Peri effects in the mass spectra of some 8-substituted 1-naphthoic acids and 1-naphthylcarbinols

Abstract

The mass spectra of several 8-substituted 1-naphthoic acids and 1-naphthylcarbinols have been examined to determine if peri interactions are involved in the fragmentation. The substituents at the C8 position include CHsO, CHS, Br, and N02. The spectrum of the 8-methoxy acid shows a strong M -CH3OH ion due to peri interaction whereas its isomeric 2-methoxy acid does not. The loss of water in the spectra of the 8-methyl acid and alcohol and of HBr from the 8-bromo alcohol are indicative of interaction between peri substituents. The expulsion of these neutral molecules from the molecular ion is presumably facilitated by the peri cyclization to form a stable product. The weak molecular ion and facile loss of the 8 substituent in the spectra of the 8-bromo and 8-nitro acids are interpreted as being due to peri interactions. The presence of M -H20 and M -OH -OH ions in the spectrum of the 8-nitro alcohol also indicates the interaction between the peri substituents.

Importance of peri-Interactions on the Stereospecificity of Rat Hydroxysteroid Sulfotransferase STa with 1-Arylethanols

“…In view of the geometry of naphthalene, substituents located at these positions are in much closer proximity than similar substituents located ortho to each other, and steric interactions should be more severe. This closer proximity has been responsible for the appearance of several unique properties of peri -substituted naphthalenes that have been reported by different groups over many years ( − ).…”

Intramolecular hydrogen transfer in mass spectra. III. Rearrangements involving the loss of small neutral molecules

“…A recent example of this reaction is found in the substituted naphthoic acid 28, which loses water readily although other isomers lose water either less readily or not at all. 88 This effect is also found in dipositive ions studied free of interference from monopositive ions; anthranilic acid (29), for example, loses water from M2+, while the meta isomer loses only HO• followed by other species.89 28 29…”