A concise approach to the spiroiminal fragment of marineosins A and B is described. The key steps involve an acid-catalyzed N-acyliminium ion cyclization and a Vilsmeier-Haack type reaction with Tf2O.

A series of benzaldehyde substituted phenyl carbonyl hydrazones has been synthesized and their formylation has been carried out by using Vilsmeier-Haack reaction. All the hydrazones and their formyl derivatives were screened for antibacterial activity.

A convenient and efficient method for selective replacement of the primary hydroxyl groups of sugars by chlorine with concomitant O-formylation, compatible with the presence of a variety of functional groups, has been developed using the Vilsmeier-Haack reaction. Sugars having free primary hydroxyl groups mostly afforded the chloro-O-formylated product while sugars devoid of primary hydroxyl gr...

The title compound, C(17)H(11)Cl(3)O, was synthesized via the Vilsmeier-Haack reaction. The dihydro-naphthalene ring system is non-planar, the dihedral angle between the two fused rings being 10.87 (13)°; it forms a dihedral angle of 81.45 (10)° with the dichloro-phenyl ring. The crystal structure features inter-molecular C-H⋯O hydrogen bonds.

Vilsmeier-Haack reaction of 2,3,3-trimethyl-3H-benzo[g]indole, then aqueous basic work-up, leads to benzo[g]indol-2-ylidene- malondialdehydes. These react with various arylhydrazines and quinolin-2-ylhydrazine to form 3,3-dimethyl-2-(1-aryl-1H-pyrazol-4-yl)- 3H-benzo[g]indoles in good yields.

The title compound, C(7)H(7)NO(2), was synthesized via a one-pot Vilsmeier-Haack and subsequent Friedel-Crafts reaction. The pyrazole ring makes dihedral angles of 4.50 (9) and 2.06 (8)°, respectively, with the aldehyde and acetyl groups. In the crystal, classical N-H⋯O hydrogen bonds and weak C-H⋯O inter-actions assemble the mol-ecules into a chain along the b axis.

An environmentally benign and practical preparation method for the Vilsmeier-Haack reagent (VH) has been developed by using phthaloyl dichloride with DMF in toluene or 2-chlorotoluene. Phthalic anhydride as the byproduct was recovered in high yield by simple filtration. Some aromatic acids have been transformed into the corresponding acid chlorides in good yields by employing the isolated VH. T...

vilsmeier-haack reaction of 2,3,3-trimethyl-3h-benzo[g]indole, then aqueous basic work-up, leads to benzo[g]indol-2-ylidene- malondialdehydes. these react with various arylhydrazines and quinolin-2-ylhydrazine to form 3,3-dimethyl-2-(1-aryl-1h-pyrazol-4-yl)- 3h-benzo[g]indoles in good yields.