Nucleophilic reactions of l-methyl-2-methoxy-2-phenyl-3-oxo-2,3-dihydroindole

The title compound (1) was prepared via methylene blue (MB)-sensitized photooxy-genation of l-methyl-2-phenylindole (2d) in methanol. Acid-catalyzed nucleophilic substitution of 1 with nucleophiles gave 1,2,2-trisubstituted 3-oxo-2,3-dihydroindoles (3–6). Reduction of 1 with lithium aluminum hydride, followed by acidic workup yielded 4d and 2d, whereas the same reduction reaction of 1, followed by neutral workup gave l-methyl-2-phenyl-3-hydroxy-2,3-dihydroindole (15), together with 3. The reaction pathways of nucleophilic substitution and reduction of 1 were discussed.     

The determination of vanadium in steel samples by x-ray fluorescence spectrometry after precipitation with 4-caprinoyl-3-methyl-1-phenyl-5-pyrazolone

Vanadium(V) is quantitatively precipitated from aqueous solution with 4-caprinoyl-3-methyl-1-phenyl-5-pyrazolone at pH 1, and collected as a film on a membrane for x-ray fluorescence spectrometry. The limit of detection is ca. 2 μg of vanadium. The procedure gave satisfactory results on standard steels containing 0.003–0.091% vanadium.     

Trithia- and dithiaselenapentalenes from benzylidene-1,2-dithioles and heterocumulenes

Deprotonation of the 5-aryl-3-benzyl-1λ⁴,2-dithiol-1-ylium iodides ( 6a–6d ) obtained by reaction of the 1-aryl-4-phenylbutan-1,3-diones ( 5a–5d ) with hydrogen sulfide and iodine in ethanol gave the stable 5-aryl-3-benzylidene-3H-1,2-dithioles ( 3a–3d ), respectively. The dithioles ( 3a–3d ) underwent thermal cycloaddition reactions with isoselenocyanates and isothiocyanates to give the 2-(substituted amino)-5-aryl-3-phenyl-6,6aλ⁴-dithia-1-selenapentalenes ( 7a–7h ) andthe 2-(substituted amino)-5-aryl-3-phenyl-1,6,6aλ⁴-trithiapentalenes ( 8a–8l ), respectively. The dithioles( 3a–3d ) reacted with isocyanates to give the N-substi-tuted-2-phenyl-2-(5-aryl-3H-1,2-dithiol-3-ylidene) acetamides ( 11a–11h ). © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8 : 233–244, 1997.     

ω-氯氟烷基醇,烯烃及环氧化物的合成

本文报道在引发剂存在下, ω-氯氟烷基碘与烯丙基化合物(CH~2=CH-CH~2X, X=OH,OAC) 及乙烯基化合物CH~2=CH-OAC 发生自由基加成反应, 生成相应的加成产物Cl(CF~2)~nCH~2CHICH~2OH (2a～d), Cl(CF~2)~nCH~2CHICH~2OAC (3a～d)和Cl(CF~2)~nCH~2CHIOAC (4a～d) , 产率较好.2a～d用LiAlH~4脱碘生成Cl(CF~2)~nCH~2CH~2CH~2OH(5a～d), 反应条件温和. 2a～d与KOH-CH~3OH反应， 主要得到醇Cl(CF~2)~nCH=CHCH~2OH (6a～c), 若2a～d与NaOH-水溶液反应则得到环氧丙烷化合物. 在少量HOAC存在下， 异丙醇溶剂中， 锌粉与2a～d和3a～d反应得到消除产物Cl(CF~2)~n-CH~2CH=CH~2 (8a～d) . 4a～d与锌反应，再经KOH-CH~3OH-H~2O水解得到Cl(CF~2)~n(CH~2)~2OH(10a～d).     

