Isocyanate p-chlorophenyl

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. 

Phenyl isocyanate, p-tolyl isocyanate, p-toluenesulfonyl isocyanate, and p-chlorophenyl isocyanate were purchased from Aldrich Chemical Company and were distilled under vacuum prior to use. 

The acid hydrolysis of biguanides under a variety of conditions 5uelds chiefly amidinoureas the subject has been reviewed by Ray (531). The reaction proceeds slowly under very mild conditions at room temperature thus, Paludrine, when stored in 2N hydrochloric add slowly deposits N-p-chlorophenyl-N -isopropylamidinourea hydrochloride (140). That this product was not the isomeric N-isopropyl-N -p-chlorophenyl-amidinourea was verified by its rmequivocal s3uithesis from isopropyl-guanidine and p-chlorophenyl isocyanate (140) ... 

The yields from the reactions, carried out at room temperature and a pressure of 2-4 at, increase with increasing electronegativity of the substituent X. The yield with phenyl isocyanate is 13%, with p-chlorophenyl isocyanate 55% and with p-nitrophenyl isocyanate it is 100%. Primary and secondary carba-moylphosphines cannot be isolated even when equi-molar quantities of phosphine and isocyanate are used. Their intermediate formation is probable but apparently they are more reactive towards isocyanates than phosphine itself. Similarly, phosphine does not react with free cyanic acid whereas primary and secondary phosphines react with cyanic acid, as with isocyanates, to form the corresponding carbamoylphosphines Attempts to make phosphine react with phenyl isothiocyanate did not succeed... 

Kozikowski and Stein (281) used the INOC strategy to prepare the 2-methyle-necyclopentanone derivative 172, which in turn was converted to sarkomycin (173), an antitumor agent (Scheme 6.81). The key step involved the treatment of nitroalkene 169 (obtained from bromide 168) with p-chlorophenyl isocyanate-triethylamine, which furnished a single diastereomeric isoxazoline 170 in 55% yield. This compound was transformed to the aldol product 171 by Raney nickel hydrogenation using wet acetic or boric acid, followed by dehydration to the a,p-enone 172 (281), a precursor of 173. 

Another related synthesis made use of the intramolecular cycloaddition of co-nitroalkene 243, also derived from geraniol epoxide 237. Generation of the expected nitrile oxide dipole using p-chlorophenyl isocyanate and triethylamine quantitatively gave the annulated isoxazoline 244 as a 2 1 mixture of diastereo-isomers (Scheme 6.94). Reductive hydrolysis of the cycloadduct to the aldol product followed by dehydration provided enone 245, which was used to prepare the sesquiterpene nanaimoal 246 (242). 

To a flask containing 17.0 gm (0.11 mole) of p-chlorophenyl isocyanate in 30 ml of ether is added 13.8 gm (0.11 mole) of 3-cyclohexylamino-l-butyne over a period of hr at 25°-35°C. An additional 300 ml of ether is added to the gelatinous slurry, and the mixture is stirred for 5 hr at room temperature. Filtration yields 11 gm of colorless crystals. An additional 20 gm of crude solid is obtained by concentrating the ether layer. The total product is recrystallized from petroleum ether (30°-60°C) to obtain 18.6 gm (60 %), m.p. 107°-109°C. 

Shibasaki and co-workers used an intramolecular nitrile oxide cycloaddition to prepare the skeleton of phorbol (272) (Scheme 6.99), a tumor promoter that activates protein kinase C (PKC) (333). Nitroalkene 268 was elaborated in several steps from (+)-3-carene (267) and was subjected to cycloaddition by means of p-chlorophenyl isocyanate-triethylamine to give cycloadduct 269 in 88% yield. Reductive hydrolysis employing Raney Ni and boric acid afforded hydroxyketone 270, that was subsequently used for the construction of the optically active derivative 271, which contains the phorbol skeleton (333). 

Although many oxadiazoles can be distilled (<300 °C) without noticeable decomposition, an open flame will cause slow decomposition. For example, compound (114) gave p-chlorophenyl isocyanate and p -methoxybenzonitrile as products. 

