Geminal frustrated Lewis pairs (FLPs) are expected to exhibit increased reactivity when the donor and acceptor sites are perfectly aligned. This is shown for reactions of the nonfluorinated FLP tBu(2)PCH(2)BPh(2) with H(2), CO(2), and isocyanates and supported computationally.

A strategy involving palladium-catalyzed cyclization of halo-phenyl hydrazones and aryl isocyanates provides a convenient approach to the synthesis of 1,3,4-benzotriazepines (4) or 1-arylamide-1H-indazoles (5) in good isolated yields. Microwave irradiation was found to afford high reaction efficiency, while the choice of halophenyl hydrazone had an effect on the pathway of the reaction.

A new approach towards the synthesis of indole derivatives via triflic acid-promoted cycloisomerization with rearrangement of 2-(alkyn-1-yl)phenyl isothiocyanates and 2-(alkyn-1-yl)phenyl isocyanates has been achieved. By this methodology, structurally diverse types of indole derivatives such as thieno- and furo-indoles, spiro-indolethiones, spiro-oxindoles, and 3-alkylidene-oxindoles were synt...

Cationic gold-catalyzed cycloisomerizations of propargylureas, derived in situ from secondary propargylamines and aryl or alkyl isocyanates, have been studied. The reaction outcome was found to be different from what was previously observed for the tosyl isocyanate-derived ureas in terms of both regio- and chemoselectivity. As a result, the current protocol offers efficient access to the 3,4-di...

Human exposure to harmful compounds in the environment, from intake via food, occupational exposures or other sources, could have health implications. Exposure to reactive compounds/metabolites can be identified and quantified as hemoglobin (Hb) adducts by mass spectrometry. This thesis aimed at improved synthetic pathways for reference standards, and improved analytical methods for adducts to ...

A 31-year-old man working as process operator in the manufacture of polyurethane adhesives was referred to the Department of Occupational and Environmental Dermatology in Malmö (DOED) with suspected allergic contact dermatitis caused by isocyanates. His main work task was to monitor the manufacturing process, which he did from a separate control room. Three months prior to the visit, he changed...

By the reactions of ketimines bearing a pyridyl or a picolyl group on a nitrogen atom of the imine moiety with tosylisocyanate, 4H-pyrido[1,2-a]pyrimidin-4-one derivatives could be obtained in quantitative yields. In these reactions, tosylisocyanate acts as a carbonyl precursor. The pyridyl or picolyl group is a key functional group because it is not only the constituent structure of the 4H-pyr...

This article contains original experimental data, figures and methods to the preparation of non-isocyanate poly(hydroxyurethanes) by an environmentally friendly method without the use of toxic phosgene and isocyanates from bis(2,3-dihydroxypropyl)ether dicarbonate and various diamines (Tryznowski et al., Submitted for publication) [1]. Bis(2,3-dihydroxypropyl)ether dicarbonate was obtained from...

Air-fed visors are commonly used for protection against exposure to airborne isocyanates during paint spraying. Protection levels for this class of equipment are theoretically adequate, yet isocyanate sensitization in this occupation still occurs. The work reported here set out to establish the level of respiratory protection that is achieved during real paint spraying activities when air-fed v...