Sur l'arǒme de viande de bœuf grillée III. Pyrrolo [1,2-a]pyrazines,identification et synthèse

Synthesis of alkylpyrrolo[1,2-a]pyrazines, roasted meat flavor constituents Seven alkylpyrrolo[1,2-a]pyrazines have been identified for the first time in a roasted meat aroma obtained by thermolysis of the hydrosoluble flavor precursors of raw meat. Identification of individual components was done by capillary gas chromatography/mass spectroscopy coupling. The structure of these nitrogen heterocyclic compounds was for some time in doubt because of the similarity of the MS. with those of other diazaindene and diazanaphthalene derivatives such as benzimidazoles, indazoles, cyclopenta [b]pyrazines and dihydroquinoxalines. The structure of these new flavor components was completely elucidated in some cases by interpretation of NMR. spectra, the others being deduced by analogy. Hypotheses are formulated concerning the formation of this skeleton by a non-enzymatic browning reaction between carbohydrates and amino acids. Four different schemes have been adopted to synthesize substituted isomers selectively.     

Recherches sur les arǒmes. 17e communication. Sur l'arǒme de framboise,IV

The neutral fraction of medium volatility from raspberry oil has been analysed by gas chromatography and mass spectrometry. From the large number of constituents thirtynine have been identified, 24 of them for the first time, including dihydro-β-ionone (I), epoxy-β-ionone (II), damascenone (III)¹, theaspirane (IV) and 2-hexen-4-olide (V). According to these results raspberry oil consists mainly of alcohols, ketones, aldehydes and lactones.     

两种市售牛肉香基的气相色谱-质谱法测定及成分比较

采用气相色谱-质谱联用（GC-MS）和气相色谱（GC）方法对两种市售牛肉香基1号和2号进行了定性及定量分析,并对两种牛肉香基的主要成分及组成进行了比较。结果表明,两种香基中的检出成分均在美国食品香料与萃取制造者协会批准编号（FEMA．NO．）允许安全食用的范围内。杂环化合物和含硫、氮化合物构成了牛肉香基的主体,进一步说明各种成分对牛肉香基香气的贡献大小。     

Die Kristallstruktur des „Thalliumdichlorids,TlCl2”︁

The Crystal Structure of Thallium Dichloride, TlCl₂ Thallium dichloride, TlCl₂, crystallizes tetragonal in the I4₁/a space group with cell constants a = 696.45(8) pm and c = 1 552.8(3) pm. The structure is of the CaWO₄ type so that the compound must be formulated as thallium(I)-tetrachlorothallate(III).     

Sur la composition de l'arǒme de the noir V

Methyl anthranilate, geranylacetone and five lactones: γ-valerolactone, γ-heptalactone, γ-décalactone, δ-décalactone, 5-hydroxy dec-7-enoic acid-lactone have recently been identified in black tea aroma by means of GC./MS. and by sniffing the effluent from a gas chromatograph. Their intrinsic character, rather fruity and flowery, gives a certain freshness and an agreable note to the aroma.     

Recherches sur les arǒmes. 16e communication [1]. Sur l'arǒme du cacao III

The isolation and analysis of a cocoa concentrate is described: 62 constituents have been identified, 42 of which for the first time. Most identifications are based upon mass spectrometry combined in many cases with IR. spectrometry, and comparison with reference compounds. A number of minor constituents could not be identified.     

Phosphinophosphit – ein Hydrolyseprodukt des „Phosphorsuboxids,P4O”︁

Phosphinophosphite – a Hydrolysis Product of ‘Phosphorous Suboxide, P₄O’ The hydrolytic degradation of polymer phosphorus suboxide, ‘P₄O’ and of the P₄-molecule in aqueous ethanolic sodium hydroxide leads in addition to wellknown substances to a compound containing two phosphorus atoms directly attached. By ³¹P-NMR spectroscopy it was identified as phosphinophosphite, [OP(O)(H)? PH₂]^?.     

Détermination par RMN 1H et 13C de la Conformation Favorisée des Ozonides d'Acènes

The preferred conformation of 9,10-dimethylanthracene ozonide has been established by ¹³C and ¹H NMR. Results hold for other anthracenic ozonides such as those of 9,10-dimethoxyanthracene and anthracene. The latter compound, resulting from the ozonolysis of anthracene, has for the first time been shown to exist in solution.     