Macrocyclization of an unsaturated nitrile oxide (10, 309).1 Reaction of the co-nitroalkene 1 with p-chlorophenyl isocyanate results in a nitrile oxide intermediate that undergoes an intramolecular [3 + 2] cycloaddition to give 2. The yield is considerably higher than that obtained by oxidation of the corresponding unsaturated oxime. The product is converted in several steps to the may tans inoid 3. 

Dibutyltin dilaurate (DBTDL) (M T Chem. Co.), 1,4-diaza [2,2,2.]. octane (Air Products), isocyanatoethyl methacrylate (IEM) and carbamoyl chloride of IEM (Dow Chem. Co.) and hexamethylene diisocyanate were used as supplied. Phenyl isocyanate, p-tolyl isocyanate, p-chlorophenyl Isocyanate (all Aldrich Chem. Co.), 2-ethoxyethyl acetate (Eastman Kodak Co.) and n-butanol (Mallinkrodt) were purified by distillation before use. 

The yields of epoxides are 35-70% the yields of 1,3-diphenylurea are 92-98%. Yields of epoxides are improved by use of nonpolar solvents such as n-pentane or benzene. p-Chlorophenyl isocyanate gives somewhat higher yields than phenyl isocyanate. The active intermediate is probably an isocyanate-hydrogen peroxide complex rather than a peroxycarbamic acid (CgHsNHCOgH).1 N. Matsumura, N. Sonoda, and S. Tsutsumi, Tetrahedron Letters, 2029 (1970)... 

A solution of diisopropyl phosphite (3.32 g) in dry hexane (20 ml) is treated with sodium (5 mg). When the metal has dissolved, a solution of p-chlorophenyl isocyanate (3.3 g) in hexane (10 ml) is added rapidly at about 30° with stirring and exclusion of moisture. The temperature then rises to about 40°. After 10 min the mixture is heated under reflux for 1.5 h, then filtered and concentrated. The product (4.4 g, 69% m.p. 122-127°) crystallizes and after several recrystallizations from hexane has m.p. 128-128.7°. 

SOME PHYSICAL AND PHYSICOCHEMICAL CONSTANTS OF M- AND P-CHLOROANILINE AND OF M- AND P-CHLOROPHENYL ISOCYANATE. 

SOME PHYSICOCHEMICAL PROPERTIES OF P-CHLOROPHENYL ISOCYANATE AND 3,4-DICHLOROPHENYL ISOCYANATE. 

SOME PHYSICOCHEMICAL PROPERTIES OF P-CHLOROPHENYL ISOCYANATE AND 3,4-DICHLOROPHENYL ISOCYANATE. //ENGLISH TRANSLATION OF ZHUR. PRIKLAD. KHIM. 40 /5/ 1084-87,1967.//... 

Uses As an intermediate in prod, of herbicides, pesticides, and pharmaceuticals Manuf./Distrib. Acros Org. http //www.acros.be, Aldrich http //www.sigma-aldrich.com, Lancaster Synthesis Pfaltz Bauer http //www.pfaitzandbauer.com, TCI Am. http //www.tciamerica. com 4-Chlorophenyl isocyanate CAS 104-12-1 EINECS/ELINCS 203-176-9 Synonyms Benzene, 1-chloro-4-isocyanato- 1-Chloro-4-isocyanatobenzene 4-Chloroisocyanatobenzene Chlorophenyl isocyanate p-Chlorophenyl isocyanate Isocyanic acid, p-chlorophenyl ester PCIC PCPI... 

This would make dicyandiamide a material of only limited utility because there is a need for materials that cure at lower temperatures such as 250 F (121 C), The need was filled a number of years ago by materials such as the dimethylamine urea of p-chlorophenyl isocyanate which act as accelerators for the dicyandiamide cure by lowering the... 

The same alternating copolymers are obtained from methoxyallene and p-chlorophenyl isocyanate. Initiators are not required in this copolymerization reaction (62). 

The formation of mixed dimers also occurs. For example, treatment of an equimolar mixture of p-tolyl- and p-chlorophenyl isocyanate with a few drops of triethylphosphine affords the mixed dimer in 88 % yield... 

Similarly, vinylpyrrolidines react with aryl isocyanates to give l,3-diazepin-2-ones. For example, from 375 and p-chlorophenyl isocyanate (R = 4-ClPh) an 82 % yield of the cycloadduct 376 is obtained... 

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