Process for the preparation of azidobenzal compounds

Claim 1

A process for preparing a 2,6-bis-((4-azidophenyl)-methylene)-cyclohexanone of the formula ##STR7## wherein R is hydrogen or alkyl of 1-6 C atoms, comprising (a) freshly preparing 4-aminobenzaldehyde by reacting 4-nitrotoluene with sodium sulfide and sulfur in aqueous-alcoholic sodium hydroxide solution and removing unreacted 4-nitrotoluene, whereby there is produced 4-aminobenzaldehyde substantially uncontaminated by products of self-condensation; (b) directly after step (a), condensing the residual 4-aminobenzaldehyde, without purification, with a cyclohexanone of the formula ##STR8## wherein R is as defined above, in the presence of an alkaline condensing agent, whereby there is prepared a 2,6-bis-((4-aminophenyl)-methylene)-cyclohexanone of the formula ##STR9## wherein R is as defined above, which is substantially uncontaminated by products derived from the self condensation of 4-aminobenzaldehyde; and (c) diazotizing the 2,6-bis-((4-aminophenyl)-methylene)-cyclohexanone product and reacting the diazotization product with an alkali metal azide.