Phenyl isocyanate, condensation with

Methylenebis(4-phenyl isocyanate). This compound is also known as methyl diisocyanate [101-68-8] (MDI) and is produced by the condensation of aniline and formaldehyde with subsequent phosgenation. Its principal end use is rigid urethane foams other end uses include elastic fibers and elastomers. Total formaldehyde use is 5% of production (115). 

Sodium methanenitronate reacts with phenyl isocyanate in benzene to give the readily separable sodium salts of nitroacetaniUde and nitromalondiarkhde. Except as the salt, nitromethane is unreactive with phenyl isocyanate at temperatures up to 100°C the higher homologues do not give condensation products that can be isolated. 

I-Cyano-3-phenylurea, first obtained by the alkaline hydrolysis of 5-anilino-3- -toluyl-l,2,4-oxadiazole, has been prepared by tlic condensation of phenyl isocyanate and the sodium salt of cyanamide. However, in these publications an incorrect structural assignment for the product was made. 1-Cyano-3-phenyl-urea is obtained also, together with other products, by warming gently l-cyano-3-phenylthiourea with caustic soda in the presence of ethylene chlorohydrin, or by gradually adding caustic )otash to a boiling solution of 1-phenyldithiobiuret and ethylene clilorohydrin in ethanol. ... 

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. 

Condensation of arylhyrazonooxomalononitrile with methyl isocyanate gave 286, which could be cyclized to iminotriazinecarbonitrile 287 (R = H). Its reaction with phenyl isocyanate gave 287 (R = CONHPh), which was cyclized by the action of triethylamine to give 288 (X = NH), which was in turn hydrolyzed to 288 (X = 0) (78HCA1175). 

The condensation of isocyanate esters with diguanides proceeds in an entirely comparable manner, providing a corresponding series of s-triazin-2-ones (i.e. substituted ammelines) 378). However, since loss of water from carbamoyl-intermediates [e.g. RNHCONH C( NH)NH C( NH) -NH2] occurs much less readily than loss of hydrogen sulphide from their thiocarbamoyl-analogues, melamines are not formed in this reaction 378). The production of adducts from phenyl isocyanate and tetra-. 

Tamariz et al. reported the synthesis of mukonine (11) based on a regioselective Diels-Alder reaction of N-phenyl-4,5-dimethylidene-2-oxazolidinone (634) with methyl propiolate (635). The diene 634 was prepared in moderate yield from the condensation reaction of 2,3-butanedione (632) with phenyl isocyanate (633). In an optimized reaction procedure using drastic basic hydrolytic conditions (KOH/ MeOH), followed by methylation with dimethyl sulfate, the adduct 636, was... 

B. 4-Phenyl-l-carbethoxysemicarbazide. In a 1-1. three-necked round-bottomed flask equipped with a liquid-sealed mechanical stirrer (Note 3), a constant-pressure dropping funnel, and a reflux condenser fitted with a drying tube containing silica gel is placed a solution of 52 g. (0.5 mole) of ethyl hydrazine-carboxylate in 550 ml. of dry benzene (Note 4). The solution is cooled in an ice bath, and the stirrer is started. To the solution is added 59.7 g. (55 ml., 0.5 mole) of phenyl isocyanate (Note 5) dropwise over a period of 45 minutes. After about one-half of the isocyanate has been added, a white precipitate of the product appears, and the reaction mixture becomes progressively thicker. After addition is complete the ice bath is removed, and the mixture is stirred at room temperature for 2 hours and then is heated under reflux for 2 hours. The suspension is allowed to cool to room temperature, and 4-phenyl-1-carbethoxysemi-carbazide is isolated by suction filtration, washed with 500 ml. of benzene, and dried in a vacuum desiccator. The yield is 108 g. (97%), m.p. 151-152°. The product is not further purified before being used in the next step. It may be recrystallized from ethyl acetate to yield white crystals, m.p. 154-155°, vmax 1645, 1687, 1797, and 3300 cm.-1 (Note 6). 

Polymerizations were carried out in a dried 250 ml three-necked flask equipped with a nitrogen inlet, magnetic stirrer, reflux condenser, dropping funnel, and recording thermocouple. The reaction flask was immersed in a constant temperature bath, 50 ml solution of phenyl isocyanate in acetonitrile (cone. 1 mol kg l) was pipetted into the flask and stirred magnetically while the catalyst solution in acetonitrile (50 ml) was placed in the thermostat-controlled dropping funnel. When constant temperature (+ 0.1oC) was reached in the flask as well as in the funnel, the catalyst solution... 

