bluuebunny/crossref_metadata_2025_split huggingface dataset:
1‐Halo‐1‐acceptor‐/1,1‐diacceptor‐substituted Allenes, 9. Functionalized Allenes, Haloallenes, and Bisallenes via [2,3]/[3,3]‐Sigmatropic Rearrangements and Their Reactivity
Authors: Saalfrank Rolf W. , Welch Andreas , Haubner Martin , Bauer Udo 
Published: June 2010

AbstractReaction of carbonyl compounds 1 with trimethylsilylacetylene 2 leads to the alkynols 3, which are excellent precursors of acceptor‐substituted allenes. Compound 3 reacts with carbamoyl chloride 4, diethyl chlorophosphate 6, or hypohalite 8 to give the substituted alkynols 5, 7, 9, Reaction of 9 with sulfinyl chloride 10 leads to the sulfinic esters 11, which on heating undergo a [2,3]‐sigmatropic shift to yield the halosulfonyl allenes 12. In the same manner the reaction of 7 and 9 with chlorophosphanes 13 or sulfenyl chlorides 15 gives rise to the generation of the phosphoryl allenes 14 and the haloallenyl sulfoxides 16, respectively. Alkynyl ketene acetal intermediates 18 are formed by starting from the alkynols 9 and orthoesters 17. Spontaneous [3,3]‐sigmatropic rearrangement of 18 gives the haloallenyl esters 19. Reaction of alkynols 5 with sulfur dichloride leads to the alkynylsulfinyl esters 20, which on heating rearrange to the bisallenyl sulfones 21. Pyrolysis of 21 yields the thiophene 1,1‐dioxides 22. Bisphosphorylbisallene 24 is synthesized from hexadiyndiol 23 by reaction with chlorodiethoxyphosphite. Halophosphoryl allenes 14 react with bromine to yield the oxaphospholenes 25 by cyclization and subsequent elimination of ethanol, or oxaphospholenes 26, if no appropriate leaving group is present in the molecule. Sulfonyl‐1,3‐dienes 27 can be synthesized by reaction of halosulfonylallenes 12 with bromine, followed by elimination of HBr. Haloallenyl ester 19a is converted in a non‐generalizable reaction with bromine into the tribromo‐3 6‐dihydro‐2‐pyranone 30.
Efficient Synthesis of 1,4‐Thiazepin‐3‐one Derivatives and Their Ring Transformations
Authors: Zaleska Barbara , Cież Dariusz , Grochowski Jacek , Serda Pawel , Winnik Witold 
Published: June 2010

AbstractA new one‐pot synthesis of title compounds 2 by reaction of β‐aminothiocinnamic acid anilides 1 with α‐haloacid halides is described. The ring of 1,4‐thiazepine 2 in basic medium undergoes transformation to thiazolidin‐4‐ones 5.
Pronounced Electronic Effect of Allylic Amino Groups on the π‐Facial Stereoselectivity and Reactivity of the Iodoetherification of N‐Substituted 3‐Amino‐4‐penten‐1‐ols
Authors: Tamaru Yoshinao , Harayama Hiroto , Bando Takashi , Nagaoka Hirooki , Yoshida Zen‐Ichi 
Published: June 2010

AbstractThe iodoetherification of N‐substituted 3‐amino‐4‐penten‐1‐ol (1) [I2 and NaHCO3 (2 equivalents each) in ether/H2O at 0°C], providin the mixtures of N‐substituted cis‐ and trans‐ 3‐amino‐2‐iodomethyltetrahydrofurans (9), displayed diastereoselectivity which was found to correlate with the Taft σ* constants of the N‐substitutents (SO2CF3, SO2Me, SO2‐P‐Tol, COPh, COMe): log(cis‐9/trans‐9) = 0.616σ* – 1.67 (r = 0.997). the 2‐methyl‐substituted derivatives of 1 exhibit larger ρ values, while for the 4‐methyl derivative of 1 is approximately zero, Iodoetherification of a variety of N‐tosyl (σ* = 3.32) 1‐ and 2‐substituted derivatives of 1 afforded the corresponding cis isomers with 70 – >95% selectivities, while that of the N‐benzoyl (σ* = 2.20) derivatives furnished the trans isomeres with 70–80% selectivities. These results are interpreted in terms of a πC(4)–C(5)‐σ*C(3)–N interaction of conformer II. The N‐CO2R (R = Et, t‐Bu) and N‐SO2NMe2 derivatives of 1 display anomalously high cis selectivities.
Additions of Silyl Enol Ethers to β‐Formyl Esters – a Chelate‐controlled Synthesis of the Pheromone (+)‐Eldanolide
Authors: Angert Hubert , Czerwonka Regina , Reißig Hans‐Ulrich 
Published: June 2010

