5H-[1]benzopyrano[3,4-c]-pyridine derivatives which, in turn, are hydrolyzed with acid to 4-imino-3-alkyl-2-phenyl-3,4-dihydro-5H-[1]benzopyrano[3,4-c]pyridin-5-ones. When more vigorous conditions are employed for the reactions of 1 with primary amines, Dimroth rearrangements take place and the products are derivatives of 4-alkyl- (or aryl)amino-5-alkyl- (or aryl)imino-2-phenyl-5H-[1]benzopyrano-[3,4-c]pyridine. The latter compounds are hydrolyzed by acid to the corresponding 5-pyridone derivatives. The reaction of 1 with piperidine gives 2-phenyl-4-piperidyl-5H-[1]benzopyrano-[3,4-c]pyridin-5-one. Sodium methoxide reacts with 1 to give 3-cyano-2-methoxy-4-(2-hydroxyphenyl)-6-phenylpyridine. Two benzologs of 1 have been allowed to react with primary and secondary amines and the products are analogous to those obtained from 1 .     

Vilsmeier reaction with 4-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one

4-Phenyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one reacts with the Vilsmeier reagent to give a 3-dimethylaminomethylidene derivative, the hydrolysis of which leads to 3-formyl-4-phenyl-2,3-dihydro-1H-1,5-benzodiazepinone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 223–225, February, 1984.     

Reactions of Methyl 4-Aminofurazan-3-carboximidate with Nitrogen-Containing Nucleophiles

Methyl 4-aminofurazan-3-carboximidate reacts with aromatic amines and hydrazines to give the corresponding amidines and amidrazones. The reaction of the title compound with o-phenylenediamine yields 3-amino-4-(2-benzimidazolyl)furazan, and with acylhydrazines N²-acyl-4-aminofurazan-3-carbohydrazides are formed. The latter undergo thermal intramolecular cyclization with formation of 3-amino-4-(1,2,4-triazol-3-yl)furazan derivatives containing various substituents in position 5 of the triazole ring.     

Hydrogenation and carbon-sulfur bond hydrogenolysis of benzothiophene promoted by Re2(CO)10 and H4Re4(CO)12

In the search for metal complexes that promote the cleavage of C-S bonds in thiophenes, we observe that the reaction of Re(2)(CO)(10) and benzothiophene (BT) under a hydrogen atmosphere gives the trinuclear cluster Re(3)(mu-H)(2)(mu(3)-S-2-EtC(6)H(4))(mu-2,3-DHBT)(CO)(9) (1), which contains a hydrogenated BT ligand and a thiolate ligand resulting from the hydrogenation and cleavage of a C-S bond in BT. A detailed study of the reaction shows that Re(2)(CO)(10) initially reacts with H(2) to give H(3)Re(3)(CO)(12), which subsequently converts to H(4)Re(4)(CO)(12), which finally reacts with BT to give 1.     

2-(3-ethyl-2,2-dimethylcyclobutyl-methyl)-4(3H)-quinazolinones

Anthranilic acid and its 5-bromo and 4-chloro derivatives react with pinanoic and pinonoic acid chlorides to give the corresponding N-acyl derivatives. The pinanoyl derivatives give the corresponding 2-(3-ethyl-2,2-dimethyl-cyclobutylmethyl)-4-(3H)-quinazolinones when refluxed in formamide. Pinanoylanthranilic acid reacts with dicyclohexylcarbodiimide to give 2-(3-ethyl-2,2-dimethylcyclobutylmethyl)benz-3,1-oxazin-4(H)-one and subsequently with hydrazine hydrate to give 3-amino-2-(3-ethyl-2,2-dimethylcyclobutylmethyl)-4(3H)-quinazolinone. Refluxing of the pinanoyl- and pinonoylanthranilic acids with acetic anhydride gives acetylanthranilic acid, and pinonoylanthranilic acid gives 4(3H)-quinazolinone with formamide.Riga Technical University, Riga LV-1658, Latvia; e-mail: marina@osi.lanet.lv. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 811–817, June, 1999.     

s-Triazine derivatives. 4. Some peculiarities of the reactions of dicarbethoxymethylenetriazine derivatives

2- (Carbethoxycyanomethylene)-4,6-dimethoxy-1,2-dihydro-s-triazine reacts with hydrochloric acid to give 2-(carbethoxycyanomethylene)-4,6-dioxohexahydro-s-triazine (I) and with boric acid to give a mixture of the first compound with 2-(carbethoxy-cyanomethylene)-4-oxo-6-methoxy-1,2,3,4-tetrahydro-s-triazine. The products of the reaction of 2,4,6-tris(dicarbethoxymethylene)hexahydro-s-triazine with aniline are 2-(dicarbanilidomethylene)-4-methyl-6-phenylamino-1,2-dihydro-s-triazine (43%), N,N-diphenylurea (18%), and malonic acid dianilide (18%). In aqueous dioxane in the presence of A1₂O₃ this compound is converted to 2,4-bis(dicarbethoxy-methylene)-6-methyl-1,2,3,4-tetrahydro-s-triazine, which reacts with liquid ammonia to give 2-(dicarbethoxymethyl)-4-amino-6-methyl-s-triazine.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 684–687, May, 1981.     