ω-氯氟烷基醇,烯烃及环氧化物的合成

全氟烷基碘的加成反应一直活跃在氟化学中,即使近来也依然受到注意,这是因为由它们出发可做许多有用的中间体,其中氟烷基取代的醇可做织物表面处理剂,氟烷基取代的环氧化合物可做润滑剂。我们曾用引发剂,使ψ—碘代全氟烷基磺酰氟与多键类化合物在较温和条件下进行加成。黄维垣教授等用NaHCO_3—K_3[Fe(CN)_6]引发Cl(CF_2)_(4.6)I与烯丙醇顺利加成。     

Photoinduzierte 1, 3-dipolare Cycloaddition von 3-Phenyl-2H-azirinen an Azodicarbonsäure-diäthylester. 32. Mitteilung über Photoreaktionen

Irradiation of 2, 2-dimethyl-3-phenyl- ( 1a ), 2, 3-diphenyl-2H-azirine ( 1b ) or the azirine-precursors 1-azido-1-phenyl-propene ( 2a ) and 1-azido-1-phenyl-ethylene ( 2b ), respectively, in benzene in the presence of azodicarboxylic acid diethylester, yields the corresponding 1, 2-carbethoxy-3-phenyl-Δ³-1, 2, 4-triazolines 4a–d (Scheme 1). Refluxing 4 ( a, c or d ) in 0, 2–0, 4M aqueous ethanolic potassium hydroxide leads to the formation of the 1-carbethoxy-3-phenyl-Δ²-1, 2, 4-triazolines 6 ( a, c or d ). Under the same conditions 4b is converted to 3, 5-diphenyl-1, 2, 4-triazole ( 7b , Scheme 2). In 10M aqueous potassium hydroxide solution heating of either 4 ( c or d ) or 6 ( c or d ) yields the 3-phenyl-1, 2, 4-triazoles 7 ( c or d ). Photolysis of 1-carbethoxy-5, 5-dimethyl-3-phenyl-Δ²-1, 2, 4-triazoline ( 6a ) in benzene in the presence of oxygen and trifluoroacetic acid methylester gives the 5-methoxy-2, 2-dimethyl-4-phenyl-5-trifluoromethyl-3-oxazoline ( 13 , Scheme 5). 5, 5-Dimethyl-3-phenyl-1, 2, 4-triazole seems to be the intermediate, which on losing nitrogen gives the benzonitrile-isopropylide ( 3a ).     

Microwave‐Assisted Synthesis of Arylated Pyrrolo[2,1‐a]Isoquinoline Derivatives via Sequential [3 + 2] Cycloadditions and Suzuki‐Miyaura Cross‐Couplings in Aqueous Medium

Treatment of 5‐bromo‐2‐(bromoacetyl)thiophene ( 1 ) with isoquinoline gave the isoquinolinium bromide 2 . Reaction of 2 with acrylic acid derivatives, in the presence of MnO₂, afforded the 3‐[(5‐bromothiophen‐2‐ylcarbonyl]pyrrolo[2,1‐a]‐isoquinolines 3a , 3b . Suzuki–Miyaura cross‐coupling reactions of the bromides 3a , 3b in aqueous solvent with several activated and deactivated aryl(hetaryl)boronic acids 4a , 4b , 4c , 4d , 4e , 4f using a Pd(II)‐complex under thermal heating as well as microwave‐irradiating conditions afforded the corresponding new arylated pyrrolo[2,1‐a]isoquinoline derivatives 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 in high to excellent isolated yields.     

