Novel Cyanoketene N,S‐Acetals and Pyrazole Derivatives using Potassium 2‐Cyanoethylene‐1‐thiolates

Novel ketene N,S‐acetals 3 were readily prepared by the reaction of cyanoacetamide or cyanothioacetamide with phenylisothiocyanate in the presence of potassium hydroxide, followed by alkylation of the produced salts with methyl iodide. The reaction of compounds 3 with hydrazines afforded different substituted pyrazoles 6.     

Reaktionsverhalten von β-Oxo-carbonsäurederivaten der Anthracenreihe bei der Synthese von Thiophenen

Summary -Oxo-1-anthracenepropionate (3) reacts step by step with phenylisothiocyanate and -CH-acidic halo compounds to keten-S,N-acetals4, followed by cyclocondensation to give the 4-(1-anthracenyl)-thiophene-3-carboxylates5. In contrast, the reaction of -oxo-9-anthracenepropionate (6) with isothiocyanates and -CH-acidic halo compounds yields 5-acyl-2-amino-3-(9-anthracenoyl)-4-hydroxy-thiophenes8. This is caused by the sterical hindrance of the keto group of the anthracene in position 9; thus, the cyclocondensation proceedsvia reaction of the ester group of the -oxo-propionate. In the same way, 9-acetylanthracene reacts with phenylisothiocyanate and -CH-acidic compounds to keten-S,N-acetals10 and, in an additional step, to 2-anilino-3-(9-anthracenoyl)-thiophenes11 and 2-(9-anthracenoyl)-methylene-3,4-diphenyl-2,3-dihydro-(1,3)-thiazole12, respectively. The structure of all new compounds was determinated by 2D NOESY NMR spectroscopy.

Herrn Prof. Dr. habil.G. Großmann zum 65. Geburtstag gewidmet     

Advances in Asymmetric Hydrogenation and Hydride Reduction of Organophosphorus Compounds

Abstract

This article describes the asymmetric synthesis of chiral organophosphorus compounds using methods of enantioselective hydride reduction and hydrogenation of corresponding unsaturated compounds. Many applications in stereoselective synthesis with reference to updated literature findings as well as the author's original research are discussed. The uses of chiral organophosphorus compounds in some asymmetric transformations leading to the formation of phosphorus analogues of important natural compounds were also presented.     

New Six-Coordinate Phosphorus Compounds. Synthesis and Stereochemistry

Abstract

Synthesis and stereochemistry of several new six-coordinate organophosphorus compounds are discussed.     

Practical Synthesis of Functionalized 2‐Thioxoimidazolidine Derivatives

High‐yielding syntheses of an unpublished series of 2‐thioxo‐imidazolidin‐4‐ones 6 bearing an N‐ethoxycarbonyl and amidyl moieties an N₁ and C₅, respectively, are reported. These derivatives were obtained by intramolecular cyclization of 3‐ethylhydrazinoacetate 3,4‐dihydro maleimides 4 in the presence of ethyl or phenylisothiocyanate 2 under neutral conditions.     

Novel Synthesis of some Spiro Heterocycles Derived from 3-Hydroxy-3(2-Oxocyclohexyl)-Indolin-2-One

The reaction of 3-hydroxy-3(2-oxocyclohexyl)indolin-2-one 1 with some active methylene, bidentates, phenylisocyanate, phenylisothiocyanate, carbon disulfide, benzaldehyde, ketoketene S,S-acetal, cyanoketene S,S-acetal, active halo compounds or benzylidenemalononitrile affords a series of new spiro heterocyclic systems.     

Synthesis of New Functionalized Organophosphorus Acids and their Derivatives

Abstract

Functionalized organophosphorus acids and their derivatives are of great interest as chelating ligands, bioactive substances with various properties and the key compounds for the synthesis of phosphorus containing peptides. We have developed the convenient methods of the synthesis of new functionalized organophosphorus acids and their derivatives using a series of PH-acids and their esters with highly reactive fragments PH and POSi as well as phosphorus containing arnines with fragments PCHNH and PCHNSi. These organophosphorus synthons react smoothly with α-heterosubstituted derivatives of various amines and amides, functionalized alkenes and their oxides, as well as with acyl and sulfonyl chlorides giving the perspective compounds with high yields. New available types of new functionalized organophosphorus acids and their derivatives are presented below.     

