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Since gaining approval for the treatment of chronic lymphocytic leukemia (CLL), the BCL-2 inhibitor venetoclax has transformed the treatment of this and other blood-related cancers. Reflecting the large and hydrophobic BH3-binding groove within BCL-2, venetoclax has significantly higher molecular weight and lipophilicity than most orally administered drugs, along with negligible water solubility. Although a technology-enabled formulation successfully achieves oral absorption in humans, venetoclax tablets have limited drug loading and therefore can present a substantial pill burden for patients in high-dose indications. We therefore generated a phosphate prodrug (3, ABBV-167) that confers significantly increased water solubility to venetoclax and, upon oral administration to healthy volunteers either as a solution or high drug-load immediate release tablet, extensively converts to the parent drug. Additionally, ABBV-167 demonstrated a lower food effect with respect to venetoclax tablets. These data indicate that beyond-rule-of-5 molecules can be successfully delivered to humans via a solubility-enhancing prodrug moiety to afford robust exposures of the parent drug following oral dosing.

1. Measured pKa values of ABBV-167 (Table S1. Ionization constants of ABBV-167) 2. Preparation of ABBV-167 on large scale (Scheme S1: Synopsis of GMP synthesis of ABBV-167) 3. Preparation of clinical ABBV-167 drug supply 4. Animal pharmacokinetics (Table S2. Single dose pharmacokinetics of prodrug 3 and parent venetoclax in mouse and dog after IV dosing of prodrug 3. Table S3. Single dose pharmacokinetics of 3 after oral dosing in mouse and dog. Table S4. Single dose pharmacokinetics of parent venetoclax in mouse and dog after oral dosing of 3.) 5. Clinical study (Study design, Pharmacokinetic and statistical analysis, Safety and tolerability assessments, Clinical pharmacokinetic results, Table S5. Effect of prodrug and food on venetoclax bioavailability, Safety results) 6. Crystallography methods (Protein preparation. BCL-2 ABBV-167 complex crystallization. X-ray structure determination. Table S6. Diffraction data collection and refinement statistics for BCL-2 in complex with ABBV-167 (PDB code 7LHB))

Since gaining approval for the treatment of chronic lymphocytic leukemia (CLL), the BCL-2 inhibitor venetoclax has transformed the treatment of this and other blood-related cancers. Reflecting the large and hydrophobic BH3-binding groove within BCL-2, venetoclax has significantly higher molecular weight and lipophilicity than most orally administered drugs, along with negligible water solubility. Although a technology-enabled formulation successfully achieves oral absorption in humans, venetoclax tablets have limited drug loading and therefore can present a substantial pill burden for patients in high-dose indications. We therefore generated a phosphate prodrug (3, ABBV-167) that confers significantly increased water solubility to venetoclax and, upon oral administration to healthy volunteers either as a solution or high drug-load immediate release tablet, extensively converts to the parent drug. Additionally, ABBV-167 demonstrated a lower food effect with respect to venetoclax tablets. These data indicate that beyond-rule-of-5 molecules can be successfully delivered to humans via a solubility-enhancing prodrug moiety to afford robust exposures of the parent drug following oral dosing.

The process development of a new synthetic route leading to an efficient and robust synthetic process for venetoclax (1: the active pharmaceutical ingredient (API) in Venclexta) is described. The redesigned synthesis features a Buchwald-Hartwig amination to construct the core ester 23c in a convergent fashion by connecting two key building blocks (4c and 26), which is then followed by a uniquely effective saponification reaction of 23c using anhydrous hydroxide generated in situ to obtain 2. Finally, the coupling of the penultimate core acid 2 with sulfonamide 3 furnishes drug substance 1 with consistently high quality. The challenges and solutions for the key Pd-catalyzed C-N cross-coupling will also be discussed in detail. The improved synthesis overcomes many of the initial scale-up challenges and was accomplished in 46% overall yield from 3,3-dimethyldicyclohexanone (6), more than doubling the overall yield of the first generation route. The new process was successfully implemented for producing large quantities of 1 with99% area purity.

Thermal hazard analyses of two reactions, one with DMSO as the solvent and a reactant and one with DMSO as the solvent and a byproduct, identified low-probability but severe consequence process risks associated with violent decomposition of DMSO during heating control failure or external heating. Although DMSO cannot be totally eliminated from these reactions, using an alternative solvent to replace DMSO proved to be an effective measure in reducing the thermal hazards to allow safe scale-up.