AbstractChelate‐controlled Mukaiyama reaction of silyl enol ethers 2a, 2b, 2c, and 2d with β‐formylcarboxylate 1 in the presence of TiCl4 provided γ‐lactones 3a, 3b, 3c, and 3d in very good yields and with good to excellent trans selectivities. The use of BF3, SnCl4, and SnBr4 as Lewis acids afforded 3a with moderate cis selectivity thus excluding chelate control. Starting with (S)‐1 TiCl4‐promoted reaction with 2b, we obtained optically active γ‐lactone 3b which was efficiently converted into the pheromone (+)‐eldanolide in two steps. The enantiomeric excess of 87% proved that the sequence proceeds without detectable racemization.
Total synthesis of Aklanonic Acid and Derivatives by Baker–Venkataraman Rearrangement
Authors: Krohn Karsten , Roemer Ernst , Top Michael 
Published: June 2010

AbstractAklanonic acid (1) and the derivatives 2 and 15a–f were prepared by Baker‐Venkataraman rearrangement of the corresponding ortho‐acetyl anthraquinone esters 13a–e and 14 using lithium hydride in THF.
Antibiotics from Gliding Bacteria, LXX Chondramides A–D, New Cytostatic and Antifungal Cyclodepsipeptides from Chondromyces crocatus (Myxobacteria): Isolation and Structure Elucidation
Authors: Jansen Rolf , Kunze Brigitte , Reichenbach Hans , Höfle Gerhard 
Published: June 2010

AbstractAs a result of the extension of our screening to strains of Chondromyces four new antifungal and highly cytostatic depsipeptides were isolated, the chondramides A (1) – D (4). Their macrocyclic structures comprise three amino acids and a polyketide, viz. alanine, N‐methyltryptophan, α‐methoxyl‐β‐tyrosine, and a 7‐hydroxytrimethyloctenoic acid. Thus, they were found to be closely related to a small class of cyclodepsipeptides including jaspamide, the geodiamolides, and neosiphoniamolide which all have been isolated from marine sponges.
Wavelength Control in the Photochemical Addition of Tricyclic [g]‐Fused 1‐Thiocoumarins or Coumarins to Alkenes Yielding Mono‐ and Bis([2 + 2]‐Cycloadducts)
Authors: Klaus Christian P. , Margaretha Paul 
Published: June 2010

AbstractOn long‐wavelength (>395 nm) irradiation in the presence of 2,3‐dimethylbut‐2‐ene the benzobis(thiinones) 6 and 7 afford 4:1 mixtures of cis‐ and trans‐fused monocycloadducts. Similarly, irradiation of thiinobenzopyrandione 8 affords 50% of a 4:1 mixture of cis‐ and trans‐fused monocycloadducts at the thiinone moiety and in addition further 50% of the cis‐fused monocycloadduct at the pyranone ring. Irradiation of 6–8 at shorter wavelength (>340 nm) in the presence of the same alkene furnishes mixtures of all bis(photocycloadducts), of which some were isolated by chromatography and analyzed by 1H‐NMR spectroscopy. – Mixed bis([2 + 2]‐photocycloadducts) of such molecules become easily accessible, as illustrated by the irradiation of benzobispyranone 9, first (>350 nm) in the presence of 2,3‐dimethylbut‐2‐ene and then (>300 nm) in the presence of isobutene.
Heterocumulenes, 9 Ethenedione Oxime: Photochemical Generation and Matrix‐spectroscopic Identification
Authors: Maier Günther , Reisenauer Hans Peter , Röther Bernd , Eckwert Jürgen 
Published: June 2010

AbstractThe title compound 2, a very close derivative of the still elusive ethenedione (1), was generated by photocleavage of the three different precursor molecules 7–9 in an argon matrix at 10 K. The structure elucidation of monoxime 2 is based on the comparison of the experimental and calculated IR spectrum.
Ethynediol: Photochemical Generation and Matrix‐spectroscopic Identification
Authors: Maier Günther , Rohr Christine 
Published: June 2010

AbstractIrradiation of squaric acid (4) in an argon matrix at 10 K leads to ethynediol (dihydroxyacetylene) (1) via bis (hydroxyketenyl) 5 and deltic acid (6). The identification of 1 is based on the comparison between the experimental and calculated IR spectrum.
Synthesis of Medium and Large Ring Compounds, XLI Synthesis and Reactions of Optically Active Bridged Methyl Deoxyfuranosides
Authors: Tochtermann Werner , Mattauch Anne‐Katrin , Kasch Michael , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg 
Published: June 2010

AbstractThe resolution of the earlier reported racemic bridged methyl deoxyfuranosides 1 and 3 was achieved via fractional crystallization of the ephedrinium salts 2 or by column chromatography of the camphanoates 5. The absolute configurations of 1 and 3 were established by X‐ray structural analysis of the (S)‐α‐naphthylethylammonium carboxylate (+)‐4 and by correlation with the other enantiomerically pure compounds of this type. (+)‐3 was converted into the 2,5‐bridged altrose derivative (+)‐8.
Reaction of Chiral Nucleophiles with Pyridinium Compounds. Total Synthesis of the Indole Alkaloids (−)‐Isovallesiachotamine and (+)‐Vallesiachotamine
Authors: Amann Robert , Arnold Karen , Spitzner Dietrich , Snatzke Günther , Majer Zsuzsanna 
Published: June 2010

AbstractThe addition of the chiral nucleophiles Na‐2 and Li‐5 to pyridinium compounds 1 and the subsequent ring closure (Pictet‐Spengler cyclization) to indoloquinolizines 3a and 7b, respectively, proceed stereoselectively (d.e. for 3a: 54%; for 7b: ≥95%). Proof for the absolute configuration of these products is provided by their CD spectral data and the transformation of 7b into the indole alkaloids (+)‐vallesiachotamine [(Z)‐6] and (‐)‐isovallesiachotamine [(E)‐6].
Unsaturated Hetero Chains, V Synthesis, Structure, and Reactivity of Alkoxy‐substituted 2,4‐diazapentadienylium‐, 2,4,6‐Triazaheptatrienylium‐, and 2,4,6,8‐Tetraazanonatetraenylium Salts
Authors: Schulte Norbert , Fröhlich Roland , Hecht Jürgen , Würthwein Ernst‐Ulrich 
Published: June 2010

AbstractThe 1‐mono‐ and 1,ω‐dialkoxy‐substituted 2,4‐diazapentadienylium, and 2,4,6,8‐tetraazanonatetraenylium salts 3, 5, and 10 were synthesized by oxonium salt alkylation of the corresponding 1‐oxa‐3,5‐diazahexatrienes 1, of the 1‐oxa‐3,5,7‐triazaoctatetraenes 4, and of the 1‐oxa‐3,5,7,9‐tetraazadecapentaenes 7. The salts 3 and 10 are sufficiently stable to facilitate their isolation whereas salt 5 decomposes readily. For the synthesis of the alkoxysubstituted 1‐oxa‐3,5,7,9‐tetraazadecapentaenes 7 a new general pathway was developed, which involves the condensation of the salts 3 with the N‐acylamidines 6. The structural properties in the crystalline state were determined for the salts 3d and 10a as well as for the neutral compound 7a by X‐ray crystallography. All three compounds are characterized by non‐planar helical chains, much in contrast to their planar all‐carbon analogous polyenes and polymethinium salts. From the UV/Vis spectra we deduce that these compounds prefer non‐planar structures also in solution. All stable compounds were completely characterized by analytical and spectroscopic methods.
On the Homoconjugation Between Donor and Acceptor Fragments. Synthesis and Properties of Bishomosquaric Acid Derivatives
Authors: Gleiter Rolf , Doerner Thomas , Irngartinger Hermann 
Published: June 2010

