The Reaction of Diethylthiophosphinyl Iodide,Et2P(S)I,with Nucleophiles

The compound Me₂AsSI can exist in two different forms, either as dimethylarsinosulfenyl iodide [or (iodothio)dimethylarsane)], Me₂As–S–I ( A ), or as dimethylthioarsinyl iodide (or dimethylarsinothioic iodide), Me₂As(S)–I ( B ). To confirm that the structure of the product of the reaction between Bunsen's cacodyl disulfide Me₂As(S)–S–AsMe₂ and iodine is A and not B , the known diethylthiophosphinyl iodide (or diethylphosphinothioic iodide), Et₂P(S)–I ( 2 ) was prepared and its hydrolytic stability and reactivity towards a variety of nitrogen, phosphorus(III), arsenic(III), oxygen, and sulfur(II) nucleophiles were studied. The results indicated that only a few reactions of 2 resembled those of A , thus strengthening the proposal that the reaction of Bunsen's cacodyl disulfide with iodine produced A and not B . A series of ³¹P NMR chemical shifts of diethylthiophosphinyl moiety is also reported. Et₂P(S)–DMAP, synthesized and isolated during the presented study, is the ethyl analogue of Me₂P(S)–DMAP, previously described as an important molecule. In our case, Et₂P(S)–DMAP was found to be a good intermediate for the synthesis of phosphoryl or thiophosphoryl derivatives since it was more reactive than 2 towards nucleophiles.     

Samurai Chemists,Charles Graham and Alexander William Williamson at University College London, 1863–1872

Abstract

This article analyses the dynamic interactions between Japanese samurai students in the 1860s and their chemistry teachers at University College London (UCL) in chemical laboratories and other socialising spaces with the concept of “contact zones.” In addition to Alexander William Williamson (1824–1904), the professor of chemistry and practical chemistry, this article sheds light on the important role of lesser-known figures, especially Williamson's ex-student Charles Graham (1836–1909), who, as a junior teacher, had undoubtedly more chance to interact with samurai students and yet has been overlooked by historians to date.     

An Introduction to The Bibliography of Alchemy—Part I

Abstract

This article contributes to a growing body of research on the dissemination, dispersion or diffusion of scientific knowledge via pedagogical networks. By examining students’ handwritten lecture notes, I compare the eighteenth-century chemistry lectures given by William Cullen (1710–1790) at Glasgow and Edinburgh Universities with those of his one-time student George Fordyce (1736–1802), in London, at first privately and then as part of the medical education of physicians at St. Thomas's Hospital. Part I examines the broad structure of Cullen's and Fordyce's courses, comparing both course content and pedagogical approaches to ask how far knowledge flowed directly ‘downstream,’ and the extent to which it was transformed, translated or transmuted in the process of transmission. Part II (forthcoming) will approach the affinity theories of Cullen and Fordyce in greater depth, revealing the dynamics of knowledge transfer. The results shed light on the transmission of knowledge and skills between master and student, and reflect on whether Fordyce can be better described as Cullen's pedagogical progeny, or less straightforwardly as a tactical translator.     

Alexander Crum Brown and his Doctoral Thesis of 1861

Abstract

Organic chemistry began at the universities in the Habsburg Empire about 1840, when Josef Redtenbacher, a post-graduate student of Liebig in Giessen, established the first organic laboratory at Charles University, Prague. Following Liebig's teaching methods, he required laboratory work from his students. Redtenbacher's students then headed the new chemistry departments, which were established after the revolution of 1848. Several of Redtenbacher's students had also been trained as botanists and they focussed their research on phytochemical questions. Austrian chemists also contributed to theoretical organic chemistry. In 1853 Rochleder published a paper in which the quadrivalence of carbon was assumed. A more important contribution was made by Josef Loschmidt in 1861, when he published the graphical formulae of several hundred compounds. In contrast to the ideas of Gerhardt and Kekulé, Loschmidt assumed that the constitution of a compound can be deducted from its reactions. Loschmidt's work attracted little interest abroad and was only rediscovered many years later by Richard Anschütz.     

Novel amides and Schiff's bases derived from 1,3,4-oxadiazole derivatives: synthesis and mesomorphic behaviour

The synthesis and liquid crystalline properties of novel achiral amides (Ia–g, IIa–g and IVa,b), achiral Schiff's bases (IIIa–g and Va–g), chiral amides (VI, VII) and chiral Schiff's bases (VIII–XI) incorporating a 1,3,4-oxadiazole ring are reported. All amides of the series I and II display an enantiotropic smectic A phase. The amide IVa,b did not show mesomorphic properties. Amides of the series Ia–g and IIa–g contain a flexible n-tetradecylthio chain, the other terminal substituent is an n-alkoxy chain and n-alkyl chain, respectively (n?=?4–10) and the 1,3,4-oxadiazole is in the terminal rigid core. Amides Ia–g have broader mesomorphic range and higher thermal stability than the corresponding amides IIa–g. Amides IVa,d contain the 1,3,4-oxadiazole ring in the centre of the rigid core and two flexible alkoxy chains as flexible terminal substituents. Thus, the mesomorphic properties are favoured if 1,3,4-oxadiazole is shifted to a terminal position of the rigid core. Schiff's bases IIIa–g display an enantiotropic dimorphism smectic C–smectic A. Schiff's bases IIIa–g have a broader mesomorphic range than the analogous amides Ia–g. Schiff's bases Va–g exhibit a dimorphism smectic A–nematic, and in contrast to this the analogous amide IVa,b did not show mesomorphism. The chiral amides VI and VII and chiral Schiff's bases X and XI did not show mesomorphic properties and only the chiral Schiff's bases VIII and IX display a chiral smectic C phase in a short mesomorphic range. A density functional theory theoretical study at the B3LYP/6–311++G(d,p) level was performed in order to analyse the structural features that must be related with the mesomorphic behaviour of the reported compounds.     

Acylation Studies with Meldrum's Acid

Meldrum's acid (1) on bisacylation with succinyl chloride afforded a neutral diketo product (2); however, the dimer enolic products (3) with acidic nature resulted in glutaryl and adipyl dichlorides. Monoacylation of (1) with acetyl chloride gave acidic 5‐acetyl Meldrum's acid (4) in enol form.     

Synthesis and Structural Analysis of Higher Analogs of Sucrose

ABSTRACT

Three sucrose monoalcohols with free hydroxyl groups at C-1', C-6, and C-6' (1, 4, and 6) were prepared selectively and in good yield from 2,3,3',4,4'-penta-O-benzylsucrose. These compounds were oxidized to aldehydes and reacted with stabilized ylide, Ph₃P=CHCO₂Me to afford appropriate α,β-unsaturated esters 10, 11, and 12. Each olefin was cis-hydroxylated with OsO₄/NMO to stereoisomeric diols 13/14, 15/16, and 17/18, configurations of which were assigned by chemical correlation and CD evaluation. Stereoselectivity of the osmylation reaction was surprisingly low (ca 3:2), especially as compared to a similar process performed on simple derivatives of 6,7-unsaturated methyl glycosides for which the ratio of isomeric diols was assigned as 10:1. The osmylation of 11 (derivative homologated by a C₂-unit at the glucose part) did not obey Kishi's rule. Horner-Emmons reaction of sucrose aldehyde 7 with a sugar-derived phosphonate 22 afforded α,β-unsaturated derivative 24, homologated by a C₇-unit at the glucose end.     

The Other Face of Bunsen's Cacodyl Disulfide,Me2As(S)‐S‐AsMe2: The Lewis‐Base Behaviour Towards Heavy Metal Cations

The reaction of Bunsen's cacodyl disulfide, Me₂As(S)‐S‐AsMe₂, with heavy metal cations in methanol produces insoluble salts (complexes) of dimethyldithioarsinic acid, Me₂AsS₂H, and dimethyl arsenium ion, Me₂As:⁺. This arsenium ion prefers to react with Me₂As(S)‐S‐AsMe₂, when in excess, compared to AcO^? or MeOH/H₂O and it is also reactive towards sulfur (S_x, x = 1‐8) producing the stabilized dimethylarsino sulfenium cation, . The complexes (Me₂AsS₂)_xM (x = 1 or 2) are unstable in the presence of their own heavy metal cations decomposing to colored solids. In an attempt to prepare salts of Me₂AsSH, the reactions of (Me₂AsS₂)_xM with triphenylphosphine and trimethyl phosphite gave the metal sulfide and Me₂As‐S‐AsMe₂ instead.     

