An efficient synthesis of 2,2-bis(1H-indol-3-yl)-2H-acenaphthen-1-one catalyzed by recyclable solid superacid SO_4~(2-)/TiO_2 under grinding condition

<正>An efficient synthesis of symmetrical 2,2-bis(1H-indol-3-yl)-2H-acenaphthen-1-one is achieved via a reaction of acenaphthe-nequinone and indoles catalyzed by solid superacid SO_4~(2-)/TiO_2 under solvent-free conditions at room temperature by grinding, which provides an efficient route to the synthesis of symmetrical 2,2-bis(1H-indol-3-yl)-2H-acenaphthen-1-one.This procedure offers several advantages including solvent-free conditions,excellent yields of products,simple work-up as well as reuse of catalysts which makes it a useful and attractive protocol for the synthesis of these compounds.     

Vanadium-catalyzed sulfenylation of indoles and 2-naphthols with thiols under molecular oxygen

Vanadium oxyacetylacetonate [VO(acac)(2)] works as a catalyst for the direct synthesis of 3-sulfanylindoles from indoles and thiols under an atmospheric pressure of molecular oxygen as a reoxidant. For example, the reaction of 2-phenylindole with benzenethiol in the presence of a catalytic amount of VO(acac)(2), potassium iodide, and 2,6-di-tert-butyl-p-cresol in chlorobenzene under molecular oxygen proceeds to afford 2-phenyl-3-(phenylsulfanyl)indole in 86% yield. This catalytic system can also be applied to 2-naphthols instead of indoles to give the corresponding 1-sulfanyl-2-naphthols in up to 57% yield.     

5-Schwefelsubstituierte 1,2-Dithiol-3-one

1, 2-Dithioles with sulfur substitutents in position 5 are prepared by reaction of 4-chloro-1, 2-dithiol-3-ones with thiols, sulfinates, dithiocarbamates, or potassium ethylxanthate. Bis-(4-chloro-1, 2-dithiol-3-on-5-yl) sulfide is produced from 4, 5-dichloro-1, 2-dithiol-3-one with sodium thiosulfate and other thiol forming reagents. The 5-alkylthio- and 5-arylthio-1, 2-dithiol-3-ones can be oxidized with peracids to sulfoxides and, partly, to sulfones; the sulfones can also be obtained from sulfinates. 4-Chloro-5-(α-methyl-benzylthio)-1, 2-dithiol-3-one reacts differently with peracetic acid, giving bis-(4-chloro-1, 2-dithiol-3-on-5-yl) disulfide besides 4-chloro-1, 2-dithiol-3-one. With oxalyl chloride, 4-chloro-5-alkylthio-1, 2-dithiol-3-ones form 3, 4-dichloro-dithioliumchlorides, which react with anilines to give 3-phenylimino-4-chloro-5-alkylthio-1, 2-dithioles.     

Reactions of 6,7-dimethoxy- 3,4-dihydroisoquinoline with <Emphasis Type="Italic">o</Emphasis>-quinone methides

Products of heterocyclization, 9,10-dimethoxy-12,13-dihydro-7aH,15H-naphtho[1',2':5,6][1,3]oxazino-[2,3-a]isoquinolines, were isolated on condensing 6,7-dimethoxy-3,4-dihydroisoquinoline with 1-dimethylaminomethyl-2-naphthols. In the case of o-hydroxybenzyl alcohols products of a Michael aza reaction, 2-[(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)methyl]phenols were obtained.     

Synthesis of 2-(arylthio)benzoates by [3+3] cyclocondensations of 3-arylthio-1-silyloxy-1,3-butadienes with 3-oxo-orthoesters, 1,1,3,3-tetramethoxypropane and 1,1-bis(methylthio)-1-en-3-ones

A variety of 2-arylthio-4-methoxybenzoates are regioselectively prepared by TiCl₄-mediated [3+3] cyclocondensations of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 3-oxo-orthoesters. Unsubstituted 2-(arylthio)benzoates were prepared by Me₃SiOTf-catalyzed cyclization of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 1,1,3,3-tetramethoxypropane. The TiCl₄-mediated cyclization of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 1,1-bis(methylthio)-1-en-3-ones results in regioselective formation of 2-arylthio-6-(methylthio)benzoates.     

