A powerful new one-pot method has been developed for the reductive alkylation of malononitrile with aromatic aldehydes. This new procedure has vastly improved the yield and efficiency and increased the scope for the aromatic aldehydes. Incorporating water as the catalyst in ethanol for the condensation step allows stoichiometric amounts of malononitrile and aldehyde to be employed. After dilution and cooling the reduction step takes place quickly and efficiently with sodium borohydride to give monosubstituted malononitriles.The product from the reductive alkylation of malononitrile with 2-quinolinecarboxaldehyde quickly rearranges to a novel indolizine on silica gel or with heat, while alkylation of the monosubstituted derivative provides an unsymmetrically disubstituted malononitrile.We have also investigated this improved one-pot reductive alkylation using various 2-hydroxybenzaldehydes where intramolecular cyclization occurs following the condensation step and various 2-amino-3-cyano-4H-chromenes are formed. / Department of Chemistry

Isoxazoles and isoxazolines have been shown in the literature to be an important scaffold for pharmaceuticals and insecticides, as well as a source of synthetic versatility important to many syntheses. As a substitute for other aromatic rings, isoxazoles are known to change the efficacy of a given compound. Isoxazolines can be used as a precursor to many other functional moieties that may be effected during earlier synthetic steps. There are many routes to the heterocyclic moiety, allowing for their insertion in a wide range of molecules. Our group has previously reported a condensation of arylaldehydes with hydroxylamine to first make an aryloxime which can, after generating the nitrile oxide, then cyclize with an alkene or alkyne in situ and create the isoxazoline or isoxazole, respectively. The Knoevenagel Condensation reaction is identified as the addition of an activated methylene complex, malononitrile or cyanoacetamide, with a carbonyl followed by dehydration.. Our group has previously reported a facile, one-pot reductive alkylation of benzyl malononitriles. These compounds have been noted as having many insecticidal uses, as well as being potent pharmacophores. The scope of this project is to further explore and optimize the condensation of aryl aldehydes and methylene complexes. The condensed and reduced methylene complex will then be alkylated to join the heterocyclic moiety to reach the final disubstituted methylene product. A second approach will also be explored in which the monosubstituted malononitrile will first be alkylated with allyl or propargyl bromide, which can then undergo a 1,3-dipolar cycloaddition with a nitrile oxide. The library of compounds generated will be sent to collaborators to test the biological activity of the molecules. / Introduction and background literature -- Reactions of methylene complexes -- Synthesis of disubstituted methylene complexes. / Department of Chemistry

The quinoline-5,8-diones are an important class of compounds with a wide spectrum of biological activites such as antibacterial, antiasthmatic, antifungal, antitumour and antiparasitic agents. Over the past three decades many variously substituted derivatives of quinoline-5,8-diones have been synthesized and reported. The majority of them dealt with the chemistry of C-6 and/or C-7 substituted quinolinediones and were related to Lavendamycin. Our lab has developed several procedures for the condensation (Knoevenagel) and reduction of aldehydes and ketones with malononitrile. When this reductive alkylation procedure was attempted with quinoline-2-carboxaldehyde, a crude product was observed by NMR spectroscopy. This product rearranged upon attempted purification via recrystallization or column chromatography. The nucleophilic attack of the quinoline N on the C of the nitrile followed by a proton transfer and a tautomerization resulted in the creation of indolizine. We will study the reductive alkylation of a series of quinoline-5,8-diones with carboxaldehydes at the C-2 position with malononitrile. This reaction is carried out in 95% ethanol with no catalysts present. This reaction mixture is then diluted with additional 95% ethanol and then cooled in an ice/water bath before the addition of sodium borohydride (NaBH4) to afford the desired monosubstituted malononitrile. We have also carried out the reactions with a range of other substituted quinoline compounds. In these cases the indolizines were not observed. It is assumed that the indolizine product does not form due to the presence of substituents on the C-8 position. Additional studies will focus on unsubstituted C-8 quinoline rings to prepare other novel indolizines. Otherwise, various reactions are performed to force the formation of indolizine. / Introduction/background -- Preparation of quinoline derivatives and their respective carboxaldehydes -- Preparation of monosubstituted malononitriles and indolizines. / Department of Chemistry

No description available.