Radical Polymerization and Copolymerization of Methyl α-(Fluoroalkoxymethyl)acrylates and Characterization of Their Polymers

Abstract

Representatives of a new type of fluorine-containing monomer, methyl α-(fluoroalkoxymethyl)acrylates (MCFMA's), were prepared. The fluoroalkoxy groups introduced were OCH₂CF₃, OCH₂CF₂CF₂H, and OCH(CF₃)₂. All the monomers synthesized readily polymerized to number-average molecular weights of 55,000 to 110,000 at a 2 mol/L monomer concentration in dioxane using 5 × 10^?3 mol/L of 2,2′-azobisisobutyronitrile at 60°C. The polymerization rate tended to decrease slightly with an increase in the size of the alkoxy group. Copoly-merization of MCFMA's with styrene revealed that the fluoroalkoxy-methyl group functions as an electron-attracting group depending on the number of fluorine atoms. According to thermogravimetric analysis, poly(MCFMA)'s were thermally less stable than poly(methyl methacrylate). Greater contact angles of the polymers from MCFMA's with water than poly(methyl methacrylate) were observed.     

Differential Thermal Analysis as an Acidity Probe in Zeolite Catalysts

Abstract

Differential thermal analysis is used as an acidity strength probe for a series of mordenite (zeolite) catalysts via determining the temperature at which presorbed pyridine completely desorbs from the catalyst. The findings obtained for metal(s) containing mordenite catalysts have been correlated with the Pearson's assumption concerning Lewis acids and bases and the Pauling's electronegativity of the metals contained and found compatible.

The investigated catalysts can be arranged in their observed order of acidity strength as follows: HTI > Th-HM > Re-HM > Pt-HM > Pt-Th-HM > Pt-Re-HM.     

Simple,Safe, Large Scale Synthesis of 5-Arylmethyl-2,2-dimethyl-1,3-dioxane-4,6-diones and 3-Arylpropanoic Acids

Reaction of aryl aldehydes with Meldrum's acid 2 in the presence of formic acid and triethylamine gives 5-arylmethyl Meldrum's acid derivatives 4 at room temperature, whereas at 80–100°C 3-arylpropanoic acids 5 are formed.     

NEW PRODUCTS OF REACTION OF LAWESSON'S REAGENT WITH DIOLS

Reaction of the Lawesson's reagent (LR) with aliphatic 1,2- and 1,3-diols as well as with aromatic 2,2′-dihydroxybiphenyl led to new products. Stable di-tert-butylammonium salts of bis-anisyldithiophosphonic acids 6 were isolated and were then converted into unique 9-, 9-, and 10-membered cyclic disulfides 7 and into S,S-dimethyl esters 8. The salts of bis-anisyldithiophosphonic acids 6 were shown to be capable of splitting the disulfide bond of Ellman's reagent.     

Sydnone Ring as an ortho-Director of Lithiation, 3: One-Pot Regiospecific o-Acylation and Subsequent Sydnone 4-Substitution

Readily available 3-phenylsydnone (1) reacts with n-butyllithium/N,N,N′,N′-tetramethylethylenediamine (TMEDA) to form the dilithio species 2, which can be acylated regiospecifically at the ortho-aryl position using N-methoxy-N-methylamides (Weinreb's amides) followed by reaction with a second, more reactive electrophile at the sydnone C-4 position. Asymmetrically substituted arylsydnones 7 are obtained in 57–86% yield.     

Interpretation and the Hieroglyphic Monad: John Dee's Reading of Pantheus's Voarchadumia

