Eight salt forms of sulfadiazine

Proton transfer to the sulfa drug sulfadiazine [systematic name: 4‐amino‐N‐(pyrimidin‐2‐yl)benzenesulfonamide] gave eight salt forms. These are the monohydrate and methanol hemisolvate forms of the chloride (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium chloride monohydrate, C₁₀H₁₁N₄O₂S⁺·Cl⁻·H₂O, (I), and 2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium chloride methanol hemisolvate, C₁₀H₁₁N₄O₂S⁺·Cl⁻·0.5CH₃OH, (II)); a bromide monohydrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium bromide monohydrate, C₁₀H₁₁N₄O₂S⁺·Br⁻·H₂O, (III)), which has a disordered water channel; a species containing the unusual tetraiodide dianion [bis(2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium) tetraiodide, 2C₁₀H₁₁N₄O₂S⁺·I₄²⁻, (IV)], where the [I₄]²⁻ ion is located at a crystallographic inversion centre; a tetrafluoroborate monohydrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium tetrafluoroborate monohydrate, C₁₀H₁₁N₄O₂S⁺·BF₄⁻·H₂O, (V)); a nitrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium nitrate, C₁₀H₁₁N₄O₂S⁺·NO₃⁻, (VI)); an ethanesulfonate {4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium ethanesulfonate, C₁₀H₁₁N₄O₂S⁺·C₂H₅SO₃⁻, (VII)}; and a dihydrate of the 4‐hydroxybenzenesulfonate {4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium 4‐hydroxybenzenesulfonate dihydrate, C₁₀H₁₁N₄O₂S⁺·HOC₆H₄SO₃⁻·2H₂O, (VIII)}. All these structures feature alternate layers of cations and of anions where any solvent is associated with the anion layers. The two sulfonate salts are protonated at the aniline N atom and the amide N atom of sulfadiazine, a tautomeric form of the sulfadiazine cation that has not been crystallographically described before. All the other salt forms are instead protonated at the aniline group and on one N atom of the pyrimidine ring. Whilst all eight species are based upon hydrogen‐bonded centrosymetric dimers with graph set R₂²(8), the two sulfonate structures also differ in that these dimers do not link into one‐dimensional chains of cations through NH₃‐to‐SO₂ hydrogen‐bonding interactions, whilst the other six species do. The chloride methanol hemisolvate and the tetraiodide are isostructural and a packing analysis of the cation positions shows that the chloride monohydrate structure is also closely related to these.     

A Development Environment for OSA-Based Applications over the Interworked WLAN and Cellular Networks

In this paper, we propose an OSA-based development environment for interworking WLAN and 3G cellular networks. The main goal of our work is to establish and create an environment that can serve as a demonstration of a working network for OSA-based application developers while featuring mobile services over the interworked LAN and 3G cellular networks. The proposed simulating environment has (i) a location update scheme that is used to obtain mobile users' locations and status information over the interworked WLAN and cellular networks, (ii) an instant message gateway (IMG) simulator that is developed to send and receive generic messages over the interworked WLAN and cellular networks, and (iii) a mapping of Parlay APIs onto SIP signaling messages for multiparty call applications over the interworked WLAN and cellular networks. An illustrated OSA-based application that utilizes the corresponding system functions and modules is developed and verified using the proposed simulating environment. Chung-Ming Huang received the B.S. degree in Electrical Engineering from National Taiwan University on 1984/6, and the M.S. and Ph.D. degrees in Computer and Information Science from The Ohio State University on 1987/12 and 1991/6 respectively. He is currently a professor in Department of Computer Science and Information Engineering, National Cheng Kung University, Taiwan, R.O.C. He is the director of The Promotion Center for Network Applications and Services, Innovative Communication Education Project, Ministry of Education, Taiwan, R.O.C. His research interests include broadband Internet and applications, wireless and mobile network protocols, ubiquitous computing and communications, and multimedia streaming. Tz-Heng Hsu received the B.S. degree from Department of Computer Science and Information Engineering, Feng Chia University on 1996/6, and the M.S. degree and Ph.D from Department of Computer Science and Information Engineering, National Cheng Kung University on 1998/7 and 2005/7, Taiwan, R.O.C. He is currently a assistant professor in Department of Computer Science and Information Engineering, Southern Taiwan University of Technology. His research interests are wireless and mobile network protocols, applications over interworked WLAN and cellular networks and communications, and multimedia streaming. Chih-Wen Chao received the B.S. degree from Department of Engineering Science, National Cheng Kung University on 2003/6, and the M.S. degree from Department of Computer Science and Information Engineering, National Cheng Kung University on 2005/7, Taiwan, R.O.C. His research interests are OSA-based applications and distributed multimedia systems.     

具有药物活性的离子液体

离子液体阴阳离子的可设计性使其具有可控溶解性、独特表面活性、高热稳定性、增强的生物利用率和生物活性,这些特点使离子液体在消除同质多晶现象、改变药物传输模式及可包含传统药物组分等方面具有优势,成为当前离子液体研究领域的热点之一。本文对离子液体在医药领域的应用做了全面的阐述,主要介绍了近十年来离子液体在活性药物组分、抗菌剂及除草剂方面的成果,探讨了当前存在的问题及研究方向,并对其应用做了展望。