Four-component synthesis of ferrocene-containing 1,3,4-oxadiazoles from N-isocyaniminotriphenylphosphorane (Ph3PNNC), a primary amine,a cyclic ketone and ferrocene carboxylic acid

The 1:1 imine intermediate created by the addition of a primary amine to a cyclic ketone is trapped by N-isocyaniminotriphenylphosphorane (Ph₃PNNC) in the presence of ferrocene carboxylic acid and the corresponding iminophosphorane intermediate was formed. Afterwards, ferrocene containing 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. The reaction proceeded under mild conditions at room temperature.     

Synthesis of 1,3,4-oxadiazoles from the reaction of N-isocyaniminotriphenylphosphorane (NICITPP) with cyclohexanone,a primary amine and an aromatic carboxylic acid via intramolecular aza-Wittig reaction of in situ generated iminophosphoranes

The 1:1 imine intermediate generated by the addition of a primary amine to cyclohexanone trapped by N-isocyaniminotriphenylphosphorane (NICITPP) in the presence of aromatic carboxylic acids and the corresponding iminophosphorane intermediate was formed. Disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. The reactions were completed in neutral conditions at room temperature (18-26°C). The disubstituted 1,3,4-oxadiazole derivatives were produced in excellent yields.     

N-Isocyaniminotriphenylphosphorane (Ph3PNNC) as an Efficient Reagent for the Synthesis of Fully Substituted 1,3,4-Oxadiazoles from 3-Phenyl-2-Propynoic Acid,Secondary Amines and Aromatic Bis-Aldehydes

Abstract

Reactions of N-isocyaniminotriphenylphosphorane (Ph₃PNNC) with aromatic bis-aldehydes (isophthalaldehyde and terphthalaldehyde) in the presence of 3-phenyl-2-propynoic acid and secondary amines proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions and no side reactions were observed.     

N-Isocyaniminotriphenylphosphorane (Ph3PNNC) as a metal-free catalyst for the synthesis of functionalized isoindoline-1-ones

A novel application in the field of N-isocyaniminotriphenylphosphorane (Ph₃PNNC) chemistry has been introduced in this work. A series of substituted isoindolin-1-one ring systems has been successfully synthesized through a novel and efficient multicomponent reaction of methyl 2-formylbenzoate and primary amines in the presence of N-isocyaniminotriphenylphosphorane (Ph₃PNNC) as a catalyst. This one-pot three component reaction (3-CR) gives high yield using N-isocyaniminotriphenylphosphorane (Ph₃PNNC) as a metal-free catalyst under mild conditions.     

N-Isocyaniminotriphenylphosphorane as an Efficient Reagent for the Synthesis of Disubstituted 1,3,4-Oxadiazoles Via In-Situ Generation of Sterically Congested Iminophosphorane Derivatives

Abstract

Reaction of N-isocyaniminotriphenylphosphorane with benzaldehyde derivatives in the presence of 3-phenyl-2-propynoic acid and secondary amines proceeds smoothly at room temperature and under neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions and no side reactions are observed.     

The reaction of N-isocyaniminotriphenylphosphorane (NICITPP) with some of cyclic ketones and a primary amine in the presence of 3-phenyl-2-propynoic acid

The 1:1 imine intermediate generated by the addition of a primary amine to a cyclic ketone is trapped by N-isocyaniminotriphenylphosphorane in the presence of 3-phenyl-2-propynoic acid and the corresponding iminophosphorane intermediate was formed. Disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. The reactions were completed in neutral conditions at room temperature (18–26°C). The disubstituted 1,3,4-oxadiazole derivatives were produced in excellent yields.     

The Reaction of N-Isocyaniminotriphenylphosphorane With Biacetyl in the Presence of (E)-Cinnamic Acids: Synthesis of Fully Substituted 1,3,4-Oxadiazole Derivatives via Intramolecular AZA-Wittig Reactions of in Situ Generated Iminophosphoranes

Abstract

Reaction of N-isocyaniminotriphenylphosphorane with biacetyl in the presence of (E)-cinnamic acids proceeds smoothly at room temperature and under neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in high yields. The reaction proceeds smoothly and straightforward under mild conditions and no side reactions are observed.     

One-Pot Efficient Synthesis of Fully Substituted 1,3,4-Oxadiazole Derivatives from (N-Isocyanimino)triphenylphosphorane,Carboxylic Acids,and Aromatic Bis-Aldehydes

Reactions of (N-isocyanimino)triphenylphosphorane with aromatic bis-aldehydes (isophthalaldehyde and terphthalaldehyde) in the presence of aromatic (or heteroaromatic) carboxylic acids proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in good yields. The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions were observed.

The reaction of (N-isocyanimino)triphenylphosphorane with benzoic acid derivatives: a novel synthesis of 2-aryl-1,3,4-oxadiazole derivatives

The reactions of benzoic acid derivatives with (N-isocyanimino)triphenylphosphorane proceed smoothly at room temperature to afford 2-aryl-1,3,4-oxadiazoles in high yields.     

(N-Isocyanimino)triphenylphosphorane as an Efficient Reagent for the Synthesis of 1,3,4-Oxadiazoles from 3-Substituted Benzoic Acid Derivatives

The reaction of 3-substituted benzoic acid derivatives with (N-isocyanimino) triphenylphosphorane proceeds smoothly at room temperature to afford corresponding 1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions.     

