Introduction to CAS: 705-60-2 1-Phenyl-2-nitropropene

1-Phenyl-2-nitropropene (abbreviated as P2NP), with CAS number 705-60-2, is an important aromatic nitroalkene organic compound. Its chemical formula is C₉H₉NO₂, molecular weight is 163.17, exact mass is 163.06300, polar surface area (PSA) is 45.82000, and octanol-water partition coefficient (LogP) is 2.84730, featuring a clear chemical structure and stable physical and chemical properties. This compound has important applications in organic synthesis and the pharmaceutical field, and is classified as a drug precursor and regulated by many countries due to its potential abuse risk.

In terms of physical and chemical properties, 1-Phenyl-2-nitropropene is a pale yellow to orange crystalline solid at room temperature, presenting as needle-like crystals in some cases, with a unique odor and mostly crystalline powder form. Its melting point ranges from 63-66℃, boiling point is about 263.0±9.0℃ (predicted value), density is 1.141±0.06 g/cm³ (predicted value), flash point is 115.7℃, and refractive index is 1.586. In terms of solubility, this compound is almost insoluble in water, but has good solubility in various organic solvents such as dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethanol, acetone, and chloroform. Among them, the solubility in DMF and DMSO can reach 30mg/ml, and about 10mg/ml in ethanol. This property provides a basis for the selection of solvents in its synthesis and application processes. It should be stored in a sealed container in a cool and dry place, away from oxidants, and it is recommended to store it at 2-8℃ in some scenarios to ensure stability.

In terms of synthesis, 1-Phenyl-2-nitropropene is mainly prepared by the Henry reaction (also known as the nitroaldol reaction), which is a variant of the Knoevenagel condensation reaction. The core is the condensation reaction between benzaldehyde and nitroethane under the action of a basic catalyst. The commonly used catalyst in the laboratory is a primary amine such as n-butylamine. During the reaction, the basic catalyst deprotonates nitroethane to form a resonance-stabilized nitro anion, which nucleophilically adds to the carbonyl carbon of benzaldehyde to generate a β-nitroalcohol intermediate. Subsequently, the intermediate dehydrates to remove water molecules, and finally the target product is obtained. During the reaction, the generated water needs to be actively removed to promote the complete reaction. In addition, it can also be synthesized by other routes, such as the reaction of 1-ethoxyphosphoryl-1-nitroethane with benzaldehyde, with a yield of about 94%. The crude product after synthesis can be purified by recrystallization from absolute ethanol, vacuum filtration, washing with cold ethanol and vacuum drying to obtain a high-purity product.

In terms of application and safety, the main use of 1-Phenyl-2-nitropropene is as a pharmaceutical intermediate for the synthesis of amphetamine-type drugs (such as Adderall). Such drugs are mainly used for the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. Its synthesis process requires hydrogenating the double bond and reducing the nitro group to convert the compound into 1-phenyl-2-aminopropane (i.e., amphetamine). In addition, it can also generate phenylacetone through reduction reaction, which is then used for the synthesis of methamphetamine, so it is listed as a drug precursor and strictly regulated in many countries. In terms of safety, this compound is an irritating substance, with hazard code R36/37/38, which may irritate the eyes, respiratory tract and skin. The safety instructions are S26, S36, S37/39. If it comes into contact with the eyes, rinse immediately with plenty of water and seek medical attention. Appropriate protective clothing should be worn during operation. Toxicological data show that the oral median lethal dose (LD) in rats is greater than 500mg/kg, and the intraperitoneal minimum lethal dose (LDLo) is 200mg/kg, and the specific toxicity details are not yet fully clear.

In summary, as an important organic intermediate, 1-Phenyl-2-nitropropene plays an irreplaceable role in the field of pharmaceutical synthesis. However, its potential abuse risk determines that its production, storage and use must comply with strict regulatory requirements to ensure its rational application in legal scientific research and production activities.