Iodide isothiocyanate

Adducts from various quaternary salts have been isolated, in reactions with aldehydes, a-ketoaldehydes, dialkylacylphosphonates and dialkyl-phosphonates, isocyanates, isothiocyanates, and so forth (Scheme 15) (36). The ylid (11) resulting from removal of a Cj proton from 3.4-dimethyl-S-p-hydroxyethylthiazolium iodide by NEtj in DMF gives with phenylisothiocyanate the stable dipolar adduct (12) that has been identified by its NMR spectrum and reactional product, such as acid addition and thiazolidine obtention via NaBH4 reduction (Scheme 16) (35). It must be mentioned that the adduct issued from di-p-tolylcarbodiimide is separated in its halohydrogenated form. An alkaline treatment occasions an easy ring expansion into a 1,4-thiazine derivative (Scheme 17) (35). 

Reaction of lithiated allene with methoxymethyl isothiocyanate afforded 107, after trapping with methyl iodide. The newly formed 107 isomerizes under mild conditions to triene 108. This compound is ideally setup to experience an electrocyclization to dihydropyridine 109. Heating in the presence of acid facilitates aromatization of 109 to pyridines 110. 

Cycloaddition of 2-nitrosopyridine 48 with nitrile oxides can give either di-A -oxides such as 49 or 3-mono-A -oxides such as 50 (93JHC287). In general, greater electron withdrawing character in the aromatic substituent appears to favor formation of the di-A -oxides. Sulfur ylides such as compound 51 are obtained from aryl isothiocyanates and l-amino-2-methylthiopyridinium iodides (84JCS(P1)1891) nitrogen ylides can be obtained from a similar reaction (86H(24)3363). 

It can be prepared artificially by the action of allyl iodide on an alcoholic solution of thiocyanate of potassium, the latter body being isomerised to the isothiocyanate under the influence of heat. 

The synthesis of 987 from 985 via 986 has been reported (83S759) by reaction of 985 with aryl isothiocyanates under neutral conditions. The reaction of 4-amino-6-anilino[l,2,4]triazine 988 with methyl iodide and then carbon disulfide gave 989 (90MI3, 90MI9). 

Other thietane derivatives have been obtained by isomerization of nitrogen-containing heterocycles. The reaction of an acyl isothiocyanate (RCONCS) with diphenyldiazomethane gave 20 and this isomerized in solution to the tetraphenyl-3-thietanone 21 <96BSB253>. Additionally, the isoxazolidine 22 was converted into 23 by the action of trimethylsilyl iodide and zinc iodide <96H1211>. 

Isomerized wood rosin, 32, 2 Isonicotinic acid, 37, 7 2-Isonitrosocyclohexanone, 32, 38 Isophorone, 37, 58 ISOPHORONE OXIDE, 37, 58 Isopropyl alcohol, 31, 112 Isopropyl iodide, 30, 34 31, 33 -Isopropylphenylacetamide, 32, 94 Ji-Isopropylphenyldichlorophosphine, 31,89 ISOTHIOCYANIC ACID, 1 -NAPHTHYL ESTER,... 

Contrasting with the reported formation of fused [l,3,4]thiadiazole rings in the course of the reaction of 3-substituted-4-amino-5-thio-47/-[l,2,4]triazoles 83 with various isothiocyanates (cf. Section 11.07.8.3, Table 3), the reactions with methyl isothiocyanate and with phenylisocyanate afford 3,7-disubstituted-6,7-dihydro-57/-[l,2,4]triazolo[4,3-f] [l,2,4]triazole-6-thiones 110 and -triazole-6-ones 111, respectively (Equation 29) <1986MI607, 1992IJB167>.The same reaction of 4-amino-l-methyl-3,5-bis(methylthio)[l,2,4]triazolium iodide 112 with aryl isothiocyanates yields the mesoionic compounds 113 (Equation 30) <1984TL5427, 1986T2121>. 

A typical cyclization reaction starting from a 3-aminopyrazole is the transformation of 255 <2000BML821 >. This compound was treated first with ethoxycarbonyl isothiocyanate followed by sodium methoxide to yield a cyclic intermediate which was methylated by methyl iodide to give the stable product 256. In the cases of the synthesis of 257 <1995PHA675>, the dimeric 258 <2005JHC975>, the azo-substituted 259 <2001JCM439>, and the diaryl... 

Dimethyl malonate was first treated dropwise with phenyl isothiocyanate in the presence of sodium hydride in N,7V-dimethylacetamide at 0°C. The reaction mixture was stirred at ambient temperature for 1.5 hr and then cooled to 0°C, and methyl iodide was added dropwise. After stirring for 4 hr at room temperature, (methylthio)(phenylamino)methy-lenemalonate (341) was obtained in 79% yields (69T4649). 