2,4-Dichloro-5,5-dimethylhydantoin (DCDMH) was found to be a mild and efficient reagent for the direct oxidative conversion of sulfur compounds to the corresponding arenesulfonyl chlorides in good to excellent yields through oxidative chlorination. The method is suitable for many types of sulfur substrates (thiols, disulfides, and benzylic sulfides). The overall process is simple, practical, and it provides convenient access to a variety of aryl or heteroarylsulfonyl chlorides. The mild reaction conditions and the broad substrate scope render this method attractive and complementary to existing syntheses of aryl or heteroarylsulfonyl chlorides.

A facile and scaleable synthesis of potent and selective histamine H3 receptor antagonist 1 is described, starting from commercially available 6-bromo-naphthalene-2-carboxylic acid methyl ester 3a. The key intermediate, 2-(6-bromonaphthalen-2-yl)ethanol 5 was prepared in good yield (78%) and purity (99%) via a one-carbon homologation of 3a. The coupling of 5 with pyridazinone 12 was accomplished effectively by a copper-catalyzed cross-coupling reaction. Activation of the hydroxyl group of 4, followed by displacement reaction with 2(R)-methylpyrrolidine 13, afforded the free base of 1, which was subsequently converted to its corresponding salt. The new process consisted of eight chemical steps and one salt formation step and required no chromatographic purification throughout the synthesis. It has been successfully implemented on pilot plant scale to prepare over 10 kg quantities of the target compound 1 in 43% overall yield in high purity (99%) and with the desired physical properties.

A stereoselective synthesis of the hydroxyethylene dipeptide isostere 1 is described. The route employs a substrate-directed kinetic protonation of an alpha/gamma-substituted lactone to afford the desired stereochemistry. A method for converting the diastereomerically enriched intermediate lactone to the ring-open form with retention of stereochemistry is demonstrated. A novel procedure for utilizing N,N-dibromo-5,5-dimethylhydantoin in Hofmann rearrangements is disclosed. This route was used to prepare amino alcohol 1, the core portion of the HIV protease inhibitor A-792611, in 46% yield from phenylalanine-derived epoxide 2.

An efficient and convergent process for the preparation of a potent and selective H 3 receptor antagonist, ABT-239, 1A was accomplished with an overall yield of 64%. The key step in the synthesis is a Sonogashira coupling/cyclization reaction of 1-but-3-ynyl-2-( R )-methylpyrrolidine ( 9 ) with 4′-hydroxy-3′-iodo-biphenyl-4-carbonitrile ( 3 ). Additionally, the key amine component 2-( R )-methylpyrrolidine ( 7 ) was effectively synthesized from the readily available Boc- l -prolinol with a simple catalytical hydrogenolysis as the key step. This column chromatography-free process is highlighted by several simple work-up and purification procedures and is amendable to the large-scale preparation of 1A .

A practical and highly efficient process for the preparation of β-arylethylamines 7 was developed. Benzylic organozinc compounds 10 were reacted with the iminium salts 9 generated in situ from the amine salt 8 and paraformaldehyde in one pot and in a polar and aprotic solvent, such as NMP. A variety of the β-arylethylamines were prepared in 43–91% yields.

A facile and scaleable synthesis of a potent and selective histamine H3 receptor antagonist, ABT-239 (1), was developed starting from commercially available 4‘-hydroxy-biphenyl-4-carbonitrile (2). The synthesis comprised four chemical steps and a salt formation step with an overall yield of 40%. A highly selective monoiodination of a phenol was developed and used to prepare iodophenol (3b) in near quantitative yield using NIS in AcOH in the presence of a small amount of H2SO4. A Pd-catalyzed cross coupling reaction of the iodophenols (3b) with butyn-3-ol (4a) provided benzofuran (5) in one step in >80% yield, en route to 1. The new process required no chromatographic purification throughout the synthesis and was successfully demonstrated on scale-up to prepare 1.7 kg of the target ABT-239 (1).

