A facile synthesis of N-Z/Boc-protected 1,3,4-oxadiazole-based peptidomimetics employing peptidyl thiosemicarbazides

Synthesis of 1,3,4-oxadiazole containing peptidomimetics is described by a p-TsCl/pyridine-mediated cyclization of the corresponding dipeptidyl thiosemicarbazides, which are readily prepared by coupling N-protected amino acid hydrazides with amino acid-derived isothiocyanato esters. Further, the protocol has also been extended for the synthesis of orthogonally protected 1,3,4-oxadiazole tethered mimetics as well. The synthetic route is simple and mild conditions are used so that the chirality of the starting amino acids is retained. © 2010 Elsevier Ltd. All rights reserved

Synthesis and crystal structure analysis of 2-(4-fluorobenzyl)-6-phenylimidazo2,1-b1,3,4thiadiazole and its chlorophenyl derivative

Preparations of 2-(4-fluorobenzyl)-6-phenylimidazo2,1-b1,3,4thiadiazole (3a) and its chlorophenyl derivative (3b) are described. Preliminary analysis was done spectroscopically by means of 1H NMR, 13C NMR spectra, mass spectra and elemental analyses. Further the structures were confirmed by X-ray crystal structure analyses. The compound (3a) has crystallized in a triclinic P-1 space group with three independent molecules in the asymmetric unit, while the compound (3b) belongs to P21/c space group with one molecule in the asymmetric unit. The molecule (3b) differs from molecule (3a) by the presence of chlorine substituent. Additionally, the imidazo-thiadiazole entity is as usual planar. Intramolecular C-Hâ¯N hydrogen bonding between the imidazole and the phenyl ring of the molecule can be observed in (3a) & (3b). The molecules of (3a) are linked into two dimensional supramolecular hexagonal hydrogen bonded network sustained by C-Hâ¯F interaction, while those of (3b) are linked by bifurcated C-Hâ¯N interactions. Further, the molecular packing of both the compounds is stabilized by Ï-Ï stacking interactions between the benzene and imidazo-thiadiazole ring systems. © 2011 Elsevier B.V

Synthesis and Crystal Structure Analysis of 2-(Fluorobenzyl)-6-(4-Nitrophenyl) Imidazo[2,1-b][1,3,4]Thiadiazole

Preparation of 2-(4-fluorobexzyl)-6-(4-nitrophenyl)imidazo[2,1-b][1,3,4]thiadiazole is described and its crystal structure is discussed. The compound crystallizes in the monoclinic space group C2/c with a = 39.941(6) Å, b = 5.698(2) Å, c = 13.272(5) Å β = 90.880°, V = 3020(2) Å3, z = 8. The crystal structure is stabilized by weak intermolecular C-H…N,C-H…O,C-H…S, and C-H…F interactions

A convenient synthesis of 1,3,4-thiadiazole and 1,3,4-oxadiazole based peptidomimetics employing diacylhydrazines derived from amino acids

Synthesis of novel orthogonally protected 1,3,4-thiadiazole and 1,3,4-oxadiazole tethered dipeptide mimetics is described. Both the heterocycles are prepared via a set of diacylhydrazines derived from amino acids. 1,3,4-Thiadiazoles are synthesized by dehydrosulfurization using Lawesson's reagent while 1,3,4-oxadiazoles are obtained by EDC mediated cyclodehydration. © 2010 Elsevier Ltd. All rights reserved

Synthesis, spectroscopic and crystal structure analysis of 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)imidazo2,1-b1,3,4thiadiazole and its morpholinomethyl derivative

The preparation of 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)-5-morpholin-1-ylmethyl imidazo2,1-b1,3,4thiadiazole via the intermediate 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)Imidazo2,1-b1,3,4 thiadiazole is described. Elemental analysis, IR spectrum, 1H NMR and X-ray crystal structure analyses were carried out to determine the compositions and molecular structures of the two compounds. The crystal packing exhibits intermolecular C-H...O, C-H...N, C-H...F and Ï-Ï stacking interactions leading to the formation of the supramolecular network. © 2011

Synthesis, spectroscopic and crystal structure analysis of 2-amino-5,5-dimethyl-7-oxo-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile and-3-carboxamide

The preparation of 2-amino-5,5-dimethyl-7-oxo-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide via the intermediate 2-amino-5,5-dimethyl-7-oxo-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile is described, along with details of the crystal structure analysis of both compounds

3-{[6-(4-Chlorophenyl)imidazo[2,1-b][1,3,4]thiadiazol-2-yl]methyl}-1,2-benzoxazole

In the title compound, C18H11ClN4OS, the benzisoxazole and imidazothiadiazole rings are inclined at an angle of 23.81 (7)degrees with respect to each other. The imidazothiadiazole and chlorophenyl rings make a dihedral angle of 27.34 (3)degrees. In the crystal, intermolecular C-H center dot center dot center dot N interactions generate a chain along the c axis and C-H center dot center dot center dot O interactions form centrosymmetric dimers resulting in an R-2(2)(26) graph-set motif. Moreover, the C-H center dot center dot center dot N and S center dot center dot center dot N [3.206 (4) angstrom] interactions links the molecules into R(7) ring motifs. The packing is further stabilized by pi-pi stacking interactions between the thiadiazole rings with a shortest centroid-centroid distance of 3.497 (3) angstrom. In addition, C-H center dot center dot center dot pi interactions are observed in the crystal structur

Synthesis of Hybrid Peptidomimetics and Neoglycoconjugates Employing Click Protocol: Dual utility of Poc-group for inserting carbamate-triazole units into peptide backbone

Synthesis of new types of peptidomimetics and glycosylated amino acids possessing 1,2,3-triazole and carbamate moieties is described. Poc-protected amino acid esters/1-amino sugars were subjected to Cu(I) catalyzed 2+3cycloaddition with desired azides under click protocol to obtain novel peptide and carbohydrate mimetics. The reaction is rapid, efficient and all the products are isolated in good yield and excellent purity. © 2010 Springer Science+Business Media, LLC

Synthesis and crystal structure of 2-(4-Fluorobenzyl)-6-phenylimidazo2,1- b1,3,4thiadiazole-5-carbaldehyde

The crystal and molecular structure of 2-(4-fluoro-benzyl)-6-phenyl- imidazo2,1-b1,3,4thiadiazole-5-carbaldehyde is described. The compound crystallizes in the monoclinic space group P21/n with a=7.419(3), à b=8.287(3), à c=25.734(10)à , β=91.686(8)°, V=1,581.6(10)à 3, z=4. The crystal structure is stabilized by intermolecular C-HN, C-HO, and C-HF interactions. Copyright © Taylor & Francis Group, LLC