Novel lavendamycin analogues with various substituents were synthesized and evaluated as potential NAD(P)H:quinone oxidoreductase (NQO1)-directed antitumor agents. Pictet-Spengler condensation of quinoline- or quninoline-5,8-dione aldehydes with tryptamine or tryptophans yielded the lavendamycins. Metabolism studies with recombinant human NQO1 revealed that addition of NH2 and CH2OH groups at the quinolinedione-7-position and indolopyridine-2'-position had the greatest positive impact on substrate specificity. The best and poorest substrates were 37 (2'-CH2OH-7-NH2 derivative) and 31 (2'-CONH2-7-NHCOC3H7-n derivative) with reduction rates of 263 +/- 30 and 0.1 +/- 0.1 micromol/min/mg NQO1, respectively. Cytotoxicity toward human colon adenocarcinoma cells was determined for the lavendamycins. The best substrates for NQO1 were also the most selectively toxic to the NQO1-rich BE-NQ cells compared to NQO1-deficient BE-WT cells with 37 as the most selective. Molecular docking supported a model in which the best substrates were capable of efficient hydrogen-bonding interactions with key residues of the active site along with hydride ion reception.

The novel 7-(N-formyl-, 7-(N-acetyl-, and 7-(N-isobutyrylamino)-2-methylquinoline-5,8-diones were synthesized in excellent overall yields in three steps via the nitration of the commercially available 8-hydroxy-2-methylquinoline followed by a reduction-acylation step and then oxidation. Acid hydrolysis of 7-(N-acetylamino)-2-methylquinoline-5,8-dione (14a) afforded the novel 7-aminoquinoline-5,8-dione 7 in excellent yields. Due to our efficient preparation of dione 14a, we now report a short and practical method for the total synthesis of the potent antitumor agent lavendamycin methyl ester (1b) with an excellent overall yield.

A series of 7-N-acyllavendamycins with zero, one or two substituents at the C-2', C-3', and C-11' were synthesized through short and efficient methods. Pictet-Spengler condensation of 7-N-acylamino-2-formylquinoline-5,8-diones with tryptamine or tryptophans produced the desired lavendamycins. Screening data on a panel of three ras oncogene-transformed cell lines and the non-transformed parent cell line showed that a significant number of these analogues are potent antitumor agents and appear to be particularly active against K-ras transformed cells. Compared with the corresponding quinolinediones, these novel lavendamycins are much more inhibitory toward the transformed cells indicating that the beta-carboline moiety of the lavendamycin analogues plays an important role in its potency and selective toxicity.

[reaction: see text] The efficient construction of an ingenol intermediate exhibiting "insideminus signoutside" intrabridgehead stereochemistry is reported. The sequence features the net conversion of a cis-intrabridgehead compound into a highly strained trans-species via palladium-mediated isomerization of an allylic epoxide followed by a low-temperature alkoxide-accelerated 1,5-hydrogen migration.

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(+)-Methyl 4β-(4-chlorophenyl)-1-methylpiperidine-3α-carboxylate hydrochloride (CTDP 31,446) is known as a dopamine reuptake inhibitor. This cocaine analogue lacking the tropane skeleton is being considered for potential treatment of cocaine addiction. Herein we report the development of a scalable process for the preparation of this compound. This study was mainly aimed at improving the process throughput, eliminating chromatographic purifications for the separation of (±)-6-cis isomer from (±)-6-trans isomer, and developing a robust crystallization for isolation of pure (±)-6-cis in a single crop with a good mass recovery. The process development work also highlights an efficient recycle of (±)-6-trans via a kinetic epimerization followed by crystallization of the resulting (±)-6-cis isomer. The resolution of (±)-6-cis and the crystallization of the final HCl salt were optimized and implemented to afford CTDP-31,446 with high purity and good mass recovery.

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Highly Efficient and Practical Syntheses of Lavendamycin MethylEster and Related Novel Quinolindiones.-An efficient method for the preparation of multigram amounts of the potent antitumor agent lavendamycin methyl ester (VI) is reported. The procedure is based on a novel route to the dione intermediate (V). -(BEHFOROUZ, M.; HADDAD, J.; CAI, W.; ARNOLD, M. B.; MOHAMMADI, F.; SOUSA, A. C.; HORN, M. A.;