Kachigere B. Harsha

Diastereoselective synthesis of fused oxazolidines and highly substituted 1H-pyrrolo [2,1-c][1,4] oxazines via C–H functionalization

The first one pot protocol for the diastereoselective synthesis of oxazolo[2,3-c]isoquinoline was achieved by a metal-free, benzoic acid catalyzed reaction of 1,2,3,4-tetrahydroisoquinoline or trypoline with aldehydes under mild conditions via C–H, C–O bond functionalization. A new approach for the synthesis of highly substituted 1H-pyrrolo[2,1-c][1,4]oxazine was carried out.

Easy access for the synthesis of 2-aryl 2,3-dihydroquinazolin-4(1H)-ones using gem-dibromomethylarenes as synthetic aldehyde equivalent

One step synthesis of 2,3-dihydroquinazolin-4(1H)-ones from gem-dibromomethylarenes using 2-aminobenzamide is described. Gem-dibromomethylarenes are used as aldehyde equivalent for the efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones, this synthesis takes shorter reaction time with quick isolation and excellent product yield.

Highly diastereoselective synthesis of polycyclic amines via redox neutral C–H functionalization

Synthesis of polycyclic amines was achieved by benzoic acid catalysed reaction of 1-aryl THIQs and 1-aryl trypolines with o-allyl salicylaldehydes through the in situ generated azomethine ylide intermediates that undergo intramolecular [3+2]-cycloadditions with four new stereogenic centers in excellent diastereoselectivities under simple and mild conditions.

One-step approach for the synthesis of functionalized quinoxalines mediated by T3P®–DMSO or T3P® via a tandem oxidation–condensation or condensation reaction

An easy and efficient propylphosphonic anhydride (T3P®)–DMSO or T3P® mediated oxidation–condensation or condensation reaction for the synthesis of quinoxalines derived from the interaction of different arrays of condensing partners with ortho-phenylene diamines (o-PDs) under simple and mild reaction conditions in one step has been reported for the first time.

Novel and Efficient Method for the Synthesis of Racemic Fexofenadine

Abstract Fexofenadine is a selective H1-histamine receptor antagonist, which is an attractive alternative treatment for allergy symptoms. An efficient and environmentally friendly synthetic approach for the preparation of fexofenadine was developed from commercially available cumene. The method involves the Friedel–Crafts reaction, substitution, reduction, bromination, and the Grignard reaction.

1-(2'-Ethoxy-4'-fluoro-[1,1'-biphenyl]-4-yl)-4-phenyl-1H-1,2,3-triazole

In the title compound, C22H18FN3O, the triazole ring is planar. The plane of the triazole ring makes dihedral angles of 19.31 (10), 20.52 (10) and 39.82 (9)° with the planes of the benzene rings, indicating the overall nonplanarity of the molecule. No classical hydrogen bonds were observed in the structure.

Three closely related 4,5,6,7-tetra­hydro-1H-pyrazolo­[4,3-c]pyridines: synthesis, mol­ecular conformations and hydrogen bonding in zero, one and two dimensions

In each of 1-(4-fluorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C21H19F4N3O2S, (I), 1-(4-chlorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C21H19ClF3N3O2S, (II), and 1-(3-methylphenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C22H22F3N3O2S, (III), the reduced pyridine ring adopts a half-chair conformation with the methylsulfonyl substituent occupying an equatorial site. Although compounds (I) and (II) are not isostructural, having the space groups Pbca and P212121, respectively, their molecular conformations are very similar, but the conformation of compound (III) differs from those of (I) and (II) in the relative orientation of the N-benzyl and methylsulfonyl substituents. In compounds (II) and (III), but not in (I), the trifluoromethyl groups are disordered over two sets of atomic sites. Molecules of (I) are linked into centrosymmetric dimers by C-H...π(arene) hydrogen bonds, molecules of (II) are linked by two C-H...O hydrogen bonds to form ribbons of R33(18) rings, which are themselves further linked by a C-Cl...π(arene) interaction, and a combination of C-H...O and C-H...π(arene) hydrogen bonds links the molecules of (III) into sheets. Comparisons are made with the structures of some related compounds.