Studies on sulfinatodehalogenation XXI. A new and convenient syntheses of 2-(F-alkyl) aldehydes,alcohols, acids and ketones

Reaction of perfluoroalkyl iodides ( 1a–e ) with the unsaturated ethers such as 1-ethoxy-1-propene (2) , 1-methoxy-1-butene (3) under the sulfinatodehalogenation condition gave the corresponding 2-(F-alkyl) propanals ( 5a–e ) and butanals ( 6c, d ) very readily in high yield, which were converted to 2,4-dinitrophenylhydrazones ( 7a–e, 8c, d ) and characterized. The reaction products 5 and 6 were oxidized with Jone's reagent and reduced with NaBH₄ in ethanol to give the corresponding acids ( 9, 10 ) and alcohols ( 11, 12 ) in good yield. Treatment of compounds 5 and 6 with pyridine gave the dehydrofluorination products 13 and 14 . Under the same condition, perfluoroalkyl iodide reacted with 2-ethoxy-1-propene (4) only to form R_FSO₂Na and R_FH as the major products, but in aqueuous DMF (DMF: H₂O = 5:1) to give the perfluoroalkylacetone (15) in good yield. Thus, the reaction provides a convenient, effective new method for syntheses of these useful organofluorine intermediates.     

Synthesis of indole and indolenine derivatives starting from indoline‐2‐thiones

Indoline‐2‐thiones 1a‐b,d,f,h , which have at least one hydrogen at the 3‐position reacted with α‐halo ester 2a‐d , α‐halo ketones 2e‐f , and a‐bromoacetonitrile 2g to give 2‐alkylthioindole derivatives 3–11 . In a similar manner treatment of 3,3‐disubstituted indoline‐2‐thiones 1c,e with α‐halo esters 2a,c,d and α‐halo ketone 2e gave 2‐alkylthioindolenines 12–16 . Treatment of 1,3,3‐ trisubstituted indoline‐2‐thiones 1g,i with ethyl bromo‐acetate 2a resulted in recovery of starting materials. Desulfurization of indolenine 14 with triphenylphosphine gave 2‐alkylideneindoline 19 .     

Studies on organophosphorus compounds: Synthesis and reactions of [1,2,4,3]triaza‐phospholo[4,5‐a]quinoxaline derivative

2,4‐Bis‐(4‐methoxyphenyl)‐1,3,2,4‐dithiadiphosphetane‐2,4‐disulfide (Lawesson's reagent) ( 1 ) reacted with 2‐hydrazino‐3‐methyl‐quinoxaline ( 2 ) to give [1,2,4,3]‐triazaphospholo[4,5‐a]quinoxaline derivative 3 . The Mannich reaction using different amines on compound 3 gave Mannich bases 4a–d . Also, compound 3 reacted with formaldehyde to give the corresponding 2‐hydroxymethyl derivative 5 , which upon reaction with thionyl chloride gave the corresponding chloromethyl derivative 6 . Treatment of compound 6 with some thiols yielded the corresponding sulfides 7a–d . Acylation of compound 3 gave acylated compounds 8a,b . Compound 9 , which was prepared through the reaction of compound 3 with ethyl cyanoacetate, was investigated as a starting material for the synthesis of some new heterocyclic systems 10–13 . Also, reaction of compound 9 with carbon disulfide and 2 equivalents of methyl iodide in a one‐pot reaction yielded the corresponding ketene‐S,S‐acetal 14 , which in turn reacted with bidentates to give some new heterocycles 15–17 . © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:520–529, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20473     

Studies with polyfunctionally substituted heteroaromatics: New routes for the synthesis of polyfunctionally substituted pyridines and 1,2,4-triazolo[1,5-a]pyridines

The 1-substituted ethylidenemalononitriles 1a–c condensed with triethyl orthoformate in refluxing acetic anhydride to yield the dienes 2a–c . On the other hand, a mixture of N,N-dimethylformamide and triethyl orthoformate condensed with 1a–d to yield the N,N-dimethylaminopentadienonitriles 2d–g . The pentadienonitriles 2d–g were also formed from the reaction of 1a–d with dimethylformamide dimethylacetal in refluxing acetic acid. When compounds 1a–c were treated with dimethylformamide dimethylacetal in refluxing p-xylene, a mixture of 3 , 4 and 2e–g was formed. The reaction of 2a , b with hydrazine hydrate afforded the N-amino-2-iminopyridines 5a , b . These were converted into the triazolo[1,5-a]pyridines 8a–d on treatment with benzoyl chloride and with dimethylformamide dimethylacetal. On the other hand, the reaction of 2c with hydrazine hydrate afforded the pyrazolo[3,4-b]pyridine 7c . Treatment of 2a , c or 2e , g with cyanoethanoic hydrazide afforded the N-(cyanoacetamido)pyridines 9a , b . The dienes 2d , f , g afforded the pyridones 11a–c on treatment with acetic acid and hydrochloric acid mixture. Compounds 11b , c were also formed on treatment of 2b , c with acetic acid hydrochloric acid mixture. The reaction of 2d , g with ethanolic sodium ethoxide gave the ethoxypyridines 13a , b .     

