77398-79-9Relevant academic research and scientific papers
On the chemoselectivity and mechanism of desilylation of tert- butyldimethylsilyl ethers with TMSOTf
Hunter, Roger,Hinz, Wolfgang,Richards, Philip
, p. 3643 - 3646 (2007/10/03)
A modified literature procedure is presented for desilylating primary and secondary tert-butyldimethylsilyl ethers involving TMSOTf followed by breakdown of the bis-silyloxonium ion in methanol. The chemoselectivity of the process with respect to TBDPS, T
Enantiospecific syntheses of leukotrienes C4, D4 and E4 and [14,15-3H2]leukotriene E4 dimethyl ester
Cohen,Banner,Lopresti,et al.
, p. 3661 - 3672 (2007/10/02)
A 'chiral-pool' approach was employed to synthesize various leukotrienes (slow-reacting substance of anaphylaxis, SRS-A) enantiospecifically. The pivotal (S,S)-trans-epoxy alcohol 9 was prepared by efficient and facile routes starting from erythorbic acid (D-araboascorbic acid, 13). This epoxide could also be produced starting from D-glucose. The epimeric (S,R)-cis-epoxide 38 was obtained utilizing L-tartaric acid as the chiral starting material. Elaboration of 9 into leukotriene A4 methyl ester (5) and the potassium salts of leukotrienes C4 (4a), D4 (4b), and E4 (4c) was accomplished by standard methods. These salts exhibited potent contractile activities in the in vitro guinea pig ileum assay. Reduction of 14,15-dehydroleukotriene A4 methyl ester (44) with tritium gas gave [14,15-3H2]-5 and subsequently the dimethyl ester of [14,15-3H2]leukotriene E4 having a high specific activity of 40 Ci/mmol.
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.
Synthesis of optically active leukotriene (SRS-A) intermediates
Cohen, Noal,Banner, Bruce L.,Lopresti, Rocco J.
, p. 4163 - 4166 (2007/10/02)
In an approach to SRS-A and analogues thereof, the key (5S, 6S)-epoxy alcohol 9 and its 6-epimer 18 were prepared starting from D-araboascorbic acid and L-diethyl tartrate, respectively.
