Synthesis and N-Alkylation of 6-Benzyloxypurine Under Phase-Transfer Conditions

Synthesis of 6-benzyloxypurine and its N-alkylation under phase-transfer conditions represents a high-yield and simple procedure for the preparation of 9- and 7-substituted 6-benzyloxypurines and, therefore, related hypoxanthines.     

Rapid and Convenient Thioester Synthesis Under Phase-Transfer Catalysis Conditions

Various thioesters were obtained through an efficient phase-transfer catalysis method, by treating several thiophenols with different acyl chlorides, in a biphasic system composed of 10% aqueous NaOH and dichloromethane in the presence of tetrabutylammonium chloride. The thiolation reaction was complete in only 5 minutes, at 0°C.     

Facile Synthesis of Substituted N-Monoalkylaromatic Amines Under PTC Conditions

Substituted aromatic amides were alkylated under PTC conditions. Compounds with ortho electron withdrawing substituents furnished exclusively monoalkyl amines. A plausible mechanism has been suggested.     

Construction of Quaternary Carbon Center by Catalytic Asymmetric Alkylation of 3-Arylpiperidin-2-ones Under Phase-Transfer Conditions

A highly enantioselective synthesis of δ-lactams having a chiral quaternary carbon center at the α-position has been developed through an asymmetric alkylation of 3-arylpiperidin-2-ones under phase-transfer conditions. In this transformation, a 2,2-diarylvinyl group on the δ-lactam nitrogen atom plays a crucial role as a novel protecting group and an achiral auxiliary for improving both yield and enantioselectivity of the reaction.     

N-Alkylation of Phenobarbital Under Phase-Transfer Catalysis Conditions

This communication describes a convenient procedure for the preparation of alkylated derivatives of phenobarbital using phase-transfer catalysis without solvent conditions.     

Alkylation of 3-Acetylthiophene Under Phase-Transfer Conditions

Reactions of 3-acetylthiophene with C₁-C₄-alkyl iodides in a two-phase benzene/solid KOH system in the presence of l8-crown-6 afford di-C-alkylated derivatives-(3-thienyl)COCHR₂ in satisfactory yields (～50%) with high regioselectivity (70–100%).     

Simple Synthesis of Pyrroles Under Solvent-Free Conditions

Paal–Knorr condensation of 2,5-hexadione with primary amines in the presence of a catalytic amount of praseodymium(III) trifluoromethanesulfonate under solvent-free conditions has been accomplished with an excellent yield. This method is a very easy, rapid, and high-yielding reaction for the synthesis of N-substituted pyrrole derivatives.     

A Convenient Preparation of Diazo Carbonyl Compounds Under Tri-Phase Phase-Transfer Catalysis Conditions

A simple and convenient one-pot preparation method for pure diazo carbonyl compounds under tri-phase phasetransfer catalysis conditions is described.     

Synthesis and Spectral Characterization of 2-Mercaptobenzimidazole Derivatives Using a new Active Phase Transfer Reagent Under PTC Conditions

The phase transfer catalyzed synthesis of 2-Mercaptobenzimidazole derivatives using the new active phase transfer reagent namely, 2-benzilidine-N,N,N,N',N',N'-hexaethyl propane-1,3-dimonium dibromide (Dq-Br) have been described. The structures of all the fifteen compounds have been established by spectroscopic means.     

Catalytic Synthesis of 3-Alkoxyacrylic Acid Esters Under Neat Conditions

Triethylamine or Ph₃P (0.05 eq.) was found to catalyze the addition of alcohols to alkyl propiolates. The reaction occurred much more rapidly without solvent than in solvent. The E/Z ratio was relative to the reaction temperature. Water was found to inhibit the reaction.     

A Simple Method for the Synthesis of Acylated Pyranoid Glycals Under Aprotic Conditions

Abstract

Per-O-acylated glycals³ (1,4- or 1,5-anhydro-2-deoxyald-1-enitols, e. g., 9) represent one of the most useful types of carbohydrate derivatives available for various syntheses. The classical method⁴ for their preparation is the reaction of acetobromo sugars (e. g., 2) with zinc dust in aqueous acetic acid, but the yields are variable and solvolysis products, among others, are formed in side reactions.⁵     

A Conventent Synthesis of Functonalised Heterocuclic Enamines from Alpha-Thioiminium Salts and Active Methylene Compounds Under Solid-Liquid PTC Conditions

Functionalised enanines constitute a category of synthetic intermediates useful in carbon, carbon bond formation reactions and have been procured through a variety of condensaticn and extrusion reactions.¹ In one approach active methylene compounds have been condensed with lactin thioethers in the presence of a base at relatively higher temperature.^2,3 In view of our interest in the synthesis of function alised enamines through sulphur extrusion reactions⁴, we have studied the title reaction under non-hydrolytic solid-liquid PTC using solid KF(base)/TEBA(catalyst). A recent report⁵ on the sulphur extrusion of α -thio-iminium salts and their reactions with active methylene compounds prompts us to report our results.     

Stereocontrolled Preparation of (Z)-1,4-But-2-endiol Estersin Phase-Transfer Conditions

Isomerically pure esters of (Z)-1,4-but-2-endiol are prepared, in satisfactory yields, under phase-transfer conditions.     

A Simple Method for the Synthesis of Nitriles from Primary Amides Under Neutral Conditions

1-(3-Dimethylaminopropyl)-3-ethylcarbodiimidehydrochloride (EDCI) is a very useful reagent for the preparation of nitriles in good yields under neutral conditions.     

左旋多巴Schiff碱的合成及其不对称相转移催化烷基化

通过天然左旋多巴与不同芳香醛酮的反应, 合成出5种左旋多巴Schiff碱5a～5e, 其中5c～5e是文献中未见报道的化合物. 然后以这些左旋多巴Schiff碱为底物, 通过不对称相转移催化烷基化反应, 合成出具有光学活性的甲基多巴及其类似物. 同时, 研究探讨了不同相转移催化剂及不同反应条件对左旋多巴Schiff碱甲基化反应的影响.     

Synthesis of 2-substituted 3,4-bis(diethoxyphosphorylmethyl)furans

Bromination of ethyl 4-(diethoxyphosphorylmethyl)-5-methylfuran-2-carboxylate and 4-(diethoxyphosphorylmethyl)-5-methylfuran-2-carbonitrile with N-bromosuccinimide followed by phosphorylation via the Arbuzov reaction have yielded the corresponding 2-substituted 4,5-bis(diethoxyphosphorylmethyl)furans. Synthesis and transformations of bisphosphorylated 2-furoic acid and its derivatives are described.

     

The Synthesis of 1,3-bis(Phenylseleno)-2-Propanol Under Microwave Irradiation Conditions

A simple, rapid and efficient method for the synthesis of 1,3-bis(phenylseleno)-2-propanol under microwave irradiation is described.     

手性2-(口恶)唑烷酮的无溶剂合成法

在无溶剂条件下,手性的β-氨基醇和脲在160-180℃反应0．5-1 h,在200℃反应0．5 h,高产率地获得手性噁唑烷酮。     

Simple and Efficient Synthesis of 2-Aryl-2,3-Dihydroquinolin-4(1H)-ones Using Silica Chloride as a New Catalyst Under Solvent-Free Conditions

A mild, efficient, and high-yielding method for the synthesis of 2-aryl-2,3-dihydroquinolin-4(1H)-ones from their corresponding 2-amino chalcones using silica chloride (SiO₂Cl) under solvent-free conditions is described. A series of 2-aryl-2,3-dihydroquinolin-4(1H)-ones containing both electron-donating and electron-withdrawing substituents were synthesized.