Synthesis of Some New Thiazolo[3,2‐a]pyrimidine Derivatives and Their Applications as Disperse Dyes

A series of novel thiazolo[3,2‐a]pyrimidine derivatives were synthesized by using β‐ketoanilides 1a–c as starting materials and as key intermediates for preparation of new pyrimidinecompounds 3a–e and fused heterocyclic pyrimidine derivatives 5a–c . The new compounds were transformed to disperse dyes 6a,b and 7 . The chemical structures were elucidated by spectroscopic and elemental analyses and found to be in good agreement with the proposed structures. The versatility of compounds 6a,b and 7 for textile dyeing as disperse dyes was reported. The synthesized dyes were applied to polyester fabrics by using high temperature dyeing method at 120°C. The dye uptake expressed as color strength (k/s) of the dyed samples has been measured. Moreover, the color strength was examined in detail. In addition, the position of color in CIELAB coordinates (L*, a*, b*, h, and C*) was assessed. The color fastness of the dyed samples gave excellent results for washing and rubbing; however, the light fastness was moderate. Raman spectra of dyed samples unequivocally excluded ring dyeing and found to match with the proposed structures.     

A Convenient Synthetic Route of Diethyl (4‐Oxo‐chromeno[2,3‐d]pyrimidin‐2(5)‐yl)phosphonates

Novel diethyl (4‐oxo‐3,4‐dihydro‐2H‐chromeno[2,3‐d]pyrimidin‐2‐yl)phosphonate as two enantiomers and diethyl (4‐oxo‐1,5‐dihydro‐4H‐chromeno[2,3‐d]pyrimidin‐5‐yl) phosphonate were obtained in easy procedure via reaction of 2‐imino‐2H‐chromene‐3‐carboxamide, dimethylformamide dimethyl‐acetal, and diethyl phosphite in a simple one pot. Possible reaction mechanisms were proposed. The structures of the obtained products were confirmed by elemental analyses and spectral tools.     

Synthesis and Anticancer Evaluation of Some Novel Quinazolin‐4(3H)‐one Derivatives

A new series of quinazolinone derivatives bearing pyridine, pyrimidine, pyrazole, or pyran moieties were synthesized for the purpose of anticancer cell line evaluation. Synthesis of these derivatives was achieved by the reaction of the ketone 2 with the appropriate aldehydes in the presence of either ethylcyanoacetate or malononitrile and ammonium acetate in one‐pot reaction. Chalcones 6 reacted also with hydrazine hydrate to give the corresponding pyrazolines 7 and reacted with urea or thiourea to give the 2‐oxopyrimidines or the 2‐thioxopyrimidines 8 , respectively. Evaluation of some representative examples of the newly synthesized compounds against cancer cell lines showed promising activity as anticancer agents.     

Synthesis and Biological Evaluation of Glycosides and Acyclic Nucleosides Derived 2‐Oxonicotinonitriles

Synthesis and biological evaluations of a series of 2‐oxonicotinonitriles (2‐ONNs) derivatives are described. Incorporation of branching and solubilizing groups to the 2‐ONN derivative 7 was attained by coupling with several organo‐halides/alkylating agents including three glycosyl bromides under basic conditions. Coupling of 2‐ONNs occurred mainly at the ring nitrogen position and to a lesser extent at the 2‐oxo position giving the O‐alkylated products. Alkylated ONNs and free nucleosides/glycosides derived from the 2‐ONN derivative 7 were tested for their antibacterial, antifungal, and antiviral activities. N‐propargyl and N‐allyl derivatives 23 and 25 showed significant anti‐SARS‐CoV. The N‐butylacetate and O‐allyl derivatives 18 and 26 showed potent antibacterial activities against both Gram‐positive (Staphylococcus aureus, Micrococci luteus) and Gram‐negative (Pseudomonas aeruginosa, Escherichia coli) bacterial strains. The N‐glucoside derivative 8 showed significant antifungal activity.     

Ring Opening and Recyclization Reactions with Chromone‐3‐carbonitrile

Chemical transformations of chromone‐3‐carbonitrile ( 1 ) with some substituted hydrazines, namely, thiosemicarbazide, S‐methyl/benzyldithiocarbazate, 7‐chloro‐4‐hydrazinoquinoline, and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine, led to substituted pyrazoles 2 , 5 – 8 . Ring opening of carbonitrile 1 followed by recyclization with 3‐amino‐1,2,4‐triazole and 2‐aminobenzimidazole gave triazolo[1,5‐a]pyrimidine 9 and pyrimido[1,2‐a]benzimidazole 10 , respectively. Treatment of carbonitrile 1 with some heterocyclic amines produced 2‐amino‐3‐substituted‐chromones 11 and 12 . The novel 3‐hydroxychromeno[4,3‐b]pyrazolo[4,3‐e]pyridin‐5(1H)‐one ( 13 ) was efficiently synthesized from the ring conversion of carbonitrile 1 with cyanoacetohydrazide. A mixture of chromeno[2,3‐b]naphthyridine 14 and chromeno[4,3‐b]pyridine 15 was obtained from base catalyzed transformation of carbonitrile 1 with malononitrile dimer. A diversity of novel annulated chromeno[2,3‐b]pyridines 16 – 22 was also synthesized. Chromeno[2,3‐b]pyrrole‐2‐carboxylate 23 was obtained from the reaction of carbonitrile 1 with ethyl chloroacetate. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data.     

