2-chloro trityl

Fmoc-Tyr(S03Na)-OH (3 equiv) DIC (3 equiv)/ HOBt (3 equiv) 2-chloro- trityl-resin AcOH/TFE/CH2C12 (1 1 3), 20 °C, 20 min /V-acetyl-sulfated Leu-enkephalin n.r. [149]... 

Fig. 17.19 Synthesis of rosamine library on solid support, (a) K2C03, Cu, DMF, 130°C (b) H2S04, 80°C (c) modification for R1 (d) SnCl2, EtOH, 90°C (e) 2-chloro-trityl chloride resin, pyr, CH2C12/DMF (f) R2 Grignard reagent, THF, 62°C (g) 1 %TFA, CH2C12...

ResinsAinkers used 2-chloro-trityl resin, CMPP (chloro-methylphenyl pentyl polystyrene), Merrifield or Wang. 

Boehm [363] has described for the first time the synthesis of oxygen-bridged tetrahydropyridones by a three-component condensation among coumarin-3-carboxylic acid, ketones, and primary amines. A solid-phase version of this reaction has recently been reported [364]. 1,3-Propylenediamine was immobilized onto chloro-trityl polystyrene resin (loading of 0.65 mmol g ). The supported amine (470) was then treated with coumarin-3-carboxylic acid and 8 different ketones in NMP/THF... 

Several other methods for the introduction of halo atoms at C-6 in hexose derivatives have been known since the late 1920s. One of the earlier methods involved the reaction of methyl 2,3,4-tri-0-acetyl-6-0-trityl-a-D-glucopyranoside with phosphorus pentachloride which resulted only in an 8% overall yield of methyl 6-chloro-6-deoxy-a-D-glucoside (57). In contrast, the reaction of methyl 2,3,4-tri-0-acetyl-6-0-trityl-a-D-altropyranoside with phosphorus tribromide and bromine afforded a 73% yield of the corresponding 6-bromo-6-deoxy derivative (91). 

When 1 mole of sucrose was treated with 2 moles of chloro-triphenylmethane in pyridine for 96 h at room temperature, it gave, after counter-current distribution and column chromatography, mono-O-tritylsucroses, di-O-tritylsucroses, and 6,l, 6 -tri-0-trityl-... 

Halogen atoms have been placed at C-6 of substituted 6-deoxy-hexoses by a variety of interesting ways, and the products provide potential routes to 6-deoxyhexoses. Helferich and coworkers 4 reported a low yield of methyl 6-chloro-6-deoxy-a-D-glucoside which they prepared by reaction of the (suitably protected) corresponding 6-trityl ether with phosphorus pentachloride. Sinclair 44 has provided a convenient procedure for the preparation of the 6-chloro derivative in yields of 30-35% by allowing methyl a-D-glucopyranoside to react with sulfur monochloride, SjClj, in N,/V-dimethylformamide. A much better yield (73%) of the 6-bromo derivative was reported1 in the reaction of methyl 2,3,4-tri-O-benzoyl-6-O-trityl-a-D-altroside with phosphorus tribromide and bromine. 

Abbreviations AllocOSu, allyloxycarbonyl-A-hydroxysuccinimide BCIP, 5-bromoA-chloro-3-indolyl Boc, tert-butyloxycarbonyl tBu, tert-butyl DCM, dichloromethane Dde, l-(4,4-dimethyl-2,6-dioxocyclohex-l-ylidene)ethyl Ddz, a, a-dimethyl-3,5-dimethoxyben-zyloxycarbonyl DIC, A,A -diisopropylcarbodiimide DIEA, A,fV-diisopropylethylamine DMF, iV,./V-dimethylformamide FmocOSu, 9-fluorenylmethyloxycarbonyl-AMiydroxysucci-nimide OBOC, one-bead one-compound PBS, phosphate-buffered saline Pmc, 2,2,5,7,8-pentamethylchroman-6-sulfonyl PTH, phenylthiohydantoin RR, relative reactivities Teoc, 2-(trimethylsilyl)ethoxycarbonyl TFA, trifluoroacetic acid Trt, trityl. 

In Schemes 8.204 and 8,205 above we showed that tritylamines can be generated by reductive amination and N-alkylation of trityiamine. However, N-alkyla-tion of amines by triphenylmethyl chloride (mp 110-112 °C) or triphenylmethyl bromide (mp 152-154 °C) in an aprotic solvent such as chloroform or chloro-form-DMF mixtures together with a base such as triethylamine is the most common method for introduting the trityl group [Scheme 8,212]434 4,4 -Dimethoxy-trityl tetrafluoroborate and 4i4, 4"-trimethoxytrityl tetrafluoroborate are also... 

Trityl hexachloroantimonate polymerizes styrene only at relatively high concentrations (>10-2 M) [145]. This is apparently due to rapid formation of the covalent chloro adducts, which are relatively inactive in the presence of only a small amount of Lewis acid. Moreover, the SbCls generated in this reaction can add to styrene to form a 1,2-dichloroadduct and inactive SbCI3. In contrast, polymerization is fast with trityl hexaflu-oroantimonate [145], demonstrating the SbF6 counterion does not decompose to SbFs and F-terminated chains. 

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