New heteroaromatic compounds—XIII Reactions of 10-substituted 9-ethoxycarbonyl-10:9-Borazarophenanthrenes

10-Ethoxycarbonyl derivatives of 10:9-borazarophenanthrenes have been prepared by reaction of the 10-lithio derivatives with ethyl chloroformate. Unlike the parent compounds they are rapidly oxidized by air to products in which the BN bond is broken. These reactions suggest that the stability of the present compounds to oxidation and hydrolysis must be due to resonance stabilization. A measurement of the dipole moment of 10-methyl-10:9-borazarophenanthrene by Professor R. Huisgen and his collaborators is reported.     

New heteroaromatic compounds—XII Further evidence for the aromaticity of the borazarenes

Snyder and his co-workers² have reported that the cyclic boric ester (I) is stable to hydrolysis and may be nitrated. These observations suggests that the stability of the heterocyclic boron compounds described in previous papers of this series might be due to their cyclic nature rather than to aromatic resonance. Their reactions with bases, and a comparison of the properties of 2:1-borazaronaphthalenes with those of their 3:4-dihydro derivatives seem to make this unlikely.     

The NMR spectra and conformations of cyclic compounds—IV: The conformation of 3,4-cyclopropyl-proline

The ¹H magnetic resonance spectrum of the title compound has been completely analysed, using 60, 100 and 220 MHz spectrometers. The values of the chemical shifts and coupling constants obtained confirm the proposed structure and also provide information on the conformation. The molecule is slightly boat-shaped.     

Studies on organophosphorus compounds—IV: HMPA as precursor for dimethylamine in nucleophilic aromatic substitution reactions

The potential leaving groups (NO₂, Cl, Br, OH, OMe) in nucleophilic aromatic substitution reactions are replaced by a dimethylamino group simply by heating the aromatic compounds (activated by cyano- or nitro-groups) in HMPA at elevated temperature.     

Fragmentation and rearrangement processes in the mass spectra of perhalogenoaromatic compounds—VIII: Fluoroaromatic heterocyclic derivatives of group IV

The metastable ion supported fragmentations and fluorine transfer rearrangements of a series of fluoroaromatic heterocyclic derivatives of silicon, germanium and tin are reported. Of particular interest is the unique loss of neutral SiF₄ from the parent ion of (C₁₂F₈)Si yielding the [C₂₄F₁₂]⁺˙ ion. These and similar rearrangements are discussed and structures are proposed for some of the ions observed. The general case of cyclic rearrangement intermediates prior to the loss of neutral metal fluorides from perfluoroaromatic derivatives is discussed. Losses of neutral metal fluorides from the parent ions appear to involve a species with increased co-ordination number about the central atom as an intermediate. In addition to (C₁₂F₈)₂M, the following compound types were studied: (C₆H₅)₂Ge(C₁₂F₈), (C₁₂F₈S)₂M and R₄Sn₂(C₆F₄)₂ (where M = a Group IV metal and R = CH₃ or C₆H₅).     

Reactions of copper(II) halides with aromatic compounds—XI : Reactions of 9-alkyl- and 9-arylanthracenes in methanol

9-Alkyl and 9-arylanthracenes react with copper(II) bromide in methanol to give 10-alkyl (or aryl)-10-methoxyanthrones as the major product. 9-Methylanthracene additionally affords 10-methoxy-10-methoxymethylanthrone. The formation of all these products can be interpreted in terms of an initial electron-transfer oxidation of the aromatic moiety to the radical cation.     

Spectrométrie de Masse—IV: Fragmentation des Dicétones—ϵ

The mass spectra of ten symmetrical ?-diketones are reported and a number of fragmentation patterns are documented by deuterium labelling experiments. The McLafferty rearrangement involving one of the carbonyl groups is not an important fragmentation pathway although such a double rearrangement is observed for long-chained ?-diketones. Special attention has been given to the ions resulting from the loss of either a molecule of water or the neutral species C₂H₄ which may involve an electron-impact induced formation of cyclobutanol-type ions analogous to the photochemical Yang's reaction.     

Terpenoids and related compounds—IX Molecular rearrangements involving glutenols

The molecular rearrangements of glutenols on treatment with phosphorus pentachloride and phosphorus oxychloride and pyridine as well as on solvolysis of the corresponding tosyl derivatives have been investigated. Glut-5-en-3β-ol (Ia) and glut-5(10)-en-3-ol (IId) gave diene A (III). Glut-5-en-3-ol (Id) gave diene B (VII) and glut-5(10)-en-3β-ol (IIa) gave diene C (XIII) by ring contraction.     

Friedelin and related compounds—V The action of N-bromosuccinimide on friedelin and derivatives

Friedelin gives 4-bromofriedelin on treatment with N-bromosuccinimide. 2-Bromofriedelin, 4-bromofriedelin and friedelane are preferentially oxidized to the corresponding Δ¹⁸-olefins.     

Pharmacologically interesting compounds—I: High resolution mass spectra of phenothiazines

The mass spectra of twenty-six commercially available medicinal phenothiazines have been determined at high resolution. In each compound, the side chain attached to the 10-position of the phenothiazine ring contains nitrogen and fission of the C? C bond α to this nitrogen gives in most cases the base peak. Some of the compounds are also substituted at the 2-position and this substituent generally remains intact, though some substituents such as acetyl, propionyl, methoxyl and methylthio can undergo fragmentation. Fragmentations fall into three groups; those which give ions representing a part of the side chain; those which give ions representing the intact phenothiazine ring with part of the side chain attached; those which give ions representing a partially fragmented ring system.     