14C-Labeled CI-1012 and CI-1013 of the 2,2′-dithiobis[benzamide] and benzisothiazolone series, inhibitors of viral replication and potential anti-HIV agents, were prepared. The radiolabeling of CI-1013, a six-step synthetic sequence, started with the treatment of N-t-BOC-aniline (2) with 2·0 equivalents of t-BuLi, followed by carboxylation of the ortho-lithiated center in the resulting lithiated dianion 2b with [14C]carbon dioxide, to give N-t-BOC-2-Amino-[7-14C]benzoic acid (3). Product 3 was then deprotected with trifluoroacetic acid to give 2-Amino-[7-14C]benzoic acid as its TFA salt (4). The latter was diazotized and treated with Na2S2, generated in situ, to give 2,2′-dithiobis[7-14C]benzoic acid (5). The acid chloride from 5, obtained by treatment with thionyl chloride, was subsequently coupled with L-isoleucine tert-butyl ester and deprotected with TFA to produce [S-(R*,R*)]-2-{2-[2-(1-Carboxy-2-methylbuty)[14C]carb-amoyl)phenyldisulfanyl]-[7-14C]benzoylamino}-3-methylpentanoic acid ([14C2]CI-1013) (8). Treatment of 8 with bromine yielded the benzisothiazolene, [S(R*,R*)]-3-Methyl-2-(3-oxo-3H-[3-14C]benz[d]isothiazol-2-yl)pentanoic acid ([14C]CI-1012) (9). Copyright © 1999 John Wiley & Sons, Ltd.

Malachite green (MG), a traditional agent used in aquaculture, is structurally related to other carcinogenic triphenylmethane dyes. Although MG is not approved for use in aquaculture, its low cost and high efficacy make illicit use likely. We developed sensitive and specific methods for determination of MG and its principal metabolite, leucoMG (LMG), in edible fish tissues using isotope dilution liquid chromatography atmosphere pressure chemical ionization mass spectrometry. MG and LMG concentrations were measured in filets from catfish treated with MG under putative use conditions (ca. 250 and 1000 ppb, respectively) and from commercial trout samples (0–3 and 0–96 ppb, respectively). Concentrations of LMG in edible fish tissues always exceeded those of MG. A rapid cone voltage switching acquisition procedure was used to simultaneously produce molecular ions for quantification and diagnostic fragment ions for confirmation of MG and metabolites. The accurate and precise agreement between diagnostic ion intensity ratios produced by LMG in authentic standards and incurred fish samples was used to unambiguously confirm the presence of LMG in edible fish tissue. This suggested the validity of using LMG as a marker residue for regulatory determination of MG misuse. Additional metabolites derived from oxidative metabolism of MG or LMG (demethylation and N-oxygenation) were identified in catfish and trout filets, including a primary arylamine which is structurally related to known carcinogens. The ability to simultaneously quantify residues of MG and LMG, and to confirm the chemical structure of a marker residue by using LC/MS, suggests that this procedure may be useful in monitoring the food supply for the unauthorized use of MG in aquaculture. © 1998 John Wiley & Sons, Ltd.

Heterocyclic aromatic amines (HAAs) are formed in cooked meats through pyrolysis reactions of different amino acids in the presence or absence of creatine/creatinine and sugars. HAAs are mutagens, colon/mammary gland carcinogens in rodents, and are suspected in the etiology of human cancers. In this study, cooked meats containing incurred HAAs as well as control (microwave) meat, were spiked with four labeled HAA internal standards (MeIQx, IQ, AAC and PhIP) and extracted using a liquid/liquid cleanup procedure. Isotope dilution measurements were made using on‐line liquid chromatography atmosphere pressure chemical ionization tandem mass spectrometry with multiple reaction monitoring to provide the sensitivity and specificity needed for trace analysis in these complex matrices. The procedure was validated using control meat spiked with the four native HAAs at 0–50 ppb. The levels of HAAs found in cooked meats ranged from non‐detectable (limit of detection 0.1–1.0 ppb) in microwave‐cooked hamburger to 226 ppb PhIP and 104 ppb AAC in well‐done grilled chicken. This methodology has the potential to provide accurate data on the consumption of HAAs in the diet for use in human cancer risk assessment.

4-Chloromethylbenzofuran (10) was synthesized from 2,3-dimethylanisole in 7 steps. The corresponding Grignard reagent prepared from magnesium-anthracene complex reacts with 14CO2, SOCl2, and PD130812 successively to give [14C]enadoline (2), a non-peptide, selective kappa opioid receptor agonist. This method could be readily modified for the rapid, one-pot synthesis of [11C]enadoline.

