An Unexpected Hydrolysis Product from Strobilurin Fungicide： Azoxystrobin

The hydrolysis reaction of azoxystrobin in a methanol solution was studied, obtaining a novel compound 3,3-dimethoxy-2-(2-(6-methoxy pyrimidin-4-yloxy)phenyl) propanoic acid. The hydrolysis reaction may be helpful to explaining the degradation mechanism of azoxystrobin in soil or plant, which is also a method for further study on metabolism in vitro. The crystal structure was confirmed by 1H NMR and MS and determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 8.5662(2), b = 10.5074(6), c = 10.9849(7), α = 62.8370(10), β = 73.2170(10), γ = 73.3100(2)o, C16H18N2O6, Mr = 334.32, V = 828.09(9)3, Z = 2, Dc = 1.341 g/cm3, F(000) = 352, μ = 0.104 mm-1, S = 1.075, the final R = 0.0665 and wR = 0.1593 for 2083 observed reflections with I > 2σ(I) and 220 variable parameters. The crystal analysis shows that the hydrolysis product contains two rings, and a one- dimensional chain structure is formed via the intermolecular hydrogen bond O(1)-H(101)···N(2).     

Unexpected Novel Rearrangement Reaction: Synthesis of Benzo‐Medium‐Ring Anhydride

When we attempted to synthesize (E)‐3‐(benzo[d][1,3]dioxol‐5‐ylmethylene)‐4‐(propan‐2‐ylidene)‐dihydrofuran‐2,5‐dione, we found a novel rearrangement and obtained the unexpected compound that is assigned as benzo‐medium‐ring anhydride instead of the expected compound. We described the novel rearrangement and a potential method for the synthesis of benzo‐medium‐ring anhydride derivatives.     

Synthesis of α-Methylenecarbonyl Compounds: An Unexpected Product from the Mannich Reaction On 2-Carbomethoxycyclohexanone

During a study of a general synthesis of α-methylenecarbonyl compounds,¹ we investigated the Mannich reaction of 2-carbomethoxycyclohexanone with formaldehyde and various secondary amines. The unexpected formation of 6-methylene-2-carbomethoxycyclohexanone, existing mainly in the enol form, as the only isolable product is the subject of this report.     

Substrate-Controlled Hydrogenation of Flavanones: Selective Synthesis of 2′-Hydroxy-1,3-Diarylpropanes and Flavans

A new substrate-controlled hydrogenation of flavanones to selectively obtain different hydrogenation products is herein reported. Thus, hydrogenation of flavanones bearing different electron-donating and electron withdrawing substituents (Cl, Br, Me, OMe, OH) provided the corresponding 1,3-diarylpropanes in excellent yields. This procedure offers a straightforward, simple, and cost-effective method for the preparation of glycosylated 2′-hydroxy-1,3-diarylpropanes derived from natural flavanones such as Naringin and Hesperedin. On the contrary, when the hydrogenation was performed over fluorinated flavanones, the corresponding flavans were selectively obtained in excellent yields.     

Unexpected Microwave Reaction of 1,3‐Disubstituted Imidazolium Salts: A Novel Synthesis of 1,3‐Disubstituted Imidazole‐2‐thiones

Microwave‐promoted reaction of 1,3‐disubstituted imidazolium salts with potassium thioacetate or potassium thiocyanate under solvent‐free conditions provided a rapid and efficient synthesis of 1,3‐disubstituted imidazole‐2‐thiones.     

Potassium Fluoride on Alumina: An Easy Synthesis of 4-Alkylidene-2-Thione-1,3-Oxathiolanes from α-Acetylenic Alcohols

α-acetylenic alcohols and carbon disulfide in the presence on potassium fluoride on alumina without solvent give selectively 4-alkylidene-2-thione- 1,3-oxathiolanes     

Communication: An exact short-time solver for the time-dependent Schrödinger equation

The short-time integrator for propagating the time-dependent Schro?dinger equation, which is exact to machine's round off accuracy when the Hamiltonian of the system is time-independent, was applied to solve dynamics processes. This integrator has the old Cayley's form [i.e., the Pade? (1,1) approximation], but is implemented in a spectrally transformed Hamiltonian which was first introduced by Chen and Guo. Two examples are presented for illustration, including calculations of the collision energy-dependent probability passing over a barrier, and interaction process between pulse laser and the I(2) diatomic molecule.     

Microwave‐Assisted Beckmann Rearrangement: Convenient Synthesis of 1,3‐Diaza‐bicyclo[3.2.2]nonane

Small heterocyclic amines such as 1,3‐diaza‐bicyclo[3.2.2]nonane are known to be key components of biologically active molecules. A convenient synthesis of this compound utilizing a key Beckmann rearrangement of (Z)‐1‐aza‐bicyclo[2.2.2]octan‐3‐one oxime (6) with conc. H₂SO₄ under microwave irradiation was achieved. The desired compound (1) was obtained in 20% yield overall.     

Communication: Use of an α-Haloether for the Acetonation of Carbohydrates.