Allyl isothiocyanate, 1471 Allyllithium, 1177 Allylmercury(II) iodide, 1173 l-Allyloxy-2,3-epoxypropane, 2434 Allyl phosphorodichloridite, 1169 /V-Ally lthiourca. 1600... 

Moeller and Vicentini (48) have reported the complexes of DMA with lanthanide perchlorates in which the number of DMA molecules per metal ion decreases from eight for La(III)—Nd(III) to six for Tm(III)—Lu(III).apparently due to the decrease in the cationic size. The complexes of the intermediate metal ions have seven molecules of DMA in their composition. Complexes of lanthanide chlorides with DMA (49, 50) exhibit a decrease in L M from 4 1 to 3 1 through 3.5 1. These complexes probably have bridging DMA molecules. The corresponding complexes with lanthanide iodides (51), isothiocyanates (52), hexafluorophosphates (57), nitrates (54, 55), and perrhenates (49, 56) also show decreasing L M with decreasing size of the lanthanide ion. However, complexes of DMA with lanthanide bromides (55) do not show such a trend. Krishnamurthy and Soundararajan (41) have reported the complexes of DPF with lanthanide perchlorates of the composition [Ln(DPF)6]... 

Probably, the first series of lanthanide complexes with neutral oxygen donor ligands is that of AP with the lanthanide nitrates. In 1913, Kolb (79) reported tris-AP complexes with lighter lanthanide nitrates and tetrakis-AP complexes with heavier lanthanide nitrates. Subsequently, complexes of lanthanide nitrates with AP which have a L M of 6 1 and 3 1 have also been prepared (80-82). Bhandary et al. (83) have recently shown through an X-ray crystal and molecular structure study of Nd(AP)3(N03)3 that all the nitrates are bidentate and hence the coordination number for Nd(III) is nine in this complex. Complexes of AP with lanthanide perchlorates (81, 84), iodides (81, 85), and isothiocyanates (66, 86, 87) are known. While the perchlorates and iodides in the respective complexes remain ionic, two of the isothiocyanates are coordinated in the corresponding complexes of AP with lanthanide isothiocyanates. 

Further routes of cyclizations have been studied in parallel in the case of cis- and rra/J5-2-hydroxymethyl-l-cyclohexylamine (106) (880PP73). The preparation of thiourea or urea adducts 107 and 108 with phenyl isothiocyanate or phenyl isocyanate proceeds smoothly. The reaction of 107 with methyl iodide and subsequent alkali treatment, by elimination of methyl mercaptan, resulted in the iminooxazine 109 in high yields. The ring closures of both cis and trans thiourea adducts to 1,3-oxazines proceed with retention. Cyclodesulfuration of the adduct 107 by mercury(II) oxide or N,N -dicyclohexylcarbodiimide resulted in the iminooxazine 109, but the yield was low and the purification of the product was cumbersome. The ring closure of 108 with thionyl chloride led to the iminooxazine 109 in only moderate yield. 

Bismethylthio)methylene]- and 6-[(methylthio)(phenylamino)meth-ylene]- derivatives of 6,7,8,9-Tetrahydro-117/-pyrido[2,l-6]quinazolin-ll-ones (125 and 126) were obtained from 6,7,8,9-tetrahydro-l 1 //-pyrido[2,l-b]quinazolin-ll-one (7) with carbon disulfide and phenyl isothiocyanate, respectively, in dimethylsulfoxide in the presence of sodium hydride, and then methylation with methyl iodide (86ZC251). 

Dihydro-1,3-oxazines or -thiazines bearing amino groups at the 2-position are available through the addition of 3-aminopropanols to isothiocyanates. The product thioureas readily cyclize to thiazines on treatment with base (1890CB87), but in order to form the analogous oxazines consecutive treatment with methyl iodide and base is required (Scheme 89) (74KGS354). In both cases the products are best formulated as imines rather than amines (see Section 2.27.2.2.1). 

Remark. The procedure described in Section 2.8.3 for the synthesis of -V-phenyl imidothioesters gave poor results in the case of methylmagnesium iodide, mainly because of low stability of its addition product to phenyl isothiocyanate. A good yield could be secured by running the reaction at a lower temperature in ether as the solvent and addition of HMPA in the methylation step. Filtration on a very short column of silica (eluent petroleum ether/ethyl acetate 97.5 2.5) afforded a quite pure product in a 79% yield. 

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