AbstractThe tetraketone 3,3,6,6‐tetramethylcyclohexane‐1,2,4,5‐tetrone (11) and its congener bicyclo[3.2.2]nonane‐6,7,8,9‐tetrone (17) were synthesized by conventional procedures. The photoreaction of 11 and 17 with tetramethylethylene yields 3,3,4,4,7,7,10,10‐octamethyl‐2,5‐dioxabicyclo[4.4.0]dec‐1(6)‐ene‐8,9‐dione (22) and 4,4,5,5‐tetramethyl‐3,6‐dioxatricyclo‐ [6.3.2.02;7]tridec‐2(7)‐ene‐12,13‐dione (24), respectively. Both are formally diesters of a bishomosquaric acid. The interactions between the two nonconjugated diketone moities in 11 and 17 as well as between the donor and acceptor fragments in 22 and 24 were studied. X‐ray investigations of 11 and 17 show no deviation from the expected bond lengths and angles. In the case of 24 the distance between the carbon atoms of the donor and acceptor units is 2.39 Å, this is 0.11 Å shorter than the corresponding distance between the two acceptor units in 17. The PE‐spectroscopic investigations of 11 and 17 show a considerable interaction between the two acceptor units. This is concluded from the splitting of the PE bands (ca. 0.5 eV) of the four lone‐pair combinations. For 22 and 24 no interaction between the donor and acceptor part was detected by means of PE spectroscopy. The 13C‐NMR chemical data show a high‐field shift for the carbonyl carbon atoms in 11 and 17. These findings were substantiated by the investigation of the corresponding phenazine derivatives obtained from 11 and 17 by the reaction with o‐phenylenediamine. In the case of 22 and 24 a high‐field shift of the signals of the olefinic double bond was observed. The electronic absorption spectrum of 22 shows for the higher excited states a charge‐transfer contribution, whereas in the case of 24 a charge‐transfer contribution was already detected in the first excited state.
Syntheses with Nitriles, XCVIII Synthesis and Characterization of (Aminocyanomethylene)indandione and ‐pyrazolone Chromoionophores as Extractants for Alkali Metal Ions
Authors: Boila‐Göckel Andrei , Fabian Walter M. F. , Junek Hans 
Published: June 2010

AbstractA new approach to dissociable chromoionophores 5, 6a–e, 7 and 8 by reaction of (dicyanomethylene)indandione 1 and (dicyanomethylene)pyrazolones 2a–e, respectively, with aminophenyl crowns 3 and 4 is described. The complexation constants were determined by 1H‐NMR spectroscopy. For the chromoionophores 5 and 6a–e bearing a benzo[15]crown‐5 moiety, Kc values between 1100 and 1900 were found, while the chromoionophores 7 and 8 bearing the N‐phenylaza[15]crown‐5 provided binding constants which are about twenty times lower. These differences depending on the nature of the crown (aza‐crown or benzo‐crown with the same ring size) are discussed by comparison with a series of known crowns and also on the basis of molecular modelling techniques. The ability of the chromophore 6a as extractant for sodium and potassium ions in its ionic form is shown.
Deamination Reactions, 57. Bicyclo[3.2.0]hept‐3‐yl→7‐Norbornyl Rearrangements
Authors: Kirmse Wolfgang , Siegfried Rainer 
Published: June 2010

AbstractBicyclo[3.2.0]heptane‐endo‐ and ‐exo‐3‐diazonium ions (15, 17) were generated by diazotization of the analogous amines (12, 14) as well as by photolysis of bicyclo[3.2.0]‐heptan‐3‐one tosylhydrazone (13). In contrast to solvolyses of the corresponding tosylates (8, 11), the dediazoniation reactions afforded 16–30% of 7‐norbornanol. By means of deuterium labels, the rearrangement was found to proceed by way of sequential 2,3‐H and 1,2‐alkyl shifts; a protonated spirocyclopentane 5[7] is not involved in this process. While the 2,3‐H shift is but moderately exo‐selective, nucleophilic capture of the 7‐norbornyl cation (3‐D‐2) occurs stereospecifically within the limits of detection.
Photocyclization of Styrylbenzo[a]quinolizinium Salts, 2. Efficient Synthesis of 6a‐Azonia[5]helicene Salts Utilizing Steric Interactions of Substituents
Authors: Sato Kiyoshi , Nakajima Kazuaki , Arai Sadao , Yamagishi Takamichi 
Published: June 2010

AbstractThe synthesis of a series of substituted 6a‐azonia[5]helicene salts 3d–j and 12a‐azoniabenzo[ghi]perylene salts 4d and 4g by photocyclization of the corresponding 2‐styrylbenzo[a]‐quinolizinium derivatives 2d–j is described. The product ratios of 3d–j and 4d–j depend on the steric hindrance between the two substituents in the 2‐ and 13‐positions of 3d–j. Debromination of bromo‐substituted azonia[5]helicene salts 3h–j with a phosphanenickel(0) complex in methanol leads to parent and monomethyl‐substituted azonia[5]helicene salts 3a, 3b, and 3k, which could not be prepared by photocyclization.
Highly Functionalized Tris‐(σ)π‐Homobenzenes — Nine‐Membered Ring Compounds with Special Substitution Patterns — En Route to cis,cis,cis‐2,5,8‐Cyclononatriene‐1,4,7‐trione
Authors: Person Georg , Keller Manfred , Prinzbach Horst 
Published: June 2010

