Physical Sciences and Mathematics Commons^™

Chapter 1: Part A: A Unique Approach Of Preparing 3,3-Disubstituted Oxindoles From Acyclic Tetrasubstituted Aldehydes: Total Synthesis Of (-)-Coerulescine And (-)-Coixspirolactam A, Chapter 1: Part B: Synthetic Scope Of Brønsted Acid Catalyzed Reactions Of Carbonyl Compounds And Ethyl Diazoacetate,, Md Shahnawaz Ali

Theses and Dissertations

CHAPTER 1: PART A: A UNIQUE APPROACH OF PREPARING 3,3-DISUBSTITUTED OXINDOLES FROM ACYCLIC TETRASUBSTITUTED ALDEHYDES: TOTAL SYNTHESIS OF (-)-COERULESCINE AND (-)-COIXSPIROLACTAM A(-)-Coerulescine and (-)-coixspirolactam A, two naturally occurring compounds characterized with an all-carbon quaternary center containing a spirooxindole, have been synthesized asymmetrically. The key feature of their total synthesis involves a novel rational construction of the chiral 3,3-disubstituted oxindole core from the acyclic chiral tetrasubstituted aldehyde. The later scaffold was prepared in high enantioselectivity (up to 86%) from the ethyl 3-hydroxy-2-(2-nitrophenyl)acrylate 1 by exploring both intermolecular and intramolecular Pd-mediated asymmetric allylic allylations (Pd-AAA). A through optimization of these approaches is …

Part I: A Concise Asymmetric Synthesis Of Microtubule Inhibitor Tryprostatin B Part Ii: Synthesis And Biological Assessment Of Histone Deacetylase (Hdac) Inhibitors Part Iii: Acid Catalyzed Reactions Of Aromatic Ketones With Ethyl Diazoacetate, Md Mizzanoor Rahaman

Theses and Dissertations

PART I: A CONCISE ASYMMETRIC SYNTHESIS OF MICROTUBULE INHIBITOR TRYPROSTATIN B

Tryprostatin (TPS) A and B, microtubule inhibitor, are the members of a family of prenylated Trp-Pro diketopiperzine alkaloids. These two natural products were isolated in 1995 from the fermentation broth of Aspergillus fumigatus BM939 by Osada and coworkers. TPS and related diketopiperazine containing compounds such as phenylahistins, spirotryprostatins, and cyclotryprostatins are inhibitors of the mammalian cell cycle. They prevent cell cycle progression at the G2/M phase through a unique mechanism consisting of inhibiting the interaction between microtubule assisted proteins (MAP-2) and the C-terminal end of tubulin. TPS A and …

I. Palladium (0)-Catalyzed Asymmetric Rearrangement Of Allyl Enol Ether For The Synthesis Of Α -Aryl Quaternary Carbon Center. Ii. Synthesis Of Chiral Tryptophan Analogs And Studies Towards Synthesis Of Tryprostatin A And B, Md Nazim Uddin

Theses and Dissertations

The development of efficient catalytic enantioselective synthesis of all carbon quaternary centers is a significant challenge in chemical synthesis due to the difficulties of carbon-carbon bond formation at quaternary center. Using phase transfer catalyst we attempted to create quaternary carbon center via direct C-alkylation of hydroxyarylacrylates, instead we obtained O-alkylated acrylates. We succeeded in C-alkylation which involves an indirect method via the O-alkylation of 3-hydroxy aryl acrylates and a subsequent [3, 3] sigmatropic rearrangement (Claisen rearrangement). The O-alkylated products are obtained in yields ranging from 65-85%, and the corresponding Claisen rearrangement products in yields ranging from 55-90%. Typically Pd(II) catalysts …