Synthesis and Herbicidal Activity of Novel Pyrimidinyl Derivatives Containing an α-Amino Phosphonate Moiety

In order to find novel pyrimidinyl carboxylic acid analogs with high activity and low toxicity, a series of novel pyrimidinyl derivatives containing an α-amino phosphonate moiety 5 was synthesized by the condensation of 4-(4,6-dimethoxypyrimidin-2-yloxy)phenoxyacetic 3a or propionic acids 3b with dialkyl α-amino substitutedbenzyl phosphonates 4. Their structures were characterized by spectroscopic data (IR, ¹H NMR, ³¹P NMR, MS) and elemental analyses. The results of preliminary herbicidal activities (in vitro) showed that most of these compounds exhibited higher herbicidal activities against dicotyledonous weeds (Brassica campestris L) than monocotyledonous weeds (Echinochloa crus-galli). Further bioassays (in vivo) indicated that some of compounds 5 possessed selective herbicidal activity against amaranth pigweed (A. retroflexus) in post-emergence treatment.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis,Structural, and Antibacterial Studies of Some Mixed Ligand Complexes of Zn(II), Cd(II), and Hg(II) Derived From Citral Thiosemicarbazone and N-Phthaloyl Amino Acids

A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with cis-3,7-dimethyl-2,6-octadienthiosemicarbazone (CDOTSC; LH) and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal dichloride with ligands CDOTSC and N-phthaloyl derivative of DL-glycine (A₁H), L-alanine (A₂H), or L-valine (A₃H) in a 1:1:1 molar ratio in dry refluxing ethanol. All the isolated complexes have the general composition [M(L)(A)]. The plausible structure of these newly synthesized complexes has been proposed on the basis of elemental analyses, molar conductances, molecular weight measurement, and various spectral (IR, ¹H NMR, and ¹³C NMR) studies, and four coordinated geometries have been assigned to these complexes. All the complexes and ligands have been screened for their antibacterial activity.     

STUDIES IN THE HETEROCYCLIC COMPOUNDS V1. SOME REACTIONS OF 5-CHLORO-2-THIOPHENESULFONYL DERIVATIVES

Abstract

The reactions of 5-chloro-2-thiophenesulfonyl chloride are described. Treatment of the sulfonyl chloride with ammonia, hydrazine hydrate, sodium azide, indole and imidazole gave the sulfonamides (5), sulfonohydrazide (4), sulfonyl azide (3), 1-(5-chloro-2-thiophenesulfonyl)indole (27) and 1-(5-chloro-2-thiophenesulfonyl)-imidazole (26), respectively. The sulfonyl chloride was reacted further with 20 aryl-and cycloalkyl-amines to give the corresponding sulfonamides (6)-(25). Attempted chlorination of the sulfonyl chloride (2) with sulfuryl chloride or bromination of the sulfonyl azide (3) with pyridinium bromide perbromide failed. However, nitration of the sulfonyl chloride (2) with fuming nitric acid gave the 4-nitro-sulfonyl chloride (28), which with sodium azide afforded the 5-chloro-4-nitro-sulfonyl azide (29). The sulfonyl azides, (3) and (29), have been reacted with triphenylphosphine, triethylphosphite, norbornene and cyclohexene. The azides reacted further with indole and 1-methylindole to give the 2-sulfonyl-iminoindolines (34)-(36). The infra-red spectra and mass spectra of some of the substituted thiophenesulfonyl derivatives are discussed.     

The Synthesis and Bioactivity of Dimethyl (2,3- Dihydrobenzo[b][1,4]Dioxin-6-Yl)(Aryl Amino)Methylphosphonates

Abstract

A new series of α-aminophosphonates have been synthesized by a one-pot three-component reaction of 2,3-dihydrobenzo[b][1,4]dioxine-6-carbaldehyde, various amines, and dimethyl phosphite by using nano-TiO₂ as a catalyst under solvent-free conditions at 50°C. The major advantages of the present method are high yields, short reaction times, recyclable catalyst, and solvent-free reaction conditions. Among these new structurally diversified set of α-aminophosphonates, dimethyl (2,3-dihydrobenzo[b][1,4]dioxin-6-yl)(3-nitrophenylamino) methylphosphonate and dimethyl (2,3-dihydrobenzo[b][1,4]dioxin-6-yl)(4-fluoro-3-nitro-phenyl-amino) methylphosphonate have shown higher antioxidant activity in diphenyl picryl hydrazyl (DPPH) scavenging, reducing power assay, and lipid peroxidation methods.     

Synthesis and Herbicidal Activity of O,O-Diethyl N-{4-Methyl-[1,2,3]thiadiazole-5-carbonyl}- 1-amino-1-substitutedbenzyl Phosphonates

Target compounds 3 were synthesized by the condensation of O,O-diethyl α-amino substitutedbenzyl phosphonates 1 and 4-methyl-[1,2,3]thiadiazole-5-carboxylic acid 2 in the presence of dicyclohexylcarbodiimide (DCC) as a dehydration reagent. Their structures were confirmed by spectroscopic data (IR, ¹H NMR, ³¹P NMR, MS) and elemental analysis. The results of a preliminary bioassay (in vitro) indicated that some of the title compounds 3 possessed moderate to good herbicidal activities against dicotyledonous plants (Brassica campestris L) at the concentration of 100 mg/L, and most of these compounds exhibited higher herbicidal activities against dicotyledonous plants (Brassica campestris L) than monocotyledonous plants (Echinochloa crus-galli).

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and In Vitro Anti-HIV Activity of Some New Schiff Base Ligands Derived from 5-Amino-4-phenyl-4H-1,2,4-triazole-3-thiol and Their Metal Complexes

New Schiff base ligands (6–9) derived from 5-amino-4-phenyl-4H-1,2,4-triazole-3-thiol 1 and substituted benzaldehydes (2–5) as well as their metal complexes with Cu(II), Fe(II), Au(III), and Mn(II) (12–17) have been synthesized. A new benzothiazole derivative (11) was prepared from coupling of 7 with N-(benzothiazol-2-yl)-2-chloroacetamide 10. Their spectral properties were investigated. The newly designed and synthesized Schiff base ligands and the metal complexes were assayed for anti-HIV-1 and HIV-2 activity by examination of their inhibition of HIV-induced cytopathogenicity in MT-4 cells. Compounds 11 and 16 were found to be the most active inhibitors in cell culture (EC₅₀ = 12.2 μg/mL (SI = 4) and > 2.11 μg/mL (SI = > 1), respectively) against HIV-1, whereas 11 showed inhibition against HIV-2 of EC₅₀ > 10.2 μg/mL with SI = 9, which provided a good lead for further optimization.     

1-AMINO-1-ARYL- AND 1-AMINO-1-HETEROARYL-METHANEPHOSPHONIC ACIDS AND THEIR N-BENZHYDRYL–PROTECTED DIETHYL ESTERS: PREPARATION AND CHARACTERIZATION

n-Benzhydryl-protected diethyl[3.3pc] esters of 1-amino-1-aryl- (phenyl, cumyl, p-dimethylaminophenyl, piperonyl, 1′-naphthyl, 9′-anthryl, 1′-pyrenyl) and 1-amino-1-heteroaryl- (furyl, 2′-thienyl, 3′-thienyl, 2′-pyrrolyl)-methanephosphonic acids, prepared by the addition of diethyl phosphite to the corresponding benzhydryl imines, have been isolated, purified, and characterized. The presence of chiral α -carbon and prochiral phosphorus in these esters gives rise to complicated features in their NMR spectra, which are discussed. Hydrolysis of the crude 1-aryl compounds in situ gave modest yields of the corresponding aminophosphonic acids (except for 1′-pyrenyl). Of the 1-heteroaryl derivatives, only the 2′-thienyl compound gave the expected aminophosphonic acid; in other cases, alternative[-18pc] modes of decomposition may occur under hydrolytic conditions. NMR and mass spectral data are given for all products.     

A STUDY OF THE PHOTOPHYSICAL AND PHOTOCHEMICAL PROPERTIES OF THE S8 MOLECULE Photochemical Reactions in the S8 + Liquid Methanol System with and without Sensitizers: Benzene,Naphthalene and Pyrene. II

Abstract

The photochemical reactions occurring in the system S₈ + CH₃OH in the liquid phase were investigated, in the presence of, and without sensitizers. The experimental conditions were identical with those employed in studying the quenching of fluorescence.¹

The decay of S₈ is more rapid in the presence of sensitizers (the quantum yield and the degree of conversion are higher). In the system studied irradiation by UV light (λ 254 nm) causes the formation of (CH₃)₂S and of trace amounts of CH₄ and C₂H₆. The process of S₈ decay is of a mixed kinetic character—a pseudo 1st order process predominating, with a contribution from a 2nd order reaction. A possible reaction scheme, associated with excitation energy transfer from sensitizers to S₈ is discussed.     

Heterocyclization of 5-aminothieno[2,3-c]pyridazine-6-carbonitriles

Abstract

This review describes the synthesis and reactions of 5-aminothieno[2,3-c]pyridazine-6-carbonitriles as a building blocks for the synthesis of polyfunctionalized heterocyclic compounds. The antimicrobial activity of some compounds are discussed.