Direct one-step synthesis of azaheterocyclic phosphonates from diethyl ω-chloro-1-alkynylphosphonates and hydrazines

Hydrazines react with 4-, 5- and 6-chloro-1-alkynylphosphonates to provide the corresponding azaheterocyclic phosphonates in good yields and purity. The suggested mechanism consists of initial addition to the carbon-carbon triple bond to generate a zwitterionic species in which the amine is situated trans to the lone pair of the anion.     

The Thermodynamic Links between Substrate,Enzyme, and Microbial Dynamics in Michaelis–Menten–Monod Kinetics

Accurate prediction of the temperature response of the velocity v of a biochemical reaction has wide applications in cell biology, reaction design, and biomass yield enhancement. Here, we introduce a simple but comprehensive mechanistic approach that uses thermodynamics and biochemical kinetics to describe and link the reaction rate and Michaelis–Menten constants (k_T and _T) with the biomass yield and mortality rate (_T and δ_T) as explicit functions of . The temperature control is exerted by catabolic enthalpy at low temperatures and catabolic entropy at high temperatures, whereas changes in cell and enzyme–substrate heat capacity shift the anabolic electron use efficiency e_A and the maximum reaction velocity v_max. We show that cells have optimal growth when the catabolic (differential) free energy of activation decreases the cell free energy harvest required to duplicate their internal structures as long as electrons for anabolism are available. With the described approach, we accurately predicted observed glucose fermentation and ammonium nitrification dynamics across a wide temperature range with a minimal number of thermodynamics parameters, and we highlight how kinetic parameters are linked to each other using first principles.     

Convenient synthesis of α,β-unsaturated phosphonates via a Mizoroki-Heck reaction of arylboronic acids with diethyl vinylphosphonate

Palladium acetate catalyzed Mizoroki-Heck reactions of arylboronic acids with diethyl vinylphosphonates afford α,β-unsaturated phosphonates in good yields.     

Design and synthesis of diethyl(substituted 2-benzylbenzofuran-3-yl)phosphonates as antioxidant and antimicrobial agents

In continuance of our effort to improve novel and potent synthetic approaches for various bioactive phosphorylated heterocycles via C─P bond formation, a series of diethyl substituted(2-benzylbenzofuran-3-yl)phosphonate derivatives ( 4a - j ) was synthesized by one-pot reaction of various diversely substituted salicylaldehydes, phenyl acetylene, and diethyl phosphite using CuO nanoparticles as catalyst in 1:1 ethanol and water under room temperature. The new compounds have been studied for their radical scavenging activity by DPPH, H₂O₂, and NO approaches and antimicrobial activity assay against bacteria and fungi by disk diffusion method.     

The preparation of some cyclic phosphonates and their use in olefin synthesis

The preparation and the use in olefin synthesis of two 5-membered cyclic phosphonates, 2-carbethoxy-methyl 4,5-dimethyle-2-oxo-1,3,2-dioxaphospholane (4b) and 2-cyanomethyl-4,5-dimethyl-2-oxo-1,3,2-diox-aphospholane (4c) and the 6-membered phosphonates, 2-carbalkoxymethyl-5,5-dimethyl-2-oxo-1,3,2-diox-aphosphorinanes (5a and 5b) and 2-cyanomethyl-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (5c) are described. Reactions of 4b with aromatic and aliphatic aldehydes lead to preferential formation of cis-olefins. Reactions of the other cyclic phosphonates with aldehydes lead to various mixtures of cis and trans olefins.     

The development for the synthesis of chiral acyclic nucleosides and their phosphonates

Acyclic nucleosides and their phosphonates possess significantly antiviral and cytostatic activities. For acyclic nucleosides and their phosphonates, the introduction of a chiral group to their side chain or the absolute configuration of the chiral atom could affect their biological activities obviously. Thus, the asymmetric synthesis of chiral acyclic nucleosides and their phosphonates has received continuous attention. The previous reports mainly focus on employing the chiral pool and chiral auxiliary methods for the synthesis of chiral acyclic nucleosides and their phosphonates. In contrast, the asymmetric catalysis methods for the synthesis of acyclic nucleosides and their phosphonates are still in the beginning. This digest paper will serve to highlight the significant progress that has been made in these areas.     

Stereoselective synthesis of GABOB,carnitine and statine phosphonates analogues

γ-Amino acids such as GABA, GABOB, statine and carnitine have attracted considerable attention as biologically active compounds. Over the last few years, significant interest in the stereoselective synthesis of γ-aminophosphonic acids GABOB^P, phosphocarnitine, phosphostatine and derivatives has been observed. An overview of synthetic approaches of γ-aminophosphonic acids and derivatives is presented. Data on the practical applications of the γ-aminophosphonic acids are also discussed.     