Reactivity of the A-CH=N-NR-CX-B system. 4-Methyl-5-hydroxy-5-phenyl-(or thienyl)-2,3,4,5-tetrahydro-1,2,4-triazin-3-ones and their ring contraction products

The behaviour of some monosemicarbazones of phenyl- ( 1a-c ) and thienyl-glyoxal ( 2a-c ) towards cyclizing agents has been investigated. Upon aqueous sodium hydroxide treatment, 4-melhyl-semicarbazones 1a and 2a gave the addition products 3 and 4 , respectively, whereas the 2-methyl- and 2,4-dimethyl derivatives 1b,c and 2b,c gave demolition products only. On the other hand, compounds 1b,c gave the addition product 8 and the triazine 7 , respectively, on treatment with aqueous hydrochloric acid. Bromination of 1a,b gave the bromosemicarbazone 10a and a mixture of 10b and 9 , respectively. Performing the same reaction on 3 and 4 at 115°, the 1,3,4-oxadiazoles 13 and 14 have been obtained. The behaviour of bromosemicarbazones [ 10a,b ] and of the bromo-tetrahydrotriazine 9 towards heating or treatment with base has also been investigated.     

Radical Cyclization Reactions via Manganese(III) Acetate Leading to 2‐Thienyl‐Substituted Dihydrofuran Compounds

The 2‐thienyl‐substituted 4,5‐dihydrofuran derivatives 3 – 8 were obtained by the radical cyclization reaction of 1,3‐dicarbonyl compounds 1a – 1f with 2‐thienyl‐substituted conjugated alkenes 2a – 2e by using [Mn(OAc)₃] (Tables 1–5). In this study, reactions of 1,3‐dicarbonyl compounds 1a – 1e with alkenes 2a – 2c gave 4,5‐dihydrofuran derivatives 3 – 5 in high yields (Tables 1–3). Also the cyclic alkenes 2d and 2e gave the dihydrobenzofuran compounds, i.e., 6 and 7 in good yields (Table 4). Interestingly, the reaction of benzoylacetone (=1‐phenylbutane‐1,3‐dione; 1f ) with some alkenes gave two products due to generation of two stable carbocation intermediates (Table 5).     

Stereoselectivity of the Diels-Alder Reaction of (E)-γ-Oxo-α,β-Unsaturated Thioesters with Cyclopentadiene

The stereoselectivity of the Diels-Alder reaction of (E)-γ-oxo-α,β-unsaturated thioesters 3a-3d with cyclopentadiene is greatly enhanced in the presence of Lewis acids favoring the endo acyl isomers 4a-4d . In the absence of Lewis acid, Diels-Alder reaction of 3a-3d with cyclopentadiene at 25 °C gave two adducts 4a-4d and 5a-5d in a ratio of 1:1 respectively. In the presence of Lewis acids, Diels-Alder reaction of 3a-3d with cyclopentadiene gave 4a-4d and 5a-5d in ratios of 75-94:25-6 respectively. The stereoelectivity was enhanced to ratios of 95-98:5-2 with lowering the reaction temperature. The stereochemistry of the cycloadducts 4 and 5 was confirmed by iodocyclization. Reaction of the endo-thioester 5c with I₂ in aqueous THF at 0 °C gave the novel methylthio group rearranged product 6c in 80% yield, the first example of iodo-lactonization of endo-thioesters. Reaction of the endo-acyl isomer 4b with I₂ under the same reaction conditions gave an isomeric mixture of 7b and 8b in 1:2 ratio. The stereochemistry of the thioester group in 8b was proved by X-ray single-crystal analysis. The solvent effect on the endo selectivity of (Z)-γ-oxo-α,β-unsaturated thioester 2b was also examined.     

