α‐Aminophosphonates and α‐Aminophosphine Oxides by the Microwave‐Assisted Kabachnik–Fields Reactions of 3‐Amino‐6‐methyl‐2 H‐pyran‐2‐ones

The microwave‐assisted Kabachnik–Fields reaction of a series of 3‐amino‐6‐methyl‐2H‐pyran‐2‐ones, paraformaldehyde, and dialkyl phosphites or diphenylphosphine oxide led to α‐aminophosphonates or α‐aminophosphine oxides, respectively. The α‑aminophosphonates were obtained under solvent‐free conditions, whereas the α‑aminophosphine oxides in acetonitrile. The novel products were characterized by NMR and mass spectral data. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:221–225, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21086     

3,5‐Bis(arylidene)piperid‐4‐ones Containing 1,3,2‐Oxazaphosphorinane Moieties: Synthesis and Antitumor Activity

Two novel series of phosphorus‐substituted 3,5‐bis(arylidene)piperid‐4‐ones bearing 1,3,2‐oxazaphosphorinane cycle either directly attached to the piperidone core through the P N bond (diamidophosphates 4 ) or connected with it via thiocarbamoyl linker (thioureas 5 ) were obtained by the phosphorylation of NH precursors with 2‐oxo‐1,3,2‐oxazaphosphorinane chloride or the reaction of the former ones with the corresponding cyclic isothiocyanate. According to the results of cytotoxicity screening against human carcinoma cell lines (A549, CaOv3, KB), thioureas 5 were more active than the diamidophosphates 4 bearing the same arylidene rings, with compounds with electron‐withdrawing side groups displaying IC₅₀ in the micromolar range of 1.2–7 μM. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:191–199, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21082     

Dioxirane Oxidation of 2‐Aryl‐1‐vinyl‐1, 1‐diphosphane Dioxide: A Convenient Approach for the Synthesis of Novel 1,2‐Epoxy‐2‐aryl Ethylgembisphosphonates

The synthesis of tetraethyl 1,2‐epoxy‐2‐aryl ethylgembisphosphonates by direct epoxidation of 2‐aryl,vinyl‐1,1‐diphosphonate derivatives with ethyl methyldioxirane generated in situ from potassium hydrogen monopersulfate (caroate) and butanone in a phase transfer system is reported. The epoxides were isolated in excellent yields and fully characterized by spectral and microanalytical data. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:234–241, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21084     

Synthesis,structure and cytotoxicity of new 2‐[(3‐aminopropyl)dimethylsilyl]‐5‐furfural diethylacetals and 2‐[(3‐aminopropyl)dimethylsilyl]‐5‐phenylfurans

Novel 2‐[(3‐aminopropyl)dimethylsilyl]‐5‐furfural diethylacetals and 2‐[(3‐aminopropyl)di‐methylsilyl]‐5‐phenylfurans have been synthesized by a hydrosilylation reaction of aliphatic and heterocyclic N‐allylamines in the presence of the Speier's catalyst. The effects of the structure of the amine and nature of organic substituent at the furan ring on the cytotoxicity of the new compounds have been studied. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of Precursors of 4‐Phosphino‐1H‐pyrrole‐3‐carbaldehyde Derivatives

In this work, possible approaches to the synthesis of 1,2,5‐substituted 4‐phosphoryl‐3‐formylpyrroles have been considered. As a result, two methods for the synthesis of 4‐(diphenylphosphoryl)‐1‐(4‐ethoxyphenyl)‐2,5‐dimethyl‐1H‐pyrrole‐3‐carbal‐dehyde were proposed; the highest yields gives formylation of 3‐(diphenylphosphorothioyl)‐1‐(4‐ethoxyphenyl)‐2,5‐dimethyl‐1H‐pyrrole. The formyl fragment was successfully converted into a Schiff base with phenethylamine, and the phosphoryl group has been reduced to phosphine with silicochloroform, which suggests a promising approach to the synthesis of chiral bidentate phosphine ligands. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:146–151, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21069     

CuI/amino acid‐catalyzed coupling and cyclization of β‐bromo‐α,β‐unsaturated amides with terminal alkynes leading to (3Z)‐3‐alkylidenepyrrol‐1‐ones

β‐Bromo‐α,β‐unsaturated amides are coupled and cyclized with terminal alkynes in DMF at 110 °C in the presence of a catalytic amount of CuI and amino acid along with a base to give the corresponding (3Z)‐3‐alkylidenepyrrol‐1‐ones in moderate to good yields. Copyright © 2013 John Wiley & Sons, Ltd.     

1H and 13C NMR analysis of 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamido‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamide derivatives

The complete assignment of the ¹H and ¹³C NMR spectra of various 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamide‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamides with p‐methoxy, o‐chloro and m‐chloro substituents is reported. Copyright © 2013 John Wiley & Sons, Ltd.     

