Phthalaldehyde

Synthesis and reactions

The compound was first described in 1887 when it was prepared from α,α,α’,α’-tetrachloro-o-xylene. A more modern synthesis is similar: the hydrolysis of the related tetrabromo-o-xylene using potassium oxalate, followed by purification by steam distillation.

The reactivity of OPA is complicated by the fact that in water it forms both a mono- and dihydrate, C6H4(CHO)(CH(OH)2) and C6H4(CH(OH))2O, respectively. Its reactions with nucleophiles often involves the reaction of both carbonyl groups.

Biochemistry

OPA is used in a very sensitive fluorogenic reagent for assaying amines or sulfhydryls in solution, notably contained in proteins, peptides, and amino acids, by capillary electrophoresis and chromatography. OPA reacts specifically with primary amines above their isoelectric point Pi in presence of thiols. The reaction produces isoindoles, which fluoresce. is the basis of an analytical method involving spectrometric (fluorescent emission at 436-475 nm (max 455 nm) with excitation at 330-390 nm (max. 340 nm)).

Disinfection

OPA is commonly used as a high-level disinfectant for medical instruments, commonly sold under the brand names of Cidex OPA or TD-8. Disinfection with a High-level disinfectant such as OPA is indicated for semi-critical instruments that come into contact with mucous membranes or broken skin, such as specula, laryngeal mirrors, and internal ultrasound probes.

Poly(phthalaldehyde)

OPA can be polymerized. In the polymer, one of the oxygen atoms forms a bridge to the other non-ring carbon of the same phthalaldehyde unit, while the other bridges to a non-ring carbon of another phthalaldehyde unit. Poly(phthalaldehyde) is used in making a photoresist.

In winemaking

The Nitrogen by O-Phthaldialdehyde Assay (NOPA) is one of the methods used in winemaking to measure yeast assimilable nitrogen (or YAN) needed by wine yeast in order to successfully complete fermentation.

Isomeric phthalaldehydes

• isophthalaldehyde (benzene-1,3-dicarbaldehyde)
• terephthalaldehyde (benzene-1,4-dicarbaldehyde)

References

References

1. {{BlueBook2013
2. (1954). "''o''-Phthalaldehyde". Organic Syntheses.
3. [http://www.sigmaaldrich.com/catalog/product/sial/P0657?lang=en Phthaldialdehyde] from [[Sigma-Aldrich]]
4. (1887). "Nouveau Mode de Chloruration des Carbures". [[Annales de Chimie]].
5. (2004). "Reactions of Orthophthalaldehyde with Nucleophiles". Chemical Reviews.
6. Roth, Marc.. (1971-06-01). "Fluorescence reaction for amino acids". American Chemical Society (ACS).
7. (2023). "Elucidating the Mechanism for the Reaction of ''o'' -Phthalaldehyde with Primary Amines in the Presence of Thiols". The Journal of Physical Chemistry B.
8. [http://www.interchim.fr/ft/0/02727A.pdf Protocol by Uptima]
9. (2004). "Infection Control in the Physician's Office". College of Physicians and Surgeons of Ontario.
10. (1993). "Chemically amplified resists IV. Proton-catalyzed degradation mechanism of poly(phthalaldehyde)". Journal of Photopolymer Science and Technology.
11. B. Zoecklein, K. Fugelsang, B. Gump, F. Nury ''Wine Analysis and Production'' pgs 152-163, 340-343, 444-445, 467 Kluwer Academic Publishers, New York (1999) {{ISBN. 0834217015