Cycloaddition of Aroyl Isothiocyanate: A Novel Synthesis of Triazine,Oxazine, Pyrimidine,and Pyridine Derivatives

A simple and direct synthetic methodology for a novel series of azines and their annulated systems was performed. Heterocyclization of acyl isothiocyanate 2 with urea or malononitrile gave s‐triazine 4 and 1,3‐oxazine 7 derivatives, respectively. The reaction of heteroallene 1 with acetylacetone tolerated 2‐thioxopyridine derivative 9 . The latter compound underwent heterocyclization with urea, hydrazine hydrate, or phenyl hydrazine to give the annulated pyridines 10 – 12 . Pyrimidinethione 14 was resulted from reaction of acylisothiocyanate with enamine 13 . Condensation of compound 14 with hydrazine hydrate, phenyl hydrazine, urea, and 3‐nitrobenzaldehyde in the presence of ethyl cyanoacetate or sodium hydroxide afforded 15 – 20 , respectively.     

Unusual behavior of 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one towards some phosphorus reagents: Synthesis of novel diethyl 2-phosphonochromone,diethyl 3-phosphonopyrone and 1,3,2-oxathiaphosphinines

The chemical reactivity of 3-(dimethylamino)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) towards some phosphorus reagents was studied. The enaminone 1 was cyclized into diethyl 2-phosphonochromone 2 via its treatment with diethyl phosphite in basic medium. However, its reaction with triethoxy phosphonoacetate gave the substituted pyrone phosphonate 3. In addition, two novel examples of 4-(dimethylamino)-6-(2-hydroxyphenyl)-2-sulfido-4H-1,3,2-oxathia-phosphinines 6 and 7 were obtained from treatment of enaminone 1 with O,O-diethyl dithiophosphoric acid and Lawesson’s reagent. When enaminone 1 was also treated with phosphorus decasulfide, it was turned into 4H-thiochromene-4-thione while its treatment with phosphorus tribromide, phosphorus oxychloride, or phenylphosphonic dichloride, 4H-4-oxo-chromene was isolated in all cases. The possible reaction mechanisms of the formation of these products were discussed. The structures of newly isolated products were established by elemental analysis and spectral tools.     

Study of γ‐Fast Neutron Attenuation and Mechanical Characteristics of Modified Concretes for Shielding and Sheltering Purposes

The study of γ‐neutrons attenuation and mechanical characteristics of modified concrete are vital and crucial parameters for the construction of civilian radiological, nuclear shielding, and/or shelters. In this work, fifteen samples of ordinary concretes with five different additives; steel fibers, polypropylene, silica fume, and fly ash, with variation of cement percentages, were prepared and used for performing the mechanical and radiation attenuation investigations. The compressive strength, tensile strength, slump test, bulk density, and water permeability were also carried out for the prepared concrete mixes. Collimated coherent beams from ⁶⁰Co and Pu‐Be fast neutron sources were used to check the radiation penetrability through the syntheized mixed concrete‐additives. Very sensitive and well calibrated gamma‐neutron pulse shape discriminating spectrometer with its electronic componenets and stilbene organic detector and 3′′ × 3′′ NaI scintillation crystal was used to measure the radiation before and after attenuation and transmission. The integrated fast neutron removal macroscopic cross section (Σ_r) and linear attenuation coefficient of total gamma rays (μ) were calculated for all the analysed concrete mixes. The results of measurements, tests, analyses and calculations are given and explained. The investigated modified concrete mixes show good workability and properties from the view point of mechanical loads and γ‐fast neutrons penetrability and resistance. These results can be used for shielding and sheltering design.     

Micropillar‐based microfluidic device to regulate neurite networks of uniform‐sized neurospheres

The inability of neurons to undergo mitosis renders damage to the central or peripheral nervous system. Neural stem cell therapy could provide a path for treating the neurodegenerative diseases. However, reliable and simple tools for the developing and testing neural stem cell therapy are still required. Here, we show the development of a micropillar‐based microfluidic device to trap the uniform‐sized neurospheres. The neurospheres trapped within micropillar arrays were largely differentiated into neuronal cells, and their neurite networks were observed in the microfluidic device. Compared to conventional cultures on glass slides, the neurite networks generated with this method have a higher reproducibility. Furthermore, we demonstrated the effect of thapsigargin on the neurite networks in the microfluidic device, demonstrating that neural networks exposed to thapsigargin were largely diminished and disconnected from each other. Therefore, this micropillar‐based microfluidic device could be a potential tool for screening of neurotoxins.     

Separation of organohalides from their microemulsions by the pervaporation technique: Application to the n-butyl bromide/SDS/n-butanol/water system

An n-butyl bromide/sodium dodecyl sulfate/n-butanol/water microemulsion system was chosen as a model of an organohalide-containing microemulsion. Two systems were prepared using the Bourayne method: a water-rich system and an n-butyl-bromide-rich system. The destabilization of this micro-organized system and the phase separation were investigated. This microemulsion, in which the oil phase in the feed is the lower layer, was successfully destabilized using the pervaporation technique with polydimethylsiloxane and poly(vinyl alcohol) membranes. In this way, different factors governing the separation process were investigated such as the mass transfer and the effect of time and operating temperature on the microemulsion destabilization.