Stereoselective epoxidation of 2-arylidene-1-indanones and 2-arylidene-1-benzosuberones

Summary Oxidation of the (E) and (Z) isomers of 2-arylidene-1-indanones (1) and 2-arylidene-1-benzosuberones (4) by alkaline hydrogen peroxide (methodi) afforded the spiroepoxidestrans-2a–g andtrans-5a–g from both isomers as sole products in high yields. On the other hand, dimethyldioxirane epoxidation(methodii) of the (E) isomers1a–g and4a–g gave the correspondingtrans spiroepoxides in good yields, whereas the (Z) isomers1a,c,e and4a,c,e led to thecis spiroepoxides in moderate yields. Dimethyldioxirane oxidation (methodii) of (Z)-1c and (Z)-4c,e gave diones3c and6c,e as by-products as well. Epoxidation of (Z)-1a,c,e and (Z)-4a,c,e bym-chloroperoxybenzoic acid (methodiii) resulted inca. 6:1 mixtures ofcis-2a,c,e andtrans-2a,c,e orcis-5a,c,e andtrans-5a,c,e spiroepoxides.Dedicated to Prof.W. Fleischhacker on the occasion of his 65^th birthday     

Electrosynthesis of 1-indanones

The recent electrocatalytic three-component annulation-halosulfonylation of 1,6-enynes toward 1-indanones is highlighted.     

Electronic tuning cyclization of aryl-1,4-enediones: AlCl3-mediated Nazarov-type cyclization to synthesize polysubstituted-1-indanones

An electronic tuning Nazarov-type cyclization protocol was proposed for the synthesis of polysubstituted-1-indanones from the readily available starting materials 1,4-enediones. AlCl₃ was highlighted as the most efficient promoter for this reaction.     

Reaction of E-2-arylidene-1-indanones,Z-aurones,Z-1-thioaurones and Z-2-arylidene-2,3-dihydro-1H-indol-3-ones with diazomethane

1,3-Dipolar cycloaddition of E-2-arylidene-1-indanones 1a-h and Z-aurones 3a-c with diazomethane provided trans-spiro-1-pyrazolines 2a-h and 4a-c , respectively, as sole products. However, the same cycloaddition of Z-1-thioaurones 5a-f afforded a mixture of Z-α-methyl-1-thioaurones 6a-f and trans-cyclopropane derivatives 7a-f as a result of the spontaneous denitrogenation of the initially formed 1-pyrazolines. Similar reaction of Z-2-arylidene-2,3-dihydro-1H-indol-3-ones 8a,b and diazomethane yielded trans-cyclopropanes 9a,b . Structure and stereochemistry of the compounds synthesized have been elucidated by nmr spectroscopic measurements.     

Direct synthesis of 1-indanones via Pd-catalyzed olefination and ethylene glycol-promoted aldol-type annulation cascade

A wide range of multisubstituted 1-indanones of potential pharmaceutical use were synthesized in a one-pot fashion in moderate to excellent yields via palladium catalysis in ethylene glycol. The Heck reaction first installs an enol functionality on the aromatic ring; this is followed by an ethylene glycol promoted aldol-type annulation with a neighboring carbonyl group, resulting in the formation of various 1-indanones.     

Cyclization of 1-phenyl-2-propen-1-ones into 1-indanones using H-zeolite and other solid acids. The role of mono- and dicationic intermediates

Cyclization of aryl vinyl ketones into 1-indanones was previously known to proceed only in drastic acidic or superacidic conditions due to the necessity of dicationic, superelectrophilic activation of starting compounds. In this paper, we disclose that available solid acids such as HUSY-zeolite, sulfated zirconia or heteropolyacid, H₃PW₁₂O₄₀ can be successfully applied instead of superacids to perform these and related reactions. The cases, when the effective excess of acidic sites of the solid is required to carry out the reaction, are interpreted in terms of key dicationic (superelectrophilic) intermediates on the solid.     

Superacid-Promoted Hydroxyalkylation of 1,2-Indandiones

1,2-Indandione reacts efficiently with arenes to give 2,2-diaryl-1-indanones by the hydroxyalkylation reaction. The Brønsted superacid CF₃SO₃H (triflic acid) is an effective catalyst for these condensation reactions. The requisite 1,2-indandiones were prepared from the 1-indanones.     

