The CAS registry number of Trazodone hydrochloride is 25332-39-2. The IUPAC name is 2-{3-[4-(3-chlorophenyl)piperazin-1-yl]propyl}[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one hydrochloride (1:1). Its EINECS registry number is 246-855-5. In addition, the formula is C₁₉H₂₃Cl₂N₅O and the molecular weight is 408.32482. It is a kind of off-white powder.

Physical properties about this chemical are: (1)ACD/LogP: 1.66; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 0.67; (4)ACD/LogD (pH 7.4): 1.61; (5)ACD/BCF (pH 5.5): 1.09; (6)ACD/BCF (pH 7.4): 9.68; (7)ACD/KOC (pH 5.5): 19.33; (8)ACD/KOC (pH 7.4): 171.45; (9)#H bond acceptors: 6; (10)#H bond donors: 0; (11)#Freely Rotating Bonds: 5; (12)Polar Surface Area: 42.39 Å² ; (13)Flash Point: 273.4 °C; (14)Enthalpy of Vaporization: 80.34 kJ/mol; (15)Boiling Point: 528.5 °C at 760 mmHg; (16)Vapour Pressure: 2.94E-11 mmHg at 25°C.

Preparation of Trazodone hydrochloride: at first, we should use 2-chloropyridine and hydratehydrazine to prepare pyridinehydrazine. The reaction time is 24 hours by stirring. In this reaction, we should use diethyl ether to extract the product. Then we can use urea and pyridinehydrazine to prepare 1,2,4-triazolo-[4,3-a]pyridine-3(2H)-one. The reaction time is 2 hours by heating at reaction temperature of 155-160 °C. The yield is about 86.5%. At last, trazodone hydrochloride can be prepared by 1,2,4-triazolo-[4,3-a]pyridine-3(2H)-one and 1-(3-chlorophenyl)-4-(3-chloropropyl)piperazinehydrochloride. This reaction will need reagent ethanol and solvent NaOH. The product should be extracted by dichloromethane and dried by Na₂SO₄. The yield is about 67.5%.

Uses of Trazodone hydrochloride: it is a kind of antidepressants. The effect is similar with tricyclic drugs, but smaller toxicity to the cardiovascular system and no anticholinergic side effects. In addition, it is more applicable to the older or the depression with cardiovascular disease. It can treat the depression, anxiety disorders and schizophrenia in clinical.

When you are using this chemical, please be cautious about it as the following:
It is harmful if swallowed and irritating to eyes, respiratory system and skin. You should  not breathe dust. Limited evidence of a carcinogenic effect. When you are using it, wear suitable gloves and eye/face protection. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

You can still convert the following datas into molecular structure:
(1)SMILES: Cl.Clc4cccc(N3CCN(CCCN1/N=C2/C=C\C=C/N2C1=O)CC3)c4
(2)InChI: InChI=1/C19H22ClN5O.ClH/c20-16-5-3-6-17(15-16)23-13-11-22(12-14-23)8-4-10-25-19(26)24-9-2-1-7-18(24)21-25;/h1-3,5-7,9,15H,4,8,10-14H2;1H
(3)InChIKey: OHHDIOKRWWOXMT-UHFFFAOYAR

The toxicity data is as follows: