Study on the Pyrolysis of a γ-Alkoxypropylsilyl Group
- 발행기관 서강대학교 대학원
- 지도교수 문봉진
- 발행년도 2006
- 학위수여년월 200608
- 학위명 석사
- 학과 및 전공 화학
- 식별자(기타) 000000103079
- 본문언어 영어
초록/요약
To reduce the RC delay in microelectronic integrated circuits, low k material has been studied as an insulator. Introduction of nanometer-sized pores into low dielectric materials is one of the most promising approaches in producing ultra low k materials. During the study on the nanoporous silicate thin films in which per-trimethoxysilylpropylated carbohydrate porogens were employed, we have discovered that these porogens result in T- to Q-silicon conversion as checked by solid state Si-NMR spectroscopy under the annealing conditions. This unexpected phenomenon enhanced the mechanical strength of the resulting film, which is beneficial for the use as an insulator in IC. A plausible mechanism for the T- to Q-silicon conversion was proposed based on the Brook rearrangement type reaction of the alkoxysilyl moieties. To prove the mechanism, several silicate model compounds were synthesized and their pyrolysis products were analyzed by various analytical methods such as 1H-NMR, TGA and pyrolysis-GC-MS. (+)-Preussin is a natural product isolated from Aspergillus ochraceus and Preussia sp. It possesses antibiotic activity against yeasts and fungi. The construction of the pyrrolidine skeleton of (+)-Preussin was attempted via the electrophile mediated cyclization followed by ring opening of the resulting aziridinium intermediated starting from a simple aziridine derivative. The required aziridine derivative was prepared in 5 steps starting from ethyl 2,3-dibromopropionate and (R)-phenethylamine. For total synthesis of Ouabain, the main skeleton was attempted to synthesize via Ti(III)-mediated cyclization. The reductive opening of epoxyolefin with titanocene(III) chloride gives rise to radical that can be trapped by intramolecular -system in a stereospecific way to give new carbocyclic compound such as Ouabain A~C ring. As well as radical cyclization, the oxidation for introduction of alcohol group was an important step in this synthesis, so DMDO was used as oxidant for change Ti-C bond to Ti-O-C bond and the formation of alcohol was verified. It will provide effective synthetic method approach to the synthesis of Ouabain.
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