The title compound, C(23)H(18)N(2)O(2)·0.5H(2)O, a derivative of the biologically active compound curcumin, crystallizes with two organic mol-ecules and a solvent water mol-ecule in the asymmetric unit. Each of the two independent mol-ecules is close to being planar (the dihedral angles between the indole ring systems are approximately 9 and 12°) and each exists in the keto-enol form. There is ...

A novel and stereo-controlled method for the preparation of functionalized macrolactams was developed. The process involves stereoselective enol ether formation, followed by an azacyclic ring expansion via an aza-Claisen rearrangement. Herewith, we describe a systematic investigation of an aza-Claisen rearrangement-induced ring expansion of azacycles prepared by appending E/Z-enol ethers to the...

The emission transition dipole moments of single-molecule free-base phthalocyanines at an air/glass interface were visualized using defocused wide-field fluorescence microscopy at a temporal resolution of 100-200 ms. Isolated molecules showed slow proton tautomerization, which is consistent with previous theoretical calculations in the gas phase, which predicted large activation energies.

dacarbazine (dtic) is a synthetic chemical antitumor agent which is used to treat malignant melanoma and hodgkin’s disease. dtic is a prodrug which is converted to an active form undergoing demethylation by liver enzymes. the active form prevents the progress of disease via alkylation of dna strand. in the structure of this drug, the imidazole ring, a triazen chain and carboxamide group exist. ...

2-((2-Hidroksibenziliden)amino)-4-nitrofenol Schiff bazı bileşiğinin konformasyon analizi; DFT yönteminde, B3LYP metodu ve 6-311G++(d,p) temel seti ile yapılmış bileşiğin cis trans izomerlerinin konformasyonları teorik olarak hesaplanarak en kararlı konformasyonlar belirlenmiştir. Toplam enerjileri dihedral açıları keto enol formlarının tautomer kararlılıkları Enol formundaki molekülün formuna ...

Tautomerization of amino acids between the neutral form (NF) and the zwitterionic form (ZW) in water has been extensively studied, often using glycine as a model to understand this fundamental process. In spite of many advanced studies, the tautomerization reaction remains poorly understood because of the intrinsic complexities of the system, including multiple accessible reaction pathways, cha...

[chemical reaction: see text]. A direct and general synthesis of alpha-branched aldehydes and their enol derivatives is described. Carbocupration of terminal alkynes and subsequent oxygenation with lithium tert-butyl peroxide generates a metallo-enolate. Trapping with various electrophiles provides alpha-branched aldehydes or stereo-defined trisubstituted enol esters or silyl ethers. The tandem...

A tandem rhodium-catalyzed Bamford-Stevens/Claisen rearrangement is presented. The tandem reaction uses Eschenmoser hydrazones for the in situ generation of non-carbonyl-stabilized diazo alkanes, which are presumably intercepted by Rh(II) catalysts to induce a 1,2-hydride migration. This sequence provides high levels of stereocontrol for the generation of simple acyclic (Z)-enol ethers. These e...

5. The rate of synthesis of 2-naphthyl sulphamate by rat-liver preparations is increased by about 400% by 17-oxo steroids in concentrations of approximately 10-5M. 6. The rate ofsynthesis ofsulphamate byguineapig preparations is not increased by 17-oxo steroids. 7. It is suggested that the mechanism of this activation involves the formation of steroid 17-enol sulphates and that these enol sulph...

Arylation reactions are an important class of and allow the synthesis natural synthetic products. Despite efficient, but high cost toxic methodologies involving transition metals, radical arylations have gained importance after advent photoredox catalysis. enol acetates is tool for obtaining aryl ketones scope reaction limited to pattern substitution at phenyl α-carbon enol. Theoretical calcula...