Preparation and Properties of Aromatic Polycarbodiimides from Aromatic Diisocyanates.

Upper reference limits for biomarkers of exposure to aromatic diisocyanates.

OBJECTIVES The objectives of this study were to determine the levels of 2,4-toluenediamine, 2,6-toluenediamine, 1,5-naphthtalenediamine and 4,4'-methylenediphenyldianiline in hydrolyzed urine and plasma for occupationally unexposed workers and to calculate upper reference limits (URLs). These analytes are biomarkers of exposure to 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (2,4-TDI a...

Aromatic Iodides from Aromatic Organomercurials 13.2. Aromatic Bromides from Aromatic Organomercurials 13.3. Aromatic Chlorides from Aromatic Organomercurials 13.4. Aromatic Fluorides from Aromatic Organomercurials 13.5. Aromatic Nitriles from Aromatic Organomercurials 14. Improved Syntheses of Some Diaryliodonium Salts from Symmetric Diarylmercurials

This review reports some novel (or improved) synthetic methods for preparing a number of aromatic (carbocyclic and predominantly heterocyclic) organomercurials, particularly those derived from theophylline, theobromine and uracil, as well as some novel haloand cyano-demercuration reactions. We have also synthesized the first stable organic derivative of mercury(I), viz. 1,8-bis(acetoxydimercuri...

Preparation of sterically congested 1,3,4-oxadiazole derivatives from N-isocyaniminotriphenylphosphorane, aromatic acids, cyclopentanone and primary amines

Reactions of N-isocyaniminotriphenylphosphorane with cyclopentanone have been studied in the presence of aromatic carboxylic acids and primary amines, proceeds smoothly at room temperature under neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives by an intramolecular Aza-Wittig cyclization in CH2Cl2 in excellent yields. The structures of the products were deduced from...

extraction and acetylation of purified trypsin from bovin pancreas and study of some its physico-chemical properties

آنزیم تریپسین در شرایط قلیایی ناپایدار می باشد .و فعالیت پروتئولیتیکی تریپسین منجربه خود هضمی آن در جایگاههای خاصی می گردد. بنابر این آنزیمی با ناپایداری بالا محسوب میگردد. در سالهای اخیر موفق شدند که با ایجاد تغیرات شیمیایی با اضافه کردن فلزات خاص ، کلسیم و یا عمل استیلاسیون منجر به افزایش پایداری آنزیم تریپسین گردند. مطالعات در حال حاضر نشان می دهد که تریپسین استیله شده فعالیت آنزیمی خود را ...

Photophysical Properties of Aromatic and Antiaromatic Porphyrinoids