On the Michaelis–Menten behavior of pyridinium chloro chromate oxidations: Oxidation of dimethyl,dipropyl, and diphenyl sulfide in chlorobenzene–nitrobenzene mixtures

The kinetics of oxidation of dimethyl, dipropyl, and diphenyl sulfides by pyridinium chloro chromate in chlorobenzene–nitrobenzene mixtures are reported. The rate data show Michaelis–Menten behavior. The oxidation process is catalyzed by the organic acids like dichloro and trichloro acetic acids. The rate-determining step appears to be a unimolecular decomposition of a complex of the reactants.     

Synthesis of N-(alkoxycarbonyl or alkoxycarbonyl-methyl-alkoxyphosphonyl)-α-amino-O, O-diphenyl phosphonates and their bioactivities

With phosphonoformic acid (PFA) and its analog, phosphonoacetic acid (PAA), as the lead compounds, α-amino phosphonates were introduced into PFA and PAA. The derivatives of N-(alkoxycarbonyl-alkoxyphosphonyl)-α-amino phosphonates (I) and N-(alkoxycarbonyl-methyl-alkoxyphosphonyl)-α-amino phosphonates (II) with the N-terminal of amino phosphonates bonding to phosphorus atom of PFA andPAA were synthesized via the reaction of the corresponding phosphonyl chloride with α-amino phosphonates in the presence of a base. The³¹P NMR spectra of I and II were determined. It is found that the coupling constants³ J _pp with R³ being alkyl group were lower than those with R³ being (substituted) phenyl, and this result was discussed. The preliminary bioassay showed that some of the compounds I and II have better activities against tobacco mosaic virus (TMV). The inhibitory was higher than that of DHT (2, 4-dioxyhexahydro-1, 3, 5-triazine). In addition, some of the compounds showed the activity against cancer cells. Project supported by the National Natural Science Foundation of China.     

Unified total synthesis of pteriatoxins and their diastereomers

A unified total synthesis is reported to access all of the possible diastereomers of pteriatoxins A-C, with the use of an intramolecular Diels-Alder reaction as the key step to form the carbo-macrocyclic core structure. The C34/C35-diol protecting groups were found to have significant effects on both the exo/endo-selectivity and the exo-facial selectivity of the intramolecular Diels-Alder process.     

Mononuclear Schiff base boron halides: synthesis, characterization, and dealkylation of trimethyl phosphate

A series of mononuclear boron halides of the type LBX(2) [LH = N-phenyl-3,5-di-tert-butylsalicylaldimine, X = Cl (2), Br (3)] and LBX [LH2 = N-(2-hydroxyphenyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (7), Br (8); LH2 = N-(2-hydroxyethyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (9), Br (10); and LH2 = N-(3-hydroxypropyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (11), Br (12)] were synthesized from their borate precursors LB(OMe)2 (1) (LH = N-phenyl-3,5-di-tert-butylsalicylaldimine) and LB(OMe) [LH2 = N-(2-hydroxyphenyl)-3,5-di-tert-butylsalicylaldimine (4), N-(2-hydroxyethyl)-3,5-di-tert-butylsalicylaldimine (5), N-(3-hydroxypropyl)-3,5-di-tert-butylsalicylaldimine (6)]. The boron halide compounds were air and moisture sensitive, and upon hydrolysis, compound 7 resulted in the oxo-bridged compound 13 that contained two seven-membered boron heterocycles. The boron halide compounds dealkylated trimethyl phosphate in stoichiometric reactions to produce methyl halide and unidentified phosphate materials. Compounds 8 and 12 were found to be the most effective dealkylating agents. On reaction with tert-butyl diphenyl phosphinate, compound 8 produced a unique boron phosphinate compound LB(O)OPPh2 (14) containing a terminal phosphinate group. Compounds 1-14 were characterized by 1H, 13C, 11B, 31P NMR, IR, MS, EA, and MP. Compounds 5, 6, and 11-14 also were characterized by single-crystal X-ray diffraction.     

The total synthesis of (+)-16-hydroxydihydrocleav-amine and the partial synthesis of demethoxy-carbonyldeoxyvinblastine

The total synthesis of (+)-16-hydroxydihydrocleavamine and the partial synthesis of demethoxycarbonyldeoxyvinblastine are described.     

Facile synthesis of aliphatic hyperbranched polyesters based on diethyl malonate and their irreversible molecular encapsulation

Synthesis of diethyl malonate based wholly aliphatic hyperbranched polyesters having suitable polar matrix for irreversible molecular encapsulation is carried out for the first time.     