Abstract

John Dee's marginalia in his copy of Johannes Pantheus's Voarchadumia (now in the British Library) are an interesting source of information about the development of Dee's scientific ideas in the period between the Propaedeumata Aphoristica (1558) and the Monas Hieroglyphica (1564). In reading the book, Dee has systematically compared the text with Pantheus's earlier work, the Ars Metallicae, and noted any differences between the two largely identical works. Therefore, most of Dee's comments are not indications of his own interests, as has previously been assumed. Only the marginalia that are not concerned with comparing the two texts can be taken to express Dee's own views. These marginalia, probably written in 1559, provide evidence that Dee had already at this time a strong interest in cabbalistic methods as a means of gaining knowledge about natural substances. Cabbalistic speculation was to be central to Dee's thought in the Monas Hieroglyphica, and has previously been taken to indicate a dramatic change in Dee's scientific outlook, towards a spiritual quest. In his marginalia in the Voarchadumia, however, Dee appears to be using cabbalistic methods to gain information on wholly material, non-spiritual matters. The abundant use of the symbol of the hieroglyphic monad in the marginalia provides a further source of insight into the alchemical import of the symbol, five years before the publication of the Monas Hieroglyphica.     

Effect of Temperature on Henry's Constant in Simple Mixtures

Abstract

The molecular theory of dense fluids is progressing rapidly and its extension to mixtures is well underway. The purpose of this note is to call attention to a possibly serious difficulty in comparing experimental Henry's constants with those calculated from theory. The difficulty arises because whereas theorists choose temperature and density as independent variables, experimental equilibrium measurements on mixtures are often made along the saturation line where (at fixed composition) temperature and density are not both independent variables. Unless Henry's constants are defined with care, the effect of temperature on Henry's constants calculated from molecular theory may be qualitatively different from that observed.     

C-Phosphorylation of Electron-Rich Heterocycles

Abstract

C-phosphorylation of pyrrole, furan, thiophene derivatives and their benzanalogs by phosphorus tribromide has been studied. Perspective methods for involving trivalent phosphorus residues at a different position of the rings have been developed. Unknown early the heterocycle's derivatives with tri- and tetracoordinated phosphorus substituents (1–5) and novel types of phosphoruscontaining heterocycles (6,7) have been obtained.     

Reaction of 2-Thioxo-4-Thiazolidinones Toward Lawesson's Reagent,Phosphorus Pentasulfide,Dialkylaminophosphines, and Phosphorus Ylides

Abstract

2-Thioxo—3-allyl-4-thiazolidinone 1a reacts with Lawesson's reagent (LR, 2) to give the ethylenic product 5 through a coupling reaction along with the dithioxo compound 6. Coupling reaction products of types 8 and 9 are also produced upon reacting thiazolidinones 1 and with the appropriate tris(diallkylamino) phosphine reagent (3 a,b). Reaction of the thiazolidinone 1a with the ylidenetriphenylphosphorane reagents 4 a–c proceeds according to the Wittig mechanism yielding ethylenes 10a–c, respectively. Structural elucidations for the new products were based upon compatible analytical and spectroscopic measurements as well a confirmatory single crystal X-ray structure for 5.

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.     

Isonitroso-4-Methyl-2-Pentanone for Solvent Extraction and Spectrophotometric Determination of Palladium (II) at Trace Level

Abstract

Isonitroso-4-methyl-2-pentanone (HIMP) is proposed as a new reagent for extraction and photometric determination of Pd(II). The reagent forms a yellow complex with palladium in the pH range 4.0-5.0. The complex extracted into chloroform was measured at 330 nm. The molar absorptivity was found to be 5.37 × 10³ 1 mol^?1 cm^?1 and Sandell's sensitivity 20 ng cm^?2 Beer's law was obeyed over the concentration range 0.1-10.0 μg/ml of palladium. The method is applicable for palladium estimation in Ores and catalysts.     

Differential Pulse Polarographic Investigation of Copper (II) - Cephalexin Complex

Abstract

It has been found by dp polarography that cephalexin forms a complex Cu(CEF)₂, at pH = 8.7, ionic strength μ = 0.2 and room temperature. The stoichiometric ratio and stability constant values have been evaluated by Lingane's and De Ford and Hume's methods. The overall stability constants, logβ₂ = 9.44 and 9.13, have been determined with methods applied.     

An Efficient Synthesis of 4,5-Dihydro-3(2H)-pyridazinone Derivatives

Reaction of hydrazine with 5-(2-aryl-2-oxo-ethan-1-yl)-5-R Meldrum's acids 3 gives 4,6-disubstituted 4,5-dihydropyridazin-3(2H)-ones 4 at room temperature. The method is simple and the yield is good. The production of the starting material 3 also is discussed.