The carbonyl groups in several artemisinin derivatives were converted into geminal difluorinated compounds on treatment with diethylaminosulfur trifluoride. A number of other mono- and polyfluorinated artemisinin derivatives were prepared. Their in vitro antimalarial activities were all equal to or greater than the nonfluorinated analogs or precursors.

Novel silica gel-catalysed reactions of dihydroartemisinin 1b to deoxyartemisinin 11 and 11β-hydroxy-11-epidihydroartemisinin 8 to compound 9 under mild conditions are described. The structures of the products were determined by mass spectrometry and 1D- and 2D-NMR spectroscopy. A mechanism for their formation is proposed.

The triphenylphosphine hydrobromide-catalyzed addition of a proton from ethanol to anhydrodihydroartemisinin (5) has been employed for the synthesis of 2 and 4 Use of 1.5 equivalents of EtO2H or EtO3H yielded 11-[3H]-β-arteether as the major product.

The magnitude and sign of the characteristic circular dichroism spectrum of bilirubin bound to human serum albumin are highly sensitive to the presence of trace amounts of dissolved chloroform. The presence of b-40 mM chloroform in an aqueous solution containing 0.25 mM bilirubin and 0.44 mM albumin is sufficient to cause complete inversion of the circular dichroism curve obtained without chloroform. Addition of chloroform to the albumin solution before or after the bilirubin has the same effect. The sign inversion is not due to a chemical reaction because it was reversed completely on removal of chloroform, regenerating curves characteristic of chloroform-free solutions

Iodoacetylene 1 was prepared in situ from the reactions of ethynylmagnesium bromide or tributyl(ethynyl)tin with iodine. It was used as a dipolarphile in the [2 + 3] cyclization reaction with 1,3-dipolar nitrile oxide derivatives to produce 2-(5-iodoisoxazol-3-yl)pyridine 2 and 3-(4-fluorophenyl)-5-iodoisoxazole 8 in good yield (70-90%). Subsequently, several 5-substituted isoxazole derivatives 3 were obtained by Pd-catalyzed reactions. [reaction: see text]

2,4-Dichloro-5,5-dimethylhydantoin (DCDMH) was found to be a mild and efficient reagent for the direct oxidative conversion of sulfur compounds to the corresponding arenesulfonyl chlorides in good to excellent yields through oxidative chlorination. The method is suitable for many types of sulfur substrates (thiols, disulfides, and benzylic sulfides). The overall process is simple, practical, and it provides convenient access to a variety of aryl or heteroarylsulfonyl chlorides. The mild reaction conditions and the broad substrate scope render this method attractive and complementary to existing syntheses of aryl or heteroarylsulfonyl chlorides.

Unlike the parent diacid, the dimethyl ester of (αR,α'R)-dimethylmeso-bilirubin-XIIIα exhibits only a weak bisignate circular dichroism (CD) spectrum in a wide variety of solvents. This implies a loss of conformation stabilization afforded (in the diacid) by intramolecular hydrogen bonding, and with it the loss of an allosteric effect that forces the parent acid into the P-helicity conformational enantiomer.

(αRα′R)-Mesobilirubin-XIIIα, a tetrapyrrole dicar☐ylic acid with P-helicity conformation stabilized by intramolecular hydrogen bonding, exhibits intense bisignate circular dichroism in CHCl3 (Δe436max+246, Δe398max−133) and many other solvents, except in (CH3)2SO, where the intensity drops 10-fold (Δe428max+18, Δe393max−9). In contrast, the dicar☐ylate anion exhibits intense circular dichroism in both CHCl3 (Δe438max+194, Δe394max−130) and (CH3SO (Δe433max+260, Δe390max−164).

(4Z,15Z)-Bilirubin IXα, the cytotoxic yellow tetrapyrrole pigment of jaundice, readily adopts either of two interconverting, enantiomeric conformations, which are stabilized through complementary intramolecular hydrogen bonding between the pyrrole and lactam N-H and C=O residues of one dipyrrinone moiety and the CO 2 H group of propionic acid side chains on the second dipyrrinone. One conformational enantiomer can be destabilized relative to the other through allosteric action by judicious placement of methyl groups in the propionic acid side chains. Thus, insertion of a methyl group at the pro-R site on the α-carbon of the propionic acid destabilizes the M-chirality intramolecularly hydrogen-bonded conformational enantiomer by introducing a severe nonbonded CH 3 |CH 3 steric interaction with a pyrrole methyl substituent

N-Arylation of pridazinone derivatives 1 with an aryl or heteroaryl bromide or iodide 2 has been achieved in 70–94% isolated yield using catalytic amounts of the stable and structurally well defined copper catalyst 4b under standard Ullmann–Goldberg reaction conditions. The structure of copper catalyst 4b was characterized by ESI-MS, DSC and the single crystal X-ray.