Microwave assisted synthesis of substituted furan-2-carboxaldehydes and their reactions

A series of 5-unsubstituted and 5-substituted furfurylidenes have been prepared, under thermal and non-thermal microwave irradiation methods, via condensation of furfural and its derivatives with some of active methylene compounds. Furthermore, various condensate products from these furfurylidenes, which contain halogen or sulpher atoms, were also prepared. Structural elucidation of the synthesized compounds were determined on the basis of various spectroscopic methods.     

Site‐selective synthesis and characterization of BODIPY–acetylene copolymers and their transistor properties

To study the effect of site‐selective copolymerization of borondipyrromethene (BODIPY) with acetylene on the structural and optoelectronic properties, three copolymers P1–P3 were synthesized by the Sonogashira cross‐coupling of BODIPY units with diacetylene and bromine capping through all the possible linkages: α‐α ( P1 ), α‐β ( P2 ), and β‐β ( P3 ). The optoelectronic properties of the polymers were investigated systematically to understand the effect of site‐selective polymerization. The HOMO levels of the polymers were significantly tuned from P1 to P3 with negligible change in the LUMO levels. Broadening of absorption spectra from P3 to P1 was observed because of increase in the extent of conjugation. Additionally, the charge transport properties of these polymers in organic thin‐film transistors (OTFTs) revealed that P1 and P3 exhibited only p‐type mobility, whereas P2 exhibited electron mobility. Notably, the further investigations of the surface morphology of polymer films by atomic force microscopy (AFM) unveiled that comb like nanostructural arrangements in P3 was beneficial for the charge‐carrier mobility over the circular arrangements in P1 and P2 . © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1978–1986     

Rational assembly of soluble copper(II) phosphonates: synthesis, structure and magnetism of molecular tetranuclear copper(II) phosphonates

The reactions of the dinuclear copper complexes [Cu(2)(L)(OAc)] [H(3)L = N,N'-(2-hydroxypropane-1,3-diyl)bis(salicylaldimine) or [Cu(2)(L')(OAc)] (H(3)L' = N,N'-(2-hydroxypropane-1,3-diyl)bis(4,5-dimethylsalicylaldimine)] with various phosphonic acids, RPO(3)H(2) (R = t-Bu, Ph, c-C(5)H(9), c-C(6)H(11) or 2,4,6-i-Pr(3)-C(6)H(2)), leads to the replacement of the acetate bridge affording tetranuclear copper(II) phosphonates, [Cu(4)(L)(2)(t-BuPO(3))](CH(3)OH)(2)(C(6)H(6)) (1), [Cu(4)(L)(2)(PhPO(3))(H(2)O)(2)(NMe(2)CHO)](H(2)O)(2) (2), [Cu(4)(L')(2)(C(5)H(9)PO(3))](CH(3)OH)(2) (3), [Cu(4)(L')(2)(C(6)H(11)PO(3)](MeOH)(4)(H(2)O)(2) (4) and [Cu(4)(L')(2)(C(30)H(46)P(2)O(5))](PhCH(3)) (5). The molecular structures of 1-4 reveal that a [RPO(3)](2-) ligand is involved in holding the four copper atoms together by a 4.211 coordination mode. In 5, an in situ formed [(RPO(2))(2)O](4-) ligand bridges two pairs of the dinuclear subunits. Magnetic studies on these complexes reveal that the phosphonate ligand is an effective conduit for magnetic interaction among the four copper centers present; a predominantly antiferromagnetic interaction is observed at low temperatures.     

Boron trifluoride–etherate mediated synthesis of 3-desoxyanthocyanidins including a total synthesis of tricetanidin from black tea

The synthesis of a series of 3-desoxyanthocyanidins via a BF₃·Et₂O-mediated aldol condensation between a substituted acetophenone and salicylaldehyde derivatives is described. Using this new synthetic methodology the synthesis of tricetanidin, a natural pigment isolated from black tea, was accomplished.     

Diverted total synthesis of melodorinol analogues and evaluation of their cytotoxicity

A series of melodorinol analogues were synthesized via a diverted total synthesis approach, leading to structural modifications on several regions of the molecule. Their cytotoxicity was evaluated against five human cancer cell lines (KB, HeLa-S3, MCF-7, HT-29 and A549). Structure-activity relationship studies revealed key parameters that affect the cytotoxicity. In particular, the novel 4-bromo-furanone analogues exhibited greater cytotoxicity compared to the corresponding non-brominated analogues. The stereochemistry at C-6 and the nature of acyl substituents on the C-6 and C-7 hydroxyl groups also play an important role. The most potent analogues exhibit approximately 15-fold higher cytotoxicity towards KB and HeLa-S3 than melodorinol and also show exceptionally high potency against MCF-7, HT-29 and A549 cell lines.