The reactions of 2,2-difluoro-4-methylnaphtho[l,2-e]-1,3,2-dioxaborin and its [2,1-e]isomer with N,N-dimethylformamide

The title compounds react with dimethylformamide in acetic anhydride to give dimethylamino-vinyl derivatives which, on treatment with base, yield benzochroman-4-ones. The [1,2-e] isomer reacts with the Vilsmeier complex to give 3-formylbenzo[f]chrom-4-one and 9-hydroxy-1-phenalenone, and the [2,1-e]isomer gives 3-formylbenzo[h]chrom-4-one.     

Unexpected Products from Carbonylation of Lithiated Quinazolin-4(3H)-one Derivatives

Doubly lithiated 3-pivaloylaminoquinazolin-4(3H)-one reacts with carbon(II) oxide at 0°C to give 77% of a mixture of azetidinone and indole derivatives, each incorporating a diisopropylamide unit from lithium diisopropylamide used for lithiation. No analogous reaction occurs with doubly lithiated 3-acetylaminoquinazolin-4(3H)-one and 3-acyl-2-alkylquinazolin-4(3H)-one. Carbonylation of doubly lithiated 2-alkyl-3-aminoquinazolin-4(3H)-ones at 0°C results in deamination to give 2-alkylquinazolin-4(3H)-ones in good yields.     

Comparative Studies on the Behavior of 3-Amino-2-phenyl-4(3 H )-quinazolinone Towards Some Organophosphorus Reagents

The reaction of 3-amino-2-phenyl-4(3H)-quinazolinone with oxovinylidenetriphenylphosphorane afforded 5-phenylpyrazolo[1,5-c] quinazoline-2(3H)-one and triphenylphosphine oxide. On the other hand, when quinazolinone reacts with phosphorus ylides, the corresponding phosphorane adducts were obtained. Moreover, quinazolinone reacts with trisdialkylaminophosphines to give the new (dialkylamino)oxophosphonium dipolar products. Possible reaction mechanisms are considered and the structural assignments are based on analytical and spectroscopic results.     

Regioselective Synthesis of 4-Acetyl-and 5-Acetyl-3-methylisoxazole: Their Conversion into Silyl-and Methyl Enol Ethers

Acetonitrile oxide reacts regioselectively with 3-buten-2-one and (E)-4-methoxy-3-buten-2-one to give 5-acetyl-2 and 4-acetyl-3-methylisoxazole 3, respectively. Treatment of ketones 2 and 3 with trimethylsilyl trifluoromethanesulfonate gave the silyl enol ethers 4 and 5, whereas the methyl enol ethers 8 and 9 were obtained via elimination of methanol from the corresponding dimethyl ketals.     

Zur Darstellung und Reaktivität von Tetraalkylcyclobutadienplatin(II)-Komplexen [PtCl2(C4R4)L]

Preparation and Reactivity of Platinumcyclobutadiene Complexes [PtCl₂(C₄R₄)L] H[PtCl₃(C₄H₈)], prepared by reduction of H₂[PtCl₆] with n-butanol reacts with 2-pentyne to give equal amounts of the regioisomers [PtCl₂(C₄Et₂Me₂)] ( 3 a, 3 b ). An equimolar mixture of 2-butyne/3-hexyne reacts under the same conditions to give [PtCl₂(C₄Me₄)] ( 1 ), [PtCl₂(C₄Et₄)] ( 2 ) and [PtCl₂(C₄Et₂Me₂)] ( 3 a ) in a molar ratio 1:1.3:6.6. 1 and 2 react with ligands L (L = py a , p-tol b , PPh₃ c , AsPh₃ d , SbPh₃ e ) to give complexes of the type [PtCl₂(C₄R₄)L]. The complexes were characterized by microanalysis as well as by i.r., ¹H- and ¹³C-n.m.r. spectroscopy.     

Synthesis of 3,3,4,4-tetrafluoro-4-iodobutylamine,a bifunctional reagent for ionic and free-radical reactions

1,1,2,2-Tetrafluoro-1,4-diiodobutane reacts with NaN3 under phase-transfer catalysis conditions to give 3,3,4,4-tetrafluoro-4-iodobutyl azide. The reduction of the azide with triphe-nylphosphine followed by hydrolysis of intermediate iminophosphorane affords 3,3,4,4-tetra-fluoro-4-iodobutylamine.