PPA-SiO2–Catalyzed Multicomponent Synthesis of Amidoalkyl Naphthols

Silica gel–supported polyphosphoric acid (PPA-SiO₂) was found to be an efficient catalyst for the multicomponent condensation reaction of aryl aldehydes, 2-naphthol, and urea or amides to afford the corresponding 1-amidoalkyl-2-naphthols in good to excellent yields. This new approach consistently had short reaction times, high conversions, clean reaction profiles, and simple experimental and workup procedures.     

N－取代－6－芳硫基吡啶酮类化合物的合成与生物活性研究

以3－羟基－2－烷基－4（1H）－吡喃酮为原料与胺反应制备N－取代－4（1H ）－吡啶酮，再与亲核试剂发生氧化－迈克尔加成反应，合成了相应的N－取代－ 6－芳硫基吡啶酮化合物。生物活性研究结果发现，N－取代－6－芳硫基吡啶酮类 化合物对5－脂氧合酶具有良好的抑制作用。     

Four-Component Domino Reaction for the Synthesis of 1-(1H-Indol-2-yl)-1H-pyrazolo[1,2-b]phthalazine-5,10-diones

Facile, efficient, four-component domino reaction of dialkylphthalates, hydrazine hydrate, indole-3-carboxaldehydes, and malononitrile/ethyl cyanoacetate leads to the formation of 1-(1H-indol-2-yl)-1H-pyrazolo [1,2-b] phthalazine-5,10-diones in the presence of InCl₃ as catalyst in refluxing ethanol for 1 h in good yields. This four-component domino reaction transformation presumably proceeds via sequential addition, dehydration, condensation, and cyclization steps.     

P2O5-Hexamethyldisiloxane (HMDS): An Efficient System to Induce the Three-Component Reaction of Enolic Systems,Aromatic Aldehydes,and Acetonitrile

Three-component reaction of an enolizable compound, such as acetophenone, methyl acetoacetate, 4-hydroxycoumarin, 2-naphthol, or 3-hydroxy-2-naphthoic acid; an aromatic aldehyde, and acetonitrile induced by phosphorus pentoxide and hexamethyldisiloxane leads to 2-acetylamino ketones, methyl 3-(acetylamino aryl methyl)-3-oxobutanoates, 3-(acetylamino aryl methyl)-4-hydroxycoumarins, 1-(acetylamino aryl methyl)-2-naphthols, or 4-(acetylamino aryl methyl)-3-hydroxy-2-naphthoic acids in excellent yields.     

Syntheses and properties of new herbicidal 2-arylthio-1 ,2,4-triazolo[1,5-a] pyrimidine derivatives

In search of novel herbicides with high activity, a series of 2-arylthio-1,2,4- triazolo [1, 5-a ] pyrimidines (3) were synthesized by cyclization of 5-amino-3-arylthio-1,2,4-triazoles with 1,3-diketones or by the nucleophilic substitution of substituted thiophenols with 2-methylsulfonyl-1, 2, 4-triazolo [ 1, 5-a]-pyrimidine. The structures of all compounds prepared were confirmed by 1H NMR and MS spectroscopy along with elemental analyses. Preliminary bioassays indicated that some of the compounds 3 had good herbicidal activity against rape. In addition, the regioselectivity in the reaction of 5-amino-3-sub-stituted arylthio-1,2,4-triazoles with benzoylacetone was studied.     

Pd-catalyzed ring opening of oxa- and azabicyclic alkenes with aryl and vinyl halides: efficient entry to 2-substituted 1,2-dihydro-1-naphthols and 2-substituted 1-naphthols

An efficient syntheses of 2-substituted 1,2-dihydro-1-naphthols and 2-substituted 1-naphthols has been developed that involves the sequential palladium-catalyzed ring opening of oxabicyclic alkenes with aryl and vinyl halides followed by oxidation of with IBX. In the first step of the sequence, a combination of Pd(OAc)2, PPh3, Zn, and PMP in dry DMF was employed to catalyze the ring opening of 7-oxabenzonorbornadienes with aryl and vinyl halides to afford the corresponding cis-2-substituted 1,2-dihydronaphthols in good to excellent yields. These reactions occurred under very mild conditions with a variety of aryl halides bearing electron-withdrawing or -donating groups. Similarly, a 7-azabenzonorbornadiene substituted with an electron-withdrawing group on the nitrogen atom underwent facile ring-opening reaction with aryl halides to provide cis-2-substituted (1,2-dihydro-1-naphthyl)carbamates in excellent yields. Oxidation of the intermediate 1,2-dihydro-1-naphthols using IBX yielded the corresponding 2-substituted 1-naphthols in good to excellent yields.     