Thesis advisor: Amir H. Hoveyda / We have developed a broadly applicable strategy for the enantioselective and diastereodivergent synthesis of unprotected α-secondary amines, secondary and tertiary alcohols from nitriles. Through a bis-phosphine–Cu-catalyzed enantioselective multicomponent allyl addition to nitriles, we generate stable β,γ-unsaturated N–H ketimines with internal C=N to B(pin) chelation. We achieved stereodivergent amine synthesis through maintaining the C=N to B(pin) chelation or disruption of this internal chelation in the ketimine intermediate throughout the reduction. In the preparation of syn-homoallylic amines, a non-productive side catalytic cycle was introduced to selectively delay the function of a competitive catalyst, making several catalysts cooperate productively. The utility of this method is demonstrated through a diastereo- and enantioselective synthesis of (+)-tangutorine in gram quantities. We have also developed the syntheses of enantiomerically enriched secondary and tertiary alcohols through diastereodivergent reduction and diastereoselective addition of a C-based nucleophile to β,γ-unsaturated ketones, prepared from hydrolysis of the aforementioned N–H ketimines. Tertiary alcohols containing two non-differentiable functional groups, are prepared with high stereoselectivity through our strategy. We demonstrated the utility of this approach by a concise preparation of a key intermediate in (+)-rubriflordilactone B synthesis. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

This report discusses research which was conducted in two areas: the synthesis of potential agrochemicals and the study of vinamidinium and azavinamidinium salt chemistry. Four classes of compounds were synthesized and characterized in the study of new potential agrochemicals. These compounds include diacylhydrazines, semicarbazides, 2,5-disubstituted-1,3,4-oxadiazoles and bis-2,5-disubstituted-1,3,4-oxadiazoles. The reaction of [3-(dimethylamino)-2-azaprop-2-en-1-ylidene] dimethylammonium chloride (Gold's reagent) with organometallic/borane reagents was examined in efforts to find convenient syntheses for N,N-dimethylamino substituted alkyl and aryl compounds. Additionally, the reaction of 1,5-diazapentadienium chloride (Nair's reagent) with nitrile activated alkanes was examined to find a convenient synthesis of 3-substituted pyridines. Subsequent intramolecular ring closure of the dienaminonitriles was unsuccessful. Finally, this report reveals the experimental procedures and conditions used for the synthesis of these products and offers explanations of the data as well as recommendations for future research.

