N-Detosylation

The Baran group has reported an unusual deprotection of allyl esters in micro-wave-superheated water. A diallyl ester structurally related to the sceptrin natural products (see Scheme 6.87) was cleanly deprotected at 200 °C within 5 min (Scheme 6.168) [181]. Other standard deprotection transformations carried out under microwave conditions, specifically N-detosylations [317], trimethylsilyl (TMS) removal [318, 319], and N-tert-butoxycarbonyl (Boc) deprotection [231], are summarized in Scheme 6.169. 

Divinylpyrroles 204 were prepared by direct N-vinylation with acetylene of the corresponding 3-vinylpyrroles 203 according to the Trofimov s superbasic conditions (Equation 43) <1998JOC10022>. 3-(2-Phenylvinyl)-l-vinyl-pyrrole 204 (R = Ph) has been also obtained directly from the corresponding 3-(2-phenylvinyl)-l-tosylpyrrole, by its treatment with acetylene in KOH/DMSO, the N-detosylation and the N-vinylation occurring in one-pot. 

The N-detosylation of 6,6-difluorohomopiperazine 749 by heating with 30% anhydrous hydrogen bromide in acetic acid and phenol gave traces of 750. However, when this reaction was performed under MWI, compounds 750 were produced in... 

Synthesis.—A new route to alkyl-substituted crown compounds involves" the reaction of polyethylene glycols with alkenes in the presence of a positive halogen source (Scheme 51), followed by base-catalysed cyclization of the halohydrins produced. One approach to aza-crown molecules relies on alkylation of toluene-p-sulphonamide anions, and a study of some methods for N-detosylation of the cyclic products has been published. 

N NaOH followed by ethanol and S,S-dimethyl-N-tosyliminodithiocarbonimi-date added to an aq. soln. of 1,4-diaminobutane dihydrochloride, and refluxed 4 hrs. 2-p-toluenesulfonylamino-4,5,6,7-tetrahydro-l,3-diazepine (Y 76%) stirred 2 hrs. in anhydrous HF at room temp, in a sealed vessel, and the product isolated as the hydrodiloride 2-amino-4,5,6,7-tetrahydro-l,3-diazepine hydro-diloride (Y 98%). - The above N-detosylation method has limited applicability. F. e. s. J. V. Rodricks and H. Rapoport, J. Org. Chem. 36, 46 (1971). 

Triazoles and a-diazocarboxylic acid esters from (a-acylalkylidene)phosphoranes N-Detosylation... 

Amines from thiourethans N-Detosylation s. a. Amines from sulfonic acid amides —, oxidative 20, 562 suppl. 20 —, preferential 16, 367 0-Detosylation of nucleosides 18, 8... 

N-nitrosamines 28, 19, 355 sulfonic acid amides s. N-Detosylation ureas 26, 23 urethans s. N-De-carbalkoxylation... 

Reduction s. a. Clemmensen reduction. Elimination, reductive. Hydrogenation, Photoreduction, Ring closure, reductive -, asym., reversal of stereospecificity 17, 865 suppl. 28 -, electrodiemical -, S-debenzylation by -27,18 suppl. 28 -, N-detosylation by - 27, 18... 

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