Catalytic annulation of 1-substituted-3-en-1-yn-5-als with cycloalkanones using acid-base dual catalysts

CpRu(PPh₃)₂Cl and DBU dual catalysts in combination enable a one-pot annulation of 1-R-3-en-1-yn-5-als (R = aryl, alkenyl, alkyl) and cycloalkanones to give highly substituted benzene products. This catalytic reaction consists of a tandem aldol condensation, dehydration and aromatization through a 1,7-hydrogen shift; the resulting 1-indanones and α-tetralones are obtained in moderate to good yields.     

含2-三氟甲基苯并咪唑的双噁二唑硫醚及其亚砜衍生物的合成

芳甲酰肼和氯乙酸在二甲苯中反应生成了一系列的2-芳基-5-氯甲基-1,3,4-噁二唑(1a～1j), 继而与2-(2-三氟甲基苯并咪唑-1-亚甲基)-5-巯基-1,3,4-噁二唑(2)在乙醇-水的溶液中反应得到了一系列的含2-三氟甲基苯并咪唑的双噁二唑硫醚3a～3j, 再用硝酸氧化得到相应的亚砜衍生物4a～4j. 化合物的结构经元素分析, IR, ¹H NMR确证.     

Phenylmercury derivatives of aminomethylene- and hydroxymethylene-substituted 1-methyloxindoles, 1-indanones,and 1,3-indanediones

A number of phenylmercury derivatives of 3-hydroxymethylene- and 3-aminomethylene-substituted 1-methyloxindoles, 1-indanones, and 1,3-indanediones were synthesized. It is shown that the preferred tautomeric structures of the potentially metallotropic and prototropic hydroxymethylene keto (hydroxy vinyl aldehyde) derivatives of the indicated compounds and 3-hydroxybenzo[b]-2-formylthiophene coincide precisely. An aminomethylene structure with an N-H bond is realized for the phenylmercury derivatives of the corresponding azomethines in all cases.Communication 28 from the series Benzenoid-Quinoid Tautomerism of Azomethines and Their Structural Analogs. See [1] for communication 27.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 65–68, January, 1979.     

Conformational analysis by LIS. II. 2-and 3-alkyl substituted 1-indanones

The preferred conformations of the alkyl groups relative to the cyclopentenone ring of 2-ethyl-, 2-benzyl-, 2-isopropyl-, and 3-isopropyl-1-indanone were determined by means of the lanthanide-induced-shift technique (LIS). Two different models were used in the calculation of LIS. Coupling data-where available-were compatible with the conformations derived from LIS data. O. Hofer, Mh. Chem.109, 405 (1978).     

Asymmetric Cross [10+2] Cycloadditions of 2-Alkylidene-1-indanones and Activated Alkenes under Phase-Transfer Catalysis

Isobenzofulvene species are versatile synthons in organic chemistry, which have been employed in diverse challenging higher-order cycloaddition reactions. Here, the first chemoselective and asymmetric cross [10+2] cycloaddition reaction between activated 2-alkylidene-1-indanones and a variety of electron-deficient alkenes has been developed, relying on the in situ generation of dearomative 1-hydroxyl isobenzofulvene anion intermediates under the catalysis of a newly designed bulky cinchona-derived phase-transfer compound. An array of fused frameworks with multifunctionalities were generally furnished in excellent diastereo- and enantioselectivity, even at 1 mol % catalyst loadings.     

3,3]-Sigmatropic rearrangement/5-exo-dig cyclization reactions of benzyl alkynyl ethers: synthesis of substituted 2-indanones and indenes

Substituted benzyl alkynyl ethers, prepared from the corresponding α-alkoxy ketones in a two-step sequence involving enol triflate formation and KOtBu-induced E2 elimination, undergo [3,3]-sigmatropic rearrangement/intramolecular 5-exo-dig cyclization at 60 °C to form substituted 2-indanones in good overall yields. 1,3-cis-Disubstituted-2-indanones are formed preferentially when the benzylic substituent R(1) is bulky. Substituted indenes may be prepared from 2-indanones in high yields by Horner-Wadsworth-Emmons reaction.     

Synthesis and Biological Activities of O-Alkyl,O-Aryl,O-{Z-[1-Phenyl-2-(1H-1,2,4-triazol-1-yl)ethylidene]amino} Phosphorothioates

A series of title compounds 2 were efficiently synthesized via the condensation of 1-phenyl-2-(1H-1,2,4-triazol-1-yl)ethanone oxime with various asymmetric thiophosphoryl chlorides in sodium hydroxide powder and acetonitrile system. The structures of title compounds 2 were confirmed by IR, ¹H NMR, ³¹P NMR, EI-MS, and elemental analysis. The results of preliminary bioassays indicated that the title compounds 2 possessed good to moderate insecticidal activity against aphides at the dosage of 250 mg/L, and some of them exhibited moderate fungicidal activities at the concentration of 100 mg/L.     

Reaction of thiosemicarbazide with n-cyanoguanidine: synthesis of 3,5-diamino-1-thiocarbamoyl-and 3,5-diamino-1-thiazol-2-yl-1,2,4-triazoles

The reaction of thiosemicarbazide with N-cyanoguanidine in an acidic medium afforded 3,5-diamino-1-thiocarbamoyl-1,2,4-triazole, whose condensation with α-halo ketones gave 3,5-diamino-1-thiazol-2-yl-1,2,4-triazoles 7a–d. The latter were also prepared by the independent synthesis from 2-hydrazinothiazoles and N-cyanoguanidine. Acylation of compounds 7a,d under mild conditions and their condensation with aldehydes occur at the C(3′)NH₂group. The structure of aroyl derivative 11c was established by X-ray diffraction. Acylation of diaminothiazolyltriazole 7a in boiling Ac₂O afforded 3,5-diacetylamino-1-(4-phenylthiazol-2-yl)-1,2,4-triazole. Hydrogenation of arylidene derivatives 14b,c and aroyl derivative 11c gave the corresponding benzylaminotriazoles 15a,b. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 329–334, February, 2006.     

Synthesis, spectroscopic properties and crystal structure determination of 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole derivatives

Substituted 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole derivatives 2, 3 and 6 were synthesized. 2-(2-Pyridin-4-yl-vinyl)-1H-benzimidazole 2 and 6-methyl-2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 3 were prepared by condensation reaction from 3-pyridin-4-yl-acrylic acid and corresponding 1,2-phenylenediamines in polyphosporic acid (PPA). 2,7,11-b-Triaza-benzo[c]fluorene 4 was prepared by photochemical dehydrocyclization reaction of ethanolic solution of 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 2. 2-(2-Pyridin-4-yl-vinyl)-3H-benzimidazole-6-carbonitrile 6 was prepared by condensation reaction from 3-pyridin-4-yl-propenal and 4-cyano-1,2-phenylenediamine using p-benzoquinone as oxidants. The structure of novel benzimidazole derivatives has been studied by ¹H and ¹³C NMR, IR, MS, UV/Vis and fluorescence spectroscopy. The structure of 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 2 was confirmed by X-ray single crystal structure analysis. The conformation of the molecule is E in regard to substituents position around vinyl double C=C bond. The non-planar molecules are mutually connected via the N–H···N and C–H···N type of intermolecular hydrogen bonds into infinite chains spreading along y axis.     

1-Amino-2-hydrazinopyrimidin-N-ylides. Unusual tautomers of 1-aminopyrimidin-2-hydrazones

Summary 1-Amino-2-methylthiopyrimidinium iodides3 have been synthesized by reaction of 3-isothiocyanato-2-propeniminium perchlorates1 with hydrazines and subsequent methylation of the resulting 1-amino-2(1H)-pyrimidinthiones2. Reaction of3 with hydrazine causes substitution of the methylthio group and results in the formation of deeply coloured 1-amino-2-hydrazinopyrimidin-N-ylides5 as unusual tautomers of the commonly expected 1-amino-2(1H)-pyrimidinhydrazones4. The structure of these N-ylides has been proved by spectroscopic methods as well as by subsequent transformation to 3-amino-1,2,4-triazolo[2,3-a]pyrimidinium salts9 by dehydration or to pyrimidotriazinium salt10 c by oxidation. Reaction of N,N-disubstituted 1-amino-2-methylthiopyrimidinium salt7 a with hydrazine also causes substitution of methylthiol, the resulting orange N,N-disubstituted 1-amino-2(1H)-pyrimidinhydrazone8 a, however, cannot tautomerize to N-ylides.

