Synthesis and anti-oomycete activity of novel quinazolin- and benzothiazol-6-yloxyacetamides: Potent aza-analogs and five-ring analogs of quinoline fungicides.

Novel quinazolin- and benzothiazol-6-yloxyacetamides show excellent in vivo activity against the three economically most important Oomycete pathogens Phytophthora infestans, Plasmopara viticola and Pythium ultimum. They are polar analogs of known quinolin-6-yloxyacetamides, which are not active against the soil-borne damping-off disease caused by Pythium ultimum. The Bogert quinazoline synthesis, an almost forgotten heterocyclization technique, proved to be highly useful for the concise construction of required quinazolin-6-ol building blocks.

A chemical potentiator of copper-accumulation used to investigate the iron-regulons of Saccharomyces cerevisiae.

The extreme resistance of Saccharomyces cerevisiae to copper is overcome by 2-(6-benzyl-2-pyridyl)quinazoline (BPQ), providing a chemical-biology tool which has been exploited in two lines of discovery. First, BPQ is shown to form a red (BPQ)2 Cu(I) complex and promote Ctr1-independent copper-accumulation in whole cells and in mitochondria isolated from treated cells. Multiple phenotypes, including loss of aconitase activity, are consistent with copper-BPQ mediated damage to mitochondrial iron-sulphur clusters. Thus, a biochemical basis of copper-toxicity in S. cerevisiae is analogous to other organisms. Second, iron regulons controlled by Aft1/2, Cth2 and Yap5 that respond to mitochondrial iron-sulphur cluster status are modulated by copper-BPQ causing iron hyper-accumulation via upregulated iron-import. Comparison of copper-BPQ treated, untreated and copper-only treated wild-type and fra2Δ by RNA-seq has uncovered a new candidate Aft1 target-gene (LSO1) and paralogous non-target (LSO2), plus nine putative Cth2 target-transcripts. Two lines of evidence confirm that Fra2 dominates basal repression of the Aft1/2 regulons in iron-replete cultures. Fra2-independent control of these regulons is also observed but CTH2 itself appears to be atypically Fra2-dependent. However, control of Cth2-target transcripts which is independent of CTH2 transcript abundance or of Fra2, is also quantified. Use of copper-BPQ supports a substantial contribution of metabolite repression to iron-regulation.

Synthesis and fungicidal activity of quinolin-6-yloxyacetamides, a novel class of tubulin polymerization inhibitors.

A novel class of experimental fungicides has been discovered, which consists of special quinolin-6-yloxyacetamides. They are highly active against important phytopathogens, such as Phytophthora infestans (potato and tomato late blight), Mycosphaerella graminicola (wheat leaf blotch) and Uncinula necator (grape powdery mildew). Their fungicidal activity is due to their ability to inhibit fungal tubulin polymerization, leading to microtubule destabilization. An efficient synthesis route has been worked out, which allows the diverse substitution of four identified key positions across the molecular scaffold.

Efficacy of mifepristone - Prostaglandin analogue combination in medical termination of pregnancy up to and beyond 7 weeks of amenorrhea: The RYMMa study.

