Isothiocyanate phenyl

In a 500-cc. round-bottom flask (Note i) fitted with a mechanical stirrer and surrounded by an ice-salt cooling bath, are placed 54 g. (0.71 mole) of carbon disulfide and 90 cc. (1.3 moles) of concentrated ammonium hydroxide (sp. g. 0.9). The stirrer is started and 56 g. (0.6 mole) of aniline (Note 2) is run into the mixture from a separatory funnel at such a rate that the addition is complete in about twenty minutes. The stirring is continued for thirty minutes after all of the aniline has been added, and then the reaction mixture is allowed to stand for another, thirty minutes. During this time a heavy precipitate of ammonium phenyl dithiocarbamate separates and may even stop the stirrer. 

The salt is dissolved in 800 cc. of water (Note 3) and transferred to a 5-I. round-bottom flask. To the solution is added with constant stirring a solution of 200 g. of lead nitrate (0.6 mole) in 400 cc. of water. Lead sulfide separates as a heavy brown precipitate which soon turns black. The mixture is then distilled with steam into a receiver containing 5-10 cc. of. i N sulfuric acid as long as any oil comes over (Note 4). About 2-3 1. of distillate is collected. The product is separated from the water and weighs 63-66 g. 

The oil is dried over a little calcium chloride and distilled under reduced pressure. The yield of phenyl isothiocyanate 

If the reaction is carried out in a beaker, so much ammonia is lost by volatilization that the crystalline ammonium phenyl dithiocarbamate is not formed. The temperature should be from 0-10° to avoid loss of ammonia. 

Ordinary technical aniline was used in these experiments. 

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Add 0 -5 ml. of phenyl isothiocyanate to the distillate and shake the mixture vigorously for 3-4 minutes. If no derivative separates, crystallisation may be induced by cooling the flask in ice and scratching the walls with a glass rod. Filter off the crude product, wash it with a little 50 per nent. ethanol, and recrystaUise from hot dilute alcohol. (See Table 111,123 for melting points of phenylthiourea derivatives of amines.)... 

Phenylthioureas. Primary and secondary amines react with phenyl isothiocyanate to yield phenylthioureas ... 

Phenyl isothiocyanate is not sensitive to water the reaction may be carried out with an aqueous solution of an amine. 

Alternatively, mix equal amounts (say, 0-2 g. of each) of the amine and phenyl isothiocyanate in a test-tube and shake for 2 minutes. If no reaction occurs, heat the mixture gently for 2 minutes and then cool in ice until the mass soUdifies. Powder the soUd, wash it with a little light petroleum (b.p. 100-120°), and recrystallise from rectified spirit. 

Heating of this latter compound with an excess of phenyl isothiocyanate in acetonitrile (65) leads to 2-phenylimino-3-phenyl-4-thioxo-se enazole[3.2-a]tetrahydro-s-triazin (Scheme 61). 

Step 1 A peptide is treated with phenyl isothiocyanate to give a phenylthiocarbamoyl (PTC) derivative... 

Edman degradation (Section 27 13) Method for determining the N terminal amino acid of a peptide or protein It in volves treating the material with phenyl isothiocyanate (CgH5N=C=S) cleaving with acid and then identifying the phenylthiohydantoin (PTH derivative) produced Elastomer (Section 10 11) A synthetic polymer that possesses elasticity... 

Amides result from the reaction of aromatic hydrocarbons with isocyanates, such as phenyl isocyanate [103-71-9], ia the presence of aluminum chloride. Phenyl isothiocyanate [103-72-0] similarly gives thioanilides (136). 

Substitution of alkaline cyanates by isocyanates allows the preparation of 3-substituted hydantoias, both from amino acids (64) and amino nitriles (65). The related reaction between a-amino acids and phenyl isothiocyanate to yield 5-substituted 3-phenyl-2-thiohydantoiQS has been used for the analytical characterization of amino acids, and is the basis of the Edman method for the sequential degradation of peptides with concomitant identification of the /V-terminal amino acid. 

Ethoxy-6-methylpyrimidine 1-oxide (499) reacts with phenyl isocyanate to eliminate carbon dioxide and give a mixture of 4-ethoxy-6-methyl-N-phenylpyrimidin-2-amine (SOO) and (the derived) 7V-(4-ethoxy-6-methylpyrimidin-2-yl)-7V,7V -diphenylurea (SOI) phenyl isothiocyanate reacts quite differently (79CPB2642). 