Novel quaternary ammonium borates as latent catalysts for epoxy–phenolic resins

Novel tetrabutylammonium tetrakis(substituted benzoyloxy)borate salts ( 1a – 1d ) were synthesized by the reaction of tetrabutylammonium tetraphenylborate and corresponding substituted benzoic acids. Polyaddition reactions of diglycidyl ether of bisphenol A (DGEBA) and 4,4′‐bisphenol F (44BPF) or bisphenol F (BPF‐D) with the ammonium borates were investigated as model reactions of epoxy/phenol–novolac resin systems with respect to the thermal latency and storage stability of the catalyst. The polyaddition of DGEBA/44BPF with the ammonium borates in diglyme at 150 °C for 6 h proceeded up to 84–94% conversions and gave polymers with number‐average molecular weights of 3750–5750, whereas the polyaddition at 80 °C for 6 h gave less than 9% conversions. The catalytic activity of ammonium borates 1a – 1d depended on the substituent of the phenyl group of the borates, and the order of activity was 1b (p‐OMe) > 1a (? H) > 1c (p‐NO₂) > 1d [3,5‐(NO₂)₂]. The ammonium borate catalyst with the substituent that yielded lower acidity of the corresponding substituted benzoic acid tended to reveal higher activity. In comparison with tetrabutylammonium bromide (TBAB) as a conventional ammonium salt, 1a – 1d revealed better thermal latency. The storage stability of DGEBA/BPF‐D with the ammonium borate catalysts in bulk at 40 °C was better than that with TBAB. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2689–2701, 2002     

Nitrone formation in phosphate buffer and aqueous solutions: novel chemistry inspired by a natural product

Nitrones are formed from the reaction of aspergillusol A (1) and a ketone/aldehyde in phosphate buffer and aqueous solutions with pH ranges of 6.8–8.6, resembling physiological conditions. The reaction of 1 with 1-substituted cyclohexanones gave the (1′S¹,2′R¹)-isomer, diastereoselectively.     

CHLOROSULFONATION OF SOME CRISSCROSS CYCLOADDUCTS FROM ISOCYANATES AND DIARYL AZINES

Abstract

Reaction of chlorosulfonyl isocyanate (1) with arylaldehyde azines (7) gave the 2:1 crisscross adducts (8);attempts to prepare a disulphonamide of 8a gave only a mixture of the monosulfamide 9 and the diureide 10. The latter with trichloromethanesulfenyl chloride afforded the derivative 12a. and with chlorosulfonic acid hydrazinodicarbonamide (11). The azine 7a with benzoyl isocyanate (2) gave the expected crisscross adduct 13. With thiobenzoyl isocyanate (3) however, both 7a and 7d gave the 1: 1 adducts (14). whereas 7c gave a different 2: 1 adduct (15). Treatment of 14a with 1 gave the ureide 16. With both methyl isocyanate (4) and phenyl isocyanate (S), 7a gave the expected crisscross adducts (17a and b), and 7c with 5 similarly gave 17c. When 7a was treated with 1 followed by aqueous potassium iodide, the diureide (10) was formed; concentrated nitric acid converted 10 into the triazolenone (18). Treatment of 18 with chlorosulfonic acid-thionyl chloride gave the sulfonyl chloride (19) which was characterised as the sulfonamides (20 a-d).