Electrochemical Synthesis of Organophosphorus Compounds on the Base of Elemental Phosphorus

Abstract

The straight synthesis of organophosphorus compounds on the base of white phosphorus may solve a lot of problems concerning with simplification technology proceeding as a whole. At present time we are investigating procedures for the electrochemical generation of organophosphorus compounds directly white phosphorus The ability to carry out this type of procedure in single step will have considerable environmental benefits. Thus procedure affording trialkylphosphates in a yield more than 90% and purity up to 98% for row material in undivided cell has been elaborated.     

Colorlmetric Analysis of Malathion and Parathion Using Fluoboric Acid

Abstract

Monohydroxyfluoboric acid is described as a reagent for the determination of the organophosphorus compounds malathion and parathion. The reagent breaks the ether linkage to phosphorous to form a phosphoro-or phosphono-fluoridate which is then coloriraetrically determined by reaction with hydrogen peroxide and 2,7-diaroinofluorene. From 0.01 to 0.50 mg./ml. of the organophosphorus compounds can be determined.     

X-Ray Structural Study of the Novel Tautomeric Orgaijophosphorus Compounds

Abstract

A number of acylsubstituted (diphenylphosphoryl)meth-yl-triphenylphosphonium salts I-IV, which are keto-enolic organophosphorus compounds with the new type of the phos-phoryl-hydroxyylide tautomerism, were studied by X-ray diffraction method.     

New Carbamoyl Organophosphorus Compounds

Abstract

The syntheses of various organophosphorus compounds, which contain a function with potentially agropharmaceutical properties (acylureas [1], acylsemicarbazides [2] or imidazolidinetriones [3]) are described.     

NEW APPROACHES TO THE SYNTHESIS OF ORGANOPHOSPHORUS COMPOUNDS

Abstract

The past two decades have brought us a snowballing development of organophosphorus chemistry. Indeed organophosphorus compounds have found wide practical application (in agriculture, petroleum industry, as drugs, etc.) and continue to afford promising objects for the study of theoretical matters such as tautomerism, ambiphilicity, ambidenticity, and other problems of organic chemistry. On the other hand, however impressive this progress may be, the search for new methods of synthesis, improving the known methods and forecasting new types of organophosphorus compounds remain as challenging problems as before.     

The Phenylphosphinidene C6H5P is Stable Under Unimolecular Conditions - A Theoretical Prediction

Abstract

As members of the family of low-coordinated phosphorus compounds, the phosphinidenes (RP) containing subvalent phosphorus (σ¹,λ¹-P) are of current interest. Until now, no Organophosphiaidene RP (R=Alkyl, Aryl) is known to be stable in the condensed phase. As the results of trapping experiments are questioned, the formation of RP as intermediates is still doubtful [1]. The mass spectrometric decay of some organophosphorus compounds yields radical cations [C₆,H₅,P]^+? m/z 108. For these species structures 1 and 2 are conceivable:     

Spectral Assignment of Phenanthrene Derivatives Based on 6H-Dibenzo[C,E][1,2] Oxaphosphinine 6-Oxide by NMR and Quantum Chemical Calculations

Abstract

Organophosphorus compounds such as 6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO, 1) and its derivatives are important and versatile compounds for a broad field of applications. However, a thorough spectral assignment is often subordinate to its chemical properties. This article presents and unambiguously attributes the ¹H and ¹³C NMR spectra of DOPO (1), selected products yielded from the Atherton–Todd reaction (2–4), DOPO-HQ (5) as well as sulfur derivatives (6–7) via a set of 1D- and 2D-NMR experiments. The complex P-C and P-H coupling patterns are discussed and compared with the derivatives possessing different chemical environments around the phosphorus atom. In addition, we compared our results with density functional theory calculations. Even though the prediction of NMR data of organophosphorus compounds via molecular modeling is limited, this study presents a method that yields good results for this class of heterocycles. This knowledge should help to quickly assign NMR spectroscopic data of other DOPO (1) derivatives and can be extrapolated to organophosphorus compounds in general.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: NMR Spectra of Compounds 1-7 (Figures S1 - S15).     

