Tacrolimus (CAS NO.104987-11-3) was among the first macrolide immunosuppressants discovered, which was discovered in 1984 by a Japanese team headed by T. Goto, T. Kino and H. Hatanaka. The name tacrolimus is derived from 'Tsukuba macrolide immunosuppressant'. Tacrolimus is owned by Astellas Pharma Inc., and is sold under the tradenames Prograf, Advagraf, and Protopic. It was first approved by the Food and Drug Administration (FDA) in 1994 use in liver transplantation, trachea, skin, cornea, and limb transplants.

The Tacrolimus, with the CAS registry number 104987-11-3,is also known as Tsukubaenolide. It belongs to the product categories of Pharmaceuticals; API;Chiral Reagents.Its EINECS number is 242-042-4. This chemical's molecular formula is C₄₄H₆₉NO₁₂ and molecular weight is 804.02. What's more,Its systematic name is 15,19-Epoxy-3H-pyrido(2,1-c)(1,4)oxaazacyclotricosine-1,7,20,21(4H,23H)-tetrone.It is a White Crystalline Solid which is used after allogeneic organ transplant to reduce the activity of the patient's immune system and so lower the risk of organ rejection. In recent years, it has been used to suppress the inflammation associated with ulcerative colitis. It is a recent addition in the treatment of eczema, particularly atopic dermatitis, and suppresses inflammation in a similar way to steroids.

Physical properties about Tacrolimus are:
(1)ACD/LogP:  3.96; (2)# of Rule of 5 Violations:  2; (3)ACD/LogD (pH 5.5):  3.96; (4)ACD/LogD (pH 7.4):  3.96; (5)ACD/BCF (pH 5.5):  602.10; (6)ACD/BCF (pH 7.4):  600.47; (7)ACD/KOC (pH 5.5):  3398.48; (8)ACD/KOC (pH 7.4):  3389.29; (9)#H bond acceptors:  13; (10)#H bond donors:  3; (11)#Freely Rotating Bonds:  10; (12)Index of Refraction:  1.549; (13)Molar Refractivity:  214.131 cm3; (14)Molar Volume:  673.124 cm3; (15)Surface Tension:  51.2929992675781 dyne/cm; (16)Density:  1.194 g/cm3; (17)Flash Point:  481 °C; (18)Enthalpy of Vaporization:  143.946 kJ/mol; (19)Boiling Point:  871.721 °C at 760 mmHg; (20)Vapour Pressure:  0 mmHg at 25°C.

You can still convert the following datas into molecular structure:
(1)SMILES:O=C3C(=O)N1CCCC[C@H]1C(=O)O[C@H](C(=C/[C@@H]2CC[C@@H](O)[C@H](OC)C2)/C)[C@H](C)[C@@H](O)CC(=O)[C@@H](/C=C(\C[C@@H](C[C@H](OC)[C@H]4O[C@]3(O)[C@H](C)C[C@@H]4OC)C)C)C\C=C;
(2)Std. InChI:InChI=1S/C44H69NO12/c1-10-13-31-19-25(2)18-26(3)20-37(54-8)40-38(55-9)22-28(5)44(52,57-40)41(49)42(50)45-17-12-11-14-32(45)43(51)56-39(29(6)34(47)24-35(31)48)27(4)21-30-15-16-33(46)36(23-30)53-7/h10,19,21,26,28-34,36-40,46-47,52H,1,11-18,20,22-24H2,2-9H3/b25-19+,27-21+/t26-,28+,29+,30-,31+,32-,33+,34-,36+,37-,38-,39+,40+,44+/m0/s1;
(3)Std. InChIKey:QJJXYPPXXYFBGM-LFZNUXCKSA-N.

The toxicity data of Tacrolimus are as follows: