Effect of reclaimed water and dehydrated sludge on the morpho-physiology and yield of sorghum

The effect on the morpho-physiological parameters and yield of sorghum cultivated in a greenhouse with reclaimed water (RW) and (dehydrated sludge (DS) obtained in a sewage treatment plant, was evaluated. Six treatments (T), with five repetitions each, were carried out in entirely randomized blocks. Water (W) was used in T1 (W) (control), T2 (W + NPK), and T3 (W + DS); RW was used in T4 (RW), T5 (RW + P), and T6 (RW + DS). The results showed that irrigation with only RW (T4), or W + DS (T3) was very suitable for the cultivation since an adequate nutritional supply was provided. The positive effects on the morpho-physiological parameters, plant height, stem diameter and stem length (in cm), were: T3 - 148.8, 1.50, and 103, respectively; T4 - 154, 1.70, and 107, respectively; and on the grain production in weight of 1000 seeds (g), and productivity in grains per plant: T3 - 6.97 and 1453, respectively; T4 - 6.81 and 1636, respectively. Both treatments showed for most of the parameters, no significant differences compared with those of T2 or T5 with supplementary fertilizers. A high production of metabolites (mg g-1) like free amino acids was also shown: T3 - 6.45; T4 - 8.43 and proline: T3 - 1.86; T4 - 1.77, known to be a good indication of a plant natural defence against stress conditions, and in soluble protein: T3 - 11.20; T4 - 13.51. Therefore, since the production of such grains with RW or DS can be environmentally and economically beneficial, their use is recommended for small and medium farmers in semiarid regions.

Pd(II)- and Pt(II)-Assisted P-C Activation/Cyclization Reactions with a Luminescent α-Aminophosphine

There is unceasing interest toward transformations of phosphine derivatives, which are facilitated by transition metals. We report a facile Pd(II)- and Pt(II)-assisted P-C bond cleavage in a luminescent 2-phenylbenzothiazole-based α-methylaminophosphine (PCN, 1). Specifically, reactions between 1 and [M(COD)Cl2] (M = Pd, Pt; COD = cycloocta-1,5-diene) in different solvents (methylene chloride, acetonitrile, pyridine, toluene) resulted in the formation of PPh2-, captured either as a bridging ligand in binuclear complexes with a {M2(PPh2)2} moiety or as an adduct to COD in [Pt2(PPh2COD)2Cl2]. The heterocyclic part transforms to annulated c-CN+ species with a 1,2-dihydroquinazoline cycle formed. In the presence of pyridine as a base, annulated form c-CN+ destabilizes and undergoes reverse cyclization transforming to deprotonated CN form. Quantum-chemical density functional theory (DFT) calculations predict that a crucial step in the reactions involves proton transfer from the N atom of the amino group of PCN to a neighboring molecule. A combination of high photophysical sensitivity of c-CN+ toward its immediate environment and rich structural capabilities in assembling (c-CN)22+ pairs in different crystal packings in a family of phases with the general formula (c-CN)2[M2(PPh2)2Cl4] allows one to fine-tune the luminescence properties of the latter. The results were rationalized as a variation of π-π intercationic spacings, which tunes the degree of excited-state charge transfer between c-CN+ cations. As a result, compounds with relatively short interplanar π-π-separation between the cations show a stronger charge-transfer-mediated bathochromic shift.

Sensitive 1,4-Disubstituted Nitro-Containing Cubanes: Structures and Properties

The cubane cage system is characteristic and well known for its high strain energy, qualifying it as a promising precursor for energetic materials. 1,4-Disubstituted cubanes are the easiest accessible derivatives. A further developed laboratory-scale procedure for cubane-1,4-dicarboxylic acid dimethyl ester is presented. From this central precursor, the bis-trinitroethyl and bis-nitromethyl esters as well as the bis-methylcarbamate and bis-methylnitrocarbamate were synthesized and characterized by multinuclear NMR spectroscopy and X-ray crystallography. In addition, their physical and energetic properties were determined and studied.

