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D P Curran

Publications and source records attributed to D P Curran.

22 records · Page 2Linked to original sources
PubMed1989

Photoaffinity labeling of the mammalian dopamine transporter.

A high affinity (1-2 nM) radioiodinated, photoaffinity probe for the dopamine transporter, 1-(2-[bis-(4-fluorophenyl)-methoxylethyl)-4-(2-[4-azido-3- [125I]iodophenyl]ethyl)piperazine ([125I]FAPP) has been synthesized. Upon photolysis, [125I]FAPP incorporates into a striatal polypeptide of apparent Mr 62,000 as visualized by autoradiography following sodium dodecyl sulfate-PAGE. Photoincorporation of [125I]FAPP into the Mr 62,000 polypeptide was stereoselectively inhibited by various dopamine uptake agents with a potency order typical of the dopamine transporter. The glycoprotein nature of the apparent Mr 62,000 polypeptide was assessed following specific exo- and endoglycosidase treatment. The dopamine transporter appears to be associated with complex-type oligosaccharides as indexed by its susceptibility to neuraminidase but not alpha-mannosidase digestion. Complete N-linked deglycosylation of the neuronal dopamine transporter with the endoglycosidase, glycopeptidase-F, increased the electrophoretic mobility of the 62 kDa polypeptide to apparent Mr 48,000. [125I]FAPP should prove to be a useful probe for the molecular characterization of the dopamine uptake site in various tissues and under certain pathophysiological states.

Affinity Labels↗
PubMed1987

Selective mono-Claisen rearrangement of carbohydrate glycals. A chemical consequence of the vinylogous anomeric effect.

The mono-Claisen rearrangement of carbohydrate glycals is demonstrated to be a synthetically useful and mechanistically significant reaction. Addition of per-O-acetyl glycal-tert-butyldimethylchlorosilane mixture to lithium diisopropylamide generated a bis (or tris)ketenesilylacetal which, upon heating, underwent smooth mono-Claisen rearrangement to provide a C-glycosyl compound after methylation. A second apparently similar Claisen rearrangement required significantly higher temperatures in all cases. Thus, similar hydroxy groups were differentiated without resort to selective protection. A stereoelectronic rationale based on the newly-introduced vinylogous anomeric effect (VAE) is put forth to explain the accelerated Claisen rearrangements of these glycals. Molecular orbital and resonance descriptions of the VAE are included, and the VAE is also used to rationalize ground-state conformational preferences of carbohydrate glycals. The C-glycosyl compounds produced by mono-Claisen rearrangement were suitable for Pd(0)-catalyzed allylic alkylations, providing an unusually facile entry into the pseudomonic acid-ring systems. A nine-step synthesis of a known precursor of pseudomonic acid C is reported.

Aldehydes↗
PubMedDate not supplied

Solution phase synthesis of libraries of polycyclic natural product analogues by cascade radical annulation: synthesis of a 64-member library of mappicine analogues and a 48-member library of mappicine ketone analogues.

An improved cascade radical annulation route to (+/-)-mappicine, (S)-mappicine, and mappicine ketone is reported. The route is used to prepare libraries of mappicine and mappicine ketone analogues in a semiautomated fashion. Key diversity generating steps include the addition of an aldehyde to a Grignard reagent derived from a D-ring iodopyridine, N-propargylation of a subsequently derived iodopyridone, and cascade radical annulation with an isonitrile to form a mappicine analogue. Parallel oxidation of mappicine analogues produced mappicine ketones. The route is general and flexible and could be used to make very large libraries. It is also illustrative of how late stage cascade reactions can be employed strategically to generate libraries of polycyclic natural product analogues.

Alkaloids↗