Volume 20, Issue 3

The heterocyclic hydroxylamine- O -sulfonates constitute a novel family of formal O -substituted hydroxyguanidines and hydroxyamidines that serve as functional precursors to a variety of fused heterocyclic ring systems incorporating N-N, N-O, N-S, or N-N + moiety. They are readily accessible from the reaction of 2-chloroazoles, 2-chloroazines, and 2-chlorodiazines with hydroxylamine- O -sulfonic acid. They have a rich chemistry exemplified by tandem reactions, such as nucleophilic addition-electrophilic amination, nucleophilic addition-electrophilic 5- endo-trig cyclization or fluorogenic Mannich-electrophilic amination reaction. The heterocyclic hydroxylamine- O -sulfonates have significant potential for use in synthesis of anticancer, antiviral, and antimicrobial agents. The newly discovered fluorogenic reaction and fluorescent dyes (Safirinium-P and Safirinium-Q) have found applications in fluorescent detection and labeling.

A series of pyridine derivatives were synthesized as potential inhibitors of chemokine receptor type 4. This chemokine receptor has been linked to various disease pathways including HIV-1 proliferation, autoimmune disorders, inflammatory diseases, and cancer metastasis. The compounds were tested for activity using an affinity binding assay and an assay that tests the ability to inhibit cell invasion. Two hit compounds ( 2b and 2j ) have been identified for further evaluation that inhibit cell invasion by at least 50% and have an effective concentration of less than 100 n m in the binding affinity assay. The structures of the synthesized compounds were confirmed by spectral data.

For a series of active phosphonate esters, the anhydride abbreviated as ANPTA ( 6a ) exhibits the highest reactivity in the preparation of ceftriaxone. The synthesis of ceftriaxone was optimized with the pilot-scale yield reaching 95.7%. The results were explained from the structural viewpoint and supported by analysis of the calculated Mulliken atomic charge distribution.

In the present investigation, the incorporation of the oxepine ring into a polycyclic-fused quinoline system leading to a series of structurally novel hybrids benzo[ h ]areno[6,7]oxepino[3,4- b ]quinolin-8(14 H )-ones has been achieved through a simple, and economical two-step procedure that involves the one-pot synthesis of 2-(aryloxymethyl)benzo[ h ]quinoline-3-carboxylic acids followed by intramolecular Friedel-Crafts acylation reaction using Eaton’s reagent.

2-Aminobenzothiazolinium nitrate ( 1 ) was characterized by elemental analysis, melting point, IR, 1 H NMR, and X-ray crystallography. The driving force for the 2-aminobenzothiazole tautomerism in methanol solution was studied using theoretical calculations. It is suggested that the 2-aminobenzothiazolinium cation is an intermediate product between the amino form ( 2 ) and imino form ( 3 ) of 2-aminobenzothiazole. The tautomerization reaction can proceed in two steps through protonation and deprotonation between the two forms 2 and 3 .

5-Aminothiazole-4-carboxamide is a precursor for the synthesis of thiazole [4,5- d ] pyrimidines. In this work, a new synthesis method with a high total yield (79%) of 5-aminothiazole-4-carboxamide was reported. The starting material is aminocyanacetamide. This synthesis method is environment-friendly and is suitable for industrial production.

One- and two-step syntheses of 2,2′-bibenzimidazole were compared. Diethylene glycol was used as solvent that provides good solubility of the substrates. The limitation of the one-step preparation is the formation of the by-product, fluoflavine. The two-step synthesis proceeds with the separation of the intermediate product, 1,4-dihydroquinoxaline-2,3-dione, and the final product is only 2,2′-bibenzimidazole. The total yield of the two-step synthesis is above 85%.

A novel, one-pot, simple, environmentally benign and efficient protocol has been employed for the synthesis of chromeno[4,3- b ]quinoline derivatives in the presence of catalytic amounts of Cu(II)-Schiff base/SBA-15 under solvent-free conditions in excellent yields and rates.

o -Formyl- m -hydroxycinnamic acid, the most oxidized salicylaldehyde-type phytotoxin isolated from rice blast fungus, Magnaporthe grisea , was synthesized for the first time using 5-(2,2-dimethyl-4 H -1,3-benzodioxin)methanol as the starting material, and the proposed structure was confirmed.