Mass spectra of organometallic compounds—IX: Compounds with metal-metal bonds

The mass spectra of the following compounds have been investigated: (i) The organotin derivatives (CH₃)₃SnMo(CO)₃C₅H₅ and (CH₃)₃SnNCW(CO)₅; (ii) The mercury derivatives Hg[Mn(CO)₅]₂, Hg[Co(CO)₄]₂, Hg[Mo(CO)₃C₅H₅]₂ and ClHgMo(CO)₃C₅H₅; (iii) The polynuclear cyclopentadienyl metal derivatives [C₅H₅Ru(CO)₂]₂, [C₅H₅Cr(CO)₃]₂, [C₅H₅Cr(NO)₂]₂ and [C₅H₅Fe-CO]₄; (iv) The trinuclear cobalt carbonyl derivatives YCCo₃(CO)₉ (Y = Cl and CH₃); (v) The binuclear triene-iron carbonyl derivatives C₄H₄Fe₂(CO)₆ and C₈H₁₀Fe₂(CO)₆. The mass spectra of the trimethyltin derivatives exhibited stepwise loss of methyl groups as well as of carbonyl groups. The mass spectra of the mercury derivatives exhibited the facile loss of mercury. The mass spectrum of [C₅H₅Cr(CO)₃]₂ indicated a very weak chromium-chromium bond since it exhibited no ion containing two chromium atoms. The mass spectrum of the nitrosyl derivative [C₅H₅Cr(NO)₂]₂ exhibited the stepwise loss of its four nitrosyl groups. The mass spectrum of [C₅H₅FeCO]₄ was rather complex and exhibited a variety of unusual processes including eliminations of neutral Fe and C₅H₅Fe fragments. Unusual ions observed in the mass spectrum of CH₃CCo₃(CO)₉ include the bare polymetallic ions [Co_n]⁺ (n = 3 and 2). Many examples of the elimination of neutral CO, C₂H₂ and H₂ fragments were noted in this work.     

Mass spectra of organoboron compounds—II: The mass spectra of triphenylboroxine and its precursor phenylboronic acid

The mass spectrometric fragmentation pattern of phenylboronic acid has been determined and that of triphenylboroxine redetermined and extended, and the origin of some high abundance ions, previously unassigned, have been identified.     

A New Technique of Synthesizing 10—Hydroxy—5—methyl—5,10—dihydrophenophosphazine 10—Oxide

10-Hydroxy-5-methyl-5,10-dihydrophenophosphazine 10-oxide(1)was prepared by a new technique of treating 10-methoxy-5,10-dihydrophenophosphazine 10-oxide(2)with an equivalent of NaH in anhydrous DMF,and then at 120℃ for 3-4h,which not only avoided poisonous and expensive methyl iodide used in literature,but made the consumption of NaH greatly decrease as well.The possible reaction mechanism was also described.The chemical structure of 1 was confiremed by IR,NMR,and mass spectroscopy.     

Conversion of 9-hydroxy-10-methyl-9,10-dihydroacridine into bis(10-methyl-9,10-dihydroacridin-9-yl)ether

The action of aqueous alkali on N-methylacridinium salts gives as the main product bis-(10-methyl-9,10-dihydroacridin-9-yl) ether, and not 9-hydroxy-10-methyl-9,10-dihydroacridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1119–1121, August, 1970.     

Synthesis and antitumor activity of 9-methyl-10-hydroxycamptothecin

A novel camptothecin analogue, 9-methyl-10-hydroxycamptothecin （4）, was unexpectedly synthesized from 10-hydroxycamptothecin in two steps. The key step included an efficient Mannich-type reaction. The overall yield was 47.2%. An ether analogue of 4, 9-methyl-10-benzylaminomethoxycamptothecin （5）, was also prepared. These new camptothecin analogues were evaluated for in vitro cytotoxicity against four human cancer cell lines, and exhibited more potent antitumor activities than contrals camptothecin and topotecan against several cancer cells.     

Aminomethylating 9-methyl-3, 4- and 9-methyl-1, 2-benzoacridine

Aminomethylating 9-methyl-3, 4-benzoacridine with cycloalkylamine (pyrrolidine, piperidine, and morpholine) hydrochlorides in alcohol is described. The isomeric 9-methyl-1, 2-benzoacridine does notaminomethylate under similar conditions, apparently because the annulated benzene ring at positions 1, 2 in the acridine gives rise to steric hindrance, and the reaction product is 9--hydroxyethyl-1, 2-benzoacridine, converted by further heating to 9-vinyl-1, 2-benzoacridine.     

The tautomerism of heteroaromatic compounds with five-membered rings—VII Isoxazolin-3-ones—3-hydroxyisoxazoles

The preparation of some 3-hydroxyisoxazoles from β-keto-esters and the proof of their structure is described. These compounds are shown to exist largely in the hydroxy form.     

Skelettumlagerungen Unter Elektronenbeschuss—IV: Zur Struktur der C13H9- und C12H9N-Ionen bei Benzylidenaminobenztriazolen

The major fragmentation of 1-(Benzylideneamino)-benzotriazole is due to a skeletal rearrangement, producing the [C₁₃H₉]⁺-ion as the base peak. 2-(Benzylideneamino)-benzotriazole also exhibits a rearrangement ion [_C12H₉N]⁺˙ of considerable abundance. It could be shown by appearance potential measurements that these ions do not have a fluorenyl or carbazole structure.