Thesis advisor: Amir H. Hoveyda / Chapter One: Development of a New Catalytic Click Reaction Involving Nitriles and Allenes (CuPDF)Catalytic click reactions, although small in number, have made a profound impact on chemistry research, including the fields of drug discovery, biological chemistry, and materials science. What is much needed are additional catalytic reactions that bring about the union of commonly occurring and robust functional groups, are mutually orthogonal to those that exist and offer a function other than connecting two fragments. We have developed a catalytic click process that connects a nitrile and a monosubstituted allene in the presence of commercially available B2(pin)2 and a readily accessible Cu(I) complex. The modification stage involves alkene isomerization by base and condensation with a hydrazine and both processes are performed in situ. The resulting linkages contain a robust diazaborinine that is fluorescent. We demonstrate that the click process, which we have named copper(I)-catalyzed phenoxydiazaborinine formation (CuPDF) is mutually orthogonal to copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) as well as sulfur-fluorine exchange (SuFEx). These click reactions can therefore be used for efficient synthesis of sequence-defined oligomers that may contain modifiable linkages and peptide-drug conjugates. For applications in aqueous media, we have also developed, copper(I)- and palladium-catalyzed quinoline formation (Cu/PdQNF). These latter processes generate fluorescent connectors as well. Chapter Two: Development of a Catalytic Click Reaction Involving Ketones and Allenes (CuAKA) We have developed another click reaction, this time bringing about the union of a ketone and, similar to CuPDF, a monosubstituted allene and B2(pin)2. We label this click reaction copper(I)-catalyzed allene–ketone addition or CuAKA. As a consequence of shared reactants, identifying catalysts that would allow CuAKA and CuPDF to be mutually orthogonal was at the center of our investigations. Our studies resulted in the identification of copper(I) complexes that can be used to perform a click reaction on a nitrile or a ketone. Furthermore, we found that mutual orthogonality can be achieved between CuAKA and CuAAC using an amino phosphine–Cu(I) catalyst. Computational and kinetics studies were performed that shed light on the origins of catalyst-controlled chemoselectivity. Importantly, similar to CuPDF, CuAKA can be performed in aqueous media. Chapter Three: Preparation of Multi-drug Conjugates with Mutually Orthogonal Click Reactions We show that with CuAAC, CuPDF and CuAKA, three mutually orthogonal click processes can be efficiently merged to assemble complex molecules efficiently with no protection/deprotection needed. With CuAKA, similar to CuAAC and CuPDF, being also orthogonal to SuFEx, a four-armed core molecule may be used in a similar fashion. A central finding in this part of study was the discovery that CuAKA, similar to CuAAC but unlike CuPDF, can be used to link molecules that contain acidic protons, such as phenol or a carboxylic acid moieties. Chapter Four: Controlled Rupture of CuAKA-Generated Linkages A distinct attribute of CuAKA is that it forms a linkage that is cleavable under mild aqueous oxidative conditions. We show that the tertiary hydroxy group accelerates the oxidation of the nearby C–B bond within the connector to generate a -hydroxy ketone that undergoes a retro-aldol reaction to effect rupture. We show that an aryl linker between the ketone and the carrier molecule, such a bile acid or a cell-penetrating peptide (CPP) may be used to achieve the steric and electronic parameters that are needed for optimal clicking and clipping rates. To demonstrate applicability, we used CuAKA was used for efficient linking of camptothecin, an anti-cancer agent with low selectivity, to a ketone attached to unprotected penetratin, a CPP. The ensuing release of the payload proceeded readily in a 68 mM aqueous solution of hydrogen peroxide at 37 °C with control experiments indicating that a proximal lysine residue accelerates the retro-aldol reaction. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Dentre os diversos tipos de patologias, as doenças negligenciadas apresentam grande prevalência na população em países tropicais. A leishmaniose é uma doença negligenciada endêmica no Brasil, com incidência em áreas urbanas e rurais. A ineficácia e elevados efeitos colaterais de fármacos como a Anfotericina B, que é atualmente empregada, tem levado a pesquisa e desenvolvimento de substâncias bioativas antileishmaniose. Um alvo macromolecular de interesse terapêutico é a cisteíno protease B (CPB) devido a sua atuação e importância em diversas etapas do ciclo de vida da Leishmania. Assim, o Grupo de Química Medicinal (NEQUIMED) estuda inibidores covalentes reversíveis da cisteíno protease CPB com potencial atividade antileishmaniose. Neste projeto, a síntese de derivados de dipeptidil-nitrilas é realizada para que com potencial atividade inibidora da CPB e antileishmaniose seja acessado por meio dos ensaios biológicos correspondentes. Neste projeto, derivados e estereoisômeros do composto N-(1-cianociclopropil)-3-fenil-2-((-2,2,2-trifluoro-1-fenil-etil)amino) propanamida foram produzidos e caracterizados. 15 substâncias foram produzidas e purificadas por HPLC e sua pureza determinada por medição de ponto de fusão e HPLC-MS, com caracterização por RMN (1H e 13C) e FT-IR. A partir desta série, a estereosseletividade enzimática para a CPB será acessada por meio de ensaios bioquímicos e biofísicos e também por ensaios celulares a serem realizados por outros membros do grupo. / Among several types of pathologies, neglected tropical diseases present high prevalence in the population in tropical countries. Leishmaniasis is a neglected disease which endemic in Brazil, with incidence in urban and rural areas. The ineffectiveness and numerous side effects of drugs such as amphotericin B, which is currently used for treatment has led to the research and development of bioactive antileishmanial substances. A macromolecular target of therapeutic interest is the enzyme cysteine protease B (CPB) because of its performance and importance at various stages of the Leishmania life cycle. Thus, the Medicinal Chemistry Group (NEQUIMED) studies covalent inhibitors of cysteine protease CPB with potential antileishmanial activity. In this study, the synthesis of dipeptidyl nitrile derivatives is performed so that with potential inhibitory activity for CPB and antileishmaniasis is accessed through the corresponding biological assays. In this project, it was produced and characterized derivatives and stereoisomers of the compound N-(1-cyanocyclopropyl)-3-phenyl-2-((2,2,2-trifluoro-1-phenyl-ethyl)amino)propanamide. 15 substances were produced and purified by HPLC and determined purity by melting point measurement and HPLC-MS, characterizing by NMR (1H and 13C) and FT-IR. From this series, the enzymatic stereoselectivity for CPB will be accessed through biochemical and biophysical assays and by cellular assays to be performed by other members of the group.

No presente estudo, uma triagem foi realizada com 12 fungos marinhos Penicillium miczynskii CBMAI 930, Penicillium raistriicki CBMAI 931, Aspergillus sydowii CBMAI 933, Aspergillus sydowii CBMAI 934, Aspergillus sydowii CBMAI 935, Bionectria sp. CBMAI 936, Penicillium oxalicum CBMAI 1185, Penicillium citrinum CBMAI 1186, Penicillium decaturense CBMAI 1234, Penicillium raistriicki CBMAI 1235, Cladosporium sp. CBMAI 1237 e Aspergillus sydowii CBMAI 1241 para avaliar o potencial enzimático destes micro-organismos frente à fenilacetonitrila 1. Estes micro-organismos foram isolados de esponjas e alga coletadas do litoral norte do estado de São Paulo. A triagem foi realizada em meio sólido mineral suplementado com glicose e fenilacetonitrila 1 como única fonte de nitrogênio. Dentre os fungos, 8 adaptaram-se muito bem ao substrato 1 nas respectivas quantidades 5 µL (0,04 mmol), 10 µL (0,08 mmol) e 15 µL (0,12 mmol). Em seguida, a triagem foi realizada em meio líquido (20 µL (0,17 mmol), 40 µL (0,35 