Yeldez El Kilany

Bio: Yeldez El Kilany is an academic researcher from Alexandria University. The author has contributed to research in topics: Ascorbic acid & Hydrazone. The author has an hindex of 13, co-authored 50 publications receiving 465 citations. Previous affiliations of Yeldez El Kilany include Umm al-Qura University.

Recent Advances in the Dimroth Rearrangement: A Valuable Tool for the Synthesis of Heterocycles

Abstract: Publisher Summary The Dimroth rearrangement (DR) is a translocation of two heteroatoms in a heterocyclic system, with or without changing its ring structure The conversion of a heterocycle to a rearranged isomeric product can give one or two isomers via anintermediate, which selectively or specifically forms one of them as the major one The stability of the rearranged product is the driving force for its formation, which may lead to the preference of one isomer The heteroatoms which exchange positions in the rearrangement are S, N, O, and Se DR can be divided into two types based on the positions of the translocating heteroatom(s): either both in the ring or one in the ring and the other located in an exocyclic position of that ring This chapter discusses the translocation of heteroatoms between rings in fused heterocycles, and the translocation of exo-and endo-heteroatoms within a heterocyclic ring In the process of rearrangement by translocation of heteroatoms between rings in fused heterocycles, the translocated heteroatoms are part of the ring The translocation process changes the position of the heteroatom or the substituent on that ring leading to either a retained or a changed ring structure The presence of a heteroatom within a five-membered ring and also at an exocyclic position of the adjacent ring is a promoting factor for the rearrangement In the translocation of exo-and endocyclic heteroatoms in heterocyclic rings the translocation of heteroatom X (endocyclic in the ring) and Y (exocyclic to the ring) takes place during the rearrangement All the processes are driven by the stability of the product, solvent, aromaticity of the ring, heteroatom valence, and bulkiness of the substituent

Synthesis and Crystal Structures of Benzimidazole-2-thione Derivatives by Alkylation Reactions

Abstract: Alkylated, benzylated and bromoalkylated benzimidazole-thione that intramolecularly heterocyclized to 3,4-dihydro-2H-[1,3]thiazino[3,2-a]benzimidazole were synthesized. The chemical structure of the synthesized product was characterized by Infra Red, ¹H-NMR, (13)C-NMR, and Mass spectroscopy. Furthermore, the molecular structures of 8 and 9 were confirmed by X-ray single crystallography in different space groups, Pbca and P2₁/c, respectively.

Chapter 1 Dimedone: A Versatile Precursor for Annulated Heterocycles

Abstract: Publisher Summary This chapter explores that dimedone is a versatile precursor for annulated heterocycles. Dimedone(1) is an alicyclic compound having 1,3-dicarbonyl groups flanked by a methylene group and exists in a tautomeric transenolized form where intramolecular hydrogen bonding is not possible. Dimedone is an excellent precursor for partially hydrogenated fused heterocycles where two of the carbon atoms of dimedone are part of the backbone of the formed heterocycles. The chapter illustrates that dimedone's structural features and its reactivity to form more functionalized derivatives have led to the construction of a wide range of fused or spiral biheterocycles. Finally, this chapter emphasizes the role of 1 in the synthesis of fused heterocycles, classified according to the size of the ring and the number of heteroatoms in the heterocycle fused to the cyclohexane ring and subdivided according to the heteroatoms and their arrangement in the ring.

Histone deacetylase inhibitors

Abstract: Histone deacetylase is a metallo-enzyme with zinc at the active site. Compounds having a zinc-binding moiety, such as, for example, a hydroxamic acid group or a carboxylic acid group, can inhibit histone deacetylase. Histone deacetylase can repress gene expression, including expression of genes related to tumor suppression. Accordingly, inhibition of histone deacetylase can provide an alternate route for treating cancer, hematological disorders, e.g., hemoglobinopathies, and genetic related metabolic disorders, e.g., cystic fibrosis and adrenoleukodystrophy.

Synthesis and antiviral evaluation of some sugar arylglycinoylhydrazones and their oxadiazoline derivatives.

Abstract: Sugar N-arylaminoacetylhydrazones 2-5 were prepared by the reaction of N-arylaminoacetylhydrazides 1 with equivalent amounts of the corresponding monosaccharides. Per-O-acetyl derivatives 6-9 of sugar hydrazones 2-5 were prepared by using acetic anhydride in pyridine at room temperature, while on boiling with acetic anhydride, cyclization had taken place to give the oxadiazolines 10-12. The prepared compounds were tested for antiviral activity against Herpes Simplex virus type-1 (HSV-1) and hepatitis-A virus (HAV, MBB-cell culture adapted strain). Plaque reduction infectivity assay was used to determine virus count reduction as a result of treatment with tested compounds.

Genetics in Keratoconus: where are we?

Abstract: Keratoconus (KC) is a non-inflammatory thinning and protrusion of the cornea in which the cornea assumes a conical shape. Complex etiology of this condition at present remains an enigma. Although environmental factors have been involved in KC pathogenesis, strong underlining genetic susceptibility has been proven. The lack of consistent findings among early genetic studies suggested a heterogeneity and complex nature of the genetic contribution to the development of KC. Recently, genome-wide linkage studies (GWLS) and genome-wide association studies (GWAS) were undertaken. Next-generation sequencing (NGS)-based genomic screens are also currently being carried out. Application of these recently developed comprehensive genetic tools led to a much greater success and increased reproducibility of genetic findings in KC. Involvement of the LOX gene identified through GWLS has been confirmed in multiple cohorts of KC patients around the world. KC susceptibility region located at the 2q21.3 chromosomal region near the RAB3GAP1 gene identified through GWAS was independently replicated. Rare variants in the ZNF469 gene (mutated in corneal dystrophy Brittle Cornea Syndrome) and in the TGFBI gene (mutated in multiple corneal epithelial–stromal TGFBI dystrophies) have been repeatedly identified in familial and sporadic KC patients of different ethnicities. Additional comprehensive strategies using quantitative endophenotypes have been successfully employed to bring further understanding to the genetics of KC. Additional genetic determinants including the COL5A1 gene have been identified in the GWAS of KC-related trait central corneal thickness. These recent discoveries confirmed the importance of the endophenotype approach for studying complex genetic diseases such as KC and showed that different connective tissue disorders may have the same genetic determinants.