Diarylsulfamoyl azines (21 a-f) with 1 and potassium iodide, gave the diureides 22 a-f. 4-Methoxy-3-sulfamoylbenzaldehydeazines (23 a-c) reacted with 3 to give the 1: I adducts 24 a-c, while 4-chlorosulfonylphenyl isocyanate (6) with benzaldehyde azine (7a) gave the bis-chlorosulfonyl adduct (25a). characterised as the diethylsulfonamide 25b. Attempted chlorosulfonation of the tetraphenyl cycloadduct 17b did not give the tetrasulfonyl chloride (although the reaction was successful with the more reactive rnethoxy adduct 17c); the tetrasulfonyl chloride (26a) was converted into 3 sulfonamides (26 b-d). The unsymmetrically-substituted diaryl azines (27) reacted with 1 and potassium iodide to yield the diureides 28 a-f. Analogous cycloadditions of 1 with several keto azines were unsuccessful. Selected compounds will be screened for medicinal and pesticidal activity; compounds 9,10 and 12a showed fungicidal activity against barley powdery mildew.     

Diversity of Reactions of Isomeric Aminopyridine N‐Oxides with Chloronitropyridines: An Experimental and Theoretical Study

Reaction of 2‐aminopyridine N‐oxides 1a , 1b , 1c , 1d with chloronitropyridine 7a gave 2‐[(pyridin‐2‐yl)amino]pyridine N‐oxides 8a , 8b , 8c and 9 in good yield. The reactions of 4‐ and 3‐aminopyridine N‐oxides 12a , 12b and 24 with 7a , 7b , 7c proceed in the different manner involving initial formation of the intermediary 1‐pyridyloxypyridinium salts 13a , 13b , 13c , 13d and 26 , which rearrange to 4‐[(5‐nitropyridin‐2‐yl)amino]pyridine N‐oxide 22 and 1‐(3‐aminopyridin‐2‐yl)pyrid‐2‐one derivatives 27a , 27b , respectively. However, N‐protected 2‐aminopyridine N‐oxides 17 gave quaternary 1‐pyridyloxypyridinium salts 18a , 18b , which upon treatment with aqueous ammonia afforded 2‐[(pyridin‐2‐yl)amino]pyridine N‐oxides 8a and 20 . Quantum chemical calculations at the DFT/B3LYP/6‐311++G(d,p) level were performed to explain the differences in properties of the frontal orbitals and atomic charge distribution in isomeric aminopyridine N‐oxides.     

Stereospecific substitution of enantiomerically pure 1-(2-pyridinyl)ethyl methanesulfonate with beta-dicarbony compounds

The alkylation of the sodium salt of the malonic acid diester with (R)-1-(2-pyridinyl)ethyl methanesulfonate (2) gave the dimethyl (R)-[1-(2-pyridinyl)ethyl]malonate (3a), stereospecifically. The alkylation reaction of methyl acetoacetate gave the methyl (2'S,2R/2S)-3-oxo-2-[1-(2-pyridinyl)ethyl]butanoate (3d) along with the methyl (S)-3-[1-(2-pyridinyl)ethoxy]-2-butenoate (4d). The acid hydrolysis and decarboxylation of 3d under acidic conditions gave (R)-4-(2-pyridinyl)pentan-2-one (6), and the alkylation of methyl (R)-[1-(2-pyridinyl)ethyl]acetoacetate with benzyl bromide gave a mixture of C-benzylated and O-benzylated products 7 and 8.     

Preparation of Succinyl-Chitin Nanoparticles for Biomedical Applications

The N-acylation of partially deacetylated chitin nanofibers with succinic anhydride gave N-succinyl-chitin. The introduction of succinyl groups into chitin nanofibers followed by sonication of the aqueous dispersion of N-succinyl-chitin gives rise to a stable aqueous dispersion (with particle hydrodynamic radius of 350 nm and ζ-potential of –22 mV). The particle morphology simultaneously changes from rod-like with (100–500) × (6–15) nm size to spherical with 160–400 nm size, whereas the chitin crystal structure barely changes.