Synthesis of 12 beta-allyldeoxoartemisinin from dihydroartemisinin and subsequent transformations to other 12 beta-alkyldeoxoartemisinins are described. All compounds were tested in vitro versus two drug-resistant strains (Plasmodium falciparum) of malaria. The in vivo activity and toxicity of the most active compound, 12 beta-propyldeoxoartemisinin, were comparable to that of arteether.

The endoperoxides are a new class of antimalarial agents, of which artemisinin (qinghaosu) is the prototype. We have previously shown that artemisinin is capable of alkylating proteins in model reactions. In the present study, we showed that when Plasmodium falciparum-infected erythrocytes are treated with a radiolabeled antimalarial endoperoxide, either arteether, dihydroartemisinin, or Ro 42-1611 (arteflene), the radioactivity is largely coverted into a form which can be extracted with sodium dodecyl sulfate (SDS). Autoradiograms of SDS-polyacrylamide gels showed that six malarial proteins are radioactively labeled by the three endoperoxides. This labeling occurs at physiological concentrations of drug and is not stage nor strain specific. The labeled proteins were not the most abundant proteins seen on Coomassie-stained gels. No proteins were labeled when uninfected erythrocytes were treated with these drugs, nor when infected erythrocytes were treated with the inactive analog deoxyarteether. Thus, the antimalarial endoperoxides appear to react with specific malarial proteins.

Artemisinin, a sesquiterpene which contains a labile endo-peroxide, is a promising new antimalarial drug. In order to prepare new derivatives that retain the peroxide group critical for biological activity, we employed several derivatives of dihydroartemisinin as substrates for the fungus Beauveria sulfurescens. The best substrate, arteether, yielded two mono-hydroxylated products. In the major product the C-14 methyl had been oxidized whereas the minor product contained a 9β-hydroxyl group. The structures and stereochemistry of the biotransformation products were established by mass spectrometry, 1- and 2D-NMR. The compounds were used as intermediates in the preparation of labelled compounds, an isomeric alcohol and other derivatives. This was the first time the endoperoxide group had not been destroyed in the course of introducing hydroxyl groups in an artemisinin derivative.

Conformational analysis of (4Z, 15Z)-bilirubin-IX(alpha) by molecular mechanics computations reveals a global energy minimum folded conformation. Powerful added stabilization is achieved through intramolecular hydrogen bonding. Theoretical treatment of bilirubin as a molecular exciton predicts an intense bisignate circular dichroism spectrum for the folded conformation: (Delta) (epsilon) is congruent to 270 L (DOT) mole-1 (DOT) cm-1 for the $OM450 nm electronic transition(s). Synthesis of bilirubin analogs with propionic acid groups methylated at the (alpha) or (beta) position introduces an allosteric effect that allows for an optical resolution of the pigments, with enantiomers exhibiting the theoretically predicted circular dichroism.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A new Lewis acid-catalyzed rearrangement of the peroxide group in two 1,2,4-trioxanes, deoxoartemisinin and 12β-allyldeoxoartemisinin, yielding ring enlarged oxide, is described

Bichromophoric (4Z, 15Z)-bilirubin-IX alpha, the yellow-orange cytotoxic pigment of jaundice, adopts either of two intramolecularly hydrogen-bonded enantiomeric conformations that are in dynamic equilibrium in solution. The addition of optically active amines induces the pigment solutions to exhibit intense bisignate circular dichroism in the region of the bilirubin long wavelength uv-visible absorption band. The most intense circular dichroism Cotton effects, (delta epsilon) approximately equal to 130, are induced by beta-arylamines and are comparable to those exhibited by bilirubin complexes with serum albumin and other proteins. Like serum albumin and other proteins, the optically active base acts as a chiral complexation agent to induce an asymmetric transformation of bilirubin, whose induced bisignate circular dichroism Cotton effect is characteristic of exciton splitting of the component pyrromethenone chromophores. The amines thus serve as chiral templates for molecular recognition, and the complementary action of the amine complexation sites provides insight into the binding forces important in protein-bilirubin heteroassociation.