Zur Kenntnis der Oxoplatinate Na2PtO2, Na2PtO3, „K2PtO3”︁ und „Rb2PtO3”︁

The oxoplatinates Na₂PtO₂, Na₂PtO₃, ?K₂PtO₃”? and ?Rb₂PtO₃”?. Hitherto unknown Na₂PtO₂ (greyish black) was prepared. Na₂PtO₂ (orthorhombic, D—Immm; a = 4.58₅, b = 3.11₉, c = 9.58₈ Å) is isotypic with Li₂CuO₂. α-Na₂PtO₃ (darkyellow; red as single-crystals) is monoclinic, C—C2/c (a = 5.41₉, b = 9.38₅, c = 10.75₂ Å, β = 99.67°), Li₂SnO₃-type. According to 3-dimensional single crystal data hitherto unknown β-Na₂PtO₃ (red crystals) is an orthorhombic variant of the Li₂SnO₃-type (a = 18.83₈, b = 6.28₂, c = 9.06₂ Å, Z = 16, D—Fddd; parameters see text); R = 0.080₉, R' = 0.094₈ [256 reflexes (hk0—hk6)]. The Madelung part of the lattice energy (MAPLE) is calculated and discussed for α-, β-Na₂PtO₃, α- and β-PtO₂. For the first time we got K₂PtO₃ and Rb₂PtO₃.     

Structure and electronic transport properties of the Misfit layer compound (LaSe)1.14(NbSe2)2, „LaNb2Se5”︁

The new misfit layer compound (LaSe)_1.14(NbSe₂)₂ has been synthesized from the elements at 1050- and its structure has been determined by a composite approach. The structure has an alternating stacking sequence of [LaSe] and two [NbSe₂] layers along the c direction. The misfit of the two different layers is occurring along the a direction: a₁(LaSe)=6.0191 Å and a₂(NbSe₂)=3.4372 Å therefore yielding a ratio of 1.751 which is very close to 7/4. An investigation of electrical resistivity was done. The crystal shows superconducting properties at 5.3 K.     

Prediction of beef color using time‐domain nuclear magnetic resonance (TD‐NMR) relaxometry data and multivariate analyses

Time‐domain nuclear magnetic resonance and chemometrics were used to predict color parameters, such as lightness (L*), redness (a*), and yellowness (b*) of beef (Longissimus dorsi muscle) samples. Analyzing the relaxation decays with multivariate models performed with partial least‐squares regression, color quality parameters were predicted. The partial least‐squares models showed low errors independent of the sample size, indicating the potentiality of the method. Minced procedure and weighing were not necessary to improve the predictive performance of the models. The reduction of transverse relaxation time (T₂) measured by Carr–Purcell–Meiboom–Gill pulse sequence in darker beef in comparison with lighter ones can be explained by the lower relaxivity Fe²⁺ present in deoxymyoglobin and oxymyoglobin (red beef) to the higher relaxivity of Fe³⁺ present in metmyoglobin (brown beef). These results point that time‐domain nuclear magnetic resonance spectroscopy can become a useful tool for quality assessment of beef cattle on bulk of the sample and through‐packages, because this technique is also widely applied to measure sensorial parameters, such as flavor, juiciness and tenderness, and physicochemical parameters, cooking loss, fat and moisture content, and instrumental tenderness using Warner Bratzler shear force. Copyright © 2016 John Wiley & Sons, Ltd.     

Die Kristallstruktur des „supramolekularen”︁ Cadmiumcyanid-Hexamethylentetramin-Addukts [Cd(CN)2 · 2/3 C6H12N4]

The Crystal Structure of the “Supramolecular” Cadmiumcyanide-Hexamethylenetetramine Adduct [Cd(CN)₂ · 2/3 C₆H₁₂N₄] Single crystals of a new compound in the system Cd(CN)₂-hexamethylenetetramine (HMTA) with the composition [Cd(CN)₂ · 2/3 C₆H₁₂N₄] were obtained by crystallization from an aqueous solution containing Cd(CN)₂ and HMTA. The structure consists of a ?supramolecular”? network of ? Cd? CN? Cd- and ? Cd? HMTA? Cd-chains. The structure is compared with that of an already known compound [Cd(CN)₂ · 1/3 C₆H₁₂N₄].     

Obtention de selenopysultones lors de l'oxydation de thio-1 chromenes par le dioxyde de selenium

Selenium dioxide oxidation of 1-thiochromene leads to 3-formyl (5,6)benzo-1,2 thiaseleninne-1,1-dioxide, which is a representative of a hitherto unknown class of heterocyclic compounds. Pyrolysis of this compound leads to 2-formyl benzo(b)selenophen, by loss of sulphur dioxide. The reaction can be applied to other 1 thiochromenes but no similar behaviour has been observed for their selenium isologues.     

Etude de la réactivité de la fonction carbonyle avec le cétène en présence d'un alcoxyde de titane. 1ère communication. Nouvelle méthode de synthèse de β-hydroxyesters

A new synthesis of β-hydroxyesters involving a reaction between a carbonyl compound, ketene and an alkyl-orthotitanate is described. The following carbonyl compounds have been studied: aldehydes, ketones, α-diketones, α- or γ-ketoesters. A reaction mechanism is proposed.