Thermal analysis of 5′-deoxy-5′-iodo-2′,3′-O-isopropylidene-5-fluorouridine

The melting temperature, melting enthalpy, and specific heat capacities (C _p) of 5′-deoxy-5′-iodo-2′,3′-O-isopropylidene-5-fluorouridine (DIOIPF) were measured using DSC-60 Differential Scanning Calorimetry. The melting temperature and melting enthalpy were obtained to be 453.80 K and 33.22 J g^?1, respectively. The relationship between the specific heat capacity and temperature was obtained to be C _p/J g^?1 K^?1 = 2.0261 – 0.0096T + 2 × 10^?5 T ² at the temperature range from 320.15 to 430.15 K. The thermal decomposition process was studied by the TG–DTA analyzer. The results showed that the thermal decomposition temperature of DIOIPF was above 487.84 K, and the decomposition process can be divided into three stages: the first stage is the decomposition of impurities, the mass loss in the second stage may be the sublimation of iodine and thermal decomposition process of the side-group C₄H₂O₂N₂F, and the third stage may be the thermal decomposition process of both the groups –CH₃ and –CH₂OCH₂–. The obtained thermodynamic basic data are helpful for exploiting new synthetic method, engineering design, and commercial process of DIOIPF.     

Synthesis of 3′-deoxy-3′-iminodiacetic acid and 3′-deoxy-3′-aminodiethanol thymidine analogues and NMR study of their complexation with boronic acids

The iminodiacetic acid and aminodiethanol moieties are known for their ability to generate with boronic acids bicyclic structures having a strong intramolecular NB coordination. We describe here the convergent synthesis of 3′-deoxy-3′-iminodiacetic acid and 3′-deoxy-3′-aminodiethanol thymidine analogues. The abilities of these compounds to form boronate complexes with aliphatic or aromatic boronic acids were established by 1D and 2D ¹H and ¹³C NMR. Moreover, conformational analysis of the newly synthesized compounds revealed a marked preference for an N-type sugar puckering.     

Synthesis of 2′-deoxy-2′-fluororibo- and 2′-deoxy-2′,2′-difluororibonucleosides derived from 6-(het)aryl-7-deazapurines

A series of novel sugar-modified derivatives of cytostatic 6-hetaryl-7-deazapurine ribonucleosides (2′-deoxy-2′-fluororibo- and 2′-deoxy-2′,2-difluororibonucleosides) bearing an aryl or hetaryl group in position 6, was prepared and screened for biological activity. The fluororibo derivatives were prepared by aqueous palladium catalyzed cross-coupling reactions of the corresponding 6-chloro-7-deazapurine 2′-deoxy-2′-fluororibonucleoside 11 with (het)arylboronic acids. The key intermediate 11 was prepared by a six-step sequence from the corresponding arabinonucleoside by selective protection of 3′- and 5′-hydroxyls by acid-labile groups followed by stereoselective S_N2 fluorination and deprotection. The difluororibo-series was prepared by non-stereoselective glycosidation of 6-chloro-7-deazapurine with benzoyl-protected 2-deoxy-2,2-difluoro-d-erythro-pentofuranosyl-1-mesylate followed by cross-couplings, separation of anomers and deprotection. The title nucleosides did not show considerable cytostatic or antiviral activity.     

A new synthesis of 3′-deoxy-3′-fluoroadenosine,a key intermediate of cyclic dinucleotide

A new synthesis of 3′-deoxy-3′-fluoroadenosine for use as an important intermediate of antitumor-active cyclic dinucleotide is disclosed. The synthesis started with the known 5-O-TBDPS-D-lyxofuranose 1,2-acetonides, which was first transformed into a fluorinated compound after the DAST reaction. Desilylation and acidic methanolysis were then finished in one pot. After a sequence of triflation, displacement by OBz as well as benzoylation, perbenzoylated 3-deoxy-3-fluoro-D-ribofuranoside was obtained, which would be transformed to 3′-deoxy-3′-fluoroadenosine as the key intermediate of cyclic dinucleotide after ammonolysis.     

Syntheses of Novel 3-Substituted-2′-deoxy-3-deazauridine Nucleosides

Syntheses of novel 3-ethynyl (8), 3-vinyl (10) and 3-acetoxy (13)-2′-deoxy-3-deazauridine analogs starting from the protected 2′-deoxy-3-deazauridine derivative 4 are described.     

Syntheses of 5′-O-glycosylnucleosides

A general synthetic approach to 2,3-unsaturated glycosides connecting with nucleosides involving Ferrier rearrangements of glycals is discussed. The new compounds were identified by NMR and MS (HRFAB⁺). The hydroxylation of the resulting 2,3-unsaturated glycosides was completed using OsO₄ to give 5′-O-glycosylnucleosides in good yield.     

Synthesis of Isonucleoside 5′-Triphosphates

Abstract

A series of isonucleoside 5′-triphosphates were synthesized via a rapid and efficient method. The structures of the triphosphates (8a–8d) were characterized by ³¹P NMR and TOF-MS.     

Stereoselective synthesis of 5′-hydroxyzearalenone

A first stereoselective total synthesis of 14-memebered β-resorcylic macrolactone 5′-hydroxyzearalenone (1) has been achieved. The key steps are Jocobsen hydrolytic kinetic resolution, Sharpless asymmetric dihydroxylation, Vilsmeier-Haack reaction, Mitsunobu esterification and ring-closing metathesis.     

Application of Ultrasonic Waves: An Improved Synthesis of 5′-Deoxy-5′-cyano-2′,3′-isopropylidene Adenosine

The title compound is prepared in excellent yield by the reaction of sodium cyanide with 1 in the presence of ultrasonic waves.     

Convenient Synthesis of Uridine 5′ - Oxyphosphorane

Uridine 5′-oxyphosphorane was synthesized by the reaction of 2′, 3′-di-O-acteyluridine 5′-diisopropyl phosphite with tetrachloro-1, 2-benzoquinone.     

Synthesis of 5′-benzoyl-2′-hydroxychalcones and related flavonoid compounds

Summary 5 -Benzoyl-2 -hydroxychalcones were synthesized by the condensation of 5 -benzoyl-2 -hydroxyacetophenone with aromatic aldehydes in presence of an ethanolic solution of potassium hydroxide. Derivatives of 6-benzoylflavonoids were prepared from chalcones.     

Synthesis and Crystal Structure Analysis of 5′-O-Tosyl-2,3′-anhydrothymidine

In this paper=5′-O-tosyl-2,3′-anhydrothymidine has been synthesized and its crystal structure was analyzed. The crystal belongs to the triclinic system=space group P1=with a=5.397(2)=b=6.1886(18)=c=3.507(5) =α =87.74(2)=β =89.84(4)=γ =73.79(2)°=C17H18N2O6S=Mr=378.39=Z=1=V=432.8(3)3=Dc=1.452 g/cm3=F(000)=198 and Flack =-0.11(14). No intermolecular hydrogen bonds exist in the crystal=and the angle between benzene ring and pyrimidine planes is 32.23°.     

Photochemical Synthesis of 5-Ethynyl-5′-(1-Propynyl)-2.2′-Bithiophene

The synthesis of the title compound is described. The key-step is the photochemical coupling between 5-iodo-2-thienylcarbaldehyde and 2-bromothio-phene to give 5-bromo-2,2′-bithienyl-5′-carbaldehyde.     

High-Performance Liquid Chromatography of 2′-5′Oligoadenylates and Related Oligonucleotides

Abstract

HPLC has been used for the analysis and separation of the components of p_x (A2′p)_n A (x = 1 to 3, n = 1 to ≥4). Weak anion exchange columns give excellent resolution, but their instability in phosphate buffers makes them impractical for routine use. Reverse phase chromatography using C18 columns provides a satisfactory alternative method. For preliminary analysis of crude material, ammonium phosphate pH7.0 with a linear 1:1 methanol/H₂O gradient gives a good basic separation of the individual oligomers. Resolution of the 5′ mono-, di-and triphosphorylated oligomers or of the nonphosphorylated components can be obtained using ammonium phosphate pH6.0 and potassium phosphate pH6.5 buffers respectively. The C18 columns are very stable and any one column will give retention times reproducible within 0.2%.     

Separation of Cytidine 5′-triphosphate Biosynthesized from Cytidine 5′-monophosphate on Ion-exchange Resin and HPLC Analysis of Cytidine Compounds

Conditions were studied in the biosynthesis of cytidine 5′-triphosphate (CTP) from cytidine 5′-monophosphate (CMP). A 201 × 7 anion ion-exchange resin was applied for the separation of CTP from CMP. Adsorption isotherm and elution conditions (eluant, eluant concentration, flow rate, sample volume loaded) were investigated. At the same time, a new high-performance liquid chromatography on an anion ion-exchange column WAX-1 with UV detector at 260 nm was developed to measure CMP, cytidine 5′-diphosphate (CDP), and CTP. The retention time for CMP, CDP, and CTP are 0.723, 1.448, and 4.432 min, respectively. This new rapid high-performance liquid chromatography (HPLC) method for the analysis of cytidine compounds in biological sample has a wide linear range with high precision and repeatability.     

Synthesis of 5-Alkenyl-2′-Deoxyuridines Via Organostannanes

The palladium-catalysed coupling of 3,5 Di-O-p-toluoyl-5-iodo-2′ -deoxyuridine with functionalized and non-functionalized alkenylstannanes gave moderate to good yields of the corresponding 5-alkenyl-2 -deoxyuridines.     

Stereoselective synthesis of 2-deoxy-α-d-arabino-hexopyranosides of triterpene alcohols

2-Deoxy-2-iodo--d-mannopyranosides of triterpene alcohols of the oleanane series were synthesized inca. 60% yields by glycosylation with readily accessibled-glucal triacetate in the presence ofN-iodosuccinimide as the promotor. Their deiodination by catalytic hydrogenation followed by deacetylation yielded 2-deoxy--d-arabino-hexopyranosides of glycyrrhetic acid derivatives and allobetulin.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2340–2346, September, 1996.     

Convenient Synthesis of Nucleoside‐5′‐Diphosphates from the Corresponding Ribonucleoside‐5′‐phosphoroimidazole

The reaction of ribonucleoside‐5′‐phosphoroimidazolide with a tributylammonium orthophosphate in anhydrous dimethylformamide at room temperature provides a general method for the synthesis of nucleoside‐5′‐diphosphates. The novelty of the approach is to use the triethylammonium salt of 5′‐monophosphate nucleoside derivative prior to the imidazolate reaction with imidazole, triphenylphosphine, and 2,2′‐dithiodipyridine. Deprotection, followed by displacement of the imidazole moiety using tributylammonium orthophosphate and a catalytic amount of zinc chloride in dimethylformamide gave the desired 5′‐diphosphate products. The triethyl ammonium salt of 5′‐diphosphate nucleosides was purified by flash chromatography using DEAE (diethylaminoethyl weak anion exchange resin) Sepharosa fast flow packed in an XK 50/60 column on an Akta FPLC (Fast Protein Liquid Chromatography). Synthesis procedures are reported for adenosine‐5′‐diphosphate, uridine‐5′‐diphosphate, cytidine‐5′‐diphosphate, and guanosine‐5′‐diphosphate. Yields for the displacement reactions ranged from 95 to 97%. Thus, this method offers the advantages of shorter reaction time, greater product yield, and a more cost‐effective synthetic route.     

5′-鸟嘌呤核苷三磷酸(5′-GTP)和5′-尿嘧啶核苷三磷酸(5′-UTP)二钠盐的制备

前言核苷三磷酸是含有两个高能磷酸键的高能化合物。除了参与核糖核酸合成外,在生物体内的生命活动中起着重要的作用。ATP 主要用于供给合成细胞的物质所需要的能量,也是被称为“第二信使”的环化AMP(3′5′-cyclicAMP)的前体。而后者已知与多种生化过程有关。CTP 参与重要磷脂类的合成。GTP 在蛋白质合成中是必不可少的。UTP 是肝脏中重要解毒剂尿二磷葡萄糖醛酸(UDPG)的前体,与肝糖元、酸性粘多糖的合成密切相关。根据已知的生理功能有些兄弟研究单位作了一些临床应用试验,还值得进一步探讨。     

Study of Phase Transformation of Guanosine 5′-Monophosphate in Drowning-Out Crystallization

The present study used a mechanistic approach to control the phase transformation of guanosine 5′-monophosphate (GMP) via the operating conditions of agitation and feed concentration during drowning-out crystallization. First, Fourier transform infrared and UV/vis spectrophotometry were successfully applied to monitor the mass fraction of GMP polymorphs (amorphous and hydrate crystalline GMPs) and GMP supersaturation, respectively, during the crystallization. The phase transformation of amorphous GMP into hydrate crystals was significantly influenced by the agitation, which promoted the mass transfer of GMP dissolution and growth. Therefore, the phase transformation was quickly finished when increasing the agitation speed. However, a high agitation caused breakage of the hydrate crystals, resulting in a reduced crystal size with a bimodal distribution. The phase transformation was also influenced by the GMP feed concentration, as the crystal growth was promoted and the crystal size increased when increasing the feed concentration up to 61 g/l. However, a further increase in the feed concentration caused secondary nucleation due to the induction of a high supersaturation level during the phase transformation, leading to a small crystal size with a bimodal distribution. In addition, the rectangular-shaped hydrate GMP crystals exhibited a higher growth rate in the b direction rather than the a direction. Therefore, the crystal morphology shifted from a long rectangle to a square when increasing the feed concentration.