Ethynylation of 2-(furan-2-yl)- and 2-(thiophen-2-yl)pyrroles with acylbromoacetylenes in the Al2O3 medium: relative reactivity of heterocycles

2-(Furan-2-yl)- and 2-(thiophen-2-yl)pyrroles are readily ethynylated with acylbromoacetylenes in the solid Al₂O₃ medium (no solvent, room temperature, 1 h) to afford 5-(furan-2-yl)- and 5-(thiophen-2-yl)-2-acylethynylpyrroles in 39–74% yields. In the case of 2-(furan-2-yl)pyrroles, an alternative ethynylation of the furan ring takes place, the ratio of the furan and pyrrole ring ethynylation products being 1:5–7. No ethynylation of the thiophene ring as well as ethynylation of both heterocycles in a one molecule has been detected. Thus the reactivity of the heterocycles towards the ethynylation system (acylbromoacetylenes/Al₂O₃) falls in the order: pyrrole>furan>thiophene.     

Synthesis of 3-[4-(1-Benzofuran-2-yl)-1,3-thiazol-2-yl]-2-(4-aryl)-1,3-thiazolidin-4-one Derivatives as Biological Agents

A protocol for the synthesis of 3-[4-(1-benzofuran-2-yl)-1,3-thiazol-2-yl]-2-(4-aryl)-1,3-thiazolidin-4-one derivatives (5a–e) has been developed from 1-(1-benzofuran-2-yl)-2-bromoethanone (2),which served as a key intermediate for the synthesis of the title compounds. The reaction of compound 2 with thiourea furnished 4-(1-benzofuran-2-yl)-1,3-thiazol-2-amine 3, which upon further reaction with various aromatic aldehydes, gave Schiff bases 4a–e. These Schiff bases, when treated with thioacetic acid in the presence of catalytic amount of anhydrous ZnCl₂, yielded thiazolidinone derivatives 5a–e. All the newly synthesized compounds have been characterized by analytical and spectral data and screened for their antimicrobial and analgesic activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis of polysubstituted-2-naphthols

Substituted 3-(triisopropylsilyl)-2-naphthols are prepared by an aluminum chloride catalyzed condensation of phenyl acetyl chloride derivatives and triisopropylsilyl acetylene. The yields obtained are in the range of 41% to 67%. The reaction is regiospecific and gives only the 3-(trialkylsilyl)-2-naphthol isomer.     

Cesium hydroxide-catalyzed hydrothiolation of alkynyl selenides to highly stereo- and regioselectively synthesize(Z)- -organoseleno-2-arylthio-1-alkenes

In the presence of catalytic amount of cesium hydroxide the hydrothiolation of alkynyl selenides occurred at room temperature in DMF under nitrogen atmosphere to give exclusive(Z)-1-organoseleno-2-arylthio-1-alkene in excellent yields.It could provide a new and expedient way for the preparation of(Z)-1-arylseleno-2-arylthio-1-alkene.     

Rhodium-catalyzed regio- and stereoselective 1-seleno-2-thiolation of 1-alkynes

Rhodium complex RhH(PPh(3))(4) and 1,1'-bis(diphenylphosphino)ferrocene catalyze the regio- and stereoselective additions of diaryl disulfides and diaryl diselenides to 1-alkynes giving (Z)-1-arylseleno-2-arylthio-1-alkenes. The catalyst promotes the addition reaction of dibutyl disulfide and dibutyl diselenide to 1-octyne with a similar selectivity giving (Z)-1-butylseleno-2-butylthio-1-octene but with a lower catalytic activity. The same product is obtained with a higher yield, when excess dibutyl disulfide is used against dibutyl diselenide in the presence of RhH(PPh(3))(4) and 1,4-diphenylphosphinobutane.     