New Route for the Synthesis of Pyrazole,Triazole, Triazine,and Triazepine Derivatives

N,N′‐Diphenylpiperidine‐1‐carbohydrazonamide 1 was prepared and treated with halo compounds, active nitriles, diethylhy malonate, ketones, CS₂, phenylisocyanate, phenylisothiocyanate, LR, ethyl 2‐cyano‐3,13‐dithiomethylacetate, and benzylidenenitriles to give the corresponding triazines 2–4, pyrazoles 5 and 6, triazoles 7, 8, and 10, triazaphosphole 11, and triazepines 12 – 14, respectively.     

MASS SPECTRAL STUDIES ON SYNTHETIC ANALOGUES OF ORGANOPHOSPHORUS TOXIN ISOLATED FROM PTYCHODISCUS BREVIS

Abstract

A series of structurally related organophosphorus oximes analogous to O,O-dipropyl-(E)-2-(1-methyl-2-oxopropylidene)phosphorahydrazidothioate-(E)-oxime, isolated from Ptychodiscus brevis, have been synthesised and subjected to electron impact (EI) mass spectral studies. These studies, though aimed at total identification of these compounds, resulted in certain interesting observations and hence are being reported. In order to confirm the observations under electron impact and to support the mechanism of fragmentation we have also performed tandem mass spectrometry experiments in some cases.     

Synthesis,Structures, and Fungitoxicity of Novel Organophosphorus Compounds

Abstract

A series of biologically active organophosphorus compounds have been synthesized by the reactions of O,O-diethylchlorophosphate with Schiff bases derived from 5-(phenyl/substituted phenyl)-2-hydrazino-1,3,4-oxadiazole and salicylaldehyde/2-hydroxyacetophenone. The compounds have been characterized on the basis of analyses and spectral (IR, ¹H, ¹³C NMR) data. Fungicidal activities of these derivatives against Colletotrichum falcatum, Fusarium oxysporum, and Curvularia pallescence have been evaluated. All compounds showed moderate to significant antifungal activity.     

E.P.R. STUDY OF THE ACTION OF NITROSO DERIVATIVES ON ORGANOPHOSPHORUS COMPOUNDS. II1—CASE OF 2-METHYL, 2-NITROSOPROPANE (M.N.P.)

Abstract

Nitroxides bearing α-phosphorus substituents are obtained by adding various organophosphorus compounds to solutions of 2-methyl, 2-nitroso propane (M.N.P.); furthermore, the action of nitric oxide on tetraethylpyrophosphite provides the first example of an αα' diphosphorylnitroxide. The nitroxides are identified by E.S.R. and mechanisms are proposed to explain their formation. The present work clearly shows that M.N.P. is not a good scavenger with which to study the radical reactions involving organophosphorus.     

Substituent Effects of Organophosphorus Esters in Structure Reactivity Studies

Abstract

An empirical approach for the estimation of substituent polar and steric parameters of organophosphorus compounds was suggested by experimental measurements and theoretical calculations.     

Organophosphorus Synthesis Without Phosphorus Trichloride: The Case for the Hypophosphorous Pathway

Abstract

The vast majority of organophosphorus compounds is currently synthesized from phosphorus trichloride (PCl₃), even though the final consumer products do not contain reactive phosphorus–chlorine bonds. In order to bypass phosphorus trichloride, significant interest has been devoted to functionalizing elemental phosphorus (P₄, the precursor to PCl₃), red phosphorus (P_red), or phosphine (PH₃). Yet, other industrial-scale precursors are hypophosphorous derivatives (H₃PO₂ and its alkali salts), but their use as phosphorus trichloride replacements has been completely overlooked. Here, the case is made for an alternative approach to the industrial synthesis of organophosphorus compounds based on hypophosphites.