One-pot three-component reaction for the synthesis of novel series of fully substituted 1,3,4-oxadiazole derivatives bearing pyridine moiety

(N-isocyanimino)triphenylphosphorane, 2-pyridinecarbaldehyde, and aromatic carboxylic acids (benzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 3-methoxybenzoic acid, 1-naphthoic acid, and 2-naphthoic acid) undergo a 1:1:1 addition reaction under mild conditions in a one-pot reaction to afford novel series of fully substituted 1,3,4-oxadiazole derivatives in good yields.     

(N-Isocyanimino)triphenylphosphorane-Mediated,One-Pot,Efficient Synthesis of Sterically Congested 1,1,1-Trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol Derivatives via Intramolecular Aza-Wittig Reaction

Reactions of (N-isocyanimino)triphenylphosphorane with 1,1,1-trifluoroacetone in the presence of aromatic (or heteroaromatic) carboxylic acids (3-methylbenzoic acid, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 2-furancarboxylic acid, and 2-thiophenecarboxylic acid) proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,1,1-trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions were observed.

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.     

A simple and efficient approach for the synthesis of a novel class aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives via intramolecular nucleophilic substitution reaction

In this study, we synthesized a new series of substituted aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives (6-24) in yields ranging from 42 to 70% with an interesting mechanism that involves internal nucleophilic substitution followed by an S_N2-type nucleophilic substitution. First, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanone (3) was synthesized from the reaction of 5-methyl-1,3,4-thiadiazole-2-thiol (1) with 2-bromo-1-(4-chlorophenyl)ethanone (2) in the presence of potassium hydroxide. Then, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanol (4) was synthesized by a reduction reaction of this compound using NaBH₄. Finally, 5-methyl-3-alkyl-1,3,4-thiadiazol-2(3H)-one derivatives (6-24), which are the target compounds, were synthesized from the reaction of this compound (4), which is a secondary alcohol with various alkyl halides (5a-n) in the presence of sodium hydride (NaH). This study presents an interesting reaction mechanism related to the synthesis of aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives that is not recorded in the literature.     

Spectroscopic,thermal and structural studies of a new mercury(II) one-dimensional coordination polymer, [Hg(3-bpo)2(SCN)2], 3-bpo = 2,5- bis (3-pyridyl)-1,3,4-oxadiazole

A new mercury(II)-organic polymeric complex generated from 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) as an angular dipyridyl derivative ligand, [Hg(3-bpo)₂(SCN)₂], was prepared from reactions of ligand 3-bpo with mercury(II) thiocyanate. The compound was characterized by elemental analysis, IR-, ¹H NMR-, ¹³C NMR-spectroscopy and structurally determined by X-ray single crystal diffraction. The thermal stability of [Hg(3-bpo)₂(SCN)₂] was studied by thermal gravimetric (TG) and differential thermal analyses (DTA).     

Intramolecular Phototransfer of Protons and the Quenching of Fluorescence of Derivatives of 2-(Coumarinyl-3)-5-(ortho-hydroxyphenyl)-1,3,4-oxadiazole

The spectral-luminescence properties of ortho-hydroxy derivatives of 2-(coumarinyl-3)-5-phenyl-1,3,4-oxadiazole have been studied. It is shown that the basic reason for the decreased quantum yield of emission for the compounds studied is the high-speed phototransfer of a proton (estimated as 109 s^-1). Fluorescence of the products of this reaction (phototautomers) was not observed. It was confirmed by quantum-chemical calculations that the increase in efficiency of nonradiative dissipation of the electron excitation energy in phototautomeric forms of ortho-hydroxycoumarinyloxadiazoles is explained by an increase in intramolecular donor-acceptor interaction on introduction of the coumarin unit into the molecule. As a result of the high efficiency of nonradiative deactivation of the excited state, the ortho-hydroxyderivatives studied have promise as UV photostabilizers in polymeric materials.     

Acetohydroxamic acid: a new reagent for efficient synthesis of nitriles directly from aldehydes using Bi(OTf)3 as the catalyst

An efficient method for the preparation of nitriles directly from aldehydes by reaction with AHA using Bi(OTf)₃ as the catalyst is described. Bi(OTf)₃ is shown to be an efficient catalyst also for the conversion of aldoximes into nitriles.     

Propylphosphonic anhydride (T3P): an efficient reagent for the one-pot synthesis of 1,2,4-oxadiazoles, 1,3,4-oxadiazoles, and 1,3,4-thiadiazoles

Propylphosphonic anhydride (T3P^®) has been demonstrated to be an efficient and mild reagent for the one-pot synthesis of 1,2,4-oxadiazoles, 1,3,4-oxadiazoles, and 1,3,4-thiadiazoles from carboxylic acids.     

BF3·SiO2: an efficient reagent system for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles

Silica-supported boron trifluoride (BF₃·SiO₂) is an efficient, readily available and reusable catalyst for the synthesis of 1,2,4,5-tetrasubstituted imidazoles using benzil, an aromatic aldehyde and an amine in the presence of ammonium acetate. This one-pot procedure is very simple, affording good to excellent yields.     

原位生成的Ph3C+均相有机催化剂催化4,4’-芳亚甲基-二（3-甲基-1-苯基-1H-吡唑-5-醇）高效合成（英文）简

Trityl chloride (Ph₃CCl) efficiently catalyzes the condensation of 3-methyl-1-phenyl-1H-pyrazol- 5(4H)-one and aromatic aldehydes under mild and solvent-free conditions, affording 4,4''- (arylmethylene)-bis(3-methyl-1-phenyl-1H- pyrazol-5-ol)s in high to excellent yields and in short reaction time. The presence of the requisite organocatalytic trityl carbocation (Ph₃C⁺) species was confirmed by analysis of infrared, ¹H NMR, and ultra violet spectral data. A plausible mechanism was proposed for the reaction based on the observations and literature precedent.