Catalytic asymmetric oxidative couplings of 2-naphthols by tridentate N-ketopinidene-based vanadyl dicarboxylates

[reaction: see text] A series of oxovanadium(IV) complexes derived from tridentate N-ketopinidene-alpha-amino acids were synthesized. They serve as efficient catalysts for the enantioselective oxidative couplings of various 3-, 6-, or 7-substituted 2-naphthols. The best scenario involves the use of a vanadyl complex arising from L-tert-leucine in CCl4. The asymmetric couplings of 2-naphthols can be conducted smoothly at 40-45 degrees C under a stream of gaseous oxygen, leading to 2,2'-dihydroxy-1,1'-binaphthyls in good yields (61-99%) and with enantioselectivities of up to 87%.     

Efficient Synthesis of Novel 3-[5-(1H-Benzimidazol-2-Ylmethanesulfonyl)-4-Phenyl-4H-(1,2,4)Triazol-3-Yl]-1H-(1,8)Naphthyridin-4-One Derivatives

Abstract

of 1,4-dihydro-4-oxo-1,8-naphthyridine-3-carbohydrazide (4) with substituted phenyl isothiocyanates (5) in ethanol under reflux for 30 min gave thiosemicarbazide derivatives 6, which on cyclization in 2N NaOH under refluxing conditions for 1 h resulted in 3-(5-mercapto- 4-phenyl-4H-1,2,4-triazol-3-yl)-1,8-naphthyridin-4(1H)-one (7). Alternatively, 7 could also be prepared from following sequence of reactions, i.e., 4 → 8 → 7. In another sequence of reactions, condensation of 7 with chloroacetic acid in dimethylformamide (DMF) and K₂CO₃ as a mild base at 120 °C for 2 h resulted in 2-((5-(1,4-dihydro-4-oxo-1,8-naphthyridin-3-yl)-4-phenyl-4H-1,2,4-triazol-3-yl)sulfanyl)acetic acid (10). The latter, on reaction with substituted o-phenylenediamine (11) in 6N HCl for 4 h yielded 3-(5-((1H-benzo[d]imidazol-2-yl)methylthio)-4-phenyl-4H-1,2,4-triazol-3-yl)-1,8-naphthyridin-4(1H)-one (12). Alternatively, 12 could also be prepared by reacting 7 with 13 in DMF and K₂CO₃ as a mild base at 120 °C for 2 h, followed by oxidation with H₂O₂ resulting in the corresponding sulfonyl derivatives 14.     

Reaction of 3-Aryl-1-(2-methyloxiran-2-yl)prop-2-en-1-ones with Tosylhydrazine

It was established that the reaction of 3-aryl-1-(2-methyloxiran-2-yl)prop-2-en-1-ones with tosylhydrazine leads to 3-[(E)-2-arylvinyl]-4-methyl-1-tosyl-1H-pyrazoles and 3-aryl-1-(2-methyloxiran-2-yl)-3-tosylpropan-1-ones. The latter are formed as a result of rearrangement of the intermediate hydrazino alcohols and/or addition of p-toluenesulfinic acid during reductive degradation of the tosylhydrazine. It was shown that the reaction of 3-aryl-1-(2-methyloxiran-2-yl)-3-tosylpropan-1-ones with an excess of tosylhydrazine leads to 3-(2-aryl-2-tosylethyl)-4-methyl-1-tosyl-1H-pyrazoles. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1481–1489, October, 2005.     

Ruthenium-catalyzed cyclization of epoxide with a tethered alkyne: formation of ketene intermediates via oxygen transfer from epoxides to terminal alkynes

Treatment of (o-ethynyl)phenyl epoxides with TpRuPPh(3)(CH(3)CN)(2)PF(6) (10 mol %) in hot toluene (100 degrees C, 3-6 h) gave 2-naphthols or 1-alkylidene-2-indanones very selectively with isolated yields exceeding 72%, depending on the nature of the epoxide substituents. Surprisingly, the reaction intermediate proved to be a ruthenium-pi-ketene species that can be trapped efficiently by alcohol to give an ester compound. This phenomenon indicates a novel oxygen transfer from epoxide to its terminal alkyne catalyzed by a ruthenium complex. A plausible mechanism is proposed on the basis of reaction products and the deuterium-labeling experiment. The 2-naphthol products are thought to derive from 6-endo-dig cyclization of (o-alkenyl)phenyl ketene intermediates, whereas 1-alkylidene-2-indanones are given from the 5-endo-dig cyclization pathway.