Diversity-Oriented Synthesis (DOS) of On-DNA Peptidomimetics from Acid-Derived Phosphonium Ylides

The DNA-encoded library (DEL) technology represents a revolutionary drug-discovery tool with unprecedented screening power originating from the association of combinatorial chemistry and DNA barcoding. The chemical diversity of DELs and its chemical space will be further expanded as new DNA-compatible reactions are introduced. This work introduces the use of DOS in the context of on-DNA peptidomimetics. Wittig olefination of aspartic acid-derived on-DNA Wittig ylide, combined with a broad substrate scope of aldehydes, led to formation of on-DNA α ${\alpha }$ , β ${\beta }$ -unsaturated ketones. The synthesis of on-DNA multi-peptidyl-ylides was performed by incorporating sequential amino acids onto a monomeric ylide. Di-, tri- and tetrameric peptidyl-ylides were validated for Wittig olefination and led to on-DNA α ${\alpha }$ , β ${\beta }$ -unsaturated-based peptidomimetics, an important class of intermediates. One on-DNA aryl Wittig ylide was also developed and applied to Wittig olefination for synthesis of on-DNA chalcone-based molecules. Furthermore, DOS was used successfully with electron-deficient peptidomimetics and led to the development of different heterocyclic cores containing on-DNA peptidomimetics.

Facile Synthesis of Iron-Based MOFs MIL-100(Fe) as Heterogeneous Catalyst in Kabachnick Reaction

An effective technique was proposed for the synthesis of novel α-aminophosphonates: a three-component one-pot condensation reaction of aniline, aromatic aldehydes, and triphenyl phosphite in the presence of (MIL-100(Fe)) as a heterogeneous catalyst. Initially, MIL-100(Fe) was synthesized using H3BTC and ferric nitrate at low temperature and atmospheric pressure. Further, MIL-100(Fe) was characterized using various techniques such as XRD, BET surface area, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), and thermogravimetric analysis (TGA). Herein, MIL-100(Fe) showed exceptional catalytic performance for the synthesis of α-aminophosphonate and its derivatives compared with conventional solid catalysts, and even homogeneous catalysts. The study demonstrated that MIL-100(Fe) is an ecofriendly and easily recyclable heterogeneous catalyst in Kabachnick reactions for α-aminophosphonate synthesis, with high yield (98%) and turnover frequency (TOF ~ 3.60 min−1) at room temperature and a short reaction time (30 min).

Stereoselective Synthesis of Dihydrocoumarins via [1,2]-Phospha-Brook Rearrangement in Three-Component Coupling Reaction of α-Ketoesters, o-Quinone Methides, and Dialkyl Phosphites

A highly regio- and diastereoselective approach for the synthesis of phosphate substituted dihydrocoumarins via Brønsted base catalyzed [1,2]-phospha-Brook rearrangement is reported. The two-step, one-pot Michael addition of α-phosphonyloxy enolates proceeds by coupling of dialkyl phosphite and α-ketoesters to o-quinone methides, followed by an intramolecular cyclization, providing 3,4-dihydrocoumarin frameworks.

Eco-Friendly Synthesis of Peptides Using Fmoc-Amino Acid Chlorides as Coupling Agent Under Biphasic Condition

BACKGROUND

Agro-waste derived solvent media act as a greener process for the peptide bond formation using N^α-Fmoc-amino acid chloride and amino acid ester salt with in situ neutralization and coupling under biphasic condition. The Fmoc-amino acid chlorides are prepared by the reported procedure of freshly distilled SOCl₂ with dry CH₂Cl₂. The protocol found many added advantages such as neutralization of amino acid ester salt and not required additional base for the neutralization, and directly coupling take place with Fmoc-amino acid chloride gave final product dipeptide ester in good to excellent yields. The protocol occurs with complete stereo chemical integrity of the configuration of substrates. Here, we revisited Schotten-Baumann condition, instead of using inorganic base.