AbstractIn the pursuit of the tris‐(σ)π‐homobenzene chemistry, the synthesis of potentially tri(hexa)podal, C3v‐symmetrical, polyfunctionalized 9‐membered ring systems is being explored. A rather “expensive” tris‐σ‐homobenzene (13b) is the starting material for the tris‐σ‐isomer (14b) from which 1,4,7‐trimethylene‐cyclononatriene (2), its tri(hexa)epoxides (18, 20) and triepoxytriketo derivative (19) are prepared through generally highly selective transformations. An alternative approach toward the C3v 2,5,8‐cyclononatriene‐1,4,7‐trione [4, C6H6(CO)3] starts from the relatively “cheap” all‐exo‐1,4,7‐cyclononatriene‐trioxide (32), relies on selective epoxide opening reactions, and is complicated by typical mediumring transanular cyclizations; the rather efficient six‐step sequence does not reach the stated goal but carries attractive preparative prospects. For a central intermediate in each approach (trimethylenetrioxide 18 and bromo‐hydroxy‐diepoxycyclononane 50), X‐ray structural data are presented.
Azo Bridges from Azines, XVIII. Transformation of CC Bonds into Cyclopropanes, Aziridines and Oxiranes in the Presence of Azo Groups
Authors: Hünig Siegfried , Schmitt Michael 
Published: June 2010

AbstractRigid systems of typeBin which a three‐membered ring and an azo group are located in a rigid close and parallel position were synthesized by variation of both the hetero group X and the carbocyclic framework. Both the cyclopropane (X = CH2) and the aziridine (X = N‐R) moieties are introduced by [3 + 2] cycloaddition reactions of diazomethane (1,15,18,20) or azides (26/1–5,35,38,41,44) to CC‐double bonds and subsequent denitrogenation of the cycloadducts. By thermal and photochemical (300 nm) denitrogenation the triazolines were smoothly transformed into the expected aziridines (27/1–5) whereas catalysis by silica gel party caused additional rearrangements (28,37,40,43,46). Chemoselective photo‐denitrogenation of azo/pyrazolines16and19was not possible, but could be achieved by starting from azoxide/pyrazolines21with subsequent reduction of the azoxy group (23→9,24→25). Similarly, azo/oxiranes48and55were prepared by oxygenation of unsaturated azoxides (e.g.20) and chemoselective deoxygenation of the azo group by irradiation in methanol (49→48,54→55).
Cyclopropyl Building Blocks for Organic Synthesis, 36. Unprecedented Addition of Dialkoxycarbenes to Tetrasubstituted Alkenes: Bicyclopropylidene and 2‐Chlorocyclopropylideneacetate
Authors: de Meijere Armin , Kozhushkov Sergei I. , Yufit Dmitry S. , Boese Roland , Haumann Thomas , Pole David L. , Sharma Pradeep K. , Warkentin John 
Published: June 2010

AbstractThe cycloaddition reactions of several dialkoxycarbenes generated in situ from the corresponding 2,2‐dialkoxy‐Δ3‐1,3,4‐oxadiazolines of the type3with bicyclopropylidene1afford the dialkyl acetals of dispiro[2.0.2.1]heptane‐7‐one (4), whereas the analogous addition to methyl (1‐chloromethylene‐1‐carboxylate)cyclopropane26leads to the formation of a complex mixture of products. Those products can best be rationalized in terms of nucleophilic attack of the dialkoxycarbene on the strained CC double bond, to form a dipolar intermediate capable of a variety of intramolecular rearrangements. Several chemical transformations of the compounds of type4are reported.
O‐Glycoside Synthesis under Neutral Conditions in Concentrated Solutions of LiClO4 in Organic Solvents Employing O‐Acyl‐Protected Glycosyl Donors
Authors: Böhm Gerd , Waldmann Herbert 
Published: June 2010

AbstractO‐Glycosides of pivaloyl‐protected glucose can be synthesized under neutral conditions in moderate yields by employing the pivaloylated β‐glucosyl fluoride 2d and the respective β‐benzyl phosphate 2e as glycosyl donors and 1 M solutions of LiClO4 in CH2Cl2 or CHCl3 as reaction media. The acetyl‐protected α‐ or β‐configured glucosyl trichloroacetimidates 1a and 1b were converted into the orthoesters 6 which were isolated in moderate to high yields. Under these conditions, acetyl‐protected glycosyl phosphates, acetyl‐ or pivaloyl‐protected glycosyl bromides and O‐pivaloylated glycosyl trichloroacetimidates were not converted to the desired O‐glycosides.
Selective Oxyfunctionalization of (Tricarbonylcyclohexadiene)iron‐Substituted Furans with Singlet Oxygen and Dimethyldioxirane
Authors: Adam Waldemar , Schuhmann Rosemarie M. 
Published: June 2010