This thiourea, prepared from an amino acid and phenyl isothiocyanate, is cleaved by anhydrous trifluoroacetic acid (an N-COCF3 group is stable), and by oxidation (/72-CIC6H4CO3H, 0°, 1.5 h, 73% yield H2O2/ACOH, 80°, 80 min, 44% yield). ... 

Larger runs give somewhat lower percentage yields thus 280 g. of aniline gives about 250 g. (60 per cent of the theoretical amount) of redistilled phenyl isothiocyanate. 

Phenyl isothiocyanate has been prepared from thiocarbanilide by the action of phosphorus pentoxide, hydrochloric acid, iodine, phosphoric acid, acetic anhydride, and nitrous acid. It has also been prepared from ammonium phenyl dithiocarbamate by the action of ethyl chlorocarbonate, copper sulfate lead carbonate, lead nitrate, ferrous sulfate,and zinc sulfate. ... 

A major advance was devised by Pehr Edrnan (University of Lund, Sweden) that has become the standard method for N-terminal residue analysis. The Edman degradation is based on the chemistry shown in Figure 27.12. A peptide reacts with phenyl isothiocyanate to give a phenylthiocarbamoyl (PTC) derivative, as shown in the first step. This PTC derivative is then treated with an acid in an anhydrous medium (Edrnan used nitrornethane saturated with hydrogen chloride) to cleave the amide bond between the N-terminal anino acid and the remainder of the peptide. No other peptide bonds are cleaved in this step as amide bond hydrolysis requires water. When the PTC derivative is treated with acid in an anhydrous medium, the sulfur atom of the C=S unit acts as... 

The reaction of the morpholine enamine of cyclohexanone with phenyl isothiocyanate led only to the tetrasubstituted isomer of the monoadduct (54), which failed to add any more of the phenyl isothiocyanate. The formation of only the tetrasubstituted isomer has been attributed by Hunig et al. (37) to the stronger conjugation of the C=S group with the enamine double bond than that of the C=0 group in the enamine (49). 

The reaction of the enamines of cyclic ketones with alkyl isocyanates, acyl isocyanates, phenyl isothiocyanates, and acyl isothiocyanates has also been reported 112). The products are the corresponding carboxamides. The products from the isothiocyanates have been utilized as intermediates in the preparation of various heterocyclic compounds 113). 

The reaction of enamino ketones with isocyanates and isothiocyanates has not been studied extensively. The enamino ketone (162) has been shown to react with phenyl isothiocyanate to give 163, the product of C acylation 114). Enamino ester derivatives of acetoacetic ester react similarly with isothiocyanates, also giving the C-acylated products 115). 

Elemental sulfur undergoes nucleophilic attack by amines at low temperatures. Therefore the conjugate position of an enamine is sufficiently nucleophilic to attack elemental sulfur and yield thiolated intermediate 103. When 103 is treated when phenyl isothiocyanate, the cyclic adduct 104... 

Diaminopyrimidines (22) were also cyclized with cyanogen bromide (90JHC851) or phenyl isothiocyanate (97PHA753) to give the corresponding 2-amino- or 2-anilino-l,2,4-triazolo[l,5-c]pyrimidines 30 and 31 respectively (Scheme 15). 

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). 

If the acid hydrolysis of 1,3-oxazine derivatives is followed by acting with phenyl-isothiocyanate, thiourea derivatives can be formed. ... 

A phenyl guanidine analogue is readily prepared by first I i acting 2-imino-]i-methylpyrrolidine with phenyl isothiocyanate III give synthon 21, This is next -methylated with methyl io-illcle to give 16 which itself, on reaction with pyrrolidine, is... 

Propose two structures for a tripeptide that gives Leu.. Ala, and Phe on hydrolysis but does not react with phenyl isothiocyanate. 

The reaction of 3-hydrazinophenanthro[9,10-e][l,2,4]triazine 742 with carbon disulfide, thiourea, phenyl isothiocyanate, urea, and phenyl isocyanate led [77ZN(B)569] to the formation of phenanthro[9,10-e][l,2,4]-triazolo[4,3-/j][l,2,4]triazines 743. Alkylation of 743 in aqueous alkaline... 

Finally, formation of seven-membered rings by vinylaziridines possessing carbonyl or thiocarbonyl groups are shown in Scheme 2.46. Thermolysis of 182 in toluene at reflux yielded 4,7-dihydro-l,3-oxazepine 183 [71]. Similarly, treatment of N-unsubstituted vinylaziridine 184 with phenyl isothiocyanate in ether at 0 °C gave seven-membered ring 185, via a l-thiocarboxanilide-2-vinylaziridine intermediate [72]. 

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