Bismuth Trichloride–Catalyzed C‐Alkylation of Pyrroles with Electron‐Deficient Olefins

The BiCl₃‐catalyzed reaction of pyrroles with electron‐deficient olefins generated the corresponding Michael adducts in high yields.     

α-SUBSTITUIERTE PHOSPHONATE 52.1 SYNTHESE UND REAKTIONEN VON 1- ACETOXY-1-METHYLTHIOMETHAN PHOSPHORYLVERBINDUNGEN

Abstract

The 1-acetoxy-1-methylthiomethanephosphoryl compounds (4) are prepared from methylthiomethanephosphoryl derivatives (1) by electrolysis in 0.6 molar sodium acetate/acetic acid solution. The reaction of 1-acetoxy compounds (4) with halogen carriers gives the 1-halogen-1-methylthiomethane-phosphoryl derivatives 5, 7 and 8. The reaction of 4a under PTC-conditions results in cleavage of the P-C-bond.

Die 1-Acetoxy-1-methylthiomethanphosphoryl-Verbindungen (4) wurden aus Methylthiomethanphos-phorylderivaten (1) durch Elektrolyse in 0.6 molarer Na-acetat/Essigsäure-Lösung dargestellt. Die Reaktion der 1-Acetoxyverbindungen mit Halogenüberträgern führt zu den 1-Halogen-1-methyl-thiomethanphosphorylderivaten 5, 7 und 8. Bei Reaktion von 4a unter PTC-Bedingungen beobachtet man eine Spaltung der P-C-Bindung.     

Unexpected reactivity between aromatic nitro compounds and PCl3/AlCl3. A new one-pot synthesis of phenazines

The reaction between 4-nitroalkoxybenzenes 7 and PCl₃/AlCl₃, when carried out in appropriate molar ratio, gives a prevalent formation of diazenes 8 and 2,7-dialkoxyphenazines 9 with their new chlorinated derivatives 10-13. These compounds are obtained, in satisfactory yield, in a one-pot procedure, in mild conditions, from commercially available and safe starting materials. In this reaction both the reagents PCl₃ and AlCl₃ play a fundamental role in obtaining the products, and this method might be applicable to other 4-alkoxynitrobenzenes.     

气态污染物氯化氰的分光光度法测定

探索了氯化氰（CNCI）气体在不同介质中的稳定性和可吸收性,及光度测定条件,方法用于三聚氯氰工厂烟道气、车间空气及厂区空气中CNCI含量的测定。 结果满意。     

Reductive Cyclodimerization of α, β‐ Unsaturated Ketones Promoted by AlCl3/Sm System: A Facile Synthesis of 2‐Aroyl‐1,3,4‐triaryl Cyclopentanol Derivatives

Promoted by AlCl₃/Sm bimetallic system, α, β‐unsaturated ketones underwent reductive cyclodimerization to afford cyclopentanol derivatives under mild conditions. The reaction is stereocontrolled and regioselective over the competitive carbon‐carbon double bond reduction.     

A Mechanistic Study on the Formation of Dronic Acids

Dronic acid derivatives, important drugs against bone diseases, may be synthesized from the corresponding substituted acetic acid either by reaction with phosphorus trichloride in methanesulfonic acid as the solvent or by using also phosphorous acid as the P-reactant if sulfolane is applied as the medium. The energetics of the two protocols were evaluated by high-level quantum chemical calculations on the formation of fenidronic acid and benzidronic acid. The second option, involving (HO)₂P-O-PCl₂ as the nucleophile, was found to be more favorable over the first variation, comprising Cl₂P-O-SO₂Me as the real reagent, especially for the case of benzidronate.     

InCl3·4H2O Promoted Green Preparation of Xanthenedione Derivatives in Ionic Liquids

Xanthenediones derivatives have attracted considerable interests in recent times because they constitute a structural unit in a number of natural products1 and have been used as versatile synthons due to the inherent reactivity of the inbuilt pyran ring2. The conventional syntheses of xanthenediones were acid or base catalyzed condensation of appropriate active methylene carbonyl compounds with aldehydes3. However, many of these procedures involved longer reaction times,low yields and side reactions of aldehydes. In recent years, room temperature ionic liquids (RTILs) have been used as novel green reaction media4. Considering that InCl3 is an efficient Lewis acid catalyst used in promoting many organic reactions, especially in several condensation processes, we herein wish to report a very simple and green method for the preparation of poly-hydrogenated xanthenediones through InCl3·4H2O promoted cascade reaction of aldehydes and 5,5-dimethyl-l,3-cyclohexanedione in ionic liquid,1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]). The preparative process presented here is operationally simple, environmentally benign and has the advantage of enhanced atom utilization. Furthermore, the solvent and the catalyst used can be recovered easily and reused efficiently.     

Synthesis and Structures of Titanosiloxane Cage Compounds

Reaction of (triphenylmethyl)silanetriol (1) with cyclopentadienyltitanium trichloride (CpTiCl₃) in the presence of triethylamine as a HCl scavenger gave both compounds of a partial open-cage type {[Ph₃CSiO(OH)]₃(Ph₃CSiO_3/2)(CpTiO_3/2)₄} (2) and cube type (Ph₃CSiO_3/2CpTiO_3/2)₄ (3). The 1:1 reaction of 1 and CpTiCl₃ in toluene solvent at reflux temperature for 3 d afforded compounds 2 (22%) and 3 (36%). When 1 is reacted with a 1.5 fold excess of CpTiCl₃ under the same conditions, compound 3 was obtained in high yield (81%) along with 2 in trace quantities. Compounds 2 and 3 were fully characterized by the analyses of ¹H, ¹³C, ²⁹Si NMR, IR, and FAB MS data. The solid-state structure of 3 was determined by a single crystal X-ray diffraction study. Compound 3 had shown to have catalytic activity for the oxidation of alkenes such as 1-octene, cyclooctene, and norbornene with t-butyl hydrogen peroxide. The effect of solvent was observed in this epoxidation reaction. The order of reactivity were decreased as follows: CHCl₃ > hexane THF.