Phenyl isothiocyanate, reaction with

The reaction of phenyl isothiocyanate (183) with primary alkyl azides 193 in a 2 1 ratio at 80-100 °C without solvent provides access to 4-alkyl-3,5-bis-(phenylimino)-l,2,4-dithiazolidines 194 in 29-65% yield (Scheme 38) [141]. 

Scheme 42 A Reaction of phenyl isothiocyanate (183) with TMSA (146), followed by desilylation, gives a 1,2,3,4-thiatriazole 216, B Reaction of benzoyl isothiocyanate (183) with TMSA (146), followed by desilylation, yields a cyanamide 221 [111]...

A convenient synthesis of 1,3,4-thiadiazolidines using that most versatile of reactions, the 1,3-dipolar cycloaddition, has been developed by Motoyoshiya et al Phenyl hydrazones of ketones react with phenyl isothiocyanate and with carbon disulphide to give five-membered cyclic products, although phenyl hydrazones of aldehydes sometimes fail to react in this way (Scheme 53). 

At 200 °C, the reaction of methyl isothiocyanate and alkylene oxide gives trimethyl isocyanurate. This reaction involves the trimerization of methyl isothiocyanate followed by stepwise replacement of the sulfur by oxygen via spiro compounds. Phenyl isothiocyanate reacts with ethylene oxide to give a mixture of triphenyl isocyanurate and 3-phenyloxazolidine-2-one 90 °. The formation of the oxazolidone is caused by the reaction of the initially formed 2-phenylimino oxathiolene 89 with ethylene oxide in the presence of the catalysts... 

Cyclic aldo- and ketonitrones react similarly with phenyl isothiocyanateHowever, substituted phenyl isothiocyanates react with 5,5-dimethyl-l-pyrroline-l-oxide to give cycloadducts derived from addition across the C=N bond as well as the C=S bond of the isothiocyanates. The C=S cycloadducts are unstable and undergo further transformations . The [3+2] cycloaddition reaction of 3,3,5,5-tetramethylpyrroline-l-oxide with aryl- and phenylcarbonyl isocyanates also occurs exclusively by addition across the C=S bond . ... 

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. 

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. 

In a manner analogous to classic nitrile iinines, the additions of trifluoro-methylacetonitrile phenylimine occur regiospecifically with activated terminal alkenes but less selectively with alkynes [39], The nitnle imine reacts with both dimethyl fumarate and dimethyl maleate m moderate yields to give exclusively the trans product, presumably via epimenzation of the labile H at position 4 [40] (equation 42) The nitrile imine exhibits exo selectivities in its reactions with norbornene and norbornadiene, which are similar to those seen for the nitrile oxide [37], and even greater reactivity with enolates than that of the nitnle oxide [38, 41], Reactions of trifluoroacetomtrile phenyl imine with isocyanates, isothiocyanates, and carbodiimides are also reported [42]... 

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). 

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... 

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... 

On the other hand, refluxing 9 in formic acid for 5 h afforded the N-formyl derivative 11 in high yield. Acetylation of 9 by refluxing in acetic acid, afforded acetic acid N -(2-(7-hydroxy-2-oxo-2H-chromen-4-yl)-acetyl)-hydrazide 12 in good yield. Compound 13 was also obtained by refluxing 9 with 3-(2-bromoacetyl)-4-hydroxy-2H-chromen-2-one in ethanol. Reaction of compound 9 with phenyl isothiocyanate in ethanol at room temperature gave 4-phenyl-1 - (7-hydroxy-2-oxo-2 H-chromen-4-acetyl- )thiosemicarbazide 14. 

As in the case of silanone 9, the reaction of the silylene bis[2-(dimethylamino-methyl) phenyl]silanediyl (8) with phenyl isothiocyanate was examined.29 In this reaction the expected silanethione 36 was obtained as a single product even in the presence of (Me2SiO)3, no insertion product of 36 into a Si-O bond of (Me2SiO)3 was observed (Scheme 10). 

The pyrazolotriazinecarboxylate 708 underwent cyclization with urea or thiourea to give (84PHA432) pyrazolopyrimidinotriazines 711, and with o-phenylenediamine, p-chloroaniline, or o-aminophenol to give quinolino-pyrazolotriazines 710. The reaction of the pyrazolo[5,l-c][I,2,4]triazine 709 with hydrazine hydrate gave 712, and its reaction with phenyl isothiocyanate gave 713 (83G219). 

Perhaps the earliest reported method for the synthesis of the 1,2,3-thiadiazole ring system was the one described by Pechmann and Nold in which diazomethane was reacted with phenyl isothiocyanate. Of the four possible isomers that could be obtained from the reaction, 5-anilino-l,2,3-thiadiazole 62 (R1 Ph, R2 = H) was the only product formed (Equation 16) <1896CB2588>. This method continues to be used as a route to 5-amino substituted 1,2,3-thiadiazoles. 4,5-Disubstituted 1,2,3-thiadiazoles have been produced in excellent yield by reaction of l,l -thiocar-bonyl diimidazole with ethyl diazoacetate <1988SUL155>. 

Thiohydrazides react with isothiocyanates to afford 1,3,4-thiadiazoles. The reaction proceeds via a dithioacylhy-drazine intermediate which under the reaction conditions cyclizes with loss of H2S. When the Ar-thiohydrazide pyrazole 143 is refluxed in DMF in the presence of phenyl isothiocyanate the 5-phenylamino-l,3,4-thiadiazol-2-yl pyrazole 144 is formed (Equation 54) <2000JCM544>. 

Organometallic dithiocarbimates are also known. Thus, a diarylgermanium phenyldithiocarbimate, Tbt(Tip)GeS2C=N-Ph, was obtained from the kinetic-ally stabilized diarylgermylene Tbt(Tip)Ge in a reaction with phenyl isothiocyanate, via [2+2] cycloaddition of a diarylgermanethione [Tbt(Tip)Ge=S] intermediate, evidenced by electronic spectroscopy.425... 

In the reaction of 1 with methyl or phenyl isothiocyanate, the dithiasiletanes 76 or 77 were formed, following a pathway comparable to that observed for the reaction of 1 with carbon dioxide (see Scheme 28). In the case of the reaction with phenyl isothiocyanate, more drastic conditions... 

Substituted derivatives of l-(tetrahydrobenzo[b]thiophen-2-yl-3-carboxylate)-5-phenyl-6-thio-l,2,4-triazin-4-one have been synthesized by heterocyclization reactions of different hydrazones obtained from 2-amino-tetrahydrobenzo[b]thiophene-3-carboxylate with phenyl isothiocyanate <00PS275>. Reaction of 5-methyl isothiosemicarbazide with a-amino acid vicinal tricarbonyl reactive substrates 1 and 2 yields 1,2,4-triazine substituted a-amino acids, as an equimolar mixture of regioisomers 3a/3b and 4a /4b, respectively <00JCS(P1)299>. 

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