1 -Naphthaldehyde formylation

Cyanomethylbenzo[6]thiophene condenses with 2-methylthio-1-naphthaldehyde to give 199,571 and it affords 200 on formylation with ethyl formate and sodium methoxide.524 Compound 200 reacts with hydrazine under suitable conditions to give either 201 or 3-amino-4-(3-benzo[6]thienyl)pyrazole (202).524 With ethylene-... 

There has been a number of developments in the use of salicylaldehydes as precursors of both chromenes and chromans. Alkenes activated by acyl, formyl, nitrile and phenylsulfonyl groups react with 2-hydroxybenzaldehydes and 2-hydroxy-1-naphthaldehyde under Bayliss-Hillman conditions to yield 3-substituted chromenes via the in situ dehydration of the initially formed chroman-4-ol <02JCS(P1)1318>. In like manner, P-nitrostyrenes yield 2- and 2,2-substituted derivatives of 3-nitrochromenes <02H(57)1033>. A simple route to 2-phenyl-2H-chromenes starting from salicylaldehyde and utilising a Pd(0)-catalysed cyclisation of an allylic acetate has been described <02SC3667>. 

Certain aromatic analogues of natural amino acids can be used as potential fluorescent probes of peptide structure and dynamics in complex environments. The research team of M.L. McLaughlin undertook the gram scale synthesis of racemic 1- and 2-naphthol analogues of tyrosine. The synthesis of the 1-naphthol tyrosine analogue started with the Gattermann formylation of 1-naphthol using the Adams modification to afford the formylated product 4-hydroxy-1-naphthaldehyde in 67% yield. 

A useful modification of this reaction involves the use of formyl fluoride, which is prepared by the reaction of the mixed anhydride of formic and acetic acids with anhydrous hydrogen fluoride. The formyl fluoride is continuously removed (b.p. -29 C) as it is formed. Formyl fluoride and boron trifluoride do react with naphthalene to give 1-naphthaldehyde in 73% yield (equation 65). ... 

The oxidation of formyl groups accompanied by subsequent functionalization has showcased the utility of the Baeyer-Villiger oxidation. Franck reported the Baeyer-Villiger oxidation of naphthaldehydes as precursors to pharmacologically active quinone type compounds. This was exemplified by the conversion of aldehyde 104 into formate 105, which after formate cleavage, was further oxidized to the quinone system 106.55... 

In the methylation of 2,3-dihydroxy-1-naphthaldehyde with iodomethane and potassium carbonate the 2-methyl ether is formed, a reaction attributable to the ionisation of the 2-hydroxyl group following the breaking of stabilising hydrogenbonding and the adoption of the preferred conformation shown of the formyl group (ref.64). 

A formyl group can serve as a CO surrogate by exploiting the decarbonylation reaction [28]. When the 1,6-enyne 50 was treated with 2-naphthaldehyde in the presence of a rhodium catalyst, a Pauson-Khand-type reaction proceeded to give the bicyclic cyclopentenone 51 together with naphthalene (Scheme 7.19) [28a]. 

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