Protecting groups used in the chemical synthesis of nucleic acids are reviewed in terms of protections for the hydroxyl groups, the heterocyclic amino groups and the phosphate esters. 1. Protection for hydroxyl groups 1.1 Protecting groups for the primary hydroxyl groups 1.2 Protecting groups for the secondary hydroxyl groups 1.2.1 Acyl groups 1.2.2 2'-Acetals and ketals 1.2.3 Other protecting group for hydroxyl groups 2. Protection for heterocyclic amino groups 3. Protection for phosphate esters 3.1 Protection for phosphomonoesters 3.2 Protection for phosphodiesters
Recent advances of protective groups in peptide synthesis are reviewed according to the following articles : (i) orthogonal protection, (ii) α-amino protection, (iii) carboxyl protection, and (iv) protection of side chain functions.
The IUPAC nomenclature is not always properly accepted. Many incorrect names are found in contributed papers by many authors. It may be unavoidable that naming compounds of complicated structure is attended with some confusions. On the other hand, a lack of understanding the IUPAC nomenclature is often found in the names of rather simple compounds, since older unreasonable nomenclature is surviving in these familiar compounds. Misunderstandings of the IUPAC nomenclature are also seen. This review describes a practical guide to write correct names of organic compounds. Several important items of the IUPAC nomenclature are briefly explained with many examples. On some items, examples of incorrect names are quoted from contributed papers, and mistakes are corrected giving proper advice.
Following a brief survey on significant points of poromeric man-made leather quality in comparison with that of natural leather and conventional synthetic leathers, the key points of the manufacturing process which may be closely related to its functional properties were discussed. 1. Introduction ; 2. Poromeric man-made leather and synthetic leather ; 3. Outline of promeric man-made leather manfacturing process ; 3.1. Mat making process, 3.2. Process for substrate ; 3.4. Finishing process ; 4. Problems on mat making process ; 4, 1. Elimination of strain of the mat ; 5. Problems on substrate making process ; 5.1. Polyurethane elastomer ; 5.1.1. Key points of the quality ; 5.1.2. Raw material ; 5.1.3. Form of the reaction ; 5.2. Mat impregnation with emulsion ; 5.3. Non-adhensive type resin impregnation ; 6. Problems on surface layer making process ; 7. Conclusion.
The recent development of manufacturing process of ethylbenzene and styrene is reviewed in this article. Most of the ethylbenzene in the world is made by liquid phase Friedel-Crafts alkylation using aluminium chloride, and this process has been improved on various aspects. Solid catalysts such as molecular sieves and BF3-almina have been developed for the prevention of corrosion by aluminium chloride. The dehydrogenation of ethylbenzene is still most important for the commercial production of styrene. Some technical improvements concerning reactor design, catalyst, and recovery of styrene have been made by many producers. Co-production process of propylene oxide and styrene is also important. Many other new routes to styrene have been extensively investigated.
The partial amination of sym-trichlorobenzene with aqueous ammonia was studied under various conditions. In general, sym-trichlorobenzene has been aminated with ammonia to give 3, 5-diaminochlorobenzene by way of 3, 5- dichloroaniline in the presence of Cu catalyst. Authors have found that the addition of trialkylamines such as triethylamine or tripropylamine to the system increased the relative yield of 3, 5 - dichloroaniline to 86.9 % at 250°C. Similar behaviol of the added trialkylamines was recognized in the monoamination of dichlorobenzene isomers. The effects of the added trialkylamine in the monoamination are supposedly due to ; the poisoning of Cu catalyst and /or the protection of halogen group from the successive amination.