Phenyl group isocyanate

PMDI also contains isocyanates with higher molar masses (triisocyanates, tetraisocyanates, polyisocyanates), whereby the structure and the molar mass depend on the number of phenyl groups. This distribution influences, to a great extent, the reactivity, but also the usual properties like viscosity, flowing and wetting behavior as well as the penetration into the wood surface. 

Analysis of the enantiomeric ratios of several p-blocking drugs (l-aryloxy-3-isopropylamino-2-propanol derivatives) is carried out by HPLC with UV or fluorescence detection after derivatization with (R)-NEI or (i )-(+)-l-(l-phenyl)ethyl isocyanate (in a reversed-phase system), or (S)-NEI (on silica gel) only the amine function of the drugs reacts with the NEI the hydroxy group does not. Similar schemes for HPLC determination of enantiomeric purity of tetrahydrofolate derivatives and of fluoxetine are also reported. 

We have made several other V" complexes by displacing the hydrazine ligand in [V(N2H4)(NS3)] with Cl , N3 CN , MeCN or CNBu , and have prepared a series of imido-complexes [V(NAr)(NS3)] (Ar = various substituted phenyl groups), and of hydrazido-complexes [V(NNR R )(NS3)] (R R = methyl or phenyl) from reactions of [V(0)(NS3)] with aryl isocyanates or 1,1-disubstituted hydrazines, respectively. Structural studies on several of these compounds always reveal trigonal bipyramidal coordination about the V atom. The V-N distance in the V(NS3) system, as a result of the shape of the NS3, is sensitive to... 

BaycoU AS 1160 is a highly branched polyester polyol (PL) consisting of four different constituents (see Fig. 10.2). The material typically has a low acid number, and a majority of end groups are hydroxyl that can react with a phenyl-based isocyanate to produce a polyurethane adhesive. Specification Umits require the water... 

The rhodium-catalyzed chemo-, regio- and enantioselective [2-1-2- -2] cycloaddition of unsymmetrical alkynes to isocyanates leads to a wide range of 2-pyridones [123]. This method is used satisfactorily in the synthesis of axially chiral arylpyridones 2.196 by coupling alkylisocyanates with unsymmetrical a,to-diynes 2.195 that have one o-substituted phenyl group in one acetylene branch and terminal triple bond in another (Scheme 2.68) [123],... 

The acetyl content of cellulose acetate may be calculated by difference from the hydroxyl content, which is usually determined by carbanilation of the ester hydroxy groups in pyridine solvent with phenyl isocyanate [103-71-9J, followed by measurement of uv absorption of the combined carbanilate. Methods for determining cellulose ester hydroxyl content by near-infrared spectroscopy (111) and acid content by nmr spectroscopy (112) and pyrolysis gas chromatography (113) have been reported. 

Phenyl isocyanate reacts with (82) to form (83) by ring enlargement (74JOC948). Reaction of oxaziridines with diphenylketene proceeds less obviously. Isolated products (84) and (85) contain only the R—N group of the starting material (69TL263). 

Acylations were often carried out with diaziridines. Twofold acylation is normally observed when two NH groups are present. Most acylations were performed with benzoyl chloride, acetyl chloride or phenyl isocyanate (B-67MI50800). Ring opening reactions during acylation, foreseeable for intermediates of electrophilic attack on nitrogen, were observed only seldom, provided mild conditions were used. 

Intermolecular reactions with typical cycloaddition components are also possible. Phenyl isocyanate in ether converts triisopropyldiaziridinimine (182) to the 1,2,4-triazolidine under mild conditions. Labeling with a deuterated isopropyl group revealed that cycloaddition is not preceded by N—N cleavage, which should have resulted in deuterium randomization (77AG(E)109). 

The amino group of 3,4-dihydro-2//-pyrimido[2,l-n]isoquinoline 421 (R = H) was acylated with different isocyanates and phenyl isothiocyanate (98JMC1050). 

Reaction of hydroxy groups with phenyl isocyanate and back titration of the excess isocyanate with dibutylamine. Both moisture and acidity interfere275. ... 

An alternative route to poly(m-carborane-siloxane) rubbers is via the condensation reaction between w-carborane di-hydrocarbyl-disilanol and a bis-ureidosilane.20 This mild reaction allows the incorporation of desired groups into the polymer via both the dihydrocarbyl-disilanol and the bis-ureidosilane (see scheme 8). The first step involves the formation of the carborane silanol from the butyl lithium carborane derivative. The bis-ureidosilane is prepared from the phenyl isocyanate (see step 2), and the final step involves reacting the dihydrocarbyl-disilanol with bis-ureidosilane. 

Among heteroaromatic compounds able to react with nitrile oxides as dipo-larophiles, furan, probably, is the best known. Recently, a novel nitrile oxide was generated from a sulfoximine and converted in situ to a cycloadduct with furan (Scheme 1.25) (287). The starting racemic N-methyl-S-nitromethyl-S-phenylsul-foximine 124 was prepared in 87% yield via nitration of N,S-dimethyl-S-phenyl-sulfoximine. Reaction of 124 with p-chlorophenyl isocyanate and a catalytic quantity of triethylamine, in the presence of furan, afforded dihydrofuroisoxazole 125, the product of nitrile oxide cycloaddition, in 42% yield (65 35 diastereomer ratio). The reaction of 125 with phenyllithium and methyllithium afforded compounds 126, which are products formed by replacement of the sulfoximine group by Ph and Me, respectively. 

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