Pyrido[1,2-a]pyrimidinones and Thiazolo[3,2-a]pyrimidinones: Precursors for Pyridyl- and Thiazolyliminopropadienones, R - N=C=C=C=O

2012 ◽  
Vol 65 (2) ◽  
pp. 105 ◽  
Author(s):  
Heidi Gade Andersen ◽  
Curt Wentrup
Keyword(s):  
Ir Spectroscopy ◽  
Room Temperature ◽  
Major Product ◽  
Starting Material ◽  
Open Chain ◽  
Dihydro Derivative ◽  
Analogous Manner ◽  
Matrix Ir Spectroscopy

2-Pyridyliminopropadienone 6 is formed together with 2-aminopyridine on flash vacuum thermolysis (FVT) of 2-pyridylamino-pyridopyrimidinone 16a and observed by Ar matrix IR spectroscopy, but the two products recombine on warming to room temperature to regenerate the starting material. FVT of the picolinylamino-pyridopyrimidinones 16b and 16c generated mixtures of pyridyliminopropadienone 6 and picolinyliminopropadienones 19b and 19c, respectively. These reactions can be understood in terms of fragmentation of the open-chain bis(2-pyridylamino)methyleneketene intermediates 20 or the thermal interconversion of pyridopyrimidinones 16 and mesoionic pyridopyrimidinium olates 21. 2-Thiazoyliminopropadienone 28 was obtained in an analogous manner by FVT of the 2-(methylthio)thiazolopyrimidinone 24. However, the corresponding dihydro derivative 31 yielded cyanoketene 36 as the major product.

scholarly journals Dichloro(η6-p-cymene)(P,P-diphenyl-N-propyl-phosphinous amide-κP)ruthenium(II)

Molbank ◽  
10.3390/m1217 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1217
Author(s):  
Rebeca González-Fernández ◽  
Pascale Crochet ◽  
Victorio Cadierno
Keyword(s):  
Ir Spectroscopy ◽  
Elemental Analysis ◽  
Title Compound ◽  
Room Temperature ◽  
Toluene Solution ◽  
Catalytic Behavior ◽  
Multinuclear Nmr

The title compound, i.e., [RuCl2(η6-p-cymene)(PPh2NHnPr)] (2), was obtained in a 71% yield by reacting a toluene solution of the chlorophosphine complex [RuCl2(η6-p-cymene)(PPh2Cl)] (1) with two equivalents of n-propylamine at room temperature. The aminophosphine complex 2 was characterized by elemental analysis, multinuclear NMR (31P{1H}, 1H and 13C{1H}) and IR spectroscopy. In addition, its catalytic behavior in the hydration of benzonitrile was briefly explored.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

A Study of the Interactions Between Oligoamidephosphate (OAPh) and Curatives in a Sulphenamide-Accelerated Sulphur Vulcanizing System

1999 ◽  
Vol 19 (2) ◽  
pp. 95-108 ◽  
Author(s):  
Todorka G. Vladkova ◽  
Alexander Chr. Alaminov ◽  
Milka G. Pankova
Keyword(s):  
Differential Scanning Calorimetry ◽  
Zinc Oxide ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sulphur Vulcanization

Abstract The possible interactions between oligoamidephosphate (OAPli) and the curatives of a sulphenamide-accelerated sulphur vulcanizing system were studied by differential scanning calorimetry, IR-spectroscopy, and X-ray analysis. The interactions in double mixtures were between OAPh and zinc oxide (ZnO) and OAPh and sulphur. The OAPh/ZnO interaction that starts at room temperature seems to be the key for understanding the peculiarities of sulphenamide-accelerated sulphur vulcanization in the presence of OAPh.

{K-[2 2 2]-Crypt}2Se7·H20; Synthese, IR-Spektrum und Kristallstruktur

1991 ◽  
Vol 46 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Volker Müller ◽  
Kurt Dehnicke ◽  
Dieter Fenske ◽  
Gerhard Baum
Keyword(s):  
Ir Spectroscopy ◽  
Structure Determination ◽  
Room Temperature ◽  
Helical Chain ◽  
Space Group ◽  
X Ray

{K-[2 2 2]-Crypt}2Se7·H20 has been prepared by the reaction of a solution of potassium polyselenide in dimethylformamide at room temperature as black crystals, which were characterized by IR spectroscopy as well as by an X-ray structure determination. Space group P21/n, Z = 4, 5055 observed unique reflexions, R = 0.103. Lattice dimensions at 20 °C: a = 1435(1), b = 1320(1), c = 2966(2) pm, β = 102.50(6)° The heptaselenide ion represents approximately part of a helical chain of polymeric selenium.

ChemInform Abstract: Direct Study of Unstable Dimethylgermathione, Me2Ge=S, by Vacuum Pyrolysis-MS and Low-Temperature Matrix IR Spectroscopy.

