There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Sustainable economic and industrial growth requires safe, sustainable resources of energy. For the future re-arrangement of a sustainable economy to biological raw materials, completely new approaches in research and development, production, and economy are necessary. The ‘first-generation’ biofuels appear unsustainable because of the potential stress that their production places on food commodities. For organic chemicals and materials these needs to follow a biorefinery model under environmentally sustainable conditions. Where these operate at present, their product range is largely limited to simple materials (i.e. cellulose, ethanol, and biofuels). Second generation biorefineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing including pyrolysis, Fisher Tropsch, and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This review focus on cost effective technologies and the processes to convert biomass into useful liquid biofuels and bioproducts, with particular focus on some biorefinery concepts based on different feedstocks aiming at the integral utilization of these feedstocks for the production of value added chemicals.

http://staff.cimap.res.in/PublicationFiles/Renew_Sustain_Energ_Rev_14_578.pdf

Production of first and second generation biofuels: A comprehensive review

Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S. A. S. Nagar,Mohali, Punjab-160 062, India, Institute of Biochemistry, Faculty of Medicine, Polytechnic University, Via Ranieri 67, IT-60100 Ancona, Italy,Green Biotechnology Research Group, The Special Division for Human Life Technology, National Institute of Advanced Industrial Science andTechnology, 1-8-31 Midorigaoka, Ikeda, Osaka-563-8577, Japan, and Department of Medicinal Chemistry & Natural Products,The Hebrew University of Jerusalem, School of Pharmacy-Faculty of Medicine, Jerusalem 91120, IsraelReceived March 2, 2004

Chitosan chemistry and pharmaceutical perspectives.

The synthesis of α-aminophosphonates on a large scale is not always straightforward One of the described methodologies has now been adjusted for use in a microreactor system The CPC College System was used to investigate the continuous production of α-aminophosphonates This technology couples miniaturisation to optimal reaction conditions for the production of chemical and pharmaceutical intermediates The reaction of an imine with a dialkyl phosphite in different solvents was optimised, since the use of a solvent is necessary when using a microreactor When methanol was used, a considerable reduction of the reaction time was noticed in comparison with other commonly used solvents Subsequently, several reaction parameters were optimised in batch and compared with the continuous process in the microreactor Similar yields and purities were obtained compared to the batch reaction Using the microreactor system, the scale-up problems were avoided and large amounts of αaminophosphonates could be generated in a short time

https://www.arkat-usa.org/get-file/22314/

Straightforward continuous synthesis of α-aminophosphonates under microreactor conditions

Chiral spirocylic oxaphospholenes were prepared in a three-step sequence from chiral pool terpenoid ketones. After addition of a metal acetylide, the resulting propargyl alcohols were converted stereoselectively into their allenylphosphonate counterparts. In the last step, they were conveniently cyclized into spirooxaphospholenes with one equivalent of iodine without purification. When starting from sterically hindered terpenes, allenylphosphonates were also easily obtained but showed to be unreactive or rearranged under these cyclization conditions.

Three-Step Synthesis of Chiral Spirocyclic Oxaphospholenes

The first synthesis of benzoxaphospholenes dates back to the 1960s. Since then, the structural variety of reported (benz)oxaphospholenes has steadily increased. Organophosphorus compounds have caught the interest of synthetic chemists for a couple of decades now because of their interesting biological properties. Oxaphospholenes, in particular, could serve as carbohydrate mimetics, and benzoxaphospholenes have been reported to possess bactericidal, insecticidal, herbicidal, and fungistatical properties. Transesterification reactions and addition of phosphorus nucleophiles to carbonyl compounds were reaction types that led to the production of the first (benz)oxaphospholenes. When it was discovered that allenylphosphonates could easily be obtained from propargyl alcohols and dialkyl halophosphites, the electrophile-induced cyclization reaction of these allenylphosphonate precursors resulted in a huge boom in the amount of reports on oxaphospholene synthesis. To this day, this method is still frequently used. Ring-closing metathesis and Horner-Wadsworth-Emmons reactions have also proven their potential for the preparation of oxaphospholenes. In recent years, Pd, Rh and Au-catalysis have made their entry, generating (benz)oxaphospholenes from a wide variety of simple substrates. A couple of miscellaneous methods are summarized at the end of the Review.

Fifty Years of (Benz)oxaphospholene Chemistry

2,2-Dichlorocyclobutanones reacted with various amines to give ring opening leading to 4,4-dichlorobutanamides. These compounds proved to be suitable substrates for the synthesis of 3-pyrrolin-2-ones, 2-pyrrolidinones, pyrrolidines and pyrroles.

New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, ­Pyrrolidines and Pyrroles

An efficient synthesis of furo[3,4-d]pyrimidine-2,4-diones has been accomplished via a straightforward three-step pathway. Curtius rearrangement of 4-(methoxycarbonyl)furan-3-carboxylic acid and subsequent reaction with a variety of amines resulted in the corresponding intermediate ureids, which could be ring closed to the bicyclic scaffold in good yields. Functionalization of N-1 afforded a small library of new heterocycles. (Partial) hydrogenation of the furo[3,4-d]pyrimidine-2,4-diones led to the 5,7-dihydro- and tetrahydrofuro[3,4-d]pyrimidine-2,4-diones.

Christian V. Stevens

Papers

Straightforward continuous synthesis of α-aminophosphonates under microreactor conditions

Three-Step Synthesis of Chiral Spirocyclic Oxaphospholenes

Fifty Years of (Benz)oxaphospholene Chemistry

New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, Pyrrolidines and Pyrroles

Straightforward Synthesis of Functionalized Furo[3,4-d]pyrimidine-2,4-diones

Christian V. Stevens

Papers

Straightforward continuous synthesis of α-aminophosphonates under microreactor conditions

Three-Step Synthesis of Chiral Spirocyclic Oxaphospholenes

Fifty Years of (Benz)oxaphospholene Chemistry

New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, ­Pyrrolidines and Pyrroles

Straightforward Synthesis of Functionalized Furo[3,4-d]pyrimidine-2,4-diones

New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, Pyrrolidines and Pyrroles