Efficient synthesis of β‐(1,6)‐linked oligosaccharides through microwave‐assisted glycosylation

A microwave‐assisted glycosylation method was developed for efficient synthesis of oligosaccharides. Di‐functional AB monomers, 2,3,4‐tri‐O‐acetyl‐α‐d ‐galactopyranosyl bromide ( 3a ) and 2,3,4‐tri‐O‐acetyl‐α‐d ‐glucopyranosyl bromide ( 3b ) were designed and synthesized as weakly reactive monomers to avoid unwanted glycosylation or degradation during preparation and storage. The glycosylations of these monomers gave low conversions and low molecular weight oligosaccharides at rt, reflux, and under low microwave energy irradiation. However, the glycosylation became very effective when high microwave energy was applied, giving 100% conversion and producing oligosaccharides with M_n = 4.76 kDa for 3a and M_n = 4.05 kDa for 3b. The acetylated oligosaccharides were further subjected to deprotection for structural analysis, which indicated the oligosaccharides contain predominantly linear β‐(1,6)‐glycosyl linkages. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3693–3699     

Copper(I) salt/PEG‐400 catalysis in one‐pot direct synthesis of 1‐aryl‐1H‐indazoles from 2‐bromobenzaldehydes and arylhydrazines

2‐Bromobenzaldehydes are condensed and cyclized with arylhydrazines (or their hydrochlorides) in PEG‐400 at 110 °C in the presence of a catalytic amount of a copper(I) salt along with a base to give 1‐aryl‐1H‐indazoles in high yields. Copyright © 2013 John Wiley & Sons, Ltd.     

Novel and one‐pot Synthesis of Tetrahydropyrrolo[1,2‐a]‐2‐Methylbenzothiazole‐3‐Spiro‐1′‐Cyclohexa‐2′,5′‐Dien‐4′‐one‐4,5‐Dicarboxylate Derivatives via a Three Component Reaction

The three component condensation reactions involving 2‐methylbenzothiazole or 2,5‐dimethylbenzothiazole, dialkyl acetylenedicarboxylate, and 2,6‐dimethyl phenol or 2,6‐di‐tert‐butylphenol constitute a novel and one‐pot synthesis of tetrahydropyrrolo[1,2‐a ]‐2‐methylbenzothiazoles‐3‐spiro‐1^′‐cyclohexa‐2^′,5^′‐dien‐4^′‐one‐4,5‐dicarboxylate derivatives in good yields. The reactions proceeded at room temperature without using any catalyst. This method is very useful to functionalize benzothiazole derivatives in a one‐pot operation.     

Preparation of Optically Active Six‐Membered P‐Heterocycles: A 3‐Phosphabicyclo[3.1.0] hexane 3‐oxide,a 1,2‐Dihydrophosphinine 1‐oxide,and a 1,2,3,6‐Tetrahydrophosphinine 1‐oxide

The earlier described a 3‐methyl‐1‐phenyl‐3‐phospholene 1‐oxide ( 1 ) → 6,6‐dichloro‐1‐methyl‐3‐phenyl‐3‐phosphabicyclo[3.1.0]hexane 3‐oxide ( 2 ) → 4‐chloro‐1‐phenyl‐1,2‐dihydrophosphinine 1‐oxide ( 3 ) → 4‐chloro‐5‐methyl‐1‐phenyl‐1,2,3,6‐tetrahydrophosphinine 1‐oxide ( 4 ) reaction sequence was investigated from the point of view of preparing optically active intermediates/products ( 2–4 ). In principle, both the resolution of the corresponding racemic products and the transformation of the optically active starting materials are suitable approaches for the preparation of optically active six‐membered P‐heterocycles ( 2–4 ). Racemization occurred during the dichlorocyclopropanation reaction of (S)‐3‐methyl‐1‐phenyl‐3‐phospholene 1‐oxide ((S)‐ 1 ), but the thermolytic ring opening of (−)‐ 2, and the selective reduction of α,β‐double bond of (−)‐ 3 did not cause the loss of optical activity. First in the literature, the resolution of a 3‐phosphabicyclo[3.1.0]hexane 3‐oxide ( 2 ) and a 1,2,3,6‐tetrahydrophosphinine 1‐oxide ( 4 ) was elaborated. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:179–186, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21080     

Synthesis and Fungicidal Activity of (1Z, 3Z)‐4,4‐Dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one O‐[2,4‐dimethylthiazole(or 4‐methyl‐1,2,3‐thiadiazole)]‐5‐carbonyl Oximes

A series of novel (Z)‐1‐tert‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐ethanone O‐[2,4‐dimethylthiazole (or 4‐methyl‐1,2,3‐thiadiazole) ?5‐carbonyl] oximes 5a – 5c and (1Z, 3Z)‐4,4‐dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one O‐[2,4‐dimethylthiazole (or 4‐methyl‐1,2,3‐thiadiazole)‐5‐carbonyl] oximes 6a – 6e were synthesized by the condensations of (Z)‐1‐tert‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐ethanone oximes 3 or (1Z, 3Z)‐4,4‐dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one oximes 4 with 2,4‐dimethylthiazole‐5‐carbonyl chloride or 4‐methyl‐1,2,3‐thiadiazole‐5‐carbonyl chloride in the basic condition. Their structures were confirmed by IR, ¹H NMR, mass spectroscopy, and elemental analyses. The results of preliminary bioassays showed the title compounds 5 and 6 exhibited moderate to good fungicidal activities. For example, compound 6c possessed 86.4% inhibition against Fusarium oxysporum, and compound 6b exhibited 86.4 and 100% inhibition against Fusarium oxysporum and Cercospora arachidicola Hori at the concentration of 50 mg/L, respectively.     

Synthesis of 3‐(ω‐Hydroxyalkoxy)isobenzofuran‐1(3H)‐ones by Trifluoroacetic Acid‐Mediated Lactonization of tert‐Butyl 2‐(1,3‐Dioxol‐2‐yl)‐ or 2‐(1,3‐Dioxan‐2‐yl)benzoates

An efficient two‐step method for the preparation of 3‐(2‐hydroxyethoxy)‐ or 3‐(3‐hydroxypropoxy)isobenzofuran‐1(3H)‐ones 3 has been developed. Thus, the reaction of 1‐(1,3‐dioxol‐2‐yl)‐ or 1‐(1,3‐dioxan‐2‐yl)‐2‐lithiobenzenes, generated in situ by the treatment of 1‐bromo‐2‐(1,3‐dioxol‐2‐yl)‐ or 1‐bromo‐2‐(1,3‐dioxan‐2‐yl)benzenes 1 with BuLi in THF at ?78°, with (Boc)₂O afforded tert‐butyl 2‐(1,3‐dioxol‐2‐yl)‐ or 2‐(1,3‐dioxan‐2‐yl)benzoates 2 , which can subsequently undergo facile lactonization on treatment with CF₃COOH (TFA) in CH₂Cl₂ at 0° to give the desired products in reasonable yields.     

Hydriodic Acid‐Mediated Cyclization of α‐Substituted Secondary 2‐Ethenylbenzamides: Synthesis of 2‐Substituted 2,3‐Dihydro‐3,3‐dimethyl‐1H‐isoindol‐1‐ones and 3,3‐Disubstituted (E)‐1‐(Arylimino)‐1,3‐dihydroisobenzofurans

A new and facile method for the preparation of 2‐substituted 2,3‐dihydro‐3,3‐dimethyl‐1H‐isoindol‐1‐ones 3 and 3,3‐disubstituted (E)‐1‐(arylimino)‐1,3‐dihydroisobenzofurans 6 has been developed. Thus, treatment of N‐alkyl(or aryl)‐2‐(1‐methylethen‐1‐yl)benzamides 2 with concentrated hydriodic acid (HI) in MeCN at room temperature afforded 3 . Similar treatment of N‐aryl‐2‐(1‐phenylethen‐1‐yl)benzamide 5 with concentrated HI at 0° afforded 6 .     

rac‐5‐Diphenylacetyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine and rac‐5‐formyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine

rac‐5‐Diphenylacetyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C₂₆H₂₇NOS, (I), and rac‐5‐formyl‐2,2,4‐trimethyl‐2,3,4,5‐tetrahydro‐1,5‐benzothiazepine, C₁₃H₁₇NOS, (II), are both characterized by a planar configuration around the heterocyclic N atom. In contrast with the chair conformation of the parent benzothiazepine, which has no substituents at the heterocyclic N atom, the seven‐membered ring adopts a boat conformation in (I) and a conformation intermediate between boat and twist‐boat in (II). The molecules lack a symmetry plane, indicating distortions from the perfect boat or twist‐boat conformations. The supramolecular architectures are significantly different, depending in (I) on C—H...O interactions and intermolecular S...S contacts, and in (II) on a single aromatic π–π stacking interaction.     

H‐transfer reaction during decomposition of N‐(2‐methylpropyl)‐ N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (SG1)‐based alkoxyamines

Thermal decomposition of four tertiary N‐(2‐methylpropyl)‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (SG1)‐based alkoxyamines (SG1‐C(Me)₂‐C(O)‐OR, R = Me, tBu, Et, H) has been studied at different experimental conditions using ¹H and ³¹P NMR spectroscopies. This experiment represents the initiating step of methyl methacrylate polymerization. It has been shown that H‐transfer reaction occurs during the decomposition of three alkoxyamines in highly degassed solution, whereas no products of H‐transfer are detected during decomposition of SG1‐MAMA alkoxyamine. The value of the rate constant of H‐transfer for alkoxyamines 1 (SG1‐C(Me)₂‐C(O)‐OMe) and 2 ( SG1‐C(Me)₂‐C(O)‐OtBu) has been estimated as 1.7 × 10³ M^?1s^?1. The high influence of oxygen on decomposition mechanism is found. In particular, in poorly degassed solutions, nearly quantitative formation of oxidation product has been observed, whereas at residual pressure of 10^?5 mbar, the main products originate from H‐atom transfer reaction. The acidity of the reaction medium affects the decomposition mechanism suppressing the H‐atom transfer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis and Fungicidal Activity of 5‐Aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole

A series of novel 5‐aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole 3a – 3n were synthesized by the annulation of 2‐aryloxyacetohydrazides with 3‐aryl‐1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)prop‐2‐en‐1‐ones ( 2 ) in the presence of a catalytic amount of acetic acid. Compounds 2 were obtained by the Knoevenagel reactions of 1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanone ( 1 ) with aromatic aldehydes in the presence of piperidine. Their structures were confirmed by IR, ¹H‐NMR, ESI‐MS, and elemental analyses. The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity. For example, compounds 3l , 3m , and 3n possessed 100% inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L.     

Synthesis of poly(3‐hexylthiophene)‐block‐poly(ethylene)‐block‐poly(3‐hexylthiophene) via a combination of ring‐opening olefin metathesis polymerization and grignard metathesis polymerization

Novel rod–coil–rod ABA triblock copolymers, poly(3‐hexylthiophene)‐block‐poly(ethylene)‐block‐poly(3‐hexylthiophene) (P3HT‐b‐PE‐b‐P3HT) were synthesized by using a combination of a Ru‐catalyzed ring‐opening metathesis polymerization of 1,4‐cyclooctadiene in the presence of a suitable chain transfer agent (CTA) and a Ni‐catalyzed Grignard metathesis polymerization of 5‐chloromagnesio‐2‐bromo‐3‐hexylthiophene followed by hydrogenation. Using this methodology, the molecular weights of the poly(butadiene) (PBD) or the P3HT blocks were controlled by adjusting the initial monomer/CTA or the initial monomer/macroinitiator ratio, respectively. In addition, the triblock structure was confirmed by selective oxidative degradation of the PBD block found in the intermediate P3HT‐b‐PBD‐b‐P3HT copolymer produced in the aforementioned method, followed by analysis of the degradation products. Thermal analysis and atomic force microscopy of P3HT‐b‐PE‐b‐P3HT revealed that the material underwent phase separation in the solid state, a feature which may prove useful for improving charge mobilities within electronic devices. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3810–3817     

(2S)‐2‐[1‐(2,4‐Di­fluoro‐5‐iodo­phenyl)‐2‐deoxy‐β‐d‐ribo­furanos‐5‐yloxy]‐8‐methyl‐4H‐1,3,2‐benzodioxa­phosphole 2‐oxide

The title compound, C₁₉H₁₈F₂IO₆P, prepared as a potential antiviral and anticancer agent from 3‐methyl­salicyl­chloro­phosphane and 1‐(2,4‐di­fluoro‐5‐iodo­phenyl)‐2‐deoxy‐β‐d ‐ribo­furan­ose, is one of a 1:1 mixture of two diastereomers. The diastereomers differ in their configuration, S or R, at the asymmetric phosphorus center. X‐Ray crystallographic analysis of the title compound has determined the absolute configuration at the asymmetric P center to be S.     

Polyaddition of bifunctional 1,3‐benzoxazine and 2‐methylresorcinol

A polyaddition system consisted of a bifunctional N‐n‐propyl benzoxazine and 2‐methylresorcinol ( MR ) that proceeds at ambient temperature has been developed. In this system, the aromatic ring of MR acted as a bifunctional monomer, reacting with a two equivalent amount of benzoxazine moieties via their ring‐opening reaction. The polyaddition gave the corresponding linear polymer bearing phenolic moieties bridged by Mannich‐type linkage in the main chain. The linear polymer had a high glass transition temperature, which was comparable to that of the linear polybenzoxazine synthesized by the ring‐opening polymerization of a monofunctional N‐n‐propyl benzoxazine. The employment of a bifunctional N‐allyl benzoxazine in the polyaddition system resulted in the formation of the corresponding polymer with allyl pendants, which exhibited improved heat resistance due to its thermally induced crosslinking reaction. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3867–3872