The Clofarabine, with the CAS registry number 123318-82-1,is also known as 5-(6-Amino-2-chloro-purin-9-yl)-4-fluoro-2-(hydroxymethyl)oxolan-3-ol . It belongs to the product categories of Nucleotides;Pharmaceutical intermediate. This chemical's molecular formula is C10H11ClFN5O3 and molecular weight is 303.68. What's more,Its systematic name is 2-Chloro-9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-9H-purin-6-amine .It is a White Solid which is approved in the United States for treatment of acute lymphoblastic leukaemia in paediatric patients who have relapsed.

Physical properties about Clofarabine are:
(1)ACD/LogP:  0.446; (2)# of Rule of 5 Violations:  0; (3)ACD/LogD (pH 5.5):  0.45; (4)ACD/LogD (pH 7.4):  0.45; (5)ACD/BCF (pH 5.5):  1.29; (6)ACD/BCF (pH 7.4):  1.29; (7)ACD/KOC (pH 5.5):  41.66; (8)ACD/KOC (pH 7.4):  41.67; (9)#H bond acceptors:  8; (10)#H bond donors:  4; (11)#Freely Rotating Bonds:  4; (12)Index of Refraction:  1.844; (13)Molar Refractivity:  63.578 cm3; (14)Molar Volume:  143.096 cm3; (15)Polarizability:  25.204 10-24cm3 ; (16)Surface Tension:  86.3119964599609 dyne/cm; (17)Density:  2.122 g/cm3; (18)Flash Point:  316.379 °C; (19)Enthalpy of Vaporization:  93.858 kJ/mol; (20)Boiling Point:  599.522 °C at 760 mmHg; (21)Vapour Pressure:  0 mmHg at 25°C.

Structure Descriptors of Clofarabine：
(1)Clc1nc(c2ncn(c2n1)[C@@H]3O[C@@H]([C@@H](O)[C@@H]3F)CO)N;
(2)Std. InChI:InChI=1S/C10H11ClFN5O3/c11-10-15-7(13)5-8(16-10)17(2-14-5)9-4(12)6(19)3(1-18)20-9/h2-4,6,9,18-19H,1H2,(H2,13,15,16)/t3-,4+,6-,9-/m1/s1;
(3)Std. InChIKey:WDDPHFBMKLOVOX-AYQXTPAHSA-N.

Uses of Clofarabine:
Clofarabine is second generation purine nucleoside analog; antimetabolite that inhibits DNA synthesis and resists deamination by adenosine deaminase, and is also antineoplastic. It is FDA-approved for treating relapsed or refractory acute lymphoblastic leukaemia (ALL) in children after at least two other types of treatment have failed. Furthermore, Clofarabine displays greater affinity towards dCK (deoxycytidine kinase, dCyd), an enzyme essential in nucleoside phosphorylation. As a intermediate, it can be used to manufacture antineoplastic Clofarabine.

Side effects of Clofarabine
(1)Side effects on tumor lysis syndrome (TLS): TLS is very serious and can lead to death if it is not treated right away. 
Clofarabine can quickly kills leukaemia cells in the blood. Then the body may react to this. Symptoms include fast breathing, fast heartbeat, low blood pressure, and fluid in the lungs.
(2)Side effects on Bone marrow problems (suppression). Clofarabine can stop the bone marrow from making enough red blood cells, white blood cells, and platelets. Serious side effects that can happen because of bone marrow suppression include severe infection (sepsis), bleeding, and anemia.
(3)Effects on pregnancy and breastfeeding. Girls and women should not become pregnant or breastfeed during treatment which harm the baby. (4)Effects on Dehydration and low blood pressure. Clofarabine (CAS NO.123318-82-1) can cause vomiting and diarrhea which may lead to low body fluid (dehydration). Signs and symptoms of dehydration include dizziness, lightheadedness, fainting spells, or decreased urination.
(5)Other side effects. The most common side effects are stomach problems (including vomiting, diarrhea, and nausea), and effects on blood cells (including low red blood cells count, low white blood cell count, low platelet count, fever, and infection. Clofarabine can also cause tachycardia and can affect the liver and kidneys.

Production of Clofarabine
The reaction flask was added 2-chloro-9-(2-deoxy-2-fluoro-3,5-di-O-benzoyl-beta-D arabinose yl) adenine 1.5g (3mmol) and methanol 40ml,mixed with stirring. Then it was added sodium methoxide, 0.05g (content> 50%), the reaction was stirred for 40min. Then the mixture was cooled to room temperature, adjusted to pH 7 with acetic acid, filtered, and the filter cake was washed with an ice-methanol 10ml, added to the methanol 40ml, and heated to 63 °C, and then cooled to -10 o C. Still 1h, filtered, and the filter cake was washed with an ice-methanol 10ml, drained, dried under reduced pressure to give an off-white powdery solid clofarabine 0.48g. The yield is 54%.