2-AMINO-5-BROMO-[1,3,4]THIADIAZOLE

China [CN]

Physical and Chemical Properties

1. Physical Properties

Melting Point: 223-227°C (determined by capillary melting point apparatus; the melting point range is narrow at 98% purity, with the theoretical melting point of the pure product being approximately 225°C; impurities may lower the melting point and widen the range);

Boiling Point: Unspecified (easily decomposes at high temperatures (>250°C), making distillation unsuitable for purification);

Solubility: Solvent compatibility is significantly polarity-dependent:

Soluble in highly polar aprotic solvents such as N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (room temperature solubility approximately 15-20 g/L);

Soluble in polar protic solvents such as methanol, ethanol, and isopropanol (stirring is required to aid dissolution; room temperature solubility approximately 3-5 g/L);

Slightly soluble in ethyl acetate and chloroform, poorly soluble in non-polar solvents such as ether, petroleum ether, and n-hexane, and practically insoluble in water (room temperature solubility < 0.1 g/L);

Stability: Stable for over 24 months when stored at room temperature in a dry, dark, and sealed environment. It readily absorbs moisture and forms lumps when exposed to moisture (but its chemical properties remain unchanged). It decomposes at high temperatures (>230°C), releasing sulfur and nitrogen gases.

2. Chemical Properties

Functional Group Reactivity: The two core active sites in the molecule (amino and bromine atoms) can react independently or synergistically:

Amino groups (-NH₂): exhibit the chemical properties of typical aliphatic amines, capable of undergoing acylation (reacting with acyl chlorides and anhydrides to form amide derivatives), diazotization (reacting with sodium nitrite under acidic conditions to form diazonium salts, which can then undergo coupling and substitution reactions), and condensation (reacting with aldehydes/ketones to form imines).

Bromo groups (-Br): As a leaving group on aromatic (heterocyclic) rings, they can undergo nucleophilic substitution reactions (with nucleophiles such as -NH₂, -OH, and -OCH₃), Suzuki coupling reactions (forming C-C bonds with boronic acids/boronic esters under palladium catalysis), and Heck coupling reactions (reacting with alkenes).

Heterocyclic Stability: [1,3,4]- The thiadiazole ring has high aromatic stability and is not susceptible to ring-opening reactions. Ring modification can only occur under strongly alkaline conditions (such as concentrated sodium hydroxide solution) or strongly acidic conditions (such as concentrated nitric acid).

Redox properties: The sulfur atom (-S-) in the molecule is in a low-valent state (-2) and has weak reducing properties. It can be oxidized to sulfoxides or sulfones by strong oxidants (such as potassium permanganate and hydrogen peroxide), but is chemically stable under normal conditions.