Riboflavin (CAS NO.83-88-5) was originally considered to have two components, a heat-labile vitamin B₁ and a heat-stable vitamin B₂ . In the 1920s, it was thought to be the factor necessary for preventing pellagra. Paul Gyorgi in Heidelberg was investigating egg white injury in rats in 1923,  the curative factor for this condition was called vitamin H. Since both pellagra and vitamin H deficiency were associated with dermatitis, Gyorgi decided to test the effect of vitamin B₂ on vitamin H deficiency in rat. In 1933, Kuhn, Gyorgy, and Wagner found that thiamin-free extracts of yeast, liver, or rice bran prevented the growth failure of rats fed a thiamin supplemented diet. This observation enabled them to develop a rapid chemical and bioassay to isolate the factor from egg white in 1933, they called it Ovoflavin.

The Riboflavin, with the CAS registry number 83-88-5, is also known as 7,8-Dimethyl-10-ribitylisoalloxazine; Lactoflavine; Vitamin B2.It belongs to the product categories of Vitamin Ingredients;Miscellaneous Compounds;Chiral Reagents;Heterocycles;Intermediates & Fine Chemicals. Its EINECS number is 201-507-1.This chemical's molecular formula is C₁₇H₂₀N₄O₆ and molecular weight is 376.37. What's more,Its systematic name is Riboflavin. It is nutritional factor found in milk, eggs, malted barley, liver, kidney, heart, and leafy vegetables. The richest natural source is yeast. It occurs in the free form only in the retina of the eye, in whey, and in urine; its principal forms in tissues and cells are as flavin mononucleotide and flavin-adenine dinucleotide. And it is Stable, but light-sensitive. Incompatible with strong oxidizing agents, reducing agents, bases, calcium, metallic salts. May be moisture sensitive.when you use it, avoid contact with skin and eyes.

Physical properties about Riboflavin are:(1)ACD/LogP: 0.095; (2)# of Rule of 5 Violations: 2; (3)ACD/LogD (pH 5.5): 0.10; (4)ACD/LogD (pH 7.4): 0.09; (5)ACD/BCF (pH 5.5): 1.00; (6)ACD/BCF (pH 7.4): 1.00; (7)ACD/KOC (pH 5.5): 26.82; (8)ACD/KOC (pH 7.4): 26.74; (9)#H bond acceptors: 10; (10)#H bond donors: 5; (11)#Freely Rotating Bonds: 9; (12)Index of Refraction: 1.733; (13)Molar Refractivity: 91.104 cm³; (14)Molar Volume: 227.51 cm³; (15)Surface Tension: 70.2760009765625 dyne/cm; (16)Density: 1.654 g/cm³;

You can still convert the following datas into molecular structure:
(1)SMILES:O=C2/N=C\1/N(c3cc(c(cc3/N=C/1C(=O)N2)C)C)C[C@H](O)[C@H](O)[C@H](O)CO;
(2)Std. InChI:InChI=1S/C17H20N4O6/c1-7-3-9-10(4-8(7)2)21(5-11(23)14(25)12(24)6-22)15-13(18-9)16(26)20-17(27)19-15/h3-4,11-12,14,22-25H,5-6H2,1-2H3,(H,20,26,27)/t11-,12+,14-/m0/s1;
(3)Std. InChIKey:AUNGANRZJHBGPY-SCRDCRAPSA-NC;

The toxicity data of Riboflavin as follows: