81691-58-9Relevant academic research and scientific papers
Controlling Selectivity in Alkene Oxidation: Anion Driven Epoxidation or Dihydroxylation Catalysed by [Iron(III)(Pyridine-Containing Ligand)] Complexes
Tseberlidis, Giorgio,Demonti, Luca,Pirovano, Valentina,Scavini, Marco,Cappelli, Serena,Rizzato, Silvia,Vicente, Rubén,Caselli, Alessandro
, p. 4907 - 4915 (2019)
A highly reactive and selective catalytic system comprising Fe(III) and macrocyclic pyridine-containing ligands (Pc-L) for alkene oxidation by using hydrogen peroxide is reported herein. Four new stable iron(III) complexes have been isolated and characterized. Importantly, depending on the anion of the iron(III) metal complex employed as catalyst, a completely reversed selectivity was observed. When X=OTf, a selective dihydroxylation reaction took place. On the other hand, employing X=Cl resulted in the epoxide as the major product. The reaction proved to be quite general, tolerating aromatic and aliphatic alkenes as well as internal or terminal double bonds and both epoxides and diol products were obtained in good yields with good to excellent selectivities (up to 93 % isolated yield and d.r.=99 : 1). The catalytic system proved its robustness by performing several catalytic cycles, without observing catalyst deactivation. The use of acetone as a solvent and hydrogen peroxide as terminal oxidant renders this catalytic system appealing.
STEREOSPECIFIC SYNTHESIS OF ISOMERIC 4-SUBSTITUTED 9-(2,3-DIHYDROXYBUTYL)ADENINES
HOLY, Antonin
, p. 173 - 189 (2007/10/02)
Reduction of ethyl 2,3-O-isopropylidene-D-tartrate with sodium borohydride afforded (4S,5S)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol (Va) which was benzoylated to give monobenzoyl derivative Vd and further transformed into p-toluenesulfonyl derivative Ve.Reaction of the compound Ve with sodium salt of adenine followed by methanolysis gave 2,3-O-isopropylidene derivative Vf which on acid hydrolysis afforded 9-(2S,3S)-(2,3,4-trihydroxybutyl)adenine (Ia).The enantiomer IIa was obtained from 3,4-O-isopropylidene-D-mannitol via (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol (VIa) using the same procedure.Reaction of compounds Vf and VIf with p-toluenesulfonyl chloride afforded 4-O-p-toluenesulfonyl derivatives Vg and VIg.These compounds were also obtained from Va and VIa via di-p-toluenesulfonyl derivatives Vc and VIc by reaction with sodium salt of adenine.Treatment of compounds Vg and VIg with sodium iodide gave 4-iodo derivatives Vh and VIh which on reaction with tri-n-butyltin hydride, followed by acid hydrolysis, afforded enantiomeric threo-2,3-dihydroxybutyl derivatives Ib and IIb.Compounds Vg and VIg on treatment with sodium azide, subsequent catalytic hydrogenation of the intermediates Vj and VIj and acid hydrolysis afforded enantiomeric threo-9-(4-amino-2,3-dihydroxybutyl)adenines (Ic, IIc).Reaction of methyl threo-3-phenylglycerate (VIIb) with acetone, followed by reduction with lithium aluminum hydride, gave 2,2-dimethyl-4-phenyl-1,3-dioxolane-5-methanol (VIIIb) which was converted by reaction with p-toluenesulfonyl chloride, condensation with sodium salt of adenine and acid hydrolysis into 9-(RS)-threo-(3-phenyl-2,3-dihydroxypropyl)adenine (I, IId).Methyl ester of D-eritadenine (IXb) was transformed into 2,3-O-isopropylidene derivative XIa which on reduction with sodium borohydride afforded the alcohol XIb.Its acid hydrolysis gave 9-(2R,3S)-erythro-(2,3,4-trihydroxybutyl)adenine (IIIa); tosylation of compound XIb, successive treatment with sodium iodide and tri-n-butyltin hydride and acid hydrolysis afforded 9-(2R,3S)-erythro-(2,3-dihydroxybutyl)adenine (IIIb).The enantiomers IVa and IVb were obtained analogously from L-eritadenine.The racemic derivative Ib + IIb was prepared from (RS)-threo-2,3-dihydroxybutyric acid via p-toluenesulfonyl derivative of racemic 2,2,4-trimethyl-1,3-dioxolane-5-methanol (IIIc) by reaction of sodium salt of adenine followed by acid hydrolysis.