Cyclic acetals are important and commonly used protective groups for polyhydroxy compounds, e.g., carbohydrates. The formation of cyclic acetals has been thoroughly investigated and much is now known about the factors that influence the outcome of these reactions. Several reviews have been written on this subject.^1,2,3     

An unusual [4 + 4] cycloadduct from an o-quinodimethane: Characterisation and computational studies

Trapping of a pyrimidinone-derived o-quinodimethane with tetraphenylcyclopentadienone gives a mixture of the [4 + 2] and formal [4 + 4] adducts. Computational studies show that the latter arises by a sequence of [4 + 2] cycloaddition, homolysis, radical recombination to a spiro-tetrahydrofuran and Claisen rearrangement under the thermolytic conditions.     

Unexpected Rearrangement of Diethyl (±)(S,S)-1,2-epoxy-2-Phenylpentylphosphonate by NH 3(aqu.) : An Easy Entry to Ethyl 1-Formyl-1-Phenylbutylphosphonate

A simple reaction of diethyl ( - )(S,S)-1,2-epoxy-2-phenylpentylphosphonate with 28% NH 3(aqu.) in MeOH led to the ethyl 1-formyl-1-phenylbutylphosphonate in excellent yield. The procedure consists simply in stirring the substrate and 28% NH 3(aqu.) in MeOH, at 40;C.     

Extensive Studies on the AlEt3/THF-Promoted Diastereoselec-tive Tandem Rearrangement/Reduction of a-Hydroxy (Amino) Heterocyclopropane: An Efficient Approach to 2-Quaternary 1,3-Diheteroatom Units

Introduction Diastereoselective construction of 1,3-diheteroatom units, especially 1,3-amino alcohols and 1,3-diols, has always been in high demands in synthetic organic chemistry, as they are widely present in many natural products and potent drugs, such as nucleoside antibiot-ics and the HIV protease inhibitors.1,2 They have also been used as chiral ligands for asymmetric catalysts and as synthetic intermediates.3 Although several methods for the construction of 1,3-amino alcohols have been…     

Formation of α-enaminoketones from α-azidoketones: An elimination of molecular nitrogen from α-azidoketones

α-Enaminoketones are readily accessible through reaction of α-bromoketones with sodium azide followed by an elimination of molecular nitrogen. The reaction is base catalyzed and proceeds under relatively mild conditions. An anionic mechanism is proposed.     

The 1,3-migration of phosphorus from oxygen to carbon: A new synthesis of β-ketophosphonates from enol phosphates

Enol phosphates, readily prepared from ketone enolates and dialkyl phosphorochloridate, can be converted to the analogous β-ketophosphonates by treatment with strong base.     

Base Promoted Rearrangement of Carbonate Esters Derived from Aldehyde Cyanohydrins: Application to the Synthesis of α-Keto Esters

Acylation of the cyanohydrin derivative (2) of representative aldehydes with ethyl chloroformate, followed by treatment of the corresponding mixed carbonate esters (3) with lithium hexamethyldisilazide, afforded the cyanohydrin derivative (4) of α-keto esters. Cleavage of the latter (4) with 2,6-lutidine in the presence of silver nitrate led to the procurement of α-keto esters in >50% overall yield.     

Stereoselective Synthesis of β-Hydroxy- and β-Ethoxy-δ-lactones: Model Structures for Compounds Isolated from Otoba parvifolia

Abstract: In this paper we describe a very short stereoselective synthesis of the β-ethoxylactone 13, a model structure for compounds isolated from Otoba parvifolia. The method, which also produces β-hydroxy-esters and β-hydroxy-lactones, is based on a chemo- and stereoselective Reformatsky reaction.     

An efficient synthesis of imidodicarbonic diamides from 1,3-thiazetidin-2-ones with NH_2OH·HCl via ring-opening reaction

A ring-opening process of 4-imino-l,3-thiazetidin-2-ones with NH_2OH·HC1 was described for the first time.Two different scaffolds of imidodicarbonic diamide were obtained selectively in good yields in the presence of organic base.The obtained imidodicarbonic diamides were demonstrated by X-ray diffraction analysis.     

Efficient synthesis of functionalized 1,3-dihydroisobenzofurans from salicylaldehydes:Application to the synthesis of escitalopram

An efficient synthesis of substituted 1,3-dihydroisobenzofurans is developed. In this novel route, oaroylbenzaldehydes, as key intermediates, can be obtained by lead tetraacetate oxidation of Naroylhydrazones of salicylaldehydes. The mild and general strategy enables the synthesis of various substituted 1,3-dihydroisobenzofurans in high yields. Moreover, this method can be applied to efficiently synthesize escitalopram.     

Extensive Studies on the AIEt3／THF-Promoted Diastereoselective Tandem Rearrangement／Reduction of a-Hydroxy （Amino） Heterocyclopropane： An Efficient Approach to 2-Quaternary 1,3-Diheteroatom Units

A facile and highly diastereoselective method for the construction of 2-quaternary 1,3-amino alcohols and 1,3-diols has been developed on the basis of the AlEt3/THF-promoted tandem rearrangement/reductive reaction of α-hydroxy (amino) aziridines (epoxides). The progressive achievement in this article included that both 2-epimers of the units could be constructed from the initially same substrate. Also a stereochemistry assignment we reported previously was corrected.