1-Naphthalene acetic acid
[CAS# 86-87-3]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyridazine
• Name: 1-Naphthalene acetic acid
• Synonyms: Planofix; a-Naphthylacetic acid; Fruitone; 1-Naphthaleneacetic acid; Naphthalene-1-acetic acid
• Molecular Formula: C₁₂H₁₀O₂
• Molecular Weight: 186.21
• CAS Registry Number: 86-87-3
• EC Number: 201-705-8
• SMILES: C1=CC=C2C(=C1)C=CC=C2CC(=O)O

Properties

• Solubility: 50 mg/mL (acetone) (Expl.)
• Density: 1.2±0.1 g/cm³, Calc.^*
• Melting point: 126-133 °C (Expl.)
• Index of Refraction: 1.652, Calc.^*
• Boiling Point: 373.2±11.0 °C (760 mmHg), Calc.^*
• Flash Point: 270.1±14.4 °C, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H302-H315-H318-H319-H335-H412
• Safety Statements: P261-P264-P264+P265-P270-P271-P273-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P305+P354+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Eye irritation	Eye Irrit.	2	H319
Reproductive toxicity	Repr.	2	H361
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	4	H332
Reproductive toxicity	Repr.	2	H361d
Acute toxicity	Acute Tox.	4	H312

Discovery and Applications

1-Naphthalene acetic acid (NAA) is a synthetic plant hormone belonging to the group of auxins. It is widely used in agriculture, horticulture, and research due to its ability to influence plant growth and development. NAA is an analog of indole-3-acetic acid (IAA), the naturally occurring auxin in plants, but has enhanced stability and solubility, making it more effective in certain applications.

The discovery of NAA dates back to the 1940s when it was first synthesized by researchers studying the effects of auxins on plant growth. The compound was found to have similar growth-promoting effects as IAA, such as promoting cell elongation, root initiation, and bud formation. Over time, NAA became one of the most widely used synthetic auxins due to its ability to mimic natural auxin activity while offering greater control over plant growth.

In agriculture, NAA is primarily used as a plant growth regulator to promote root formation in cuttings. It is applied to the base of plant cuttings to stimulate root development, making it a valuable tool in the propagation of many plant species. NAA is also used to promote fruit thinning in certain crops, such as apples, by inducing the shedding of excess fruit, which can help improve fruit size and quality. Additionally, NAA is utilized in the production of seedless fruits, where it can prevent the formation of seeds, leading to seedless varieties.

Beyond its role in plant growth regulation, NAA is also employed in agricultural pest control. NAA has been found to have insecticidal properties, especially against certain pests that damage crops. The compound can disrupt the growth of insect larvae, making it an important component in integrated pest management strategies.

In horticulture, NAA is used to enhance the growth and appearance of ornamental plants. It is often applied to plants to promote branching, increase foliage density, and improve overall plant vigor. NAA is also used in the rooting of ornamental cuttings, helping horticulturists propagate plants more efficiently and produce healthier plants.

NAA’s applications extend into the field of research, where it is used as a tool to study plant growth and development. Researchers use NAA to examine the mechanisms by which auxins influence various aspects of plant physiology, such as root and shoot development, tropism, and responses to environmental stimuli. This has helped expand our understanding of plant biology and improve crop management practices.

In addition to its agricultural and horticultural uses, NAA has also been studied for its potential to improve soil health and stimulate plant responses to environmental stresses. Research is ongoing to explore its applications in areas such as improving drought tolerance, enhancing nutrient uptake, and increasing plant resilience to pests and diseases.

The discovery and application of 1-naphthalene acetic acid have had a significant impact on agricultural practices, particularly in plant propagation, crop management, and pest control. As research continues, new applications for NAA are likely to emerge, further enhancing its value as a tool for improving plant growth and productivity.

References

2010. Kinetic Basis for the Conjugation of Auxin by a GH3 Family Indole-acetic Acid-Amido Synthetase. The Journal of biological chemistry, 285(39).
DOI: 10.1074/jbc.m110.146431

2024. Integrating leaf and root induced shoot regeneration and embryogenesis for the conservation of Atropa acuminata Royle ex Lindl - an endangered Himalayan herb. Plant Cell, Tissue and Organ Culture (PCTOC), 159(3).
DOI: 10.1007/s11240-024-02937-9

1964. NAPHTHYLACETIC ACIDS. 3. SYNTHESIS AND CHOLERETIC ACTION OF 5,6,7,8-TETRAHYDRO-1-NAPHTHYLACETIC ACID AND SOME OF ITS ALPHA-SUBSTITUTED DERIVATIVES. Il Farmaco; edizione scientifica, 19(11).
URL: https://pubmed.ncbi.nlm.nih.gov/14236118