---

1-Amino-2-hydrazinopyrimidin-N-ylide. Ungewöhnliche Tautomere von 1-Aminopyrimidin-2-hydrazonen

Zusammenfassung Es wurden 1-Amino-2-methylthiopyrimidiniumjodide3 ausgehend von 3-Isothiocyanato-2-propeniminiumperchloraten1 und Hydrazinen durch Methylierung der primär gebildeten 1-Amino-2(1H)-pyrimidinthione2 hergestellt. Die Reaktion dieser Pyrimidiniumsalze3 mit Hydrazin verläuft unter Substitution der Methylthiogruppe unter Bildung violett gefärbter 1-Amino-2-hydrazinopyrimidin-N-ylide5 als ungewöhnliche Tautomere der allgemein erwarteten 1-Amino-2(1H)-pyrimidinhydrazone4. Die Struktur dieser Ylide5 wird durch spektroskopische Methoden sowie durch nachfolgende Dehydratisierung zu 3-Amino-1,2,4-triazolo[2,3-a]pyrimidiniumsalzen9 bzw. Oxydation zum Pyrimidotriaziniumsalz10 c bewiesen. Die Reaktion des N,N-disubstituierten 1-Amino-2-methylthiopyrimidiniumsalzes7 a mit Hydrazin verläuft ebenfalls unter Substitution der Methylthiogruppe. Jedoch kann das gebildete orange gefärbte, N,N-disubstituierte 1-Amino-2(1H)-pyrimidinhydrazon8 a nicht zu einem N-Ylid tautomerisieren.

     

新型3-取代-6-(4-氯苯基)-7-(1H-1,2,4-三唑-1-基)-1',2',4'-三唑[3,4-b]-1",3",4"-噻二嗪衍生物的合成及抗菌活性

通过3-取代-4-氨基-5-巯基-1,2,4-三唑(3a～3m)和2-溴-2-(1H–1,2,4-三唑-1-基)-4′-氯代苯乙酮(2)的缩合反应, 合成了13个新型3-取代-6-(4-氯苯基)-7-(1H-1,2,4-三唑-1-基)-1',2',4'-三唑[3,4-b]-1",3",4"-噻二嗪衍生物4a～4m. 化合物结构经元素分析, ¹H NMR, IR和MS进行了表征. 抗菌试验表明所合成的化合物对细菌表现出中等程度的抑制活性.     

Photochemical preparation of highly functionalized 1-indanones

A series of o-alkylphenyl alkyl ketones 1 were synthesized by different methods. The presence of a leaving group X adjacent to the carbonyl group is the special peculiarity of these ketones. Upon irradiation the keto carbonyl group of these compounds undergoes an n-pi* excitation followed by a 1,5-hydrogen migration from the o-alkyl substituent to the carbonyl oxygen atom. The thus formed 1,4-diradicals are subject to a very rapid elimination of acid HX, giving 1,5-diradicals. We called this process spin center shift. After intersystem crossing these diradicals cyclize to 1-indanones 20 in good yields. Depending on the solvent and on substituents, o-alkoxyalkyl ketones 22 or benzo[c]furanes 21 are obtained as byproducts. The mechanism of the cyclization was elucidated by quantum chemical calculations and kinetic measurements.     

Synthesis of 1-indanones by intramolecular Friedel-Crafts reaction of 3-arylpropionic acids catalyzed by Tb(OTf)3

Intramolecular Friedel-Crafts acylation reaction of 3-arylpropionic acids was efficiently catalyzed by Tb(OTf)₃ at 250 °C to give 1-indanones. Even deactivated 3-arylpropionic acids with halogen atoms on the aromatic ring can be cyclized in moderation to good yields.