AbstractThe versatility of the tricarbonyliron fragment as protecting group in the oxyfunctionalization of cyclohexadienyl‐substituted furans with singlet oxygen (1O2), dimethyldioxirane (DMD) and m‐chloroperoxybenzoic acid (mCPBA) was investigated. The photooxygenation of the (tricarbonylcyclohexadiene)iron‐substituted furans 1a and 1b in methanol gave, after reduction with triphenylphosphane, the furanone 2a and the enediones 3b as mixture of Z and E isomers in good yields. Precursors to these oxyfunctionalized products were the corresponding furan endoperoxides, which were trapped by methanol. The enedione Z‐3b was also obtained in the dimethyldioxirane oxidation, which was performed in boiling acetone to minimize the oxidative destructin of the tricarbonyliron moiety. In contrast, mCPBA was unsuitable for the oxyfunctionalization of the ligand sphere of such tricarbonyliron complexes due to the liberation of the organic ligand. While the decomplexation of the furanone 2a with cerium (IV) ammoniumnitrate (CAN) led selectively to the functionalized cyclohexadiene 4a, photooxygenation of the free furan 6a resulted in a complex mixture of oxidized compounds. Thus, protection of the 1,3‐cyclohexadiene moiety by tricarbonyliron complexation, oxidation (1O2, DMD) and decomplexation (CAN) offers a convenient and useful sequence for the regioselective oxyfunctionalization of such complex furans.
Glycosyl Imidates, 74. Synthesis of Ganglioside GM1 via a GM3 Intermediate
Authors: Greilich Ulrike , Brescello Roberto , Jung Karl‐Heinz , Schmidt Richard R. 
Published: June 2010

AbstractThe synthesis of GM1 (1) via GM3 intermediate 7 was based on lactose building‐block 5, sialyl donors 6, and a Galß(1–3)‐GalN3 donor 13α. Reaction of donor 13α with acceptor 7 in the presence of TMSOTf as catalyst afforded GM1 pentasaccharide 30. Azido group reduction, N‐acetylation, hydrogenolytic O‐debenzylation, and O‐acetylation furnished O‐acyl‐protected GM1 pentasaccharide 34. Chemoselective 1a‐O‐deacetylation and generation of O‐(pentaosyl)trichloro‐acetimidate 36 provided the required glycosyl donor for the application to azidosphingosine glycosylation procedure affording GM1 (1).
Highly Photostable Organic Fluorescent Pigments – A Simple Synthesis of N‐Arylpyrrolopyrrolediones (DPP)
Authors: Langhals Heinz , Grundei Thomas , Potrawa Thomas , Polborn Kurt 
Published: June 2010

AbstractN‐Arylpyrrolopyrrolediones 1b‐g are prepared by the condensation of the corresponding lactones 2 and 5 with arylamines in the presence of dicyclohexylcarbodiimide. Bright red dye pigments are obtained with an intense red to orange solid‐state fluorescence.
Analogues of Cytostatic, Fused Indazolinones: Synthesis, Conformational Analysis and Cytostatic Activity Against HeLa Cells of Some 1‐Substituted Indazolols, 2‐Substituted Indazolinones, and Related Compounds
Authors: Arán Vicente J. , Flores María , Muñoz Pilar , Páez Juan A. , Sánchez‐Verdú Prado , Stud Manfred 
Published: June 2010

AbstractA number of indazol‐3‐ol and indazolin‐3‐one derivatives were designed as open‐chain analogues of some previously studied cytostatic tetranuclear indazolinones. The former were prepared by starting with alkylation of the parent indazolinones (11 or its 5‐H analogue). Special mention deserves the method we developed for the direct alkylation of position 2 of indazolinone 11 with benzyl or picolyl halides. The prepared compounds were evaluated as cytostatic agents against HeLa cells, but only 1‐benzylindazolol 5a and 1‐(2‐fluorobenzyl)‐3‐methoxy‐ and 1‐benzyl‐3‐methoxyindazoles 14h, i display significant activity. Additional 13C‐NMR studies and conformational analysis using molecular mechanics and quantum‐mechanical semiempirical techniques confirm that the compounds designed as analogues of the model cytostatic indazolinones are not able to mimic effectively the structural features of the latter.