Online article for Non-subscribers

Pay per view

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact:

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

Paper | Regular issue | Vol 32, No. 9, 1991, pp.1745-1755
Published online, 1st January, 1970
DOI: 10.3987/COM-91-5773
Pyrazoles and Isoxazoles Derived from 2-Hydroxyaryl Phenylethynyl Ketones: Synthesis and Spectrophotometric Evaluation of Their Potential Applicability as Sunscreens

Hermenegildo García, Sara Iborra, Miguel A. Miranda,* Isabel M. Morera, and Jaime Primo

*Departamento de Quimica/ Instituto de Tecnologia Quimica , UPV-CSIC, Universidad Politécnica de Valencia, Apartado 22012, E-46071-Valencia, Spain


Reaction of the acetylenic ketones (1) with hydrazine or hydroxylamine leads to the pyrazoles (2) or the isoxazoles (3), respectively. Spectrophotometric evaluation of the UV-photoprotecting ability as compared to p-aminobenzoic acid (PABA) shows that the predicted effectiveness of 2 and the 3-phenylisoxazoles (3B) is very close to that of PABA, while that of the 5-phenylisoxazoles (3A) is clearly lower. The pyrazoles (2) are more stable than PABA upon UV-irradiation in cyclohexane solution.