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Chiara B. Vicentini Manuela Mazzanti Carlo F. Morelli Maurizio Manfrini 《Journal of heterocyclic chemistry》2000,37(1):175-180
Ethyl 2-amino-3-methoxycarbonyl-4-oxo-2-pentenoate (3) reacts with hydroxylamine or hydrazines to give isoxazole and pyrazole ortho-dicarboxylic acid esters 4 and 5, respectively. Partial hydrolysis of diesters 4 and 5 afforded the corresponding dicarboxylic acid monoesters 6 and 7. Amidation of the intermediate acid chlorides 8,9 followed by hydrolysis of 4-methylesters 10, 11 gave the title compounds 1 and 2, respectively. 相似文献
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Joseph I. Degraw Hiroaki Tagawa Pamela H. Christie John A. Lawson Edward G. Brown Roy L. Kisliuk Yvette Gaumont 《Journal of heterocyclic chemistry》1986,23(1):1-4
The synthesis of 5,10-dideazaaminopterin by two independent routes is described. Condensation of the piperidine enamine of 4-p-carbomethoxyphenylbutyraldehyde ( 4 ) with ethoxymethylenemalononitrile followed by treatment of the resultant arylethylenaminomalononitrile ( 5 ) with methanolic ammonia produced 2-amino-3-cyano-5-p-carbomethoxyphenethylpyridine ( 6 ). Cyclization of the aminocyanopyridine with guanidine afforded 4-amino-4-deoxy-5,10-dideazapteroic acid ( 8 ). Coupling of the pteroate intermediate with glutamate yielded the target 5,10-dideazaaminopterin ( 10 ). Alternatively, reduction of 2,4-diamino-6-formyl-5-deazapteridine ( 11 ) with sodium borohydride gave the 6-hydroxymethyl compound 12 . Conversion to the bromide was followed by alkylation of dimethyl homoterephthalate to afford methyl 4-amino-4-deoxy-10-carbomethoxy-5,10-dideazapteroate ( 14 ). Decarboxylation with ester cleavage (sodium cyanide in dimethyl sulfoxide at 180°) also gave the diaminopteroic acid ( 8 ). 5,10-dideazaaminopterin ( 10 ) was an effective growth inhibitorof folate dependent bacteria, S. faecium and L. casei. 相似文献
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Giampio Bracchi Chiara Francalanci 《Computational & Mathematical Organization Theory》1997,3(3):173-198
This paper proposes a formal model of information processing inorganizations. The model takes a process view of organizations and includesboth structural and IS features of processes. Two structural properties areconsidered, networking and parallelism. Information systems are representedin terms of quantity of information used and level of informationcustomization allowed. Process performance is measured in terms of totalinformation processing capacity and flexibility afforded by a process. Therelationship between structural and information system choices and processperformance is studied by simulating the model for a range of values. Thepaper derives a set of propositions describing the independent and combinedimpact of structural and information system choices on performance. The results suggest the predominance of networking over parallelism and ofinformation customization over information quantity in determininginformation processing capacity. They also show a negative effect ofnetworking on process flexibility and an amplifying effect of networking onthe benefits of information customization. Overall, the findings validatethe interdependence between structural and information system variables indetermining process performance. 相似文献
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Severin Eder Manuel Torko Alessia Montalbetti Paride Azzari Laura Nystrm 《Molecules (Basel, Switzerland)》2021,26(11)
The pace of industrialization and rapid population growth in countries such as India entail an increased input of industrial and sanitary organic micropollutants, the so-called emerging contaminants (EC), into the environment. The emission of EC, such as pharmaceuticals, reaching Indian water bodies causes a detrimental effect on aquatic life and ultimately on human health. However, the financial burden of expanding sophisticated water treatment capacities renders complementary, cost-efficient alternatives, such as adsorption, attractive. Here we show the merits of washed and milled pigeon pea husk (PPH) as low-cost adsorbent for the removal of the EC trimethoprim (TMP) and atenolol (ATN) that are among the most detected pharmaceuticals in Indian waters. We found a linear increase in adsorption capacity of PPH for TMP and ATN at concentrations ranging from 10 to 200 μg/L and from 50 to 400 μg/L, respectively, reflecting the concentrations occurring in Indian water bodies. Investigation of adsorption kinetics using the external mass transfer model (EMTM) revealed that film diffusion resistance governed the adsorption process of TMP or ATN onto PPH. Moreover, analysis of the adsorption performance of PPH across an extensive range of pH and temperature illustrated that the highest adsorption loadings achieved concurred with actual conditions of Indian waters. We anticipate our work as starting point towards the development of a feasible adsorbent system aiming at low-cost water treatment. 相似文献
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Pamela Lynn Harvey 《Journal of voice》1997,11(2):144-152
The purpose of this paper is to 1) describe the unique issues of voice patients, ages 21–55; 2) outline the knowledge and clinical skills that speech language pathologists should possess to deal with those issues; and 3) provide suggestions for promoting vocal longevity. 相似文献