N‐Alkylation of imides using phase transfer catalysts under solvent‐free conditions

N‐Alkylation of imides in the reaction of imides and alkylhalides, catalyzed by PT catalysts under solvent‐free conditions, has been developed. The reaction occurs in the presence of K₂CO₃, and in many cases it takes place spontaneously. In the N‐benzylation reaction, it has been recognized that TBAB (tetrabutylammonium bromide) and TBATFB (tetrabutylammonium tetrafluoroborate) show highest catalytic effect. Versatility and synthetic capacity of the solvent‐free alkylation has been confirmed by N‐benzylation and N‐ethylation of various imides. The developed procedure gives easy access to N‐(ω‐bromoalkyl)imides.     

Iodine catalyzed synthesis of α,α'‐bis(substituted benzylidene)‐1‐carbethoxy‐4‐piperidone

A facile and efficient method for the preparation of α,α′‐bis(substituted benzylidene)‐1‐carbethoxy‐4‐piperidone is described using iodine as a catalyst in acetonitrile. The reaction proceeds rapidly at room temperature, giving high yields of products.     

4H‐1‐Benzopyrans by a tandem SN2‐SNAr reaction

Treatment of 2‐fluoro‐5‐nitrobenzyl bromide with active methylene compounds in the presence of excess potassium carbonate in acetone leads to the formation of highly functionalized 4H‐1‐benzopyrans by a tandem S_N2‐S_NAr reaction sequence. The reaction works well with β‐keto esters, β‐keto sulfones, β‐keto phosphine oxides, β‐keto phosphonates and β‐keto nitriles. The reaction is simple to perform and affords products in 50‐92% yields.     

A Soluble High Molecular Weight Copolymer of Benzo[1,2‐b:4,5‐b′]dithiophene and Benzoxadiazole for Efficient Organic Photovoltaics

The synthesis and characterization of a soluble high molecular weight copolymer based on 4,8‐bis(1‐pentylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene and 2,1,3‐benzoxadiazole is presented. High efficiency organic photovoltaic (OPV) devices comprised of this polymer and phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) were fabricated by additive processing with 1‐chloronapthalene (CN). When the active layer is cast from pristine chlorobenzene (CB), power conversion efficiencies (PCEs) average 1.41%. Our best condition—using 2% chloronapthalene as a solvent additive in CB—results in an average PCE of 5.65%, with a champion efficiency of 6.05%.

     

Ordered Honeycomb‐Structured Films from Dendronized PMA‐b‐PEO Rod‐Coil Block Copolymers

Summary: Fabrication of honeycomb‐patterned films from amphiphilic dendronized block copolymer (PEO₁₁₃‐b‐PDMA₈₂) by ‘on‐solid surface spreading’ and ‘on‐water spreading’ method is reported. Highly ordered honeycomb films with quasi‐horizontally paralleled double‐layered structure can be fabricated by the on‐solid surface spreading method. This work raises the possibility that such structures can be formed in amphiphilic dendronized block copolymers and extends the family of source materials.

     

Synthetic studies connected with the preparation of h+/k+‐ATPase inhibitors rabeprazole and lansoprazole

Synthesis of lansoprazole and rabeprazole using common intermediates is devised. The common intermediates, 2‐[(4‐nitro‐3‐methylpyridin‐2‐yl)methanesulfanyl]‐1H‐benzoimidazole and 2‐[(4‐chloro‐3‐methyl‐pyridin‐2‐yl)methanesulfanyl]‐1H‐benzoimidazole, were prepared in several ways.     

Phenacyl esters of acetic acid derivatives and their application for the synthesis of 2‐oxo‐4‐phenyl‐5‐(phenylhydrazono)‐2,5‐dihydro‐furan‐3‐derivatives

Coupling of various substituted phenacyl acetates 1 and diazonium salts 3 was studied. If the phenacyl acetates were substituted by an electronaceptor group such as CN or COOEt 3‐substituted phenyl‐5‐(phenyl‐hydrazono)‐5H‐furan‐2‐ones 4 were formed. Also synthesis of aza and diaza analogs is described. The compounds were characterized using MS and NMR spectroscopy.     

