Tosyl isocyanate

This sulfonyl urea, prepared from an amino acid and p-tosyl isocyanate in 20-80% yield, is cleaved by alcohols (95% aq. EtOH, n-PrOH, or -BuOH, 100°, 1 h, 95% yield). It is stable to dilute base, to acids (HBr/AcOH or cold CF3CO2H), and to hydrazine. ... 

Most 1,3-diazepine syntheses employ the insertion of a single carbon fragment between the two nitrogen atoms. This is further exemplified by the use of tosyl isocyanate and methyl isothiocyanate in the preparation of the bicyclic imidazo[4,5-e][l,3]diazepines 46 and the imidazo[4,5-rf][l,3]diazepines 47 respectively <96JHC855, 96JCS(P1)2257>. 

Under thermal conditions, o ,/3-diarylvinylcarbodiimides 349 reacted as 2-azadienes (47t-component) with /)-tosyl isocyanate at the C=0 bond (27t-component) to form the intermediate cycloadducts 350 which, through Fl-migration, gave 2-amino-l,3-oxazin-6-imines 351 in moderate yields (Scheme 65) < 1998J(P 1)3065 >. 

When acrylonitrile or ethyl acrylate was used as the dipolarophile, the azomethine adducts (134) and (135) were formed no thiocarbonyl ylide addition products were isolable in refluxing toluene or xylene, although the isoindoles (136a) and (136b) derived from them were isolated. In contrast to the reactions with fumaronitrile or AT-phenylmaleimide, the azomethine adducts (134) and (135) were still present at higher reaction temperatures — almost 50% in toluene and 4-5% in xylene. Under the same reaction conditions other electron-deficient dipolarophiles like dimethyl fumarate, norbornene, dimethyl maleate, phenyl isocyanate, phenyl isothiocyanate, benzoyl isothiocyanate, p-tosyl isocyanate and diphenylcyclopropenone failed to undergo cycloaddition to thienopyrrole (13), presumably due to steric interactions (77HC(30)317). 

The 1,2-functionalization of the allene moiety in 2-azetidinone-tethered alleny-nol derivatives has also been explored [96]. Carbamate 174 was selected as the starting material for the palladium(II)-catalyzed reaction. The above carbamate was prepared from the ot-allenic alcohol 171a by treatment with tosyl isocyanate. Reaction of compound 174 was carried out at room temperature in acetonitrile in the presence of 10 mol% of Pd(OAc)2, 5 equiv of LiBr, 2 equiv of Cu(OAc)2 and 1.2 equiv of K2CO3 under an atmospheric pressure of oxygen. The 1H-XMR spectrum of the crude material displayed neither signal corresponding to the allene... 

When 5-amino-4-(cyanoformimidoyl)imidazoles 68 are reacted with tosyl isocyanate, 70 are formed (Scheme 10 Table 8) <1996JHC855>. After a 7- o-4)g-cyclization of intermediates 69a-d, a Dimroth rearrangement takes place to give the thermodynamic products 70a-d. 

Allyl amines can also be formed by desymmetrization of allyl diols with tosyl isocyanate in the presence of chiral palladium complexes [19d,27]. Trost et al., as well as others, have recently used this approach for the synthesis of natural products [28]. 

The fully-unsaturated 1,3-benzodiazepine 310 is formed by a photoreaction of the 1-substituted isoquinoline 7V-imide 309 (Scheme 169) <1980CPB2602>. The same principle has been applied to prepare thieno-, furo-, and pyrrolo-fused 1,3-diazepines <1980CC454, 1981CPB1539>. The imidazolo-fused l,3-benzodiazepin-2-ones 313 can be prepared by the reaction of 5-amino-4-(cyanoformimidoyl)imidazoles 311 with tosyl isocyanate. The mechanism of this reaction includes a 1-exo-dig cyclization of intermediates 312 followed by a Dimroth rearrangement to give the thermodynamic products 313 (Scheme 170) <1996JHC855, CHEC-III(13.05.9.2.2)174>. 

The reaction of tosyl isocyanate with 2-methyl- 1-dimethylaminopropene yields the betaine 330. In contrast, the betaine formed from the less basic enamine 331, derived from TV-methylaniline, adds a further molecule of the isocyanate to afford the hex-ahydropyrimidinedione 332 (equation 134)163. 

Vinyl carbodiimides 51 also react with tosyl isocyanate to give [2+4] cycloadducts. When the reaction is conducted at room temperature in acetonitrile, addition across the 0=N bond of the isocyanate occurs to give 52. In contrast, reaction in refluxing benzene (15-30 hours) affords 53, resulting from addition across the C=0 bond of the isocyanate. ... 

Thermolysis of the cycloadducts 28 derived from tosyl isocyanate and nitrile oxides also affords N-sulfonylcarbodiimides 29. For example, N-p-toluenesulfonyl-N -2,4,6-trimethylphenylcarbodiimide, mp 71-72 °C, is obtained in 87 % yield. 

Semiaminal (567) reacted with nucleophiles generally by a replacement of the hydroxy group Only few exceptions were known. For example, reaction of 567 with ketene or isocyanates caused acylation and displacement of the secondary amino moiety (equation 147) cyclopropanone (84) could be detected spectroscopically in one case. A similar removal of the amino function by tosyl isocyanate (571) was observed with 570, but here compound 574 was isolated in 47% yield (equation 148). 574 resulted from a subsequent addition of the initially formed products 572 and 573 . Steric reasons led to the sequence 570 - 574 the diastereomeric endo-morpholino semiaminal reacted with 571 by displacement of the exo-hydroxy group. 

Thiiranimine 1,1-dioxide has not been isolated however, it is formed in situ when ketene is dissolved in liquid S02 at — 78 °C. It can react with imines, azines, and tosyl isocyanate (Scheme 56) <76JOC3925>. 

V-tosylcarbamoylated enamine 14b results from an analogous reaction with tosyl isocyanate (dichloromethane, reflux) ... 

Another approach to oxazolidinones is shown in Scheme 12. l-AUcylated 1,2-diols were bound to chlorosulfonylated resin 44 to produce hydroxysulfonates 45. Treatment with tosyl isocyanate gave carbamates 46, which were cychzed with DBN (l,5-diazabicyclo[4.3.0]non-5-ene) at room temperature to yield the oxazolidinones 47. The base was finally removed by filtration through silica [22],... 

Stereochemical aspects of the formation of phosphineimines by reaction of / -tosyl isocyanate (26) with phosphine oxides have been reported. The oxide... 

Diazomethylcarbonyl compounds react similarly with tosyl isocyanate to give hydantoin derivatives.106... 

There are two methods for synthesizing this system in spite of the fact that it is the newest of the oxathiazines (i) cyclocondensation of 5-[/ -(hydroxyimino)alkyl]dithiocarbonates using tosyl isocyanate (Equation (21)), and (ii) cycloaddition of a-nitrosoalkenes to thiocarbonyl compounds (Equations (31) and (32)). The scope of method (i) is limited and gives only moderate yields. Method (ii) on the other hand is high yielding and preparation of the a-nitrosoalkenes is more straightforward than that of the six-atom fragment in (i). 

Reaction with isocyanates. The reagent reacts with p-tosyl isocyanate to give the 1 1 adduct (1). In general, aryl isocyanates form 1 2 adducts (2). ... 

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