OBJECTIVE: To assess, in real-life conditions, the success rate of the protocol mifepristone 600 mg / prostaglandin analogue (PG) in women requesting medical termination of pregnancy (MToP) either up to or beyond 7 weeks of amenorrhea (WA). STUDY DESIGN: The study was performed between 2015 and 2016. This was a non-interventional prospective, multicentre, longitudinal study conducted in France, among a sample of public and/or private centres dealing with MToP. Characteristics of women, term of Mtop, modality of PG used were reported. The primary outcome was success of MToP, defined as complete abortion without surgical procedure. RESULTS: A total of 893 pregnant women with less than the legal term of 14 WA were included in this study: 490 (54.9 %) ≤7 WA and 403 (45.1 %) >7 WA comprising 29 > 9 WA. The mean age of women was 28.1 ± 6.8 years and the one of pregnancy was 7.0 WA ± 1.3 WA. The most frequently used PG combined to mifepristone 600 mg was misoprostol 400 µg (57.0 % ≤7 WA and 35.1 % >7 WA) or 800 µg per os (oral or oral transmucosal) (27.5 % ≤7 WA and 40.1 % >7 WA). Vaginal misoprostol (6.4 %, N = 48) and gemeprost (5.2 %, N = 39) were less used. In women ≤7 WA (N = 422) and women >7 WA (N = 354) for whom result of the MToP was collected, success rates were 94.5 % (95 %CI 91.9 %-96.5 %) and 92.4 % (95 %CI 89.1 %-94.9 %), respectively (p = 0.219). In multivariate regression analysis, three factors were significantly associated with a higher risk of MToP failure: increased number of previous pregnancies (OR = 1.233; 95 %CI 1.086-1.401 for one pregnancy), increased number of previous surgical ToPs (OR = 1.563; 95 %CI 1.036-2.359 for one ToP) and increased interval between mifepristone and PG intake (OR = 1.061; 95 %CI 1.012-1.112 for one hour). Term of pregnancy (OR = 1.497; 95 %CI 0.833-2.690 for ≤7 WA vs >7WA), administration route (OR = 1.553; 95 %CI 0.488-4.936 for oral vs oral transmucosal; and OR = 1.216; 95 %CI 0.625-2.366 for vaginal vs oral transmucosal), and dose of misoprostol (OR = 1.000; 95 %CI 0.999-1.001), were not associated with the risk of failure. Overall, tolerance was good. CONCLUSION: This study showed, in real-life settings, a high rate of success for MToP using mifepristone 600 mg, independent of the pregnancy term and the therapeutic protocol used. MToP was safe and well tolerated however only a small number of women beyond 9 WA have been included.

New ventures in the chemistry of avermectins.

An overview is given on recent work towards new avermectin derivatives of extremely high insecticidal and acaricidal activity. These compounds were prepared from commercially available abamectin (avermectin B1) 1. For the synthesis, many novel entries have been opened up, making use of modern synthetic methods and applying them, for the first time, to the chemistry of avermectins. Several types of avermectin derivatives can be regarded as key innovations in the field. These are, in particular, 4''-deoxy-4''-(S)-amino avermectins 3, 4'-O-alkoxyalkyl avermectin monosaccharides 5, 4''-deoxy-4''-C-substituted 4''-amino avermectins 6 and 2''-substituted avermectins 7. 4''-Deoxy-4''-(S)-amino avermectins 3 were obtained by the consecutive application of the Staudinger and Aza-Wittig reaction. 4'-O-Alkoxyalkyl avermectin monosaccharides 5 were prepared by alkoxyalkylation of 5-O-protected avermectin monosaccharide. For the synthesis of 4''-deoxy-4''-C-substituted 4''-amino avermectins 6, several methods were used to construct the fully substituted 4''-carbon centre, such as a modified Strecker synthesis, the addition of organometallics to a 4''-sulfinimine and a modified Ugi approach. In order to prepare 2''-substituted avermectins 7, 5-O-protected avermectin monosaccharide was coupled with carbohydrate building blocks. An alternative synthesis involved the hitherto unknown enol ether chemistry of 4''-oxo-avermectin and the conjugate addition of a cuprate to an avermectin 2'',3''-en-4''-one. In addition, a number of other highly potent derivatives were synthesised. Examples are 4''-O-amino avermectins 8, as well as products arising from intramolecular rhodium catalysed amidations and carbene insertions. A radical cyclisation led to an intriguing rearrangement of the avermectin skeleton. Many of the new avermectins surpassed the activity of abamectin 1 against insects and mites.

Chiral relay effect: 4-substituted 1,3-benzoxazol-2-(3H)-ones as achiral templates for enantioselective Diels-Alder reactions.

