Global ETD Search

91	N-Isocyanates : Versatile Intermediates in Heterocyclic Synthesis Vincent-Rocan, Jean-François January 2016 (has links) Nitrogen heterocycles are present in nearly 60% of all small-molecule drugs approved by the US Food and Drug Administration. New innovative methods that streamline the synthesis of such heterocycles are therefore highly desirable. The use of new or underdeveloped reactive intermediates provides an excellent opportunity to develop novel heterocyclic syntheses. For example, nitrogen-substituted isocyanates (N-isocyanates) are a class of rare amphoteric isocyanates with high, but severely underdeveloped synthetic potential. The research efforts presented in this thesis have been directed towards the use of such intermediates for the rapid construction of heterocycles using cascade reactions. Using an in situ generation approach from masked (blocked) isocyanate precursors, we were able to control the homo dimerization of these species and design several cascade reactions forming more than 10 different classes of heterocycles using appropriate nitrogen nucleophiles. Given the importance of the N-N-C=O motif in pharmaceuticals and agrochemicals, N-isocyanates provide the opportunity to synthesize highly desirable cores for different industrial applications. To illustrate the potential of this new tool in heterocyclic chemistry, more than 200 heterocycles were synthesized using this methodology. In Chapter 2, heterocycles incorporating only one atom from the N-isocyanate will be presented. More precisely, the first cascade reaction involving N-isocyanates for the rapid synthesis of saturated heterocycles will be presented. The incorporation of 2 atoms within the ring will then be discussed in Chapter 3 with the synthesis of hydantoins, imidazolones, thiazolines, pyrazoles and phthalazinones. Chapter 4 will focus on the incorporation of every atom in the heterocycle to form other bioactive cores such as azauracils, pyridazinones and azadiketopiperazines. Lastly, Chapter 5 will describe our efforts for the synthesis of acyclic molecules such as semicarbazides and aza-peptides. N-isocyanates Heterocyclic chemistry
92	Synthesis of beta-lactams Zamboni, Robert Joseph. January 1978 (has links) Note: Antibiotics. Heterocyclic compounds.
93	A study of some five-membered oxygen heterocycles / Snyder, Carl Henry January 1958 (has links) No description available. Chemistry Heterocyclic compounds
94	Synthesis and characterization of selected boron heterocycles / McAchran, Gerald Eugene January 1964 (has links) No description available. Chemistry Boron Heterocyclic compounds
95	The synthesis and reactions of 4H-thiopyran-4-one 1, 1-dioxide and derived cage molecules / Wise, Lawrence David January 1967 (has links) No description available. Chemistry Heterocyclic compounds
96	The chemistry of cyclooctatetraene dianion / Antkowiak, Thomas Anthony January 1968 (has links) No description available. Chemistry Heterocyclic compounds
97	The effect of ether oxygen in the chemistry of medium-sized rings / Scott, Malcolm Keith January 1972 (has links) No description available. Chemistry Heterocyclic compounds
98	Studies in some novel heterocycles : I. The synthesis and chemistry of pyrrolo- and furo-[2,3-D]pyrimidines. II. The synthesis toward nucleoside Q / Liu, Sai-Ho Paul January 1978 (has links) No description available. Chemistry Heterocyclic compounds
99	Synthetic studies of nitrogen containing heterocycles, particularly pyrazole and benzotriazine derivatives Nakhai, Azadeh, January 2009 (has links) Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009.
100	Synthesis of heterocycles via phenylseleno group transfer radical cyclization and chemoselective reductive amination promoted by InCl3 Lee, On-yi. January 2007 (has links) Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available in print.

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