16323-09-4

2-Acetamidophenol (AAP) is an aromatic product with promising activities in agricultural applications and medical research. At present, AAP is synthesized by chemical methods from nonrenewable fossil fuel resources, which cause environmental pollution and the reaction conditions are harsh. In this study, we constructed the artificial biosynthetic pathway of AAP with five different expressed proteins in Escherichia coli for the first time. By introducing the hydrogen peroxide degrading enzyme catalase and improving cell tolerance to toxic intermediates or products, the yield of AAP reached 33.54 mg/L using shaking-flask culture. The best-engineered strain could produce 568.57 mg/L AAP by fed-batch fermentation from glucose and precursor (2-aminophenol, 2-AP) addition. Furthermore, a one-pot whole-cell cascade biocatalytic pathway to AAP and analogues was developed and optimized. This method can efficiently produce 1.8 g/L AAP using the methyl anthranilate hydrolysis product as the substrate. This study provides not only the de novo artificial biosynthetic pathway of AAP in E. coli but also a promising sustainable and efficient strategy to enable the synthesis of AAP on a gram scale.

A novel series of antimalarial benzimidazole derivatives incorporating phenolic Mannich base side chains at the C2 position, which possess dual asexual blood and sexual stage activities, is presented. Structure-activity relationship studies revealed that the 1-benzylbenzimidazole analogues possessed submicromolar asexual blood and sexual stage activities in contrast to the 1H-benzimidazole analogues, which were only active against asexual blood stage (ABS) parasites. Further, the former demonstrated microtubule inhibitory activity in ABS parasites but more significantly in stage II/III gametocytes. In addition to being bona fide inhibitors of hemozoin formation, the 1H-benzimidazole analogues also showed inhibitory effects on microtubules. In vivo efficacy studies in Plasmodium berghei-infected mice revealed that the frontrunner compound 41 exhibited high efficacy (98% reduction in parasitemia) when dosed orally at 4 × 50 mg/kg. Generally, the compounds were noncytotoxic to mammalian cells.

Ru(II)-catalyzed chelation-assisted highly regioselective C8-hydroxylation of 1,2,3,4-tretrahydroquinolines has been developed. Various 1,2,3,4-tetrahydroquinolines underwent smooth C8-H hydroxylation with cheap and safe K2S2O8 as the oxidant and oxygen source to furnish the corresponding products in good to excellent yields with high tolerance of the functional groups. The choice of a readily installable and removable N-pyrimidyl directing group is the key to catalysis. Mechanistic studies suggest the involvement of a six-membered ruthenacycle intermediate in the catalytic cycle. The method can also be extended to the direct hydroxylation of other (hetero)arene C-H bonds.

New synthetic route of N-(4-chloro-3-cyano-7-ethoxyquinolin-6-yl)- acetamide (1) is described on a hectogram scale. The key steps include the intramolecular cyclization of 3-amino-2-(2-chlorobenzoyl)acrylonitrile 22 to give the 3-cyano-4-quinolone 7, which was chlorinated by POCl3 to give the final product 1 in 36.9% yield over 9 steps and 98.9% purity (HPLC). Purification methods of 7 and 1 were also given.

Compounds of formula (I) or pharmaceutically acceptable salts thereof are provided, wherein each of Z, X, R1, R2, R3, R4, y, n, and Ar are as defined, and described in classes and subclasses herein, which are agonists or partial agonists of the 2C subtype of brain serotonin receptors. The compounds, and compositions thereof, are useful for treating a variety of central nervous system disorders such as schizophrenia.

The invention provides compounds of formula (I) wherein m, R1, n, R2, q, X, Y, Z, R3, R4, R5, R6, R7, R8, t and R9 are as defined in the specification, processes for their preparation, pharmaceutical compositions containing them and their use in therapy.

Rate and product yield data for the decomposition of the ester derivatives of N-arylhydroxylamines and N-arylhydroxamic acids 1a-i in aqueous solution in the presence of N3- support a mechanistic scheme (Scheme 5) in which the trapping by N3- changes from trapping of the free ion, to trapping of an ion pair, to a preassociation process as the ion becomes more reactive.When the rate constant for trapping of the free ion by solvent, ks, 8 s-1, trapping by both N3- and solvent occurs almost exclusively at the free ion.When 108 s-1 s 10 s-1, a change in the mechanism occurs, and trapping of the ion pair by both solvent and N3- becomes important.In this range of reactivity there is also evidence, based on the apparent magnitude of kaz', the rate constant for N3- trapping of the ion pair, that some of the reaction with N3- occurs through a preassociation process.When ks > ca. 1010 s-1 essentially all of the observed N3- trapping occurs by a preassociation process because N3-, which cannot react with the ion pair faster than the diffusion limit, can no longer compete with solvent for the ion pair.This progression in trapping mechanisms as the ion becomes more reactive with solvent is apparently an important factor in determining the carcinogenic potential of aromatic amines and amides which are metabolized into sulfuric and carboxylic acid esters of N-arylhydroxylamines and N-arylhydroxamic acids.Nitrenium ions which undergo slow reactions with solvent are selectively trapped by biologically relevant nucleophiles such as 2'-deoxyguanosine.As the rate constant for reaction with solvent increases, the nitrenium ion is no longer capable of undergoing selective trapping by nonsolvent nucleophiles because these reactions are limited by diffusion, but solvent trapping is not.

The hydroxyl group of N-hydroxyl-N-phenylamides rearranges mainly to the ortho position of the N-phenyl ring by the system (n-Bu)3P-CCl4-CH3CN; use of less than a stoichiometric amount of (n-Bu)3P is effective for this reaction.

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A series of ring-substituted N-sulfonoxyacetanilides (1a-f) were synthesized, and their solvolysis reactions in aqueous and alcohol solvents were studied.These compounds serve as models for the carcinogenic metabolites of polynuclear aromatic amides.Kinetic and product studies yielded evidence for solvolysis via N-O bond cleavage in aqueous solution with generation of tight ion pairs and solvent-separated ion pairs.The tight ion pairs, which cannot be trapped by nucleophiles or reducing agents, give rise to o-sulfonoxyacetanilides, while the solvent-separated ion pairs can be trapped by these reagents to yield ring-substituted compounds and reduction products.The para-substituted N-sulfonoxyacetanilides yield substantial amounts of highly electrophilic p-benzoquinone imine derivatives such as 10 during solvolysis in aqueous media.In ethanol these esters solvolyze exclusively via S-O bond cleavage with apparent production of SO3.This study demonstrates that electrophilic species other than nitrenium ions can be generated during the solvolysis of N-sulfonoxy-N-arylamides.These species may play a role in the in vivo activity of these metabolites.