mmol) e 60 µL (0,50 mmol) de fenilacetonitrila 1 e obteve um bom crescimento de massa micelial dos fungos. Experimentos realizados na ausência de fenilacetonitrila 1, tanto em meio sólido, quanto em meio líquido, não promoveram o crescimento microbiano, evidenciando que as enzimas capazes de hidrolisarem nitrilas presente no sistema catalítico são construtivas. A fenilacetonitrila 1 foi biotransformada ao ácido 2-(2-hidroxifenil)acético 1b (51% pelo fungo A. sydowii CBMAI 934) por todos os fungos adaptados. Devido ao bom crescimento do fungo A. sydowii CBMAI 934 em meio mineral sólido e líquido na presença de fenilacetonitrila 1, este fungo foi selecionado para promover reações de hidrólise frente a diferentes organonitrilas, arilcetonitrilas: 4-fluorofenilacetonitrila 2, 4-clorofenilacetonitrila 3, 4-metoxifenilacetonitrila 4, 2-metilfenilacetonitrila 5, 3-metilfenilacetonitrila 6, 4-metilfenilacetonitrila 7 aos seus correspondentes ácidos carboxílicos 4-fluorofenilacético 2a (51%), 4-clorofenilacético 3a (55%), 4-metoxifenilacético 4a (43%), 2-metilfenilacético 5a (76%), 3-metilfenilacético 6a (52%) e 4-metilfenilacético 7a (46%), em nitrila alifática, 2-(1-ciclo-hexen-1-il)acetonitrila 8 ao ácido 2-(1-ciclo-hexen-1-il)acético 8a (28%) e nitrila hetero-aromática, 2-cianopiridina 19 a 2-piridinamida 19a. As reações foram acompanhadas por GC-FID e os produtos de biotransformações foram isolados e caracterizados por GC-MS, HRMS, RMN de 1H e de 13C. Este trabalho envolveu o primeiro estudo frente à biotransformação de nitrilas por micro-organismos de origem marinha. / In the present study, a screening of 12 marine fungi Penicillium miczynskii CBMAI 930, Penicillium raistriicki CBMAI 931, Aspergillus sydowii CBMAI 933, Aspergillus sydowii CBMAI 934, Aspergillus sydowii CBMAI 935, Bionectria sp. CBMAI 936, Penicillium oxalicum CBMAI 1185, Penicillium citrinum CBMAI 1186, Penicillium decaturense CBMAI 1234, Penicillium raistriicki CBMAI 1235, Cladosporium sp. CBMAI 1237 and Aspergillus sydowii CBMAI 1241 was done in order to evaluate the enzymatic potential of these microorganisms in phenylacetonitrile 1. These microorganisms were isolated from sponges and algae collected at the north shore of Sao Paulo State. The screening was carried out in solid mineral medium supplemented with glucose and phenylacetonitrile 1 as the only source of nitrogen. Among the fungi, 8 adapted to the subtract really well 5 µL (0,04 mmol), 10 µL (0,09 mmol) and 15 µL (0,13 mmol). Afterwards, a screening was carried out in liquid medium 20 µL (0,17 mmol), 40 µL (0,35 mmol) and 60 µL (0,50 mmol) of phenylacetonitrile 1) and a great mass of the fungi was obtained. The phenylacetonitrile 1 was biotransformed in the acid 2-(2-hydroxyphenyl)acetic 1b (51% by the fungus A. sydowii CBMAI 934) by all the adapted fungi. Experiments carried out without phenylacetonitrile 1, both in solid and liquid media did not show microbial growth. Enzymes which hydrolyzed nitriles present in the catalytic system were constructive. Due to the good growth rate of the fungus A. sydowii CBMAI 934 in solid and liquid mineral media in presence of phenylacetonitrile 1, this fungus was selected to promote hydrolysis reactions in different organonitriles, arylacetonitriles: 4-fluorophenylacetonitrile 2, 4-chlorophenylacetonitrile 3, 4-methoxyphenylacetonitrile 4, 2-methylphenylacetonitrile 5, 3-methylphenylacetonitrile 6, 4-methylphenylacetonitrile 7 in their corresponding carboxylic acids 4-fluorophenylacetic 2a (51%), 4-chlorophenylacetic 3a (55%), 4-methoxyphenylacetic 4a (43%), 2-methylphenylacetic 5a (76%), 3-methylphenylacetic 6a (52%) and 4-methylphenylacetic 7a (46%), aliphatic nitrile 2-(1-cyclohexen-1-yl)acetonitrile 8 to 2-(1-cyclohexen-1-yl)acetic acid 8a (28%) and heteroaromatic nitrile 2-cyanopiridine 19 to 2-pyridinecarboxamides 19a. The reactions were monitored by GC-FID and the biotransformation products were isolated and characterized by GC-MS, HRMS and 1H and 13C NMR. This work involved the first study on the biotransformation of nitriles by marine microorganisms.