Condensation gf phenyl isocyanate has also been reported reoently 88 to occur with phonyl glycidyl other and l,2-epoxy-3-phenylhutane in the presence of catalytic amounts of benzyldimethyl-amine (Eq. 973). 

Overman et al. exercised the CBS reduction strategy during synthesis of the natural opium alkaloid (—)-morphine (50)21 (Scheme 4.3q). Enantioselective reduction of 2-allylcyclohex-2-en-l-one (51) with catecholborane in the presence of the (R)-oxazaborolidinc catalyst (l )-28a provided the corresponding (S)-cyclohexenol 52 in greater than 96% ee. Condensation of this intermediate with phenyl isocyanate, regioselective catalytic dihydroxylation of the terminal double bond, and protection of the resulting diol afforded 53 in 68% overall yield from 51. The ally lie silane 54 for the upcoming iminium ion-ally lsilane cycliza-tion step was obtained in 81% yield by a stereoselective Sn2 displacement of allylic carbamate. 

Trimethylindolenine and its 5-methyl-, 5-chloro- and 7-chloro derivatives react with phenyl isocyanate and various acyl isocyanates and isothiocyanates to give 75-97% of the corresponding l-carbamoyl-2-methyleneindolines (52), which isomerize to the 2-(carbamoylmethylene) indolines (53) (41-85% yield).52 Whether these Fischer s base derivatives after further N-alkylation will condense with salicylaldehydes to form spiropyrans is not known. 

Condensation of /3-diketones with phenyl isocyanate followed by alkylation and cyclization gives 2-aminothio-phenes 256 (Scheme 49) <2001SL1731, 2002TL257, 2003T1557>. 

The condensation of active methylene compounds such as malononitrile, ethyl cyanoacetate, etc., with phenyl isocyanate followed by alkylation and cyclization gives 3-aminothiophenes 304 (Scheme 51) <2003T1557>. Dihydrothienopyrimidine-4(/7T)ones 306 are prepared by the reaction of 305 with a-halo ketones <2006HAC104>. 

With phenyl isocyanate 48 yields the 3-anilinoformyl derivative while with sulfuric acid followed by sodium hydroxide it is converted via 64 into 49.39 Although 48 is catalytically reduced to 47 it is recovered unchanged from treatment with sodium in ethanol or lithium aluminum hydride. Treatment of 47 with hydrogen peroxide and sodium hydroxide gave a dihydrodiazepine believed to be 65 which is isomerized to 48 with acid. Finally, condensation of 47 with formaldehyde gave rise to 66.39... 

Condensation of phenyl isocyanate with an aqueous solution of the sodium salt of cyanamide and acidification affords l-cyano-3-phenylurea (4). ... 

Desmoras el al. (1963) described the herbicidal properties of the D-isomer of N-ethyl 2-(phenylcarbamoyloxy)propionamide, prepared by the condensation of phenyl isocyanate with N-ethyl lactamide (carbetamide, 9). 

Akteries and Jochims reported the synthesis of l,4-bis(4-methoxyphenyl)-l,3,5-triazine-2,4,6-(17/,37/,5//)-trione (177) when chlorocarbonyl isocyanate was reacted with di-(4-methoxy-phenyl)carbodiimide. The chloro intermediate was not isolated but hydrolyzed with water to give (177) (Scheme 52) <86CB1133>. Products similar to (177) (e.g. (171)) are available by the condensation of chlorocarbonyl isocyanate directly with ureas. 

Fusion of the piperazinyl esters 16 with urea at 180-190° resulted in cyclization to the trioxobicyclic compounds 17. Reaction of the ester 16 (R = H) with phenyl isocyanate gave the ureide 18, which on refluxing in hydrochloric acid condensed to give the 7-phenyl derivative 19 in 56% yield. ... 

Two other syntheses of a less general nature have also been reported. Reaction of phenacylquinoxalinium bromide (15) with phenyl isocyanate in the presence of triethylamine gave the tetrahydro compound 16. Condensation of 2-aminoquinoxaline with the perfluoro compound 17 gave the bisimino derivative 18. °... 

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