The related pro-drug of didanosine, 2'3'-dideoxyadenosine (ddA), was initially synthesized by M.J. Robins and R.K. Robins in 1964. Subsequently, Samuel Broder, Hiroaki Mitsuya, and Robert Yarchoan in the National Cancer Institute (NCI) found that ddA and ddI could inhibit HIV replication in the test tube and conducted initial clinical trials showing that didanosine had activity in patients infected with HIV. On behalf of the NCI, they were awarded patents on these activities. Since the NCI does not market products directly, the National Institutes of Health (NIH) awarded a ten-year exclusive licensed to Bristol-Myers Squibb Co. (BMS) to market and sell ddI as Videx tablets.
Didanosine became the second drug approved for the treatment of HIV infection in many other countries, including in the United States by the Food and Drug Administration (FDA) on October 9, 1991. Its FDA approval helped bring down the price of zidovudine (AZT), the initial anti-HIV drug.
Didanosine has weak acid stability and is easily damaged by stomach acid. Therefore, the original formula approved by the FDA used chewable tablets that included an antacid buffering compound to neutralize stomach acid. The chewable tablets were not only large and fragile, they also were foul-tasting and the buffering compound would cause diarrhea. Although the FDA had not approved the original formulation for once-a-day dosing it was possible for some people to take it that way.
At the end of its ten-year license, BMS re-formulated Videx as Videx EC and patented that, which reformulation the FDA approved in 2000. The new formulation is a smaller capsule containing coated microspheres instead of using a buffering compound. It is approved by the FDA for once-a-day dosing. Also at the end of that ten-year period, the NIH licensed didanosine to Barr Laboratories under a non-exclusive license, and didanosine became the first generic anti-HIV drug marketed in the United States.
One of the patents for ddI expired in the United States on 2006-08-29, but other patents extend beyond that time.

The IUPAC name of Didanosine is 9-[(2R,5S)-5-(hydroxymethyl)oxolan-2-yl]-3H-purin-6-one. With the CAS registry number 69655-05-6, it is also named as 2',3'-Dideoxyinosine. The product's categories are Heterocyclic Compounds; Antivirals for Research and Experimental Use; Biochemistry; Chemical Reagents for Pharmacology Research; Nucleosides, Nucleotides & Related Reagents; Bases & Related Reagents; Intermediates & Fine Chemicals; Nucleotides; Pharmaceuticals; API's. It is white crystalline powder which is stable, combustible and incompatible with strong oxidizing agents. Addition, this chemical should be sealed in the container and stored in the cool and dry place.

The other characteristics of this product can be summarized as: (1)ACD/LogP: -1.33; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): -1.33; (4)ACD/LogD (pH 7.4): -1.33; (5)ACD/BCF (pH 5.5): 1; (6)ACD/BCF (pH 7.4): 1; (7)ACD/KOC (pH 5.5): 4.46; (8)ACD/KOC (pH 7.4): 4.5; (9)#H bond acceptors: 7; (10)#H bond donors: 2; (11)#Freely Rotating Bonds: 3; (12)Index of Refraction: 1.797; (13)Molar Refractivity: 57.19 cm³; (14)Molar Volume: 134 cm³; (15)Polarizability: 22.67×10^-24 cm³; (16)Surface Tension: 79.1 dyne/cm; (17)Enthalpy of Vaporization: 92.13 kJ/mol; (18)Vapour Pressure: 1.33E-14 mmHg at 25°C; (19)Rotatable Bond Count: 2; (20)Tautomer Count: 3; (21)Exact Mass: 236.09094; (22)MonoIsotopic Mass: 236.09094; (23)Topological Polar Surface Area: 88.7; (24)Heavy Atom Count: 17; (25)Complexity: 348.

Preparation of Didanosine: First, 2'-deoxyinosine (Ⅶ) reacts with 5'-O-benzoylation, and then react with3'-O-(1-imidazolyl) thiocarbonyl. Thirdly, take off 3'-oxygen and benzoyl to get the product.

Uses of Didanosine: It is a reverse transcriptase inhibitor, effective against HIV and used in combination with other antiretroviral drug therapy as part of highly active antiretroviral therapy (HAART). The most adverse effects are diarrhea, nausea, vomiting, abdominal pain, fever, headache and rash. Peripheral neuropathy occurred in 21-26% of participants in key didanosine trials.

When you are using this chemical, please be cautious about it as the following:
It can cause burns. And it is irritating to eyes and respiratory system. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. What's more, people should take off immediately all contaminated clothing. If you want to contact this product, you must wear suitable protective clothing, gloves and eye/face protection. In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)

People can use the following data to convert to the molecule structure. 
1. SMILES:O=C3/N=C\Nc1c3ncn1[C@@H]2O[C@@H](CC2)CO
2. InChI:InChI=1/C10H12N4O3/c15-3-6-1-2-7(17-6)14-5-13-8-9(14)11-4-12-10(8)16/h4-7,15H,1-3H2,(H,11,12,16)/t6-,7+/m0/s1 
3. InChIKey:BXZVVICBKDXVGW-NKWVEPMBBL

The following are the toxicity data which has been tested.