Dopaminergic agonists: comparative actions of amine and sulfonium analogues of dopamine

Sulfur-Mediated Electrophilic Cyclization of Aryl-Substituted Internal Alkynes

A sulfur-mediated electrophilic cyclization reaction of aryl-tethered internal alkynes has been developed. Triflic anhydride-activated sulfoxides induced the electrophilic cyclization and then demethylation with triethylamine in one pot, affording 3-sulfenyl-1,2-dihydronaphthalenes and related types of products in yields of ≤96%.

Synthesis, biological evaluation and mechanism study of a class of benzylideneindanone derivatives as novel anticancer agents

Our findings revealed the benzylideneindanone moiety as a new attractive scaffold for mitosis-targeting drug discovery.

12-N-Methylated 5,6-dihydrobenzo[c]acridine derivatives: a new class of highly selective ligands for c-myc G-quadruplex DNA

12-N-Methylated and non-methylated 5,6-dihydrobenzo[c]acridine derivatives were designed and synthesized as new series of c-myc G-quadruplex binding ligands. Their interactions with c-myc G-quadruplex were evaluated using fluorescence resonance energy transfer (FRET) melting assay, circular dichroism (CD) spectroscopy, surface plasmon resonance (SPR), polymerase chain reaction (PCR) stop assay, and molecular modeling. Compared with the non-methylated derivatives, 12-N-methylated derivatives had stronger binding affinity and stabilizing ability to c-myc G-quadruplex structure, and could more effectively stack on the G-quartet surface. All these derivatives had high selectivity for c-myc G-quadruplex DNA over duplex DNA. The reverse transcription (RT) PCR assay showed that compound 21c could down-regulate transcription of c-myc gene in Ramos cell line containing NHE III(1) element, but had no effect in CA46 cell line with NHE III(1) element removed.

Synthesis of benzyl substituted naphthalenes from benzylidene tetralones

A convenient and efficient synthesis of novel highly substituted dimethoxybenzylnaphthalenes, which are precursors to several dihydroxynaphthoic acids, is described. The approach involves the use of aldol chemistry to provide a number of benzylidene tetralones, which are converted to the target naphthalenes in three steps, with good to excellent yields. Grignard reaction of intermediate benzyl tetralones provided 1-substituted benzyl naphthalenes. The reported synthesis is flexible and scalable and provides access to naphthalenes having a variety of substitution patterns. These benzyl substituted naphthalenes are being converted to naphthoic acids and the bioactivities of these compounds are currently being investigated.

Synthesis of 8-thiabicyclo[3.2.1]octanes and their binding affinity for the dopamine and serotonin transporters

Cocaine is a potent stimulant of the central nervous system. Its reinforcing and stimulant properties have been associated with inhibition of the dopamine transporter (DAT) on presynaptic neurons. In the search for medications for cocaine abuse, we have prepared 2-carbomethoxy-3-aryl-8-thiabicyclo[3.2.1]octane analogues of cocaine. We report that this class of compounds provides potent and selective inhibitors of the DAT and SERT. The selectivity resulted from reduced activity at the SERT. The 3beta-(3,4-dichlorophenyl) analogue inhibits the DAT and SERT with a potency of IC(50)=5.7 nM and 8.0 nM, respectively. The 3-(3,4-dichlorophenyl)-2,3-unsaturated analogue inhibits the DAT potently (IC(50)=4.5 nM) and selectively (>800-fold vs SERT). Biological enantioselectivity of DAT inhibition was limited for both the 3-aryl-2,3-unsaturated and the 3alpha-aryl analogues (2-fold), but more robust (>10-fold) for the 3beta-aryl analogues. The (1R)-configuration provided the eutomers.

Convergent synthesis of fully functionalized ring C allocolchicinoids. Benzannulation approach

[reaction: see text]. A novel convergent approach to fully functionalized ring C allocolchicinoids is developed which is based on the benzannulation reaction of Fischer carbene complexes with alkynes. The efficacy of this strategy was established with the conversion of bromide 1a (R1 = Me, R2 = H) to the biaryl phenol 3a (R = Me, R(L) = Pr, R(S) = H) via the carbene complex 2a. Bromide 1b (R1 = t-Bu, R2 = OMe) was then used for the analogous preparation of the diastereomeric allocolchicinoids 3b (R = Me, R(L) = Pr, R(S) = H).

2-Carbomethoxy-3-aryl-8-oxabicyclo[3.2.1]octanes: potent non-nitrogen inhibitors of monoamine transporters

Cocaine is a potent stimulant of the mammalian central nervous system. Its reinforcing and stimulant properties have been associated with its propensity to bind to monoamine transporter systems. It has generally been assumed that the amino function on monoamines is a requirement for binding to monoamine transporters. In particular, the 8-amino function on the tropane skeleton of cocaine and cocaine analogs has been assumed to provide an ionic bond to the aspartic acid residue on the dopamine transporter (DAT). We have prepared the first 8-oxa analogs of the 3-aryltropanes (WIN compounds) and have found that the 3 beta-(3,4-dichlorophenyl) (6g) and 3 alpha-(3,4-dichlorophenyl) (7g) analogs are particularly potent (IC50 = 3.27 and 2.34 nM, respectively) inhibitors of the dopamine transporter. We now describe the synthesis and biology of the family of 2-carbomethoxy-3-aryl-8-oxabicyclo[3.2.1]octanes and demonstrate that an amino nitrogen is not required for binding to the DAT.