Synthesis of Some New Triphenylphosphanylidenes,Alkylphosphonates, and Heterocycles of Pyrazole Derivatives and Their Antimicrobial Activity

Abstract

The reaction of 5(4H)-pyrazolone with phosphorus ylides afforded new triphenylphosphanylidene alkanone derivatives. Moreover, its benzylidene derivative reacted with Wittig–Horner reagents to give the corresponding dialkoxyphosphoryl, alkyl phosphonate, and heterocyclic products. Treatment of pyrazole-4-carbaldehyde with Wittig–Horner reagents and trialkyl phosphites gave the respective alkyl phosphonate adducts. Mechanisms accounting for the formation of the new products are discussed. The biological activity of some of the newly synthesized compounds was also examined.     

Cyclic Ketones in Spiroannulation

Conversion of a cyclic carbonyl carbon into a quaternary carbon has been effected by a Wittig–Horner reaction with diethyl (N-benzyliden)aminomethylphosphonate and a subsequent alkylation with a protected vinyl ketone. The product was a substrate for spiroannulation after initial hydrolysis. The reaction sequence was carried out as a one-pot reaction.     

Synthesis,Photophysical Properties of Tribranched Chromophores Based on 1,3,5‐Triazine Core and Different Electro‐donating End‐groups

Three two‐photon absorption (TPA) tribranched chromophores were successfully prepared, in which 1,3,5‐triazine is been as electron deficient core, 1,4‐phenylenedivinylene as conjugated bridge, 3,4‐ethylenedioxythiophene (EDOT) ( T1 ), N‐methylpyrrole ( T2 ) or triphenylamine ( T3 ) as electron‐donating end‐groups. Their photophysical properties were studied by absorption, one‐ and two‐photon fluorescence and TPA cross‐section determination. The nonlinear transmission (NLT) measurement in femtoseconds (fs) regime at 800 nm indicates that TPA cross‐section (₂ values of T1 , T2 and T3 with extended Π‐conjugated bridge are much larger than the corresponding chromophore T4 with a short length bridge, and TPA cross‐section of T1 with end‐groups EDOT exhibits a remarkable enhancement compared with T2 and T3 having the same length Π‐system. The chromophores T1 , T2 and T3 show also remarkable up‐converted luminescence and optical limiting activity.     

An overview on synthetic strategies to coumarins

Coumarins units have recently emerged as a hot topic of research due to their diverse applications. Their synthesis is partly based on classical methodologies such as Pechmann reaction or Knoevenagel condensation, but it also sparked the discovery of completely new pathways. In very recent years so-called vertically expanded coumarins were synthesized, effectively expanding the portfolio of existing architectures. This review serves as a guide through synthesis strategies to coumarins.     

Concise Synthesis of P-Glycosyl Alkenylphosphonates and P,C-di and P,P,C tri-Glycosyl Phosphonates

A direct access to P-glycosyl-, P, P-di-glycosyl alkenylphosphonates and P, C-glycosyl phosphonates is described. The method involves the Horner reaction of an anion derived from P-monoglycosyl and P ¹, P′-diglycosyl methylenediphosphonates either on the exocyclic aldehyde group of carbohydrates or on the masked aldehydic form of the furanose hemiacetals. In this last case, the carbonyl olefination, followed by an intramolecular cyclization, leads to P,C-di and P,P,C-triglycosyl phosphonates.     

An Efficient Procedure for the Synthesis of Spiro (3H-Indole-3,4′ (1′H)pyrano[2,3-C]pyrrole]-5′-carbonitriles Using Solid Inorganic Supports and Microwave Activation

Microwave irradiation accelerates the Michael condensation of 3-dicyanomethylene-2H-indole-2-one with 2-pyrrolidone/ N-methy1-2-pyrrolidone (i) adsorbed on neutral alumina in “dry media” (ii) using absolute ethanol as energy transfer medium. 3-Dicyanoniethylene-2H-indol-2-one was synthesized under microwave irradiation using indole-2,3-dione and malononitrile. The results were compared with those obtained following the classical method. The advantages obtained by the use of microwave irradiation are demonstrated.     

Synthesis of Z‐N‐Alkenylformamides

Commercially available difluorinated benzaldehyde was converted to the Z‐N‐alkenylformamides via Horner–Emmons olefination and Curtius rearrangement, followed by reduction with tri‐tert‐butoxy‐aluminohydride.     

Concise Synthesis of Pentenyl Phenyl Acrylic Acid

Pentenyl phenyl acrylic acid is a structural unit of pepticinnamin E, a natural product and a bisubstrate inhibitor of FPTase. In this article, a new synthetic strategy was developed to prepare pentenyl phenyl acrylic acid with high stereoselectivity and high overall yield of 78.6%. The method used in producing these effects involved the application of a five‐step procedure. Pentenyl phenyl acrylic acid was synthesized starting from 2‐iodo‐benzyl alcohol through an E‐selective Wittig–Horner reaction, and then the Sonogashira reaction was used to produce 2‐(1‐pentynyl)‐E‐ethyl‐cinnamoylate, which was quantitatively hydrogenated, catalyzed by Lindlar catalyst.     

Facile Construction of the 7,8‐Olefin Linkage in Vitamin D3: A Practical Synthesis Benefiting the Vitamin D3 Analog Study

Abstract

A facile procedure for construction of the 7,8‐olefin linkage in vitamin D₃ is described. Treatment of a mixture of A‐ring phosphine oxide and CD‐ring ketone in THF with lithium hexamethyldisilazide (LHMDS) at ?20°C followed by gradual heating to 50°C gives the key intermediate of vitamin D₃ analogs in excellent yield. This simplified procedure makes possible small‐scale synthesis benefiting the vitamin D₃ analog study.     

Synthesis of (E)‐5‐Methoxy‐2‐styryl‐4‐pyrones as Potent Growth‐Inhibitory Agents Against Hepatocellular Carcinoma Cells

The present study a series of (E)‐5‐methoxy‐2‐styryl‐4H‐pyran‐4‐ones 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j was synthesized and evaluated for growth inhibitory inhibition against carcinoma cells. The growth inhibition study of eight carcinoma cell lines was examined and demonstrated that SKHep cells exhibit significant structure‐activity relationship in response to the tested compounds. Among them, 6f showed the most potent activity against SKHep, A549, AGS, and H460 cell lines with GI₅₀ values of 0.17, 8.3, 3.6, 8.0 μM, respectively.