Synthesis and antimicrobial activity of new benzofuranyl‐1,3‐benzoxazines and 1,3‐benzoxazin‐2‐ones

New benzofuranyl‐1,3‐benzoxazines and 1,3‐benzoxazin‐2‐ones are synthesized in which benzofuran is coupled with 1,3‐benzoxazines and 1,3‐benzoxazin‐2‐ones through ‐CONH‐ and ‐COCH₂‐ bridges, respectively. The antimicrobial activity of these compounds is reported.     

Full Characterization and some reactions of 1‐(2‐adamantyl)‐3‐(1‐adamantyl)aziridin‐2‐one

We found that 1‐(2‐adamantyl)‐3‐tert‐butylaziridin‐2‐one ( 5a ) is unstable. It slowly decomposes at room temperature, although detectable by IR spectroscopy (1840 cm^?1 band in CCl₄). On the other hand, a closely related analogue, 1‐(2‐adamantyl)‐3‐(1‐adamantyl)aziridin‐2‐one ( 5b ), is very stable, in concurrence with an earlier report [1]. We fully characterized aziridinone 5b , identified its thermal decomposition products ( 7 and 8 ) and reacted it with two aprotic ionic (tBuO^? and HO^?) and one protic non‐ionic nucleophile (benzylamine). All three products ( 9b , 10 , and 11 ) result from exclusive cleavage of the lactam (1‐2) bond.     

A general and efficient route to 6‐methyl‐pyrazin‐2‐yl‐amines: Alkylation of 2,6‐dichloropyrazine via malonate derivatives

We have developed a convenient two‐stage process for the synthesis of 6‐methylpyrazine‐2‐yl‐amines from commercially available materials. The procedure involves the synthesis of (6‐chloro‐pyrazin‐2‐yl)‐acetic acid via arylation of diethyl malonate and in situ hydrolysis/decarboxylation. A second decarboxylation takes place under the subsequent amination conditions allowing simple and efficient access to the intended pyrazines.     

An efficient synthesis of 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐d]pyrimidines using zinc chloride/triethylamine reagent system

The one‐pot synthesis of 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐d]pyrimidines is described. The reactions of 2‐benzamido‐4,5‐dihydro‐3‐furan(and ‐3‐thiophene)carbonitriles 1a‐d and 2a‐c with ethanol and/or methanol in the presence of zinc chloride and triethylamine gave the corresponding 4‐alkoxy‐5,6‐dihydro‐furo(and ‐thieno)[2,3‐d]pyrimidines 3a‐d , 4a‐d , 5a‐c and 6a‐c .     

The synthesis and fluorescence of novel N‐substituted‐1,8‐naphthylimides

The synthesis and characterisation of a series of novel 4‐acylamino and 4‐alkylamino‐N‐1,8‐naphthalimides is described. The UV‐visible absorption and emission properties of the compounds are reported. Significant solvent effects are noted for 4‐n‐butyl‐9‐n‐butyl‐1,8‐naphthylimide. The incorporation of acetyl and chloroacetyl groups into the 4‐substituent markedly increases the fluorescence quantum yield compared with 4‐alkylamino substituemnts.     

Regioselective synthesis of N(3)‐ and O‐acylmethyl derivatives of 2‐methylthio‐4(3H)‐quinazolinone

Reaction of 2‐methylthio‐4(3H)‐quinazolinone with chloroacetone, ω‐bromoacetophenone or ethyl bromoacetate in different solvents (methanol, acetonitrile, dimethylformamide and toluene) using sodium methoxide or potassium carbonate as a base were studied. Regioselective N₍₃₎‐alkylation took place in toluene using potassium carbonate, whereas in dimethylformamide O‐acylmethyl derivatives were obtained. However chloroacetone reacted with 2‐methylthio‐4(3H)‐quinazolinone under various conditions to give a mixture of N₍₃₎/O‐isomers.     

Synthesis of boron macrocycles from 1,2‐aminoalcohols and 2‐formylphenylboronic acid

Condensation of aminoalcohols with 2‐HC(O)C₆H₄B(OH)₂ afforded the macrocyclic compounds 1–7 with an OBOBO structural unit. Crystals of 1 were triclinic, space group P‐1, a = 9.9818(12) Å, b = 12.8302(15) Å, c = 13.1663(15) Å, α = 105.503(2)°, β = 94.860(2)°, γ = 92.585(2)°, Z = 2.     

Synthesis and further studies of chemical transformation of the 2‐aryl‐3‐halogenoquinolin‐4(1H)‐one derivatives

The C‐3 brominated and iodinated derivatives were prepared from the corresponding 2‐arylquinolin‐4(1H)‐ones and their NMe‐4‐oxo derivatives using pyridinium tribromide in acetic acid or iodine‐Na₂CO₃ mixture in THF. The results of further studies of chemical transformation of the prepared α‐haloenones and preliminary antitumour activity of the 3‐bromo NH‐4‐oxo and NMe‐4‐oxo derivatives are also described.     

Cyclocondensation reactions of heterocyclic carbonyl compounds XII. The double course of cyclization of 3‐(2‐aminobenzyl)‐1,2‐dihydro‐quinoxaline‐2‐one

The cyclocondensation reaction of compound 1 in boiling hydrochloric acid had an unexpected course. Instead of supposed 5,11‐dihydro‐quinoxalino[2,3‐b]quinoline 6a , 2‐(indol‐2‐yl)‐benzimidazole 4 was isolated as the major product.     

Multi‐Morphological Complex Aggregates Formed from Amphiphilic Poly(ethylene oxide)‐block‐Polydimethylsiloxane‐block‐Poly(ethylene oxide) Triblock Copolymers

Summary: Amphiphilic triblock copolymers (PEO_x‐b‐PDMS_y‐b‐PEO_x) with different block lengths were synthesized and multi‐morphological complex crew‐cut, star‐like, and short‐chain aggregates were prepared by self‐assembly of the given copolymers. The morphologies and dimensions of the aggregates can be well controlled by variation of the preparation conditions. TEM, SEM, FFR‐TEM, and LLS studies show the resulting morphologies range from LCMs, unilamellar or multilayer vesicles, LCVs, porous spheres to nanorods.

TEM images of the vesicles formed from PEO‐b‐PDMS‐b‐PEO.     

Highly Asymmetric Phase Diagram of a Poly(1,2‐octylene oxide)–Poly(ethylene oxide) Diblock Copolymer System Comprising a Brush‐Like Poly(1,2‐octylene oxide) Block

The phase diagram of a series of poly(1,2‐octylene oxide)–poly(ethylene oxide) (POO–PEO) diblock copolymers is determined by small‐angle X‐ray scattering. The Flory–Huggins interaction parameter was measured by small‐angle neutron scattering. The phase diagram is highly asymmetric due to large conformational asymmetry that results from the hexyl side chains in the POO block. Non‐lamellar phases (hexagonal and gyroid) are observed near f_PEO = 0.5, and the lamellar phase is observed for f_PEO ≥ 0.5.

     

A New Crystal Form,Polymorphism, and Multi‐Morphology in Biodegradable Poly(3‐hydroxypropionate)

Summary: A new crystal morphology (δ form) of poly(3‐hydroxypropionate) (PHP) is found in cast and melt‐crystallized PHPs with low molecular weight, in which the PHP chains possibly adopt a 2₁ helix rather than the trans conformation found in the β or γ form. The fusion temperature‐ and the crystallization temperature‐dependent polymorphism are responsible for the dual morphologies and the unique growth kinetics of spherulites in the melt‐crystallized PHPs.

a) A dual‐morphology developed at 70 °C in PHP films after melting at 117 °C and b) that formed during cooling at a rate of 1 °C · min⁻¹ from 130 °C.