ChemInform ◽  
2010 ◽  
Vol 22 (18) ◽  
pp. no-no
Author(s):  
V. N. KHABASHESKU ◽  
S. E. BOGANOV ◽  
P. S. ZUEV ◽  
O. M. NEFEDOV ◽  
J. TAMAS ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ir Spectroscopy ◽  
Direct Study ◽  
Vacuum Pyrolysis ◽  
Temperature Matrix ◽  
Matrix Ir Spectroscopy

Cycloalkylidenselenoketene durch Pyrolyse von 1,2,3-Selenadiazolen — Untersuchungen mit der temperaturabhängigen PE-Spektroskopie und Matrix-IR-Spektroskopie [1]

1984 ◽  
Vol 39 (11) ◽  
pp. 1536-1540 ◽  
Author(s):  
Reinhard Schulz ◽  
Armin Schweig
Keyword(s):  
Liquid Phase ◽  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Variable Temperature ◽  
Matrix Ir Spectroscopy

Abstract The gas-phase pyrolysis of cyclohexeno-1,2,3-selenadiazole and cycloocteno-1,2,3-selenadiazole has been investigated by variable temperature photoelectron spectroscopy and matrix IR spectroscopy. The ring contracted, highly reactive products cyclopentylidenselenoketene (cyclopentylidenmethanselone) and cycloheptylidenselenoketene (cycloheptylidenmethanselone) - which had not been found in liquid phase thermolysis experiments - have been detected. Additionally HeI photoelectron and IR spectra of analogous ketenes and thioketenes are presented for comparative reasons.

Synthesis of new substituted dihydroheptalene derivatives: SiO2- and base-catalyzed rearrangement of dimethyl trans-3,8-dihydroheptalene-3,8-dicarboxylate

2001 ◽  
Vol 79 (1) ◽  
pp. 35-41
Author(s):  
Nurullah Saraçoglu ◽  
Abdullah Menzek ◽  
Armagan Kinal ◽  
Metin Balci
Keyword(s):  
Room Temperature ◽  
Heat Of Formation ◽  
Major Product ◽  
Similar Reaction ◽  
Am1 Calculations ◽  
Hydrogen Shift ◽  
Proton Shift ◽  
Major Isomer ◽  
Prolonged Reaction Time ◽  
Lower Heat

Dimethyl trans-3,8-dihydroheptalene-3,8-dicarboxylate (trans-3) isomerizes to dimethyl cis-3,8-dihydroheptalene-3,8-dicarboxylate (cis-3) upon treatment with SiO2. On the other hand, base-catalyzed reaction of trans-3 undergoes a direct 1,3-intramolecular proton shift to give 6 at room temperature in 5 min. Prolonged reaction time formed isomers 7 and 8 in a ratio of 4:1. AM1 calculations indicate that the isomer 8, which is formed as minor product, has a lower heat of formation (–99.34 kcal mol–1) than that of the major isomer 7 (–92.05 kcal mol–1). However, when a similar reaction was performed at 100°C, the thermodynamically more stable isomer 8 was formed as the major product. Furthermore, cycloaddition reactions of these new dihydroheptalene derivatives 6 and 7 with different dienophiles have been studied. The mechanism has been discussed.Key words: dihydroheptalene, cycloaddition, 1,3-hydrogen shift, cycloheptatriene–norcaradiene equilibrium.

The Reaction between Acetone and Ammonia. II. Isomeric Oximinoketones related to Diacetoamine

1950 ◽  
Vol 3 (3) ◽  
pp. 450
Author(s):  
NC Hancox
Keyword(s):  
Nitrous Acid ◽  
Acid Treatment ◽  
Room Temperature ◽  
Dilute Acid ◽  
Open Chain ◽  
Mild Conditions

The compound 2,2,4,4,6-pentamethyltetrahydropyrimidine hydrate, formed in the reaction between acetone and ammonia at room temperature: is converted by nitrous acid to the 5-oximino derivative in 30 per cent. yield. This oxime is decomposed by acid under mild conditions to give acetone, ammonia, and the salt of 4-amino-4-methyl- 2,3-pentanedione 3-oxime. More vigorous acid treatment of the cyclic oxime, or reaction of the open-chain 3-oxime with boiling dilute acid, causes a migration of the oximino group to the 2 position. Evidence is adduced to show that the 2-oxinze has the α- (anti) configuration, whereas the 3-oxime has the β- (syn) configuration.

Photolysis of Thiolane Vapor

1971 ◽  
Vol 49 (8) ◽  
pp. 1316-1320 ◽  
Author(s):  
Silvia Braslavsky ◽  
Julian Heicklen
Keyword(s):  
Quantum Yield ◽  
Excited States ◽  
Room Temperature ◽  
Major Product ◽  
Unstable Product

The photolysis of thiolane vapor [Formula: see text] was studied at room temperature with 2139 Å radiation. The major product was C2H4, whose quantum yield decreased as the pressure was increased. Next in importance were 1-C4H8, C3H6, and C2H6. Also produced were CH4, c-C3H6, 1,3-C4H6, CH2CHSH, [Formula: see text], 1-C4H9SH, H2, C3H8, n-C4H10, c-C4H8, polymer, and an unstable product tentatively identified as 1-butene-1-thiol. All products were initial products of the reaction. Experiments with added C3H6 showed the absence of sulfur atoms. The results are interpreted in terms of two excited states and an intermediate which might be the diradical •CH2CH2CH2CH2S•.

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