OBJECTIVE

To develop green protocol for the synthesis of peptide bond using Fmoc-amino acid chloride with amino acid esters salt.

METHODS

The final product isolated is analyzed in several spectroscopic and analytical techniques such as FT-IR, ¹H-, ¹³C-NMR, Mass spectrometry and RP-HPLC to check stereo integrity and purity of the product.

CONCLUSION

The present method developed greener using natural agro-waste (lemon fruit shell ash) derived solvent medium for the reaction and not required chemical entity.

Asymmetric synthesis of the two enantiomers of β-phosphorus-containing α-amino acids via hydrophosphinylation and hydrophosphonylation of chiral Ni(ii)-complexes

A new approach for the synthesis of the two enantiomers of β-phosphorus-containing α-amino acids was developed via Michael addition of secondary phosphine oxides and dialkyl phosphites to chiral Ni(ii)-complexes of a dehydroalanine-Schiff base.

Unremitting progresses for phosphoprotein synthesis

Phosphorylation, one of the important protein post-translational modifications, is involved in many essential cellular processes. Site-specifical and homogeneous phosphoproteins can be used as probes for elucidating the protein phosphorylation network and as potential therapeutics for interfering their involved biological events. However, the generation of phosphoproteins has been challenging owing to the limitation of chemical synthesis and protein expression systems. Despite the pioneering discoveries in phosphoprotein synthesis, over the past decade, great progresses in this field have also been made to promote the biofunctional exploration of protein phosphorylation largely. Therefore, in this review, we mainly summarize recent advances in phosphoprotein synthesis, which includes five sections: 1) synthesis of the nonhydrolyzable phosphorylated amino acid mimetic building blocks, 2) chemical total and semisynthesis strategy, 3) in-cell and in vitro genetic code expansion strategy, 4) the late-stage modification strategy, 5) nonoxygen phosphoprotein synthesis.

Silver-Promoted Direct Phosphorylation of Bulky C(sp2)-H Bond to Build Fully Substituted β-Phosphonodehydroamino Acids

A general and practical cross-dehydrogenative coupling protocol between readily available trisubstituted α,β-dehydro α-amino carboxylic esters and H-phosphites is described. This C(sp²)-H phosphorylation reaction proceeds with absolute Z-selectivity promoted by silver salt in a radical relay manner. The bulky tetrasubstituted β-phosphonodehydroamino acids were obtained in grams and added new modules to the toolkit for peptide modifications.

Phosphonopeptides containing free phosphonic groups: recent advances

Phosphonopeptides are mimetics of peptides in which phosphonic acid or related (phosphinic, phosphonous etc.) group replaces either carboxylic acid group present at C-terminus, is located in the peptidyl side chain, or phosphonamidate or phosphinic acid mimics peptide bond. Acting as inhibitors of key enzymes related to variable pathological states they display interesting and useful physiologic activities with potential applications in medicine and agriculture. Since the synthesis and biological properties of peptides containing C-terminal diaryl phosphonates and those with phosphonic fragment replacing peptide bond were comprehensively reviewed, this review concentrate on peptides holding free, unsubstituted phosphonic acid moiety. There are two groups of such mimetics: (i) peptides in which aminophosphonic acid is located at C-terminus of the peptide chain with most of them (including antibiotics isolated from bacteria and fungi) exhibiting antimicrobial activity; (ii) non-hydrolysable analogues of phosphonoamino acids, which are useful tools to study physiologic effects of phosphorylations.

Side-Chain Modification of Peptides Using a Phosphoranylidene Amino Acid

The flexible variation of peptidomimetics is of great interest for the identification of optimized protein ligands. Here we present a general concept for introducing side-chain modifications into peptides using triarylphosphonium amino acids. Building blocks 4a and 4b are activated for amidation and incorporated into stable peptides. The obtained phosphoranylidene peptides undergo Wittig olefinations and 1,3-dipolar cycloaddition reactions, yielding peptidomimetics with vinyl ketones and 5-substituted 1,2,3-triazoles as non-native peptide side chains.