Research and development of high temperature resistant polymeric film forming material final summary report, 1 mar. 1961 - 17 apr. 1962

Preparation of poly-organometallosiloxane polymers from reactions between bis-dialkylamino metal derivatives and silanediol

Induction of Agarwood in Aquilaria Malaccensis Using Nitrogen Fertilizer and Fusarium Solani

Aquilaria malaccensis is agarwood producing species in Indonesia. Agarwood compounds are formed as a chemical response of Aquliaria malaccensis tree to various physical damages, phatogen infection, or chemical treatment. Factors influencing agarwood formation are age of the tree, season, geographical location, environment, and treatment period. Agarwood induction may be done in tree or sapling. Agarwood induction in saplings need more effort than in trees. Combination of fungi (Fusarium solani) and nutrient (Nitrogen fertilizer) treatment may be one way to induce agarwood in A. malaccensis saplings. This study aims to produce A. malaccensis agarwood (aromatic compounds and colour) by induction of F. solani and nitrogen fertilizer, and analyse the agarwood chemical content. The agarwood chemical content was investigated by Gas Chromatography Mass Spectrometry (GCMS) analysis. Results indicated that agarwood had a different colour for every treatment. The darkest brown and most fragrant agarwood were produced by A. malaccensis treated by a combination of nitrogen fertilizer (4 gr/sapling) and F. solani inoculation. Three chemical compounds were identified i.e. silanediol dimethyl, 4-ethyl benzoic acid and 1,4,7,10,13,16- hexaoxacyclooctadecane with percentages of 25.7, 17.62, and 3.56 respectively. A. malaccensis treated by nitrogen fertilizer and F. solani for 3 months is able to induce aromatic compounds formation, but the colour still dark brown. Biosynthesis of aromatic compounds in agarwood occurs first before changes in the colour of the wood

Identifikasi Komponen Volatil Tanaman Padi Fase Bunting Dan Matang Susu Sebagai Pakan Alami Yang Disukai Tikus Sawah

Rat is a major rice pest that can detect and smell feed odor better then other mammals. Rice plants at booting and milky stages are the most commonly attacked by rats. These may be due to the preference of the rat to volatile compounds available in the plants at both growth stages. Analysis of the volatile compounds was conducted at the Flavor Analysis Laboratory of the Indonesian Center of Rice Research (ICRR), Sukamandi, by a Gas Chromatography Mass Spectrometry (GCMS) using the Solid Phase Microextraction (SPME) method. There were 54 volatile compounds identified from rice plants atbooting stage and 47 volatile compounds from that of milky stage. Descriptions of the volatile aromas contained in the rice plant at booting stage and milky stage were green, sweet, fatty, buttery, creamy, fruity, pungent sour, and beany

Synthesis and structure of sterically overloaded tetra-coordinated yttrium and lanthanum disiloxides

The NSF is thanked for purchase of a JEOL ECS-400 NMR Spectrometer (CRIF-MU CHE-1048553).The synthesis, structures and reactivity of the spirocyclic yttrium and lanthanum disiloxides {[(CH2R2SiO)2]2M}H [M = Ln, Y; R = SiMe(SiMe3)2] 3 and 4 are reported. Compounds 3 and 4 were prepared from reactions of two equivalents of [CH2(R)2SiOH]2 [R = Si(SiMe3)2Me] ( 1 ) with one equivalent of M[N(SiMe3)2]2 (M = Y, La), respectively.PostprintPeer reviewe

Synthesis and evaluation of new high temperature polymers for coating applications Technical summary report, 26 Jun. 1964 - 25 Sep. 1966

Synthesis, characterization, and evaluation of organic and semiorganic heat resistant polymer coating

INHIBITION OF THE SERINE PROTEASE CHYMOTRYPSIN BY A SILANEDIOL PEPTIDE MIMIC: ASYMMETRIC SYNTHESIS AND INHIBITION STUDIES

Dialkylsilanediols are non-hydrolyzable analogs of the tetrahedral intermediate of amide hydrolysis and have shown outstanding inhibition of metallo and aspartic proteases. This research describes the synthesis and inhibition of the serine protease α- chymotrypsin by silanediol structures and the development of an efficient method to install the stereochemistry at the P1’ position of the inhibitor. In the first part, the silanediol 67 was synthesized as a potential α-chymotrypsin inhibitor, however it showed no inhibition activity at longer equilibration times with the enzyme, suggesting an instability and the need for modification in the inhibitor design. Changing Ac-leucine at P2 in 67 to the proline gave 47 and 66. Compounds 47 and 66 were good inhibitors of chymotrypsin with Ki values of 106±10nM and 65±10 nM respectively. The second part of the research concentrates on the development of an efficient method to install different substituents at the P1’ position with an emphasis on stereoselectivity. Two methods were developed. The first method used the 2-alkyl-1,3-butadiene such as 58 which, on cycloaddition with diphenyldichlorosilane forms a 2,5- dihydrosilole. Asymmetric hydroboration then sets the desired stereochemistry. This method suffered, however, from the absence of readily available 2-alkyl-1,3-dienes. The second method employed catalytic asymmetric intramolecular hydrosilylation of allyl silyl ethers 130, which sets the stereochemistry with up to 94% ee, using rhodium with a ferrotane ligand. This method provides a short and general method for installation of a broad range of alkyl groups at the P1’ position with high enantioselectivity.Chemistr

Synthesis and Hydrogen-Bond Patterns of Aryl-Group Substituted Silanediols and -triols from Alkoxy- and Chlorosilanes

Organosilanols typically show a high condensation tendency and only exist as stable isolable molecules under very specific steric and electronic conditions at the silicon atom. In the present work, various novel representatives of this class of compounds were synthesized by hydrolysis of alkoxy- or chlorosilanes. Phenyl, 1-naphthyl, and 9-phenanthrenyl substituents at the silicon atom were applied to systematically study the influence of the aromatic substituents on the structure and reactivity of the compounds. Chemical shifts in 29Si NMR spectroscopy in solution, correlated well with the expected electronic situation induced by the substitution pattern on the Si atom. 1H NMR studies allowed the detection of strong intermolecular hydrogen bonds. Single-crystal X-ray structures of the alkoxides and the chlorosilanes are dominated by π-π interactions of the aromatic systems, which are substituted by strong hydrogen bonding interactions representing various structural motifs in the respective silanol structures

Methods in organosilane assembly

Dialkylsilanediols are a novel class of non-hydrolyzable analogues of the tetrahedral intermediate of amide hydrolysis, shown to be good inhibitors of HIV-1 protease, angiotensin converting enzyme (ACE), and thermolysin. An impediment to utilization of these silanediol structures, however, has been the methods for their assembly. This research describes the reductive lithiation of hydridosilanes and alkoxysilanes, and the use of the resulting silyl anions to develop efficient methods to synthesize silanediol precursors. In the first part of research, lithiation of hydridosilanes was studied. As part of this study, a simple 1H NMR method was developed for monitoring and analyzing the progress of lithiation. In addition, this method was converted to a titration for silyllithium reagents using BHT as an internal standard. Silanediols 107 and 177 are analogues of a potent chymase inhibitor, NK-3201 (82). In the second part, diphenylsilanes 108 and 170, precursors to silanediols 107 and 177, were synthesized using addition of silyllithium to sulfinimine 113 as a key step. In the third part, lithiation of alkoxysilanes was studied. (Si,O)-Dianions, generated from lithiation of silane alcohol 175 or 2,2-diphenyl-1-oxa-2-silacyclopentane (225), were reacted with a wide variety of electrophiles to give potentially useful silicon-containing building blocks. Addition of the (Si,O)-dianion 284 to sulfinimines gave silanediol inhibitor precursors with full control of stereochemistry. In the last part, a new method featuring 1,1-diphenyl-2-azaallyllithium chemistry were utilized to synthesize a series of protected α-amino silanes 323, 329 - 331.Chemistr

Discovery and Identification of Dimethylsilanediol as a Contaminant in ISS Potable Water

In September 2010, analysis of ISS potable water samples was undertaken to determine the contaminant(s) responsible for a rise of total organic carbon (TOC) in the Water Processor Assembly (WPA) product water. As analysis of the routine target list of organic compounds did not reveal the contaminant, efforts to look for unknown compounds were initiated, resulting in discovery of an unknown peak in the gas chromatography/mass spectrometry (GC/MS) analysis for glycols. A mass spectrum of the contaminant was then generated by concentrating one of the samples and analyzing it by GC/MS in full-scan mode. Although a computer match of the compound identity could not be obtained with the instrument database, a search with a more up-to-date mass spectral library yielded a good match with dimethylsilanediol (DMSD). Inductively coupled plasma/mass spectrometry (ICP/MS) analyses showed abnormally high silicon levels in the samples, confirming that the unknown compound(s) contained silicon. DMSD was then synthesized to confirm the identification and provide a standard to develop a calibration curve. Further confirmation was provided by external direct analysis in real time time of flight (DART TOF) mass spectrometry. To routinely test for DMSD in the future, a quantitative method was needed. A preliminary GC/MS method was developed and archived samples from various locations on ISS were analyzed to determine the extent of the contamination and provide data for troubleshooting. This paper describes these events in more detail as well as problems encountered in routine GC/MS analyses and the subsequent development of high performance liquid chromatography and LC/MS/MS methods for measuring DMSD

Dimethylsilanediol (DMSD) Source Assessment and Mitigation on ISS: Estimated Contributions from Personal Hygiene Products Containing Volatile Methyl Siloxanes (VMS)

Dimethylsilanediol (DMSD) is a small organosilicon compound present in humidity condensate on the International Space Station. Aqueous DMSD originates from volatile methyl siloxane (VMS) compounds in the ISS cabin atmosphere. DMSD is not effectively removed by the WPA (Water Processor Assembly), requiring removal and replacement of both WPA Multifiltration (MF) Beds for an estimated resupply penalty of approximately 70 kg/year. Analyses indicate that WPA can handle DMSD if the concentration in the condensate can by reduced by fifty percent. Personal Hygiene Products (PHPs) used by crew are suspected to be a significant source of VMS. Source removal of VMS will be required to achieve a measurable impact to the DMSD concentration in the condensate. The inventory of total crew provisions for ISS was analyzed to identify silicon containing materials and products used for personal hygiene that emit VMS. Accounting for the wide range in mass of hygiene product applied to skin or hair, the frequency of application, the product selection, the number of crew using a given product, the range in silicon mass fraction of different products, and the potential vaporization of the product, the potential total VMS emissions from personal hygiene products for a crew of six on ISS were estimated. The total daily VMS emissions from PHPs estimate ranges from 261 to 1145 mg-Si per day, compared to total estimated VMS generation rates on ISS of 800 to 1500 mg-Si per day. The main sources of VMS were determined to be antiperspirants (173 to 696 mg-Si per day), skin lotions (63 to 248 mg-Si per day), wipes (25 to 124 mg-Si per day) and hair conditioner (0 to 69 mg-Si per day). Several siloxanes-free options are available for deodorants, wet wipes, lotions, and leave-in conditioners. These products are now being assessed for crew member use in future increments