Isocyanate, methyl, condensation with

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. 

Several syntheses of aminodeoxypentoses have employed a similar approach in which a three-carbon starting material is condensed with a two-carbon entity. For instance, the nucleophilic addition of methyl isocyanate to R)-2A is highly diastereoselective giving a mixture of erythro and threo adducts (Scheme 13.36). The major adduct is then converted into methyl 2-amino-2-deoxy-o-arabonate [77]. 

Phenmedipham is manufactured in two synthesis steps. First, m-aminophenol reacts with methyl chloroformate in the presence of MgO as acid binder. The 3-methoxycarbonylaminophenol obtained is then condensed with w-tolyl isocyanate to give phenmedipham. For the acceleration of the latter reaction a tertiary amine catalyst may be used. 

The scope of the synthesis is further extended by the use of isocyanide dichlorides (199) their condensation with iV-methyl-iV-thiobenzoyl-hydrazine (198) in boiling chloroform yields crystalline thiadiazolium chlorides (200), which are converted by ammonia in chloroform into the mesionic 1,3,4-thiadiazoles (201) e.g. anhydro-4-methyl-5-phenyl-2-phenylamino-l,3,4-thiadiazolium hydroxide). Isomerization to mesionic 1,2,4-triazoles (202) occurs in hot ethanol, or under the influence of phenyl isocyanate in benzene. The two mesionic systems (201) and (202) may be distinguished by their mass spectra. Both isomers show a molecular ion, and a common fragment ion, MeN CPh, but they are differentiated by the fragments Ph—C=NR arising from (202) and by Ph—C S from (201). ... 

Just as alkenes can be condensed with isocyanates, one alkene unit of a diene can also react, eventually leading to an alkenyl amino acid. The condensation of CSI and 1,3-pentadiene in reaction 4 is one example and it gave 2.J02.51 Removal of the sulfonyl group and hydrolysis gave methyl 3-aminohex-4-enoate (2.55),51c a synthetic intermediate for the preparation of daunosamine.51a.c Similar reaction with 1,3-... 

Figure 12. A library of 54 neamine conjugates was constructed using a solution phase multicomponent condensation strategy. A protected neamine aldehyde derivative was condensed with two isocyanates and thirteen protected amino acids to produce the PEG linked products. Cleavage from the PEG support and protecting group removal gave the neamine conjugates as either the free acid or methyl ester.

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). 

B. Polymeric Urea [Benzene, diethenyl-, polymer with ethenylbenzene, [[[[(1 methylethyl)amino]carbonyt]amino]methyl] deriv.] A 10.0-g. portion of benzylamine polymer beads prepared as in Part A and 125 ml. of tetrahydrofuran (Note 6) are combined in a 300-ml., three-necked, round-bottomed flask equipped with a magnetic stirrer, a dropping funnel, and a condenser fitted with a gas-inlet tube A nitrogen atmosphere is established in the system, and the slurry is stirred while 1.35 g. (0.0159 mole) of isopropyl isocyanate [Propane, 2-isocyanato-] is added. This causes an exothermic reaction, which subsides after about 20 minutes. The mixture is then stirred at room temperature for 22 hours and at reflux for an additional 4 hours. The beads are collected by filtration, washed with 150-ml. portions of tetrahydrofuran (Note 6) and methanol, and dried under reduced pressure over calcium chloride to yield 9.09 g, of the isopropyl urea polymer. 

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). 

In the 1950s Kolbezen and Metcalf at the University of Califomia-Riverside laid the foundation for Union Carbide s development of carbaryl (Sevin ), the first major carbamate. Still the most important carbamate insecticide, it is made by condensing 1-naphthol with methyl isocyanate. The... 

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... 

Archer and co-workers (103) have also employed the Snieckus oxidative pho-tocyclization in the key step of their synthesis of the 7//-pyrido[4,3-c]carbazole ring system (Scheme 40). Thus, a Wittig condensation between pyruvate 242 and pyridine 243 gave the unsaturated ester 244. Photocyclization gave the tetracyclic ester 245. Reduction and reaction with methyl isocyanate led to carbamate 247. Oxidation of alcohol 246 to aldehyde 248, followed by a standard one-carbon homologation, gave the desired ethyl derivative 249. These chemists also synthesized the 10-methoxyl derivative of each compound. 

Catalytic activity. Diazoalkanes, in particular phenyldiazomethane. catalyze the condensation of active hydrogen compounds, for example methyl salicylate (1), with isocyanates and isothiocyanates. The primary adduct (2) undergoes cycliza-tion to (3). The rate of the catalyzed reaction parallels the proton mobility of the... 

Potentially hazardous reactants. Spontaneons polymerizations with exothermic heat generation inclnde styrene, snbstitnted styrene, vinyl chloride, vinyl pyridine, acrylonitrile, bntadience, isoprene cyclopentadience, and methyl isocyanate reactions involving peroxides as illnstrated in Table 16.17, azides, perchlorates, or nitro componnds and decompositions, nitrations, oxidations, alkylations, aminations, combnstions, condensations, diazotizations, halogenations, or hydrogenations. 

Condensation of 14 with methyl isocyanate gave the l-(pyrimidin-4-yl)-4-methylsemicarbazides 32 which cyclodehydrated to the 3-methylamino-... 

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