[reaction: see text] A new strategy to control the enantioselectivity of Lewis acid catalyzed reactions has been investigated. The use of N-acryloyl-1,3-benzoxazol-2-(3H)-ones substituted at position 4 leads to the formation of diastereomeric complexes as a result of the presence of a chiral axis. The stereochemical outcome of the reaction is controlled by the chiral catalyst and by the chiral axis, leading to high enantioselectivity improvements and, in one case, to an inversion of enantioselectivity.

Studies on the synthesis of gymnodimine. Stereocontrolled construction of the tetrahydrofuran subunit.

[reaction: see text]. A bis-(2,6-dichlorobenzyl) ether is shown to undergo efficient and highly stereoselective intramolecular iodoetherification to yield a cis-2,5-disubstituted tetrahydrofuran, thus providing a powerful illustration of a stereodirecting effect first noted by Rychnovsky and Bartlett. The tetrahydrofuran was transformed into a subunit suitable for incorporation into the shellfish toxin gymnodimine.

Studies on the synthesis of gymnodimine. construction of the spiroimine portion via Diels-Alder cycloaddition.

An azaspiro[5.5]undecadiene corresponding to a subunit of the shellfish toxin gymnodimine was synthesized by Diels-Alder cycloaddition. One member of the pair of stereoisomeric adducts was transformed to a spiroimine, which will serve as the core around which the macrocyclic portion of the toxin will be assembled. [structure: see text]

Medical and surgical treatment for discoid lupus erythematosus.

A case is presented of a 27-year-old Caucasian woman that presented with an oval purplish patch with defined borders on her right cheek. It was swollen and tense, with a mottled surface due to scarring. Histologic examination indicated discoid lupus erythematosus and the patient was initially treated with medical therapy. The lesion relapse and cosmetic results convinced us to propose surgical option with aggressive medical treatment and follow up. In our patient, this combination therapy proved effective.

Studies on the synthesis of (-)-gymnodimine. Subunit synthesis and coupling.

Two principal subunits of the marine algal toxin (-)-gymnodimine were synthesized. A trisubstituted tetrahydrofuran representing C10-C18 of the toxin was prepared via a highly stereoselective iodine-mediated cyclization of an acyclic alkene bearing a bis-2,6-dichlorobenzyl (DCB) ether. The formation of a cis-2,5-disubstituted tetrahydrofuran in this process conforms to a stereodirecting effect by the DCB group proposed by Bartlett and Rychnovsky. A cyclohexene subunit corresponding to the C1-C8, C19-C24 portion of gymnodimine was synthesized via Diels-Alder cycloaddition of a 1,2,3-trisubstituted diene to a symmetrical dienophile obtained from Meldrum's acid. Differentiation of carbonyl groups in the cycloadduct was made by an intramolecular reaction with a neighboring alcohol to form a gamma-lactone. Linkage of the two subunits at C18-C19 was accomplished by using a B-alkyl Suzuki coupling in which a borane prepared from the pendent alkenyl chain of the cyclohexene domain was reacted with the (E)-iodoalkene attached at C16 of the tetrahydrofuran sector. Subsequent transformations positioned functional groups in the coupled product for a future macrocyclization event that would close the 15-membered ring of gymnodimine.

Chiral relay: a novel strategy for the control and amplification of enantioselectivity in chiral Lewis acid promoted reactions.

Chiral Lewis acid catalysis has emerged as one of the premiere method to control stereochemistry. Much effort has gone into the design of superior ligands with increasing steric extension to shield distant reactive sites. We report here an alternative and complementary approach based on a "chiral relay". This strategy focuses on the improved design of achiral templates which may relay and amplify the stereochemistry from ligands. The essence of this strategy is that the chiral Lewis acid would effectively convert an achiral template into a chiral non-racemic template. This approach combines the advantages of enantioselective catalysis (substoichiometric amount of the chiral inducer) with the